-
Question 1
Correct
-
A 61-year-old male comes to the emergency department with sudden onset double vision. During the examination, you observe that his right eye is in a 'down and out' position. You suspect that he may be experiencing a third nerve palsy.
What is the most probable cause of this condition?Your Answer: Posterior communicating artery aneurysm
Explanation:A possible cause of the patient’s third nerve palsy is an aneurysm in the posterior communicating artery. However, diabetes insipidus is not related to this condition, while diabetes mellitus may be a contributing factor. Nystagmus is a common symptom of lateral medullary syndrome, while lateral pontine syndrome may cause facial paralysis and deafness on the same side of the body. A stroke in the middle cerebral artery can result in sensory loss and weakness on the opposite side of the body.
Understanding Third Nerve Palsy: Causes and Features
Third nerve palsy is a neurological condition that affects the third cranial nerve, which controls the movement of the eye and eyelid. The condition is characterized by the eye being deviated ‘down and out’, ptosis, and a dilated pupil. In some cases, it may be referred to as a ‘surgical’ third nerve palsy due to the dilation of the pupil.
There are several possible causes of third nerve palsy, including diabetes mellitus, vasculitis (such as temporal arteritis or SLE), uncal herniation through tentorium if raised ICP, posterior communicating artery aneurysm, and cavernous sinus thrombosis. In some cases, it may also be a false localizing sign. Weber’s syndrome, which is characterized by an ipsilateral third nerve palsy with contralateral hemiplegia, is caused by midbrain strokes. Other possible causes include amyloid and multiple sclerosis.
-
This question is part of the following fields:
- Neurological System
-
-
Question 2
Incorrect
-
A 7-year-old girl is brought to the child assessment unit by her father. She has been experiencing lower leg pain for over 3 weeks. He reports that she has been tripping more than usual but attributes it to her new carpet. Lately, she has been having difficulty getting out of bed and sometimes complains of feeling tired. The child appears to be in good health but has a runny nose. During the examination, she falls off the bed and lands on the floor. She uses her arms and legs to help herself up as she tries to stand.
What is the observed sign in this scenario?Your Answer: Horner's sign
Correct Answer: Gower's sign
Explanation:Children with Duchenne muscular dystrophy typically exhibit a positive Gower’s sign, which is due to weakness in the proximal muscles, particularly those in the lower limbs. This sign has a moderate sensitivity and high specificity. While idiopathic toe walking may also be present in DMD, it is more commonly associated with cerebral palsy and does not match the description in the given scenario. The Allis sign, also known as Galeazzi’s test, is utilized to evaluate for hip dislocation, primarily in cases of developmental dysplasia of the hip. Tinel’s sign is a method used to identify irritated nerves by tapping lightly over the nerve to elicit a sensation of tingling or ‘pins and needles’ in the nerve’s distribution.
Dystrophinopathies are a group of genetic disorders that are inherited in an X-linked recessive manner. These disorders are caused by mutations in the dystrophin gene located on the X chromosome at position Xp21. Dystrophin is a protein that is part of a larger membrane-associated complex in muscle cells. It connects the muscle membrane to actin, which is a component of the muscle cytoskeleton.
Duchenne muscular dystrophy is a severe form of dystrophinopathy that is caused by a frameshift mutation in the dystrophin gene. This mutation results in the loss of one or both binding sites, leading to progressive proximal muscle weakness that typically begins around the age of 5 years. Children with Duchenne muscular dystrophy may also exhibit calf pseudohypertrophy and Gower’s sign, which is when they use their arms to stand up from a squatted position. Approximately 30% of patients with Duchenne muscular dystrophy also have intellectual impairment.
In contrast, Becker muscular dystrophy is a milder form of dystrophinopathy that typically develops after the age of 10 years. It is caused by a non-frameshift insertion in the dystrophin gene, which preserves both binding sites. Intellectual impairment is much less common in individuals with Becker muscular dystrophy.
-
This question is part of the following fields:
- Neurological System
-
-
Question 3
Incorrect
-
A 79-year-old woman presents to the emergency department following a fall at home. Upon examination, it is evident that her left leg is externally rotated and shorter than her right, causing her significant discomfort. An x-ray confirms a fracture of the neck of the femur, and the orthopaedic team accepts her for surgical intervention.
After the procedure, the patient is assessed and found to have reduced sensation in the distal region of her left leg. While power is preserved proximally, there is a loss of dorsiflexion. Additionally, the plantar and ankle jerk reflexes are absent, while the knee jerk reflex is present. What condition do these findings suggest?Your Answer: Common peroneal nerve injury
Correct Answer: Sciatic nerve lesion
Explanation:The loss of ankle and plantar reflex, but intact knee jerk, suggests a sciatic nerve lesion, which could be a rare complication of a neck of femur fracture. An associated acetabular fracture is unlikely to cause such symptoms. Compartment syndrome is also less likely in this context, as it presents with different symptoms. While a common peroneal nerve injury may cause some of the symptoms, it is not the most likely cause in this case. Femoral nerve injury is possible but does not match the clinical features observed.
Understanding Sciatic Nerve Lesion
The sciatic nerve is a major nerve that is supplied by the L4-5, S1-3 vertebrae and divides into the tibial and common peroneal nerves. It is responsible for supplying the hamstring and adductor muscles. When the sciatic nerve is damaged, it can result in a range of symptoms that affect both motor and sensory functions.
Motor symptoms of sciatic nerve lesion include paralysis of knee flexion and all movements below the knee. Sensory symptoms include loss of sensation below the knee. Reflexes may also be affected, with ankle and plantar reflexes lost while the knee jerk reflex remains intact.
There are several causes of sciatic nerve lesion, including fractures of the neck of the femur, posterior hip dislocation, and trauma.
-
This question is part of the following fields:
- Neurological System
-
-
Question 4
Incorrect
-
Which one of the following nerves is the primary source of innervation to the anterior skin of the scrotum?
Your Answer: Pudendal nerve
Correct Answer: Ilioinguinal nerve
Explanation:The pudendal nerve innervates the posterior skin of the scrotum, while the ilioinguinal nerve primarily innervates the anterior scrotum. The genital branch of the genitofemoral nerve also provides some innervation.
