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  • Question 1 - A 16-year-old girl presents with a gradual weakness and muscle wasting of her...

    Incorrect

    • A 16-year-old girl presents with a gradual weakness and muscle wasting of her left hand over the last 4 years. She has been a competitive long-distance runner for the past 5 years.

      Upon neurological examination, there is significant atrophy and weakness of all intrinsic muscles, particularly the thenar muscles in the left hand. Sensation is reduced along the ulnar aspect of the hand and forearm. There are no tender areas or swelling over the shoulder joint, and shoulder movement is unimpeded.

      A chest x-ray reveals the presence of cervical ribs on both sides.

      What is the most probable diagnosis?

      Your Answer: Erb's palsy

      Correct Answer: Neurogenic thoracic outlet syndrome

      Explanation:

      Thoracic outlet syndrome (TOS) is a condition where the brachial plexus, subclavian artery or vein is compressed at the thoracic outlet. One possible cause of TOS is the presence of a cervical rib, an extra rib that grows from the cervical spine. This can increase the risk of nerve or blood vessel compression, especially in individuals who engage in repetitive swimming activities.

      Erb’s palsy, also known as Erb-Duchenne palsy, is a type of obstetric brachial plexus palsy that occurs when the upper brachial plexus is injured during birth. This can result in the loss of shoulder lateral rotators, arm flexors, and hand extensor muscles, leading to the characteristic Waiter’s tip deformity.

      Klumpke paralysis is a neuropathy of the lower brachial plexus that can occur during a difficult delivery. It is typically caused by hyper-abduction traction and can result in a claw hand presentation, where the wrist and fingers are flexed and the forearm is supinated.

      Carpal tunnel syndrome is a condition where the median nerve is compressed as it passes through the wrist, leading to numbness, tingling, burning, and pain in the thumb and fingers. However, this patient’s symptoms of reduced sensation along the ulnar aspect of the hand and forearm are not consistent with carpal tunnel syndrome.

      Understanding Thoracic Outlet Syndrome

      Thoracic outlet syndrome (TOS) is a condition that occurs when there is compression of the brachial plexus, subclavian artery, or vein at the thoracic outlet. This disorder can be either neurogenic or vascular, with the former accounting for 90% of cases. TOS is more common in young, thin women with long necks and drooping shoulders, and peak onset typically occurs in the fourth decade of life. The lack of widely agreed diagnostic criteria makes it difficult to determine the exact epidemiology of TOS.

      TOS can develop due to neck trauma in individuals with anatomical predispositions. Anatomical anomalies can be in the form of soft tissue or osseous structures, with cervical rib being a well-known osseous anomaly. Soft tissue causes include scalene muscle hypertrophy and anomalous bands. Patients with TOS typically have a history of neck trauma preceding the onset of symptoms.

      The clinical presentation of neurogenic TOS includes painless muscle wasting of hand muscles, hand weakness, and sensory symptoms such as numbness and tingling. If autonomic nerves are involved, patients may experience cold hands, blanching, or swelling. Vascular TOS, on the other hand, can lead to painful diffuse arm swelling with distended veins or painful arm claudication and, in severe cases, ulceration and gangrene.

      To diagnose TOS, a neurological and musculoskeletal examination is necessary, and stress maneuvers such as Adson’s maneuvers may be attempted. Imaging modalities such as chest and cervical spine plain radiographs, CT or MRI, venography, or angiography may also be helpful. Treatment options for TOS include conservative management with education, rehabilitation, physiotherapy, or taping as the first-line management for neurogenic TOS. Surgical decompression may be warranted where conservative management has failed, especially if there is a physical anomaly. In vascular TOS, surgical treatment may be preferred, and other therapies such as botox injection are being investigated.

    • This question is part of the following fields:

      • Neurological System
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  • Question 2 - A 50-year-old woman presents to her primary care physician with complaints of fatigue...

    Incorrect

    • A 50-year-old woman presents to her primary care physician with complaints of fatigue and trouble staying alert while watching TV or reading, particularly in the evenings. Upon examination, she is diagnosed with myasthenia gravis. What is the underlying mechanism for this condition?

      Your Answer: Complete inhibition of acetylcholine release from the presynaptic membrane

      Correct Answer: Antibodies are produced against acetylcholine receptors

      Explanation:

      The accurate explanation is that myasthenia gravis involves the production of antibodies against acetylcholine receptors, leading to a decrease in the amount of available acetylcholine for use in the neuromuscular junction.

      Myasthenia gravis is an autoimmune disorder that results in muscle weakness and fatigue, particularly in the eyes, face, neck, and limbs. It is more common in women and is associated with thymomas and other autoimmune disorders. Diagnosis is made through electromyography and testing for antibodies to acetylcholine receptors. Treatment includes acetylcholinesterase inhibitors and immunosuppression, and in severe cases, plasmapheresis or intravenous immunoglobulins may be necessary.

    • This question is part of the following fields:

      • Neurological System
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  • Question 3 - A 50-year-old woman complains of increasing diplopia that worsens as the day progresses....

    Correct

    • A 50-year-old woman complains of increasing diplopia that worsens as the day progresses. She has been experiencing double vision for a few weeks now, and notes that it is more pronounced in the evenings and absent in the mornings. Upon further inquiry, the patient reports that her diplopia improves after resting her eyes.

      What is the most probable diagnosis?

      Your Answer: Myasthenia gravis

      Explanation:

      The main characteristic of myasthenia gravis is muscle weakness that worsens with use and improves with rest, without causing pain. This condition often affects the oculomotor nerve and is more prevalent in women. Diagnosis is typically confirmed through single fibre electromyography, which has a high level of sensitivity.

      While migraines can also cause double vision, they usually come with additional symptoms such as pain and nausea. A classic migraine may include a visual aura or sensitivity to light. Additionally, the patient’s age of 45 is older than the typical age of onset for migraines.

      Diabetic neuropathy can also lead to double vision, but it typically presents with a loss of sensation in the hands and feet. There is no indication that this patient has diabetes.

      Multiple sclerosis often first presents with vision problems affecting the optic nerve. Optic neuritis, for example, can cause pain, central scotoma, and colour vision loss.

      Myasthenia gravis is an autoimmune disorder that results in muscle weakness and fatigue, particularly in the eyes, face, neck, and limbs. It is more common in women and is associated with thymomas and other autoimmune disorders. Diagnosis is made through electromyography and testing for antibodies to acetylcholine receptors. Treatment includes acetylcholinesterase inhibitors and immunosuppression, and in severe cases, plasmapheresis or intravenous immunoglobulins may be necessary.

    • This question is part of the following fields:

      • Neurological System
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  • Question 4 - A 55-year-old male presents to the neurology clinic with his wife. She reports...

    Incorrect

    • A 55-year-old male presents to the neurology clinic with his wife. She reports noticing changes in his speech over the past six months. Specifically, she describes it as loud and jerky with pauses between syllables. However, he is still able to comprehend everything he hears. During your examination, you observe the same speech pattern but find no weakness or sensory changes in his limbs. Based on these findings, which area of the brain is most likely affected by a lesion?