Scrotal Sensation and Nerve Innervation
The scrotum is a sensitive area of the male body that is innervated by two main nerves: the ilioinguinal nerve and the pudendal nerve. The ilioinguinal nerve originates from the first lumbar vertebrae and passes through the internal oblique muscle before reaching the superficial inguinal ring. From there, it provides sensation to the anterior skin of the scrotum.
The pudendal nerve, on the other hand, is the primary nerve of the perineum. It arises from three nerve roots in the pelvis and passes through the greater and lesser sciatic foramina to enter the perineal region. Its perineal branches then divide into posterior scrotal branches, which supply the skin and fascia of the perineum. The pudendal nerve also communicates with the inferior rectal nerve.
Overall, the innervation of the scrotum is complex and involves multiple nerves. However, understanding the anatomy and function of these nerves is important for maintaining proper scrotal sensation and overall male health.
-
This question is part of the following fields:
- Neurological System
-
-
Question 5
Incorrect
-
An 8-year-old boy arrives at the emergency department complaining of weakness in his limbs, difficulty swallowing, and a general feeling of malaise. These symptoms began after he recently had an upper respiratory tract infection. Upon examination, it is noted that his neck muscles, as well as both his proximal and distal arm and leg muscles, are weak. Additionally, his tendon reflexes are reduced bilaterally in both his upper and lower limbs, but his sensation is only mildly affected. What is the most probable underlying condition causing these symptoms?
Your Answer: Poliomyelitis
Correct Answer: Acute inflammatory demyelinating polyneuropathy (Guillain-Barre syndrome)
Explanation:Guillain-Barre Syndrome: A Breakdown of its Features
Guillain-Barre syndrome is a condition that occurs when the immune system attacks the peripheral nervous system, resulting in demyelination. This is often triggered by an infection, with Campylobacter jejuni being a common culprit. In the initial stages of the illness, around 65% of patients experience back or leg pain. However, the characteristic feature of Guillain-Barre syndrome is progressive, symmetrical weakness of all limbs, with the legs being affected first in an ascending pattern. Reflexes are reduced or absent, and sensory symptoms tend to be mild. Other features may include a history of gastroenteritis, respiratory muscle weakness, cranial nerve involvement, diplopia, bilateral facial nerve palsy, oropharyngeal weakness, and autonomic involvement, which can lead to urinary retention and diarrhea. Less common findings may include papilloedema, which is thought to be secondary to reduced CSF resorption. To diagnose Guillain-Barre syndrome, a lumbar puncture may be performed, which can reveal a rise in protein with a normal white blood cell count (albuminocytologic dissociation) in 66% of cases. Nerve conduction studies may also be conducted, which can show decreased motor nerve conduction velocity due to demyelination, prolonged distal motor latency, and increased F wave latency.
-
This question is part of the following fields:
- Neurological System
-
-
Question 6
Correct
-
A 68-year-old male comes to the emergency department with hemiparesis. During your conversation with him, you discover that his speech is fluent but his repetition is poor. He is conscious of his inability to repeat words accurately but persists in trying. You suspect that a stroke may be the cause of this condition.
Which region of the brain has been impacted by the stroke?Your Answer: Arcuate fasciculus
Explanation:The patient is exhibiting symptoms of conduction aphasia, which is typically caused by a stroke that affects the arcuate fasciculus.
If the lesion is in the parietal lobe, the patient may experience sensory inattention and inferior homonymous quadrantanopia.
Lesions in the inferior frontal gyrus can cause speech to become non-fluent, labored, and halting.
Occipital lobe lesions can result in visual changes.
If the lesion is in the superior temporal gyrus, the patient may produce sentences that don’t make sense, use word substitution, and create neologisms, but their speech will still be fluent.
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
-
-
Question 7
Incorrect
-
Can you rephrase this inquiry and adjust the age a bit while maintaining the same paragraph format?
Your Answer: Tibialis anterior
Correct Answer: Flexor digitorum brevis
Explanation:The tibial nerve supplies the flexor digitorum.
The common peroneal nerve originates from the dorsal divisions of the sacral plexus, specifically from L4, L5, S1, and S2. This nerve provides sensation to the skin and fascia of the anterolateral surface of the leg and dorsum of the foot, as well as innervating the muscles of the anterior and peroneal compartments of the leg, extensor digitorum brevis, and the knee, ankle, and foot joints. It is located laterally within the sciatic nerve and passes through the lateral and proximal part of the popliteal fossa, under the cover of biceps femoris and its tendon, to reach the posterior aspect of the fibular head. The common peroneal nerve divides into the deep and superficial peroneal nerves at the point where it winds around the lateral surface of the neck of the fibula in the body of peroneus longus, approximately 2 cm distal to the apex of the head of the fibula. It is palpable posterior to the head of the fibula. The nerve has several branches, including the nerve to the short head of biceps, articular branch (knee), lateral cutaneous nerve of the calf, and superficial and deep peroneal nerves at the neck of the fibula.
-
This question is part of the following fields:
- Neurological System
-
-
Question 8
Correct
-
A 15-year-old boy comes to see his GP accompanied by his mother who is worried about his facial expressions. The boy has been experiencing difficulty using the muscles in his face for the past month. He also reports weakness in his arms, but no pain.
During the examination, the GP observes that the boy's facial muscles are weak, he struggles to puff out his cheeks, and has difficulty raising his arms in the classroom. Additionally, the boy has abnormally large gastrocnemius muscles and his scapulae are 'winged'.
Which nerve is responsible for innervating the muscle that prevents the scapulae from forming a 'winged' position?Your Answer: Long thoracic nerve
Explanation:The Serratus Anterior Muscle and its Innervation
The serratus anterior muscle is a muscle that originates from the first to eighth ribs and inserts along the entire medial border of the scapulae. Its main function is to protract the scapula, allowing for anteversion of the upper limb. This muscle is innervated by the long thoracic nerve, which receives innervation from roots C5-C7 of the brachial plexus.
Based on the patient’s clinical history, it is likely that they are suffering from muscular dystrophy, specifically facioscapulohumeral muscular dystrophy. The long thoracic nerve is solely responsible for innervating the serratus anterior muscle, making it a key factor in the diagnosis of this condition.
Other nerves of the brachial plexus include the axillary nerve, which mainly innervates the deltoid muscles and provides sensory innervation to the skin covering the deltoid muscle. The upper and lower subscapular nerves are branches of the posterior cord of the brachial plexus and provide motor innervation to the subscapularis muscle. The thoracodorsal nerve is also a branch of the posterior cord of the brachial plexus and provides motor innervation to the latissimus dorsi.
the innervation of the serratus anterior muscle and its relationship to other nerves of the brachial plexus is important in diagnosing and treating conditions that affect this muscle.
-
This question is part of the following fields:
- Neurological System
-
-
Question 9
Incorrect
-
A 35-year-old woman presents with a 2-month history of headaches and double vision. Her headaches are worse upon waking and when coughing or straining, and she has also experienced nausea and vomiting. She has a medical history of atrial fibrillation and takes apixaban.
During the examination, a right dilated, fixed pupil is observed, but her visual fields are intact. The rest of the examination is unremarkable.
Which cranial nerve is most likely affected in this case?Your Answer: Left CN III palsy
Correct Answer: Right CN III palsy
Explanation:The correct answer is right CNIII palsy. The patient is likely experiencing raised intracranial pressure, which commonly affects the parasympathetic fibers of the oculomotor nerve responsible for pupillary constriction. In this case, the right pupil is dilated and fixed, indicating that the right oculomotor nerve is affected. The oculomotor nerve also innervates all eye muscles except the superior oblique and lateral rectus muscles.
Left CNIII palsy is not the correct answer as it would present with different symptoms, including an abducted, laterally rotated, and depressed eye with ptosis of the upper eyelid. This is not observed in this patient’s examination. Additionally, in raised intracranial pressure, the parasympathetic fibers are affected first, so other clinical signs may not be present.
Left CNVI palsy is also not the correct answer as it would present with horizontal diplopia and defective abduction of the left eye due to the left lateral rectus muscle being affected. This is not observed in this patient’s examination.
Right CNII palsy is not the correct answer as it affects vision and would present with monocular blindness, which is not observed in this patient.
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
-
-
Question 10
Incorrect
-
A 55-year-old woman is involved in a car accident and is admitted to a neuro-rehabilitation ward for her recovery. During her cranial nerve examination, it is found that she has left-sided homonymous inferior quadrantanopia and difficulty reading. Her family reports that she can no longer read the newspaper or do sudokus, which she used to enjoy before the accident. Based on these symptoms, which area of the brain is likely to be damaged?
Your Answer:
Correct Answer: Parietal lobe
Explanation:Alexia may be caused by lesions in the parietal lobe.
This is because damage to the parietal lobe can result in various symptoms, including alexia, agraphia, acalculia, hemi-spatial neglect, and homonymous inferior quadrantanopia. Other possible symptoms may include loss of sensation, apraxias, or astereognosis.
The cerebellum is not the correct answer, as damage to this region can cause symptoms such as dysdiadochokinesia, ataxia, nystagmus, intention tremor, scanning dysarthria, and positive heel-shin test.
Similarly, the frontal lobe is not the correct answer, as damage to this region can result in anosmia, Broca’s dysphasia, changes in personality, and motor deficits.
The occipital lobe is also not the correct answer, as damage to this region can cause visual disturbances.
Brain lesions can be localized based on the neurological disorders or features that are present. The gross anatomy of the brain can provide clues to the location of the lesion. For example, lesions in the parietal lobe can result in sensory inattention, apraxias, astereognosis, inferior homonymous quadrantanopia, and Gerstmann’s syndrome. Lesions in the occipital lobe can cause homonymous hemianopia, cortical blindness, and visual agnosia. Temporal lobe lesions can result in Wernicke’s aphasia, superior homonymous quadrantanopia, auditory agnosia, and prosopagnosia. Lesions in the frontal lobes can cause expressive aphasia, disinhibition, perseveration, anosmia, and an inability to generate a list. Lesions in the cerebellum can result in gait and truncal ataxia, intention tremor, past pointing, dysdiadokinesis, and nystagmus.
In addition to the gross anatomy, specific areas of the brain can also provide clues to the location of a lesion. For example, lesions in the medial thalamus and mammillary bodies of the hypothalamus can result in Wernicke and Korsakoff syndrome. Lesions in the subthalamic nucleus of the basal ganglia can cause hemiballism, while lesions in the striatum (caudate nucleus) can result in Huntington chorea. Parkinson’s disease is associated with lesions in the substantia nigra of the basal ganglia, while lesions in the amygdala can cause Kluver-Bucy syndrome, which is characterized by hypersexuality, hyperorality, hyperphagia, and visual agnosia. By identifying these specific conditions, doctors can better localize brain lesions and provide appropriate treatment.
-
This question is part of the following fields:
- Neurological System
-
-
Question 11
Incorrect
-
A 50-year-old man with type 2 diabetes comes in for a regular eye check-up. He reports no issues with his vision. However, during the visual field test, there is a slight loss of peripheral vision in his left eye.
Upon dilation of the pupils, you observe that the cup-to-disc ratio is 0.6 in the right eye and 0.7 in the left eye. Apart from this, the examination is unremarkable. You decide to prescribe timolol.
What is the mechanism of action of timolol in treating the patient's condition?Your Answer:
Correct Answer: Reducing aqueous production
Explanation:Primary open-angle glaucoma is characterized by a gradual increase in intraocular pressure, which can lead to slight peripheral vision loss and a raised cup-to-disc ratio. The preferred initial treatment for this condition is timolol, a beta-blocker that works by reducing the production of fluid responsible for the pressure increase. Timolol is applied directly to the eye, with minimal systemic absorption that is unlikely to affect heart rate or blood pressure. It is important to note that beta blockers do not possess analgesic or anti-inflammatory properties.