      Your Answer: Superior temporal gyrus

      Correct Answer: Cerebellum

      Explanation:

      Scanning dysarthria can be caused by cerebellar disease, which can result in jerky, loud speech with pauses between words and syllables. Other symptoms may include dysdiadochokinesia, nystagmus, and an intention tremor.

      Wernicke’s (receptive) aphasia can be caused by a lesion in the superior temporal gyrus, which can lead to nonsensical sentences with word substitution and neologisms. It can also cause comprehension impairment, which is not present in this patient.

      Parkinson’s disease can be caused by a lesion in the substantia nigra, which can result in monotonous speech. Other symptoms may include bradykinesia, rigidity, and a resting tremor, which are not observed in this patient.

      A middle cerebral artery stroke can cause aphasia, contralateral hemiparesis, and sensory loss, with the upper extremity being more affected than the lower. However, this patient does not exhibit altered sensation on examination.

      A lesion in the arcuate fasciculus, which connects Wernicke’s and Broca’s area, can cause poor speech repetition, but this is not evident in this patient.

      Cerebellar syndrome is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. When there is damage or injury to one side of the cerebellum, it can cause symptoms on the same side of the body. These symptoms can be remembered using the mnemonic DANISH, which stands for Dysdiadochokinesia, Dysmetria, Ataxia, Nystagmus, Intention tremour, Slurred staccato speech, and Hypotonia.

      There are several possible causes of cerebellar syndrome, including genetic conditions like Friedreich’s ataxia and ataxic telangiectasia, neoplastic growths like cerebellar haemangioma, strokes, alcohol use, multiple sclerosis, hypothyroidism, and certain medications or toxins like phenytoin or lead poisoning. In some cases, cerebellar syndrome may be a paraneoplastic condition, meaning it is a secondary effect of an underlying cancer like lung cancer. It is important to identify the underlying cause of cerebellar syndrome in order to provide appropriate treatment and management.

    • This question is part of the following fields:

      • Neurological System
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  • Question 5 - A 36-year-old woman is referred to neurology clinic by her GP due to...

    Correct

    • A 36-year-old woman is referred to neurology clinic by her GP due to a 2-month history of gradual onset numbness in both feet. She has a medical history of well-controlled Crohn's disease on a vegan diet.

      During examination, the patient's gait is ataxic and Romberg's test is positive. There is a loss of proprioception and vibration sense to the mid shin bilaterally. Bilateral plantars are upgoing with absent ankle jerks.

      Based on these findings, you suspect the patient has subacute combined degeneration of the spinal cord. Which part of the nervous system is affected?

      Your Answer: The dorsal column and lateral corticospinal tracts of the spinal cord

      Explanation:

      Subacute combined degeneration of the spinal cord is caused by a deficiency in vitamin B12, which is absorbed in the terminal ileum along with intrinsic factor. Individuals at high risk of vitamin B12 deficiency include those with a history of gastric or intestinal surgery, pernicious anemia, malabsorption (especially in Crohn’s disease), and vegans due to decreased dietary intake. Medications such as proton-pump inhibitors and metformin can also reduce absorption of vitamin B12.

      SACD primarily affects the dorsal columns and lateral corticospinal tracts of the spinal cord, resulting in the loss of proprioception and vibration sense, followed by distal paraesthesia. The condition typically presents with a combination of upper and lower motor neuron signs, including extensor plantars, brisk knee reflexes, and absent ankle jerks. Treatment with vitamin B12 can result in partial to full recovery, depending on the extent and duration of neurodegeneration.

      If a patient has both vitamin B12 and folic acid deficiency, it is important to treat the vitamin B12 deficiency first to prevent the onset of subacute combined degeneration of the cord.

      Subacute Combined Degeneration of Spinal Cord

      Subacute combined degeneration of spinal cord is a condition that occurs due to a deficiency of vitamin B12. The dorsal columns and lateral corticospinal tracts are affected, leading to the loss of joint position and vibration sense. The first symptoms are usually distal paraesthesia, followed by the development of upper motor neuron signs in the legs, such as extensor plantars, brisk knee reflexes, and absent ankle jerks. If left untreated, stiffness and weakness may persist.

      This condition is a serious concern and requires prompt medical attention. It is important to maintain a healthy diet that includes sufficient amounts of vitamin B12 to prevent the development of subacute combined degeneration of spinal cord.

    • This question is part of the following fields:

      • Neurological System
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  • Question 6 - A 75-year-old man with a history of type 2 diabetes mellitus comes to...

    Correct

    • A 75-year-old man with a history of type 2 diabetes mellitus comes to the Emergency Department complaining of diplopia and ophthalmoplegia. Upon physical examination, it is found that his pupils are equal and reactive to light with an intact accommodation reflex. However, his right eye is abducted and looking downwards, while the rest of the examination is normal.

      Which cranial nerve is impacted in this case?

      Your Answer: Cranial nerve III

      Explanation:

      A patient with a ‘down and out’ eye is likely experiencing a lesion to cranial nerve III, also known as the oculomotor nerve. This nerve controls all extraocular muscles except for the lateral rectus and superior oblique muscles, and a lesion can result in unopposed action of these muscles, causing the ‘down and out’ gaze. Possible causes of cranial nerve III palsy include a posterior communicating artery aneurysm or diabetic ophthalmoplegia. In this case, the patient’s history of type 2 diabetes mellitus and absence of pupillary dilation suggest that diabetes is the more likely cause. Lesions to other cranial nerves, such as II, IV, V, or VI, would present with different symptoms.

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

    • This question is part of the following fields:

      • Neurological System
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  • Question 7 - A 78-year-old man visits your clinic with a chief complaint of shoulder weakness....

    Correct

    • A 78-year-old man visits your clinic with a chief complaint of shoulder weakness. He reports that his left shoulder has been weak for the past 5 months and the weakness has been gradually worsening. Upon examination, you observe atrophy of the trapezius muscle. When you ask him to shrug his shoulders, you notice weakness on his left side. You suspect that the patient's presentation is caused by a lesion affecting the accessory nerve. Which other muscle is innervated by the accessory nerve?

      Your Answer: Sternocleidomastoid

      Explanation:

      The sternocleidomastoid muscle is the correct answer. It originates from two points – the upper part of the sternum’s manubrium and the medial clavicle. It runs diagonally across the neck and attaches to the mastoid process of the temporal bone and the lateral area of the superior nuchal line. The accessory nerve and primary rami of C2-3 provide innervation to this muscle.

      Both the deltoid and teres minor muscles are innervated by the axillary nerve.

      The pectoralis major muscle is innervated by the medial and lateral pectoral nerves, which are both branches of the brachial plexus.

      The Accessory Nerve and Its Functions

      The accessory nerve is the eleventh cranial nerve that provides motor innervation to the sternocleidomastoid and trapezius muscles. It is important to examine the function of this nerve by checking for any loss of muscle bulk in the shoulders, asking the patient to shrug their shoulders against resistance, and turning their head against resistance.

      Iatrogenic injury, which is caused by medical treatment or procedures, is a common cause of isolated accessory nerve lesions. This is especially true for surgeries in the posterior cervical triangle, such as lymph node biopsy. It is important to be aware of the potential for injury to the accessory nerve during these procedures to prevent any long-term complications.

    • This question is part of the following fields:

      • Neurological System
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  • Question 8 - A 48-year-old man is referred to a neurology clinic due to experiencing uncontrolled...

    Incorrect

    • A 48-year-old man is referred to a neurology clinic due to experiencing uncontrolled movements of his limbs. The probable diagnosis is Huntington's disease, which results in the deterioration of the basal ganglia.

      Which neurotransmitters are expected to be primarily impacted, leading to the manifestation of the man's symptoms?

      Your Answer: ACh and Glutamate

      Correct Answer: ACh and GABA

      Explanation:

      The neurons responsible for producing ACh and GABA are primarily affected by the degeneration of the basal ganglia in Huntington’s disease, which plays a crucial role in regulating voluntary movement.

      Huntington’s disease is a genetic disorder that causes progressive and incurable neurodegeneration. It is inherited in an autosomal dominant manner and is caused by a trinucleotide repeat expansion of CAG in the huntingtin gene on chromosome 4. This can result in the phenomenon of anticipation, where the disease presents at an earlier age in successive generations. The disease leads to the degeneration of cholinergic and GABAergic neurons in the striatum of the basal ganglia, which can cause a range of symptoms.

      Typically, symptoms of Huntington’s disease develop after the age of 35 and can include chorea, personality changes such as irritability, apathy, and depression, intellectual impairment, dystonia, and saccadic eye movements. Unfortunately, there is currently no cure for Huntington’s disease, and it usually results in death around 20 years after the initial symptoms develop.

    • This question is part of the following fields:

      • Neurological System
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  • Question 9 - A 89-year-old man presents to his GP with a recent change in his...

    Incorrect

    • A 89-year-old man presents to his GP with a recent change in his vision. He reports experiencing a gradual painless loss of vision in his left eye for about 5 minutes, described as a 'rising curtain', which has now resolved completely. The patient has a medical history of hypertension and dyslipidemia. Upon examination, both pupils are equal, round, and reactive to light, and fundoscopy shows no apparent pathology. What blood vessel is the most likely culprit for the patient's vision loss?

      Your Answer: Ophthalmic vein

      Correct Answer: Central retinal artery

      Explanation:

      Amaurosis fugax is a type of transient ischaemic attack (TIA) that affects the central retinal artery, not stroke. The patient’s description of transient monocular vision loss that appears as a ‘rising curtain’ is characteristic of this condition. Urgent referral to a TIA clinic is necessary.

      Occlusion of the anterior spinal artery is not associated with vision loss, but may cause motor loss and loss of temperature and pain sensation below the level of the lesion.

      Occlusion of the central retinal vein may cause painless monocular vision loss, but not the characteristic ‘rising curtain’ distribution of vision loss seen in amaurosis fugax.

      Occlusion of the ophthalmic vein may cause a painful reduction in visual acuity, along with other symptoms such as ptosis, proptosis, and impaired visual acuity.

      Occlusion of the posterior inferior cerebellar artery is not associated with monocular vision loss, but is associated with lateral medullary syndrome.

      Stroke can affect different parts of the brain depending on which artery is affected. If the anterior cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the lower extremities being more affected than the upper. If the middle cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the upper extremities being more affected than the lower. They may also experience vision loss and difficulty with language. If the posterior cerebral artery is affected, the person may experience vision loss and difficulty recognizing objects.

      Lacunar strokes are a type of stroke that are strongly associated with hypertension. They typically present with isolated weakness or loss of sensation on one side of the body, or weakness with difficulty coordinating movements. They often occur in the basal ganglia, thalamus, or internal capsule.

    • This question is part of the following fields:

      • Neurological System
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  • Question 10 - A 50-year-old male with Alzheimer's disease visits the neurology clinic accompanied by his...

    Incorrect

    • A 50-year-old male with Alzheimer's disease visits the neurology clinic accompanied by his spouse. His recent MRI scan reveals extensive cerebral atrophy, primarily in the cortex. In which other region of the brain is this likely to occur?

      Your Answer: Hypothalamus

      Correct Answer: Hippocampus

      Explanation:

      The cortex and hippocampus are the areas of the brain that are primarily affected by the widespread cerebral atrophy caused by Alzheimer’s disease.

      Homeostasis is mainly regulated by the hypothalamus, and damage to this area can cause either hypothermia or hyperthermia.

      Klüver–Bucy syndrome, which is characterized by hypersexuality, hyperorality, and hyperphagia, can result from damage to the amygdala.

      Lesions in the midline of the cerebellum can cause gait and truncal ataxia, while hemisphere lesions can lead to an intention tremor, dysdiadochokinesia, past pointing, and nystagmus.

      Diseases affecting the brainstem can result in problems with cranial nerve functions.

      Alzheimer’s disease is a type of dementia that gradually worsens over time and is caused by the degeneration of the brain. There are several risk factors associated with Alzheimer’s disease, including increasing age, family history, and certain genetic mutations. The disease is also more common in individuals of Caucasian ethnicity and those with Down’s syndrome.

      The pathological changes associated with Alzheimer’s disease include widespread cerebral atrophy, particularly in the cortex and hippocampus. Microscopically, there are cortical plaques caused by the deposition of type A-Beta-amyloid protein and intraneuronal neurofibrillary tangles caused by abnormal aggregation of the tau protein. The hyperphosphorylation of the tau protein has been linked to Alzheimer’s disease. Additionally, there is a deficit of acetylcholine due to damage to an ascending forebrain projection.

      Neurofibrillary tangles are a hallmark of Alzheimer’s disease and are partly made from a protein called tau. Tau is a protein that interacts with tubulin to stabilize microtubules and promote tubulin assembly into microtubules. In Alzheimer’s disease, tau proteins are excessively phosphorylated, impairing their function.

    • This question is part of the following fields:

      • Neurological System
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  • Question 11 - A 75-year-old male has been admitted to the stroke ward after experiencing a...

    Correct

    • A 75-year-old male has been admitted to the stroke ward after experiencing a stroke 2 days ago. During a mini mental state examination, it was observed that the patient struggled with repeating sentences. Upon further assessment, the doctor discovered that the patient had difficulty with speech repetition. Nevertheless, the patient had no issues with speech comprehension or production during conversation.

      What could be the probable cause of the patient's symptoms?

      Your Answer: Conduction aphasia

      Explanation:

      The patient is likely experiencing conduction aphasia, which is characterized by fluent speech but poor repetition ability. This is caused by an impairment to the arcuate fasciculus, which connects Broca’s and Wernicke’s areas. While comprehension is usually preserved in this type of aphasia, patients may struggle with repeating words or phrases. Broca’s aphasia, global aphasia, and primary progressive aphasia are less likely explanations for the patient’s symptoms.

      Types of Aphasia: Understanding the Different Forms of Language Impairment

      Aphasia is a language disorder that affects a person’s ability to communicate effectively. There are different types of aphasia, each with its own set of symptoms and underlying causes. Wernicke’s aphasia, also known as receptive aphasia, is caused by a lesion in the superior temporal gyrus. This area is responsible for forming speech before sending it to Broca’s area. People with Wernicke’s aphasia may speak fluently, but their sentences often make no sense, and they may use word substitutions and neologisms. Comprehension is impaired.