Primary open-angle glaucoma is a type of optic neuropathy that is associated with increased intraocular pressure (IOP). It is classified based on whether the peripheral iris is covering the trabecular meshwork, which is important in the drainage of aqueous humour from the anterior chamber of the eye. In open-angle glaucoma, the iris is clear of the meshwork, but the trabecular network offers increased resistance to aqueous outflow, causing increased IOP. This condition affects 0.5% of people over the age of 40 and its prevalence increases with age up to 10% over the age of 80 years. Both males and females are equally affected. The main causes of primary open-angle glaucoma are increasing age and genetics, with first-degree relatives of an open-angle glaucoma patient having a 16% chance of developing the disease.
Primary open-angle glaucoma is characterised by a slow rise in intraocular pressure, which is symptomless for a long period. It is typically detected following an ocular pressure measurement during a routine examination by an optometrist. Signs of the condition include increased intraocular pressure, visual field defect, and pathological cupping of the optic disc. Case finding and provisional diagnosis are done by an optometrist, and referral to an ophthalmologist is done via the GP. Final diagnosis is made through investigations such as automated perimetry to assess visual field, slit lamp examination with pupil dilatation to assess optic nerve and fundus for a baseline, applanation tonometry to measure IOP, central corneal thickness measurement, and gonioscopy to assess peripheral anterior chamber configuration and depth. The risk of future visual impairment is assessed using risk factors such as IOP, central corneal thickness (CCT), family history, and life expectancy.
The majority of patients with primary open-angle glaucoma are managed with eye drops that aim to lower intraocular pressure and prevent progressive loss of visual field. According to NICE guidelines, the first line of treatment is a prostaglandin analogue (PGA) eyedrop, followed by a beta-blocker, carbonic anhydrase inhibitor, or sympathomimetic eyedrop as a second line of treatment. Surgery or laser treatment can be tried in more advanced cases. Reassessment is important to exclude progression and visual field loss and needs to be done more frequently if IOP is uncontrolled, the patient is high risk, or there
-
This question is part of the following fields:
- Neurological System
-
-
Question 12
Incorrect
-
A 45-year-old male patient presents with choreiform movements that he is unable to control or cease. During the consultation, you inquire about his family history and discover that his father experienced similar symptoms at a slightly later age. Based on this information, what genetic phenomenon is likely to have taken place between the patient and his father?
Your Answer:
Correct Answer: Anticipation
Explanation:Anticipation may be observed in Huntington’s disease due to its nature as a trinucleotide repeat disorder. The disease is caused by an autosomal dominant gene with CAG repeats in exon 1 of the Huntingtin gene. The number of CAG repeats is indicative of the severity of the disease, with individuals having 36 to 39 repeats potentially developing symptoms, while those with 40 or more repeats almost always develop the disorder. HD can occur in individuals with 36 to 120 CAG repeats.
Anticipation is observed as the number of CAG repeats increases between generations. Offspring of individuals with 27 to 35 CAG repeats are at risk of developing HD, even though the parent does not suffer from the disease. Additionally, higher numbers of CAG repeats tend to cause HD to manifest at earlier ages, resulting in younger generations being affected by the disease.
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
-
-
Question 13
Incorrect
-
A 50-year-old male visits the doctor with concerns about altered sensation in his legs. Upon examination, the doctor observes diminished vibration sensation in his legs, brisk knee reflexes, and absent ankle jerks. The doctor suspects that the patient may be suffering from subacute combined degeneration of the spinal cord.
What vitamin deficiency is commonly associated with this condition?Your Answer:
Correct Answer: Vitamin B12
Explanation:Subacute combined degeneration of the spinal cord, which typically presents with upper motor neuron signs in the legs, is caused by a deficiency in vitamin B12. Meanwhile, a deficiency in vitamin B1 (thiamine) leads to Wernicke’s encephalopathy, characterized by nystagmus, ophthalmoplegia, and ataxia. Peripheral neuropathy is a common result of vitamin B6 (pyridoxine) deficiency, while angular cheilitis is associated with a lack of vitamin B2 (riboflavin).
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
-
-
Question 14
Incorrect
-
A 67-year-old man is brought to the emergency department by his daughter with an onset of confusion, since waking up in the morning. She tells you that her father is not making any sense when he talks. There is no history of cognitive impairment or recent head injury. His past medical history includes type 2 diabetes, pancreatitis and recurrent urinary tract infections.
On examination, his observations are stable. His motor and sensory examination are unremarkable. He is able to talk in full sentences but his answers are incomprehensible. He cannot repeat spoken phrases.
What is the most likely diagnosis?Your Answer:
Correct Answer: Wernicke's aphasia
Explanation: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
-
-
Question 15
Incorrect
-
A 40-year-old woman with Down's syndrome visits her doctor accompanied by her caregiver. The doctor is informed that the woman's memory has been declining and it is now affecting her daily activities. Upon hearing their concerns, the doctor explains that individuals with Down's syndrome have a higher likelihood of developing a specific type of dementia compared to the general population.
What type of dementia is more common among individuals with Down's syndrome?Your Answer:
Correct Answer: Alzheimer's disease
Explanation:Trisomy 21, also known as Down’s syndrome, is associated with an increased risk of developing Alzheimer’s disease. This is because the amyloid precursor protein gene (APP) is located on chromosome 21, and individuals with trisomy 21 have three copies of this gene. APP is believed to play a significant role in the development of Alzheimer’s disease, and almost all people with Down’s syndrome will have amyloid plaques in their brain tissue by the age of 40. While there have been some case studies linking Down’s syndrome to other forms of dementia, such as dementia with Lewy bodies and frontotemporal dementia, the relationship is not as well established as it is with Alzheimer’s disease. There is no known association between Down’s syndrome and normal pressure hydrocephalus or vascular dementia.
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
-
-
Question 16
Incorrect
-
An 80-year-old woman is receiving end-of-life care after being diagnosed with terminal lung cancer. She has been experiencing increased pain over the last 2 weeks and has been prescribed a syringe driver with subcutaneous fentanyl to help manage her pain.