      Broca’s aphasia, also known as expressive aphasia, is caused by a lesion in the inferior frontal gyrus. This area is responsible for speech production. People with Broca’s aphasia may speak in a non-fluent, labored, and halting manner. Repetition is impaired, but comprehension is normal.

      Conduction aphasia is caused by a stroke affecting the arcuate fasciculus, the connection between Wernicke’s and Broca’s area. People with conduction aphasia may speak fluently, but their repetition is poor. They are aware of the errors they are making, but comprehension is normal.

      Global aphasia is caused by a large lesion affecting all three areas mentioned above, resulting in severe expressive and receptive aphasia. People with global aphasia may still be able to communicate using gestures. Understanding the different types of aphasia is important for proper diagnosis and treatment.

    • This question is part of the following fields:

      • Neurological System
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  • Question 12 - A builder in his 40s falls off a ladder while laying roof tiles...

    Correct

    • A builder in his 40s falls off a ladder while laying roof tiles and suffers a burst fracture of L3. The MRI scan reveals complete nerve transection at this level due to the injury. What clinical sign will be absent in the beginning?

      Your Answer: Extensor plantar response

      Explanation:

      In cases of lower motor neuron lesions, there is a reduction in various features such as muscle strength, muscle size, reflexes, and the occurrence of muscle fasciculation.

      The spinal cord is a central structure located within the vertebral column that provides it with structural support. It extends rostrally to the medulla oblongata of the brain and tapers caudally at the L1-2 level, where it is anchored to the first coccygeal vertebrae by the filum terminale. The cord is characterised by cervico-lumbar enlargements that correspond to the brachial and lumbar plexuses. It is incompletely divided into two symmetrical halves by a dorsal median sulcus and ventral median fissure, with grey matter surrounding a central canal that is continuous with the ventricular system of the CNS. Afferent fibres entering through the dorsal roots usually terminate near their point of entry but may travel for varying distances in Lissauer’s tract. The key point to remember is that the anatomy of the cord will dictate the clinical presentation in cases of injury, which can be caused by trauma, neoplasia, inflammatory diseases, vascular issues, or infection.

      One important condition to remember is Brown-Sequard syndrome, which is caused by hemisection of the cord and produces ipsilateral loss of proprioception and upper motor neuron signs, as well as contralateral loss of pain and temperature sensation. Lesions below L1 tend to present with lower motor neuron signs. It is important to keep a clinical perspective in mind when revising CNS anatomy and to understand the ways in which the spinal cord can become injured, as this will help in diagnosing and treating patients with spinal cord injuries.

    • This question is part of the following fields:

      • Neurological System
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  • Question 13 - A 20-year-old male arrives at the emergency department with a depressed skull fracture...

    Incorrect

    • A 20-year-old male arrives at the emergency department with a depressed skull fracture that requires surgical intervention. After a few days, he reports experiencing double vision while walking down stairs and reading. Upon conducting an ocular convergence test, it is observed that the left eye faces downwards and medially, while the right eye does not. Which cranial nerve is most likely responsible for this symptom?

      Your Answer: Abducens

      Correct Answer: Trochlear

      Explanation:

      The fourth cranial nerve is susceptible to injury in cases of head trauma due to its lengthy intracranial path. Acute fourth nerve palsy is most commonly caused by head trauma, resulting in vertical diplopia. The double vision is most severe when the affected eye looks inward, which typically occurs during the accommodation reflex while descending stairs.

      Disorders of the Oculomotor System: Nerve Path and Palsy Features

      The oculomotor system is responsible for controlling eye movements and pupil size. Disorders of this system can result in various nerve path and palsy features. The oculomotor nerve has a large nucleus at the midbrain and its fibers pass through the red nucleus and the pyramidal tract, as well as through the cavernous sinus into the orbit. When this nerve is affected, patients may experience ptosis, eye down and out, and an inability to move the eye superiorly, inferiorly, or medially. The pupil may also become fixed and dilated.

      The trochlear nerve has the longest intracranial course and is the only nerve to exit the dorsal aspect of the brainstem. Its nucleus is located at the midbrain and it passes between the posterior cerebral and superior cerebellar arteries, as well as through the cavernous sinus into the orbit. When this nerve is affected, patients may experience vertical diplopia (diplopia on descending the stairs) and an inability to look down and in.

      The abducens nerve has its nucleus in the mid pons and is responsible for the convergence of eyes in primary position. When this nerve is affected, patients may experience lateral diplopia towards the side of the lesion and the eye may deviate medially. Understanding the nerve path and palsy features of the oculomotor system can aid in the diagnosis and treatment of disorders affecting this important system.

    • This question is part of the following fields:

      • Neurological System
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  • Question 14 - A 65-year-old patient presents with dysdiadochokinesia, gait ataxia, nystagmus, intention tremor and slurred...

    Correct

    • A 65-year-old patient presents with dysdiadochokinesia, gait ataxia, nystagmus, intention tremor and slurred speech. What investigation would be most appropriate for the likely diagnosis?

      Your Answer: MRI Brain

      Explanation:

      When it comes to cerebellar disease, MRI is the preferred diagnostic tool. CT brain scans are better suited for detecting ischemic or hemorrhagic strokes in the brain, rather than identifying cerebellar lesions. X-rays of the brain are not effective in detecting cerebellar lesions. PET-CT scans are typically used in cancer cases where there is active uptake of the radioactive isotope by cancer cells.

      Cerebellar syndrome is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. When there is damage or injury to one side of the cerebellum, it can cause symptoms on the same side of the body. These symptoms can be remembered using the mnemonic DANISH, which stands for Dysdiadochokinesia, Dysmetria, Ataxia, Nystagmus, Intention tremour, Slurred staccato speech, and Hypotonia.

      There are several possible causes of cerebellar syndrome, including genetic conditions like Friedreich’s ataxia and ataxic telangiectasia, neoplastic growths like cerebellar haemangioma, strokes, alcohol use, multiple sclerosis, hypothyroidism, and certain medications or toxins like phenytoin or lead poisoning. In some cases, cerebellar syndrome may be a paraneoplastic condition, meaning it is a secondary effect of an underlying cancer like lung cancer. It is important to identify the underlying cause of cerebellar syndrome in order to provide appropriate treatment and management.

    • This question is part of the following fields:

      • Neurological System
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  • Question 15 - A 16-year-old male comes to the emergency department with a shoulder injury following...

    Incorrect

    • A 16-year-old male comes to the emergency department with a shoulder injury following a football tackle.

      During the examination, it is discovered that he has a dislocated shoulder, weakness in elbow flexion, weakness in supination, and a loss of sensation on the lateral side of his forearm.

      Which nerve is most likely to have been damaged?

      Your Answer: Radial nerve

      Correct Answer: Musculocutaneous nerve

      Explanation:

      When the musculocutaneous nerve is injured, it can cause weakness in elbow flexion and supination, as well as sensory loss on the outer side of the forearm. Other nerves in the arm have different functions, such as the median nerve which controls many of the flexor muscles in the forearm and provides sensation to the palm and fingers, the radial nerve which controls the triceps and extensor muscles in the back of the forearm and provides sensation to the back of the arm and hand, and the axillary nerve which controls the deltoid and teres minor muscles and provides sensation to the lower part of the deltoid muscle. The musculocutaneous nerve also has a branch that provides sensation to the outer part of the forearm.