What is the benefit of using fentanyl instead of morphine in this situation?Your Answer:
Correct Answer: Fentanyl has a faster onset than morphine
Explanation:Fentanyl is a potent opioid that provides faster pain relief than morphine due to its higher lipophilicity, allowing it to quickly penetrate the central nervous system. However, it is important to note that both fentanyl and morphine can cause constipation and are highly addictive. Additionally, fentanyl is significantly more potent than morphine, with a potency of 80-100 times greater.
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
-
-
Question 17
Incorrect
-
A 37-year-old woman presents with blurring of vision on lateral gaze. She had a previous episode of pain on eye movement and difficulty seeing red colors six months ago, which resolved on its own after a week.
She sought consultation with a neurologist who conducted an examination. The left eye failed to adduct on rightward gaze, while the right eye exhibited nystagmus. Leftward, upward, and downward gazes were unremarkable. The pupils were equal and reactive to light.
Peripheral examination yielded no significant findings. An MRI brain scan was ordered, and the results are pending.
Based on this presentation, where is the most likely location of the lesion?Your Answer:
Correct Answer: Medial longitudinal fasciculus
Explanation:The patient’s symptoms suggest a diagnosis of multiple sclerosis, as she is presenting with internuclear ophthalmoplegia, which is caused by a lesion in the medial longitudinal fasciculus. This highly myelinated tract coordinates eye movements by communicating information from the vestibular nucleus to the oculomotor, trochlear, and abducens nuclei. Her previous episode of optic neuritis further supports a diagnosis of multiple sclerosis, which affects the axonal myelin sheath and commonly affects highly myelinated areas.
A lesion of the optic chiasm would present with bitemporal hemianopia or tunnel vision, without affecting eye movements. A lesion of the optic radiation would cause homonymous hemianopia or quadrantanopia, but eye movement control is confined to the brainstem nuclei. Periventricular lesions commonly cause numbness and impaired motor function, but do not involve cranial nerves. Lesions of the oculomotor nerve would cause a more significant ophthalmoplegia with ptosis and mydriasis in the affected eye, and the eye in the ‘down and out’ position, but this presentation does not fit the patient’s symptoms.
Understanding Internuclear Ophthalmoplegia
Internuclear ophthalmoplegia is a condition that affects the horizontal movement of the eyes. It is caused by a lesion in the medial longitudinal fasciculus (MLF), which is responsible for interconnecting the IIIrd, IVth, and VIth cranial nuclei. This area is located in the paramedian region of the midbrain and pons. The main feature of this condition is impaired adduction of the eye on the same side as the lesion, along with horizontal nystagmus of the abducting eye on the opposite side.
The most common causes of internuclear ophthalmoplegia are multiple sclerosis and vascular disease. It is important to note that this condition can also be a sign of other underlying neurological disorders.
-
This question is part of the following fields:
- Neurological System
-
-
Question 18
Incorrect
-
A 25-year-old climber sustains a humerus fracture and requires surgery. The surgeons opt for a posterior approach to the middle third of the bone. Which nerve is most vulnerable in this procedure?
Your Answer:
Correct Answer: Radial
Explanation:The humerus can cause damage to the radial nerve when approached from the back. To avoid the need for intricate bone exposure, an IM nail may be a better option.
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.
-
This question is part of the following fields:
- Neurological System
-
-
Question 19
Incorrect
-
A 67-year-old female presents to a medical facility with a chief complaint of tremors. Upon examination, the physician observes that the tremors are most noticeable when the patient is at rest. The patient does not display any specific neurological deficits, but does exhibit arm rigidity throughout the full range of motion and takes some time to initiate movements. Given the probable diagnosis, what histological finding would be anticipated?
Your Answer:
Correct Answer: Lewy bodies
Explanation:When a patient presents with tremor, rigidity, and bradykinesia, Parkinson’s Disease should be considered as a possible diagnosis. The presence of Lewy Bodies, which are clumps of proteins within neurons, is a characteristic histological finding. These bodies are often found in the substantia nigra and have a cytoplasm that is rich in eosin.
In males with Klinefelter syndrome, Barr bodies, which are inactivated X chromosomes, may be observed.
Cholesterol clefts are a result of cholesterol emboli, which occur when material from an atherosclerotic plaque becomes dislodged and deposited elsewhere. This can happen during procedures such as angiography.
Keratin pearls are a feature of squamous cell lung cancer, where squamous cells form concentric layers around keratin.
The term kidney bean-shaped nuclei refers to the appearance of neutrophils.
Parkinson’s disease is a progressive neurodegenerative disorder that occurs due to the degeneration of dopaminergic neurons in the substantia nigra. This leads to a classic triad of symptoms, including bradykinesia, tremor, and rigidity, which are typically asymmetrical. The disease is more common in men and is usually diagnosed around the age of 65. Bradykinesia is characterized by a poverty of movement, shuffling steps, and difficulty initiating movement. Tremors are most noticeable at rest and typically occur in the thumb and index finger. Rigidity can be either lead pipe or cogwheel, and other features include mask-like facies, flexed posture, and drooling of saliva. Psychiatric features such as depression, dementia, and sleep disturbances may also occur. Diagnosis is usually clinical, but if there is difficulty differentiating between essential tremor and Parkinson’s disease, 123I‑FP‑CIT single photon emission computed tomography (SPECT) may be considered.
-
This question is part of the following fields:
- Neurological System
-
-
Question 20
Incorrect
-
A 48-year-old woman visits the neurology clinic for a follow-up on her long-standing generalized epilepsy. She has been experiencing seizures since childhood and has tried various medications to manage the condition. Among these medications, she believes that carbamazepine has been the most effective.
What is the mechanism of action of carbamazepine?Your Answer:
Correct Answer: Inhibits sodium channels
Explanation:Sodium valproate and carbamazepine are both inhibitors of sodium channels, which leads to the suppression of excitation by preventing repetitive and sustained firing of an action potential. Additionally, sodium valproate increases levels of GABA in the brain.
Tiagabine, on the other hand, blocks the cellular uptake of GABA by inhibiting the GABA transporter, making it a GABA reuptake inhibitor.
Ethosuximide blocks T-type calcium channels and is primarily used to treat absence seizures, while benzodiazepines elongate the opening time of GABAA receptors. Barbiturates, on the other hand, act as agonists of GABAA receptors and potentiate the effect of GABA.
Treatment Options for Epilepsy
Epilepsy is a neurological disorder that affects millions of people worldwide. Treatment for epilepsy typically involves the use of antiepileptic drugs (AEDs) to control seizures. The decision to start AEDs is usually made after a second seizure, but there are certain circumstances where treatment may be initiated after the first seizure. These include the presence of a neurological deficit, structural abnormalities on brain imaging, unequivocal epileptic activity on EEG, or if the patient or their family considers the risk of having another seizure to be unacceptable.
It is important to note that there are specific drug treatments for different types of seizures. For generalized tonic-clonic seizures, males are typically prescribed sodium valproate, while females may be given lamotrigine or levetiracetam. For focal seizures, first-line treatment options include lamotrigine or levetiracetam, with carbamazepine, oxcarbazepine, or zonisamide used as second-line options. Ethosuximide is the first-line treatment for absence seizures, with sodium valproate or lamotrigine/levetiracetam used as second-line options. For myoclonic seizures, males are usually given sodium valproate, while females may be prescribed levetiracetam. Finally, for tonic or atonic seizures, males are typically given sodium valproate, while females may be prescribed lamotrigine.
It is important to work closely with a healthcare provider to determine the best treatment plan for each individual with epilepsy. Additionally, it is important to be aware of potential risks associated with certain AEDs, such as the use of sodium valproate during pregnancy, which has been linked to neurodevelopmental delays in children.
-
This question is part of the following fields:
- Neurological System
-
-
Question 21
Incorrect
-
A 28-year-old woman presents to the emergency department with a suspected heroin overdose. Her Glasgow Coma Scale (GCS) score is 9, with only eye opening to trapezial squeeze and incoherent speech with inappropriate words. During her evaluation, the physician orders an arterial blood gas test.
What are the expected arterial blood gas results in this situation?Your Answer:
Correct Answer: Uncompensated respiratory acidosis
Explanation:Respiratory acidosis can occur as a result of opioid overdose due to the depression of the central nervous system, which leads to a reduction in respiratory rate. This causes an accumulation of carbon dioxide in the blood, resulting in the formation of carbonic acid and a subsequent decrease in blood pH.
It is unlikely that the respiratory acidosis in an acute opioid overdose would be compensated by the kidneys within the short time frame. Therefore, a normal arterial blood gas (ABG) result would be incorrect.
Partially compensated respiratory acidosis is also unlikely in this case, as the patient’s respiratory acidosis is unlikely to have been compensated at this stage.
However, partially compensated respiratory alkalosis may occur if the patient has an increased respiratory rate. This leads to a decrease in carbon dioxide levels in the blood, resulting in an alkalotic state. Over time, the bicarbonate levels in the blood will decrease to correct the pH.
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
-
-
Question 22
Incorrect
-
At what stage does the sciatic nerve typically divide into the tibial and common peroneal nerves?
Your Answer:
Correct Answer: At the superior aspect of the popliteal fossa
Explanation:The path of the sciatic nerve begins at the posterior surface of the obturator internus and quadratus femoris, where it descends vertically towards the hamstring compartment of the thigh. As it reaches this area, it is crossed by the long head of biceps femoris. Moving towards the buttock, the nerve is covered by the gluteus maximus. Finally, it splits into its tibial and common peroneal components at the upper part of the popliteal fossa.
Understanding the Sciatic Nerve
The sciatic nerve is the largest nerve in the body, formed from the sacral plexus and arising from spinal nerves L4 to S3. It passes through the greater sciatic foramen and emerges beneath the piriformis muscle, running under the cover of the gluteus maximus muscle. The nerve provides cutaneous sensation to the skin of the foot and leg, as well as innervating the posterior thigh muscles and lower leg and foot muscles. Approximately halfway down the posterior thigh, the nerve splits into the tibial and common peroneal nerves. The tibial nerve supplies the flexor muscles, while the common peroneal nerve supplies the extensor and abductor muscles.
The sciatic nerve also has articular branches for the hip joint and muscular branches in the upper leg, including the semitendinosus, semimembranosus, biceps femoris, and part of the adductor magnus. Cutaneous sensation is provided to the posterior aspect of the thigh via cutaneous nerves, as well as the gluteal region and entire lower leg (except the medial aspect). The nerve terminates at the upper part of the popliteal fossa by dividing into the tibial and peroneal nerves. The nerve to the short head of the biceps femoris comes from the common peroneal part of the sciatic, while the other muscular branches arise from the tibial portion. The tibial nerve goes on to innervate all muscles of the foot except the extensor digitorum brevis, which is innervated by the common peroneal nerve.
-
This question is part of the following fields:
- Neurological System
-
-
Question 23
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:
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
-
-
Question 24
Incorrect
-
During a clinical examination of a 26-year-old woman with a history of relapsing-remitting multiple sclerosis, you observe nystagmus of the left eye and significant weakness in adduction of the right eye when she looks to the left. What is the location of the lesion responsible for these findings?
Your Answer:
Correct Answer: Midbrain
Explanation:The medial longitudinal fasciculus is situated in the paramedian region of the midbrain and pons.
The patient’s symptoms are indicative of internuclear ophthalmoplegia (INO), a specific gaze abnormality characterized by impaired adduction of the eye on the affected side and nystagmus of the eye on the opposite side of the lesion. Based on the symptoms, the lesion is likely on the right side. INO is caused by damage to the medial longitudinal fasciculus, which coordinates the simultaneous lateral movements of both eyes. Multiple sclerosis is a common cause of this condition, but cerebrovascular disease is also associated with it, especially in older patients.
Optic neuritis, a common manifestation of multiple sclerosis, is not responsible for the patient’s symptoms. Optic neuritis typically presents with eye pain, visual acuity loss, and worsened pain on eye movement, which are not mentioned in the scenario.