      Understanding the Brachial Plexus and Cutaneous Sensation of the Upper Limb

      The brachial plexus is a network of nerves that originates from the anterior rami of C5 to T1. It is divided into five sections: roots, trunks, divisions, cords, and branches. To remember these sections, a common mnemonic used is Real Teenagers Drink Cold Beer.

      The roots of the brachial plexus are located in the posterior triangle and pass between the scalenus anterior and medius muscles. The trunks are located posterior to the middle third of the clavicle, with the upper and middle trunks related superiorly to the subclavian artery. The lower trunk passes over the first rib posterior to the subclavian artery. The divisions of the brachial plexus are located at the apex of the axilla, while the cords are related to the axillary artery.

      The branches of the brachial plexus provide cutaneous sensation to the upper limb. This includes the radial nerve, which provides sensation to the posterior arm, forearm, and hand; the median nerve, which provides sensation to the palmar aspect of the thumb, index, middle, and half of the ring finger; and the ulnar nerve, which provides sensation to the palmar and dorsal aspects of the fifth finger and half of the ring finger.

      Understanding the brachial plexus and its branches is important in diagnosing and treating conditions that affect the upper limb, such as nerve injuries and neuropathies. It also helps in understanding the cutaneous sensation of the upper limb and how it relates to the different nerves of the brachial plexus.

    • This question is part of the following fields:

      • Neurological System
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  • Question 16 - A 3 week old infant has been diagnosed with hydrocephalus due to congenital...

    Correct

    • A 3 week old infant has been diagnosed with hydrocephalus due to congenital spina bifida. Can you identify the location of cerebrospinal fluid (CSF) production?

      Your Answer: Choroid plexuses

      Explanation:

      The choroid plexuses, located in the ventricles of the brain, are responsible for the production of CSF. The cerebral aqueduct (or aqueduct of Sylvius) does not have a choroid plexus. The cribriform plate, which is a part of the ethmoid bone, does not produce or secrete anything but a fracture in it can cause CSF leakage into the nose and result in anosmia. The arachnoid granulations (or villi) serve as the communication between the subarachnoid space and the venous sinuses, allowing for the continuous reabsorption of CSF into the bloodstream. The pia mater, which is the innermost layer of the meninges around the brain, encloses the CSF within the subarachnoid space.

      Cerebrospinal Fluid: Circulation and Composition

      Cerebrospinal fluid (CSF) is a clear, colorless liquid that fills the space between the arachnoid mater and pia mater, covering the surface of the brain. The total volume of CSF in the brain is approximately 150ml, and it is produced by the ependymal cells in the choroid plexus or blood vessels. The majority of CSF is produced by the choroid plexus, accounting for 70% of the total volume. The remaining 30% is produced by blood vessels. The CSF is reabsorbed via the arachnoid granulations, which project into the venous sinuses.

      The circulation of CSF starts from the lateral ventricles, which are connected to the third ventricle via the foramen of Munro. From the third ventricle, the CSF flows through the cerebral aqueduct (aqueduct of Sylvius) to reach the fourth ventricle via the foramina of Magendie and Luschka. The CSF then enters the subarachnoid space, where it circulates around the brain and spinal cord. Finally, the CSF is reabsorbed into the venous system via arachnoid granulations into the superior sagittal sinus.

      The composition of CSF is essential for its proper functioning. The glucose level in CSF is between 50-80 mg/dl, while the protein level is between 15-40 mg/dl. Red blood cells are not present in CSF, and the white blood cell count is usually less than 3 cells/mm3. Understanding the circulation and composition of CSF is crucial for diagnosing and treating various neurological disorders.

    • This question is part of the following fields:

      • Neurological System
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  • Question 17 - A 28-year-old woman presents to the Emergency Department complaining of a headache and...

    Correct

    • A 28-year-old woman presents to the Emergency Department complaining of a headache and blurred vision. The headache began 2 days ago and is aggravated by coughing and changing position. The blurred vision started 5 hours ago. She has no history of head injuries and has never experienced these symptoms before. Her BMI is 27 kg/m² and she is currently taking the combined oral contraceptive pill.

      Upon examination, the patient has difficulty abducting her left eye. Fundoscopy reveals bilateral papilloedema.

      Vital signs:
      Blood pressure: 130/90 mmHg
      Heart rate: 80 bpm
      Respiratory rate: 16/min

      What is the most probable diagnosis?

      Your Answer: Idiopathic intracranial hypertension

      Explanation:

      The patient’s difficulty in abducting the right eye and accompanying 6th nerve palsy, along with papilloedema, are indicative of idiopathic intracranial hypertension. This is further supported by the patient’s age, BMI, and COCP use, which are common risk factors for this condition. Acute-angle closure glaucoma, meningitis, and migraine are less likely explanations as they do not fully align with the patient’s symptoms and history.

      Understanding Idiopathic Intracranial Hypertension

      Idiopathic intracranial hypertension, also known as pseudotumour cerebri, is a medical condition that is commonly observed in young, overweight females. The condition is characterized by a range of symptoms, including headache, blurred vision, and papilloedema, which is usually present. Other symptoms may include an enlarged blind spot and sixth nerve palsy.

      There are several risk factors associated with idiopathic intracranial hypertension, including obesity, female sex, pregnancy, and certain drugs such as the combined oral contraceptive pill, steroids, tetracyclines, vitamin A, and lithium.

      Management of idiopathic intracranial hypertension may involve weight loss, diuretics such as acetazolamide, and topiramate, which can also cause weight loss in most patients. Repeated lumbar puncture may also be necessary, and surgery may be required to prevent damage to the optic nerve. This may involve optic nerve sheath decompression and fenestration, or a lumboperitoneal or ventriculoperitoneal shunt to reduce intracranial pressure.

      It is important to note that if intracranial hypertension is thought to occur secondary to a known cause, such as medication, it is not considered idiopathic. Understanding the risk factors and symptoms associated with idiopathic intracranial hypertension can help individuals seek appropriate medical attention and management.

    • This question is part of the following fields:

      • Neurological System
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  • Question 18 - A 47-year-old woman is experiencing muscle spasticity due to relapsing-remitting multiple sclerosis. Baclofen...

    Incorrect

    • A 47-year-old woman is experiencing muscle spasticity due to relapsing-remitting multiple sclerosis. Baclofen is prescribed to alleviate the pain associated with spasticity.

      What is the mechanism of action of Baclofen?

      Your Answer: Muscarinic M3 receptor antagonist

      Correct Answer: Gamma-aminobutyric acid (GABA) receptor agonist

      Explanation:

      Baclofen is a medication that acts as an agonist at GABA receptors in the central nervous system. It is primarily used as a muscle relaxant to treat spasticity conditions such as multiple sclerosis and cerebral palsy. It should be noted that baclofen is not a GABA antagonist like flumazenil, nor does it act as an NMDA agonist like the toxin responsible for Amanita muscaria poisoning. Additionally, baclofen does not exert its effects at muscarinic receptors like buscopan, which is commonly used to treat pain associated with bowel wall spasm and respiratory secretions during end-of-life care. Instead, baclofen specifically targets GABA receptors.

      Baclofen is a medication that is commonly prescribed to alleviate muscle spasticity in individuals with conditions like multiple sclerosis, cerebral palsy, and spinal cord injuries. It works by acting as an agonist of GABA receptors in the central nervous system, which includes both the brain and spinal cord. Essentially, this means that baclofen helps to enhance the effects of a neurotransmitter called GABA, which can help to reduce the activity of certain neurons and ultimately lead to a reduction in muscle spasticity. Overall, baclofen is an important medication for individuals with these conditions, as it can help to improve their quality of life and reduce the impact of muscle spasticity on their daily activities.

    • This question is part of the following fields:

      • Neurological System
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  • Question 19 - A 45-year-old obese woman has recently been diagnosed with idiopathic intracranial hypertension and...

    Incorrect

    • A 45-year-old obese woman has recently been diagnosed with idiopathic intracranial hypertension and is experiencing blurred vision. Her blood tests are normal, and a CT scan of her head shows no signs of bleeding, tumors, or hydrocephalus. During a lumbar puncture, her opening pressure is measured at 30cmH2O. Her vision continues to deteriorate, and she is transferred to a neurosurgical center where her intracranial pressure is measured at 40mmHg. What is the cerebral perfusion pressure of this patient?

      Your Answer: 123

      Correct Answer: 53

      Explanation:

      The calculation for cerebral perfusion pressure involves subtracting the intracranial pressure from the mean arterial pressure, resulting in a value of 53mmHg.

      Understanding Raised Intracranial Pressure

      As the brain and ventricles are enclosed by a rigid skull, any additional volume such as haematoma, tumour, or excessive cerebrospinal fluid (CSF) can lead to a rise in intracranial pressure (ICP). The normal ICP in adults in the supine position is 7-15 mmHg. Cerebral perfusion pressure (CPP) is the net pressure gradient causing cerebral blood flow to the brain, and it is calculated by subtracting ICP from mean arterial pressure.

      Raised intracranial pressure can be caused by various factors such as idiopathic intracranial hypertension, traumatic head injuries, infection, meningitis, tumours, and hydrocephalus. Its features include headache, vomiting, reduced levels of consciousness, papilloedema, and Cushing’s triad, which is characterized by widening pulse pressure, bradycardia, and irregular breathing.

      To investigate raised intracranial pressure, neuroimaging such as CT or MRI is key to determine the underlying cause. Invasive ICP monitoring can also be done by placing a catheter into the lateral ventricles of the brain to monitor the pressure, collect CSF samples, and drain small amounts of CSF to reduce the pressure. A cut-off of > 20 mmHg is often used to determine if further treatment is needed to reduce the ICP.

      Management of raised intracranial pressure involves investigating and treating the underlying cause, head elevation to 30º, IV mannitol as an osmotic diuretic, controlled hyperventilation to reduce pCO2 and vasoconstriction of the cerebral arteries, and removal of CSF through techniques such as drain from intraventricular monitor, repeated lumbar puncture, or ventriculoperitoneal shunt for hydrocephalus.

    • This question is part of the following fields:

      • Neurological System
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  • Question 20 - A 51-year-old male comes to his doctor complaining of increasing back pain. Despite...

    Correct

    • A 51-year-old male comes to his doctor complaining of increasing back pain. Despite taking paracetamol and ibuprofen, he has not experienced sufficient pain relief. The doctor considers prescribing a weak opioid, such as codeine, and asks the medical student accompanying him for the week about the receptors that opioids act on to produce their pharmacological effects.

      Which receptors do opioids target?

      Your Answer: Mu, delta and kappa receptors

      Explanation:

      Opioids produce their pharmacological effects by binding to three opioid receptors, namely mu, delta, and kappa, whose genes have been identified and cloned as Oprm, Oprd1, and Oprk1, respectively. It is important to note that alpha and beta receptors are not involved in the mechanism of action of opioids.

      Understanding Opioids: Types, Receptors, and Clinical Uses

      Opioids are a class of chemical compounds that act upon opioid receptors located within the central nervous system (CNS). These receptors are G-protein coupled receptors that have numerous actions throughout the body. There are three clinically relevant groups of opioid receptors: mu (µ), kappa (κ), and delta (δ) receptors. Endogenous opioids, such as endorphins, dynorphins, and enkephalins, are produced by specific cells within the CNS and their actions depend on whether µ-receptors or δ-receptors and κ-receptors are their main target.

      Drugs targeted at opioid receptors are the largest group of analgesic drugs and form the second and third steps of the WHO pain ladder of managing analgesia. The choice of which opioid drug to use depends on the patient’s needs and the clinical scenario. The first step of the pain ladder involves non-opioids such as paracetamol and non-steroidal anti-inflammatory drugs. The second step involves weak opioids such as codeine and tramadol, while the third step involves strong opioids such as morphine, oxycodone, methadone, and fentanyl.

      The strength, routes of administration, common uses, and significant side effects of these opioid drugs vary. Weak opioids have moderate analgesic effects without exposing the patient to as many serious adverse effects associated with strong opioids. Strong opioids have powerful analgesic effects but are also more liable to cause opioid-related side effects such as sedation, respiratory depression, constipation, urinary retention, and addiction. The sedative effects of opioids are also useful in anesthesia with potent drugs used as part of induction of a general anesthetic.

    • This question is part of the following fields:

      • Neurological System
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  • Question 21 - Samantha, a 75-year-old female, arrives at the emergency department after falling down a...

    Incorrect

    • Samantha, a 75-year-old female, arrives at the emergency department after falling down a flight of stairs. She reports experiencing discomfort in her right upper arm.

      Upon examination, the physician orders an X-ray which reveals a mid shaft humeral fracture on the right.

      What is the most probable symptom associated with this type of fracture?

      Your Answer: Volkmann's contracture

      Correct Answer: Wrist drop

      Explanation:

      A mid shaft humeral fracture can result in wrist drop, which is a clinical sign indicating damage to the radial nerve. The radial nerve controls the muscles responsible for extending the wrist, and when it is damaged, the wrist remains in a flexed position. Other clinical signs associated with nerve or vascular damage include the hand of benediction (median nerve), ulnar claw (ulnar nerve), and Volkmann’s contracture (brachial artery).

      The Radial Nerve: Anatomy, Innervation, and Patterns of Damage

      The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.

      The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.

      Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.

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      • Neurological System
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  • Question 22 - A 29-year-old male visits an acute eye clinic with a complaint of a...

    Incorrect

    • A 29-year-old male visits an acute eye clinic with a complaint of a painful eye. During the examination, the ophthalmologist observes a photophobic red eye and identifies a distinctive lesion, resulting in a quick diagnosis of herpes simplex keratitis.

      What is the description of the lesion?

      Your Answer: Shingles rash overlying the V1 dermatome

      Correct Answer: Dendritic corneal lesion

      Explanation:

      Keratitis caused by herpes simplex is characterized by dendritic lesions that appear as a branched pattern on fluorescein dye. This is typically seen during slit lamp examination. While severe inflammation may be present, indicated by the presence of an inflammatory exudate of the anterior chamber (hypopyon), this is not specific to herpes simplex and may be associated with other causes of keratitis or anterior uveitis. It’s worth noting that herpes zoster ophthalmicus (HZO) is not caused by herpes simplex, but rather occurs when the dormant shingles virus in the ophthalmic nerve reactivates. Hutchinson’s sign, which is a vesicular rash at the tip of the nose in the context of an acute red eye, is suggestive of HZO. Lastly, it’s important to note that a tear dropped pupil is not a feature of keratitis and may be caused by blunt trauma.