Distinguishing between internuclear ophthalmoplegia and oculomotor (third) nerve palsy can be challenging. Symptoms that suggest CN III palsy include ptosis, pupil dilation, and weakness of elevation, which causes the eye to rest in a ‘down and out’ position. Clinical examination findings can help differentiate between trochlear or abducens nerve palsy and internuclear ophthalmoplegia. Abducens nerve damage results in unilateral weakness of the lateral rectus muscle and impaired abduction on the affected side, while trochlear nerve damage leads to unilateral weakness of the superior oblique muscle and impaired intorsion and depression when adducted.
Understanding Internuclear Ophthalmoplegia
Internuclear ophthalmoplegia is a condition that affects the horizontal movement of the eyes. It is caused by a lesion in the medial longitudinal fasciculus (MLF), which is responsible for interconnecting the IIIrd, IVth, and VIth cranial nuclei. This area is located in the paramedian region of the midbrain and pons. The main feature of this condition is impaired adduction of the eye on the same side as the lesion, along with horizontal nystagmus of the abducting eye on the opposite side.
The most common causes of internuclear ophthalmoplegia are multiple sclerosis and vascular disease. It is important to note that this condition can also be a sign of other underlying neurological disorders.
-
This question is part of the following fields:
- Neurological System
-
-
Question 25
Incorrect
-
A 32-year-old man is brought to the emergency department by the paramedics. His airway is clear, and he is not experiencing any respiratory or cardiac distress. He states that he was hit by a vehicle while crossing the street.
During the examination, there is significant swelling in his knee and leg, and he has lost sensation in the plantar area of his foot. He cannot plantarflex his foot and has also lost foot inversion.
Which nerve is most likely to have been damaged?Your Answer:
Correct Answer: Tibial nerve
Explanation:When the tibial nerve is injured, the foot loses its ability to plantarflex and invert. Other nerve injuries can result in loss of sensation or motor function in specific muscles, such as the saphenous nerve causing loss of sensation in the medial leg or the femoral nerve causing loss of hip flexion and knee extension. The inferior gluteal nerve injury can lead to gluteal lurch and loss of hip extension.
The Tibial Nerve: Muscles Innervated and Termination
The tibial nerve is a branch of the sciatic nerve that begins at the upper border of the popliteal fossa. It has root values of L4, L5, S1, S2, and S3. This nerve innervates several muscles, including the popliteus, gastrocnemius, soleus, plantaris, tibialis posterior, flexor hallucis longus, and flexor digitorum brevis. These muscles are responsible for various movements in the lower leg and foot, such as plantar flexion, inversion, and flexion of the toes.
The tibial nerve terminates by dividing into the medial and lateral plantar nerves. These nerves continue to innervate muscles in the foot, such as the abductor hallucis, flexor digitorum brevis, and quadratus plantae. The tibial nerve plays a crucial role in the movement and function of the lower leg and foot, and any damage or injury to this nerve can result in significant impairments in mobility and sensation.
-
This question is part of the following fields:
- Neurological System
-
-
Question 26
Incorrect
-
A 54-year-old man comes to the eye emergency department with painless vision loss in his left eye since waking up this morning. He has a medical history of hypertension and diabetes, and is currently taking ramipril and metformin. Upon examination, the patient has decreased visual acuity in his left eye. The doctor suspects that atherosclerotic changes have caused blockage of the short posterior ciliary arteries.
What clinical findings would indicate this diagnosis?Your Answer:
Correct Answer: Relative afferent pupil defect (RAPD)
Explanation:Painless monocular loss of vision and RAPD can be caused by occlusion of the short posterior ciliary arteries.
Non-arteritic anterior ischaemic optic neuropathy is more likely to occur in males aged 40-60 with hypertension, diabetes, and arteriopathy.
Giant cell arteritis should be suspected in patients with jaw claudication and weight loss.
A down and out palsy is a symptom of oculomotor nerve palsy, not optic neuropathy.
Sudden loss of vision can be a scary symptom for patients, but it can be caused by a variety of factors. Transient monocular visual loss (TMVL) is a term used to describe a sudden, temporary loss of vision that lasts less than 24 hours. The most common causes of sudden painless loss of vision include ischaemic/vascular issues, vitreous haemorrhage, retinal detachment, and retinal migraine.
Ischaemic/vascular issues, also known as ‘amaurosis fugax’, can be caused by a wide range of factors such as thrombosis, embolism, temporal arteritis, and hypoperfusion. It may also represent a form of transient ischaemic attack (TIA) and should be treated similarly with aspirin 300mg. Altitudinal field defects are often seen, and ischaemic optic neuropathy can occur due to occlusion of the short posterior ciliary arteries.
Central retinal vein occlusion is more common than arterial occlusion and can be caused by glaucoma, polycythaemia, and hypertension. Severe retinal haemorrhages are usually seen on fundoscopy. Central retinal artery occlusion, on the other hand, is due to thromboembolism or arteritis and features include afferent pupillary defect and a ‘cherry red’ spot on a pale retina.
Vitreous haemorrhage can be caused by diabetes, bleeding disorders, and anticoagulants. Features may include sudden visual loss and dark spots. Retinal detachment may be preceded by flashes of light or floaters, which are also symptoms of posterior vitreous detachment. Differentiating between these conditions can be done by observing the specific symptoms such as a veil or curtain over the field of vision, straight lines appearing curved, and central visual loss. Large bleeds can cause sudden visual loss, while small bleeds may cause floaters.
-
This question is part of the following fields:
- Neurological System
-
-
Question 27
Incorrect
-
A 32-year-old man is assaulted and stabbed in the upper abdomen. Upon arrival at the emergency department, he reports experiencing pain on the left side of his abdomen and has reduced breath sounds on the same side. Imaging studies reveal a diaphragmatic rupture. What is the level at which the inferior vena cava passes through the diaphragm?
Your Answer:
Correct Answer: T8
Explanation:The diaphragm’s opening for the inferior vena cava is situated at T8 level, while the opening for the oesophagus is at T10 level.
Anatomical Planes and Levels in the Human Body
The human body can be divided into different planes and levels to aid in anatomical study and medical procedures. One such plane is the transpyloric plane, which runs horizontally through the body of L1 and intersects with various organs such as the pylorus of the stomach, left kidney hilum, and duodenojejunal flexure. Another way to identify planes is by using common level landmarks, such as the inferior mesenteric artery at L3 or the formation of the IVC at L5.