      Understanding Herpes Simplex Keratitis

      Herpes simplex keratitis is a condition that primarily affects the cornea and is caused by the herpes simplex virus. The most common symptom of this condition is a dendritic corneal ulcer, which can cause a red, painful eye, photophobia, and epiphora. In some cases, visual acuity may also be decreased. Fluorescein staining may show an epithelial ulcer, which can help with diagnosis.

      One common treatment for this condition is topical acyclovir, which can help to reduce the severity of symptoms and prevent further complications.

    • This question is part of the following fields:

      • Neurological System
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  • Question 23 - A 6-year-old child has been in a car accident and has a fracture...

    Incorrect

    • A 6-year-old child has been in a car accident and has a fracture of the floor of the orbit. The surgeon you consulted is worried that one of the extra-ocular muscles may be trapped in the fracture site. Which muscle is most vulnerable?

      Your Answer: Levator palpabrae inferioris

      Correct Answer: Inferior rectus

      Explanation:

      The correct muscle that is most at risk in a fracture of the floor of the orbit, also known as an orbital blowout fracture, is the inferior rectus muscle. This muscle is located above the thin plate of the maxillary bone that makes up the floor of the orbit, and is therefore more susceptible to being trapped in these types of fractures.

      When the inferior rectus muscle becomes trapped in a blowout fracture, it can result in restricted eye movements and affect extra-orbital soft tissue. This type of fracture is known as a trapdoor fracture and is often associated with the oculocardiac reflex or Aschner phenomenon, which can cause symptoms such as bradycardia, nausea and vomiting, vertigo, and syncope.

      It is important to note that the inferior oblique muscle is also commonly affected in these types of fractures, but it was not an option in this question. Additionally, levator palpebrae inferioris is not an actual muscle and is therefore a dummy answer. The muscle that raises the upper eyelid is actually called the levator palpebrae superioris.

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

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      • Neurological System
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  • Question 24 - A patient in his mid-50s visits his physician with complaints of difficulty in...

    Incorrect

    • A patient in his mid-50s visits his physician with complaints of difficulty in chewing and tongue movement, leading to eating problems. The patient also reports severe headaches, and the symptoms have been worsening gradually. The doctor decides to conduct an MRI scan to diagnose the condition.

      What is the likely location of the lesion within the skull that the doctor will look for?

      Your Answer: Foramen ovale

      Correct Answer: Hypoglossal canal

      Explanation:

      The hypoglossal nerve travels through the hypoglossal canal, which is why damage to this nerve can cause symptoms related to tongue movement and reflexes such as chewing, sucking, and swallowing. The superior orbital fissure is not the correct answer as the nerves that pass through it do not provide motor innervation to the tongue, and the patient in the question does not present with any eye-related symptoms. The jugular foramen and foramen ovale are also incorrect as they do not exclusively house the hypoglossal nerve, and the nerves that pass through them do not provide motor innervation to the tongue. The foramen rotundum is also not the correct answer as only the maxillary branch of the trigeminal nerve passes through it, which does not innervate the tongue.

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

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      • Neurological System
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  • Question 25 - A 67-year-old man visits his GP complaining of alterations in his vision. In...

    Incorrect

    • A 67-year-old man visits his GP complaining of alterations in his vision. In addition to decreased sharpness, he describes object distortion, difficulty discerning colors, and occasional flashes of light. He has a history of smoking (40-pack-year) and a high BMI. Based on these symptoms, what is the most probable diagnosis?

      Your Answer: Diabetic retinopathy

      Correct Answer: Age-related macular degeneration

      Explanation:

      Age-related macular degeneration (AMD) is characterized by a decrease in visual acuity, altered perception of colors and shades, and photopsia (flashing lights). The risk of developing AMD is higher in individuals who are older and have a history of smoking.

      As a natural part of the aging process, presbyopia can cause difficulty with near vision. Smoking increases the likelihood of developing cataracts, which can result in poor visual acuity and reduced contrast sensitivity. However, symptoms such as distortion and flashing lights are not typically associated with cataracts. Similarly, retinal detachment is unlikely given the patient’s risk factors and lack of distortion and perception issues. Since there is no mention of diabetes mellitus in the patient’s history, diabetic retinopathy is not a plausible explanation.

      Age-related macular degeneration (ARMD) is a common cause of blindness in the UK, characterized by degeneration of the central retina (macula) and the formation of drusen. The risk of ARMD increases with age, smoking, family history, and conditions associated with an increased risk of ischaemic cardiovascular disease. ARMD is classified into dry and wet forms, with the latter carrying the worst prognosis. Clinical features include subacute onset of visual loss, difficulties in dark adaptation, and visual hallucinations. Signs include distortion of line perception, the presence of drusen, and well-demarcated red patches in wet ARMD. Investigations include slit-lamp microscopy, colour fundus photography, fluorescein angiography, indocyanine green angiography, and ocular coherence tomography. Treatment options include a combination of zinc with anti-oxidant vitamins for dry ARMD and anti-VEGF agents for wet ARMD. Laser photocoagulation is also an option, but anti-VEGF therapies are usually preferred.

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      • Neurological System
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  • Question 26 - Which one of the following structures is not transmitted by the jugular foramen?...

    Incorrect

    • Which one of the following structures is not transmitted by the jugular foramen?

      Your Answer: Inferior petrosal sinus

      Correct Answer: Hypoglossal nerve

      Explanation:

      The jugular foramen contains three compartments. The anterior compartment transmits the inferior petrosal sinus, the middle compartment transmits cranial nerves IX, X, and XI, and the posterior compartment transmits the sigmoid sinus and some meningeal branches from the occipital and ascending pharyngeal arteries.

      Foramina of the Base of the Skull

      The base of the skull contains several openings called foramina, which allow for the passage of nerves, blood vessels, and other structures. The foramen ovale, located in the sphenoid bone, contains the mandibular nerve, otic ganglion, accessory meningeal artery, and emissary veins. The foramen spinosum, also in the sphenoid bone, contains the middle meningeal artery and meningeal branch of the mandibular nerve. The foramen rotundum, also in the sphenoid bone, contains the maxillary nerve.

      The foramen lacerum, located in the sphenoid bone, is initially occluded by a cartilaginous plug and contains the internal carotid artery, nerve and artery of the pterygoid canal, and the base of the medial pterygoid plate. The jugular foramen, located in the temporal bone, contains the inferior petrosal sinus, glossopharyngeal, vagus, and accessory nerves, sigmoid sinus, and meningeal branches from the occipital and ascending pharyngeal arteries.

      The foramen magnum, located in the occipital bone, contains the anterior and posterior spinal arteries, vertebral arteries, and medulla oblongata. The stylomastoid foramen, located in the temporal bone, contains the stylomastoid artery and facial nerve. Finally, the superior orbital fissure, located in the sphenoid bone, contains the oculomotor nerve, recurrent meningeal artery, trochlear nerve, lacrimal, frontal, and nasociliary branches of the ophthalmic nerve, and abducent nerve.

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      • Neurological System
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  • Question 27 - A 29-year-old male arrives at the emergency department after being involved in a...

    Correct

    • A 29-year-old male arrives at the emergency department after being involved in a car accident. During the neurological examination, a decreased sense of smell is observed, indicating possible damage to the olfactory nerve. What bone does the olfactory bulb pass through?

      Your Answer: Ethmoid

      Explanation:

      The olfactory nerve is responsible solely for the sense of smell and its receptors are located in the nasal mucosa. It travels through the cribriform plate of the ethmoid bone to reach the olfactory bulb.

      The sphenoid bone is located too far back and the nasal bone only forms the outer edge of the nose, with no nerves passing through it.

      The lacrimal bone creates the inner wall of the eye socket, while the temporal bone is situated at the skull’s lateral and inferior borders.

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

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      • Neurological System
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  • Question 28 - A 46-year-old man comes to the clinic complaining of bilateral sciatica and partial...

    Correct

    • A 46-year-old man comes to the clinic complaining of bilateral sciatica and partial urinary incontinence. Upon conducting a comprehensive examination and lumbosacral magnetic resonance imaging, the diagnosis of cauda equina syndrome is confirmed at the L2 level.

      What is the most probable finding to be observed during the examination?

      Your Answer: S2-S4 anaesthesia

      Explanation:

      Lesions in the lower lumbar region cannot result in upper motor neuron signs because the spinal cord terminates at L1.

      The spinal cord is a central structure located within the vertebral column that provides it with structural support. It extends rostrally to the medulla oblongata of the brain and tapers caudally at the L1-2 level, where it is anchored to the first coccygeal vertebrae by the filum terminale. The cord is characterised by cervico-lumbar enlargements that correspond to the brachial and lumbar plexuses. It is incompletely divided into two symmetrical halves by a dorsal median sulcus and ventral median fissure, with grey matter surrounding a central canal that is continuous with the ventricular system of the CNS. Afferent fibres entering through the dorsal roots usually terminate near their point of entry but may travel for varying distances in Lissauer’s tract. The key point to remember is that the anatomy of the cord will dictate the clinical presentation in cases of injury, which can be caused by trauma, neoplasia, inflammatory diseases, vascular issues, or infection.

      One important condition to remember is Brown-Sequard syndrome, which is caused by hemisection of the cord and produces ipsilateral loss of proprioception and upper motor neuron signs, as well as contralateral loss of pain and temperature sensation. Lesions below L1 tend to present with lower motor neuron signs. It is important to keep a clinical perspective in mind when revising CNS anatomy and to understand the ways in which the spinal cord can become injured, as this will help in diagnosing and treating patients with spinal cord injuries.

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      • Neurological System
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  • Question 29 - A 45-year-old woman presents to the clinic with a history of multiple minor...

    Incorrect

    • A 45-year-old woman presents to the clinic with a history of multiple minor falls and confusion. She has been experiencing daily headaches with nausea for the past 3 years, which have worsened at night and occasionally wake her up. Imaging reveals an intracranial mass located on the left hemisphere's convexity, and a biopsy of the mass shows a whorled pattern of calcified cellular growth that forms syncytial nests and appears as round, eosinophilic laminar structure.

      What is the most probable diagnosis for this patient?

      Your Answer: Glioblastoma

      Correct Answer: Meningioma

      Explanation:

      Meningiomas are the second most frequent type of primary brain tumour, often found in the convexities of cerebral hemispheres and parasagittal regions. The biopsy findings of this patient suggest the presence of psammoma bodies, which are mineral deposits formed by calcification of spindle cells in concentric whorls within the tumour.

      Ependymomas usually present as paraventricular tumours and exhibit perivascular rosettes under light microscopy.

      Glioblastomas are the most common primary malignant brain tumour in adults. Light microscopy reveals hypercellular areas of atypical astrocytes surrounding regions of necrosis.

      Medulloblastomas are malignant cerebellar tumours that typically occur in children and are characterized by small blue cells that may encircle neutrophils.

      Brain tumours can be classified into different types based on their location, histology, and clinical features. Metastatic brain cancer is the most common form of brain tumours, which often cannot be treated with surgical intervention. Glioblastoma multiforme is the most common primary tumour in adults and is associated with a poor prognosis. Meningioma is the second most common primary brain tumour in adults, which is typically benign and arises from the arachnoid cap cells of the meninges. Vestibular schwannoma is a benign tumour arising from the eighth cranial nerve, while pilocytic astrocytoma is the most common primary brain tumour in children. Medulloblastoma is an aggressive paediatric brain tumour that arises within the infratentorial compartment, while ependymoma is commonly seen in the 4th ventricle and may cause hydrocephalus. Oligodendroma is a benign, slow-growing tumour common in the frontal lobes, while haemangioblastoma is a vascular tumour of the cerebellum. Pituitary adenoma is a benign tumour of the pituitary gland that can be either secretory or non-secretory, while craniopharyngioma is a solid/cystic tumour of the sellar region that is derived from the remnants of Rathke’s pouch.

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      • Neurological System
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  • Question 30 - A man in his early 40s comes to the clinic with facial weakness...

    Correct

    • A man in his early 40s comes to the clinic with facial weakness on one side, asymmetry, and ptosis. The physician is considering either Bell's palsy or an upper motor lesion. What would be the most significant clinical finding to suggest Bell's palsy?

      Your Answer: Loss of taste on the anterior 2/3 of the tongue, ear pain, and hyperacusis

      Explanation:

      Bell’s palsy is a clinical condition that occurs when the facial nerve (CX 7) is damaged. This nerve is responsible for gustation sensation on the anterior 2/3 of the tongue, providing sensation to an area of skin behind the ear, and innervating the stapedial muscles of the ear, which stabilizes the stapes bone and transmits sound vibrations to the inner ear. Therefore, damage to this nerve can cause these symptoms.

      Although risk factors for Bell’s palsy include diabetes and family history, it is an idiopathic condition that is diagnosed through exclusion. MRI is not useful in diagnosing this condition.

      Bell’s palsy is a sudden, one-sided facial nerve paralysis of unknown cause. It typically affects individuals between the ages of 20 and 40, and is more common in pregnant women. The condition is characterized by a lower motor neuron facial nerve palsy that affects the forehead, while sparing the upper face. Patients may also experience postauricular pain, altered taste, dry eyes, and hyperacusis.

      The management of Bell’s palsy has been a topic of debate, with various treatment options proposed in the past. However, there is now consensus that all patients should receive oral prednisolone within 72 hours of onset. The addition of antiviral medications is still a matter of discussion, with some experts recommending it for severe cases. Eye care is also crucial to prevent exposure keratopathy, and patients may need to use artificial tears and eye lubricants. If they are unable to close their eye at bedtime, they should tape it closed using microporous tape.

      Follow-up is essential for patients who show no improvement after three weeks, as they may require urgent referral to ENT. Those with more long-standing weakness may benefit from a referral to plastic surgery. The prognosis for Bell’s palsy is generally good, with most patients making a full recovery within three to four months. However, untreated cases can result in permanent moderate to severe weakness in around 15% of patients.

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      • Neurological System
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