In addition to planes and levels, there are also diaphragm apertures located at specific levels in the body. These include the vena cava at T8, the esophagus at T10, and the aortic hiatus at T12. By understanding these planes, levels, and apertures, medical professionals can better navigate the human body during procedures and accurately diagnose and treat various conditions.
-
This question is part of the following fields:
- Neurological System
-
-
Question 28
Incorrect
-
A 45-year-old man is brought to the ED by his spouse, who suspects he had a stroke. The man is exhibiting signs of slurred speech and disorientation to time and space, but there is no limb weakness.
According to collateral history, the man has a history of epilepsy, although he has not had a seizure in several months. He does not smoke and did not consume any alcohol or drugs before coming to the ED. A CT scan is normal, and a focal seizure is suspected as the cause of his symptoms.
Which part of the brain is likely affected?Your Answer:
Correct Answer: Temporal lobe
Explanation:Localising features of a temporal lobe seizure include postictal dysphasia and lip smacking.
Localising Features of Focal Seizures in Epilepsy
Focal seizures in epilepsy can be localised based on the specific location of the brain where they occur. Temporal lobe seizures are common and may occur with or without impairment of consciousness or awareness. Most patients experience an aura, which is typically a rising epigastric sensation, along with psychic or experiential phenomena such as déjà vu or jamais vu. Less commonly, hallucinations may occur, such as auditory, gustatory, or olfactory hallucinations. These seizures typically last around one minute and are often accompanied by automatisms, such as lip smacking, grabbing, or plucking.
On the other hand, frontal lobe seizures are characterised by motor symptoms such as head or leg movements, posturing, postictal weakness, and Jacksonian march. Parietal lobe seizures, on the other hand, are sensory in nature and may cause paraesthesia. Finally, occipital lobe seizures may cause visual symptoms such as floaters or flashes. By identifying the specific location and type of seizure, doctors can better diagnose and treat epilepsy in patients.
-
This question is part of the following fields:
- Neurological System
-
-
Question 29
Incorrect
-
A 45-year-old man visits his GP complaining of weakness in his right hand that has been ongoing for 2 months. He reports difficulty gripping objects and writing with his right hand. He denies any changes in sensation. The patient has a history of rheumatoid arthritis.
During the examination, there are no apparent signs of muscle wasting or fasciculation in the right hand. However, the patient is unable to form an 'OK sign' with his right thumb and index finger upon request.
Which nerve is the most likely culprit?Your Answer:
Correct Answer: Anterior interosseous nerve
Explanation:The anterior interosseous nerve can be compressed between the heads of pronator teres, leading to an inability to perform a pincer grip with the thumb and index finger (known as the ‘OK sign’).
The correct answer is the anterior interosseous nerve, which is a branch of the median nerve responsible for innervating pronator quadratus, flexor pollicis longus, and flexor digitorum profundus. Damage to this nerve, such as through compression by pronator teres, can result in the inability to perform a pincer grip. Patients with rheumatoid arthritis may be more susceptible to anterior interosseous nerve entrapment.
The dorsal digital nerve is a sensory branch of the ulnar nerve and does not cause motor deficits.
The palmar cutaneous nerve is a sensory branch of the median nerve that provides sensation to the palm of the hand.
The posterior interosseus nerve supplies muscles in the posterior compartment of the forearm with C7 and C8 fibers. Lesions of this nerve cause pure-motor neuropathy, resulting in finger drop and radial wrist deviation during extension.
Patients with ulnar nerve lesions can still perform a pincer grip with the thumb and index finger. Ulnar nerve lesions may cause paraesthesia in the fifth finger and hypothenar aspect of the palm.
The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the front of the forearm, excluding the ulnar half of the flexor digitorum profundus. It runs alongside the anterior interosseous artery along the anterior of the interosseous membrane of the forearm, between the flexor pollicis longus and flexor digitorum profundus. The nerve supplies the whole of the flexor pollicis longus and the radial half of the flexor digitorum profundus, and ends below in the pronator quadratus and wrist joint. The anterior interosseous nerve innervates 2.5 muscles, namely the flexor pollicis longus, pronator quadratus, and the radial half of the flexor digitorum profundus. These muscles are located in the deep level of the anterior compartment of the forearm.
-
This question is part of the following fields:
- Neurological System
-
-
Question 30
Incorrect
-
Which of the following is accountable for the production and discharge of calcitonin?
Your Answer:
Correct Answer: Thyroid gland
Explanation:The thyroid gland releases calcitonin, which has an opposing effect to PTH.
Maintaining Calcium Balance in the Body
Calcium ions are essential for various physiological processes in the body, and the largest store of calcium is found in the skeleton. The levels of calcium in the body are regulated by three hormones: parathyroid hormone (PTH), vitamin D, and calcitonin.
PTH increases calcium levels and decreases phosphate levels by increasing bone resorption and activating osteoclasts. It also stimulates osteoblasts to produce a protein signaling molecule that activates osteoclasts, leading to bone resorption. PTH increases renal tubular reabsorption of calcium and the synthesis of 1,25(OH)2D (active form of vitamin D) in the kidney, which increases bowel absorption of calcium. Additionally, PTH decreases renal phosphate reabsorption.
Vitamin D, specifically the active form 1,25-dihydroxycholecalciferol, increases plasma calcium and plasma phosphate levels. It increases renal tubular reabsorption and gut absorption of calcium, as well as osteoclastic activity. Vitamin D also increases renal phosphate reabsorption in the proximal tubule.
Calcitonin, secreted by C cells of the thyroid, inhibits osteoclast activity and renal tubular absorption of calcium.
Although growth hormone and thyroxine play a small role in calcium metabolism, the primary regulation of calcium levels in the body is through PTH, vitamin D, and calcitonin. Maintaining proper calcium balance is crucial for overall health and well-being.
-
This question is part of the following fields:
- Neurological System
-
00
Correct
00
Incorrect
00
:
00
:
00
Session Time
00
:
00
Average Question Time (
Secs)