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  • Question 1 - A 65-year-old man has recently undergone parotidectomy on his left side due to...

    Incorrect

    • A 65-year-old man has recently undergone parotidectomy on his left side due to a malignant parotid gland tumor. He has been back on the surgical ward for a few hours when he reports feeling weakness on the left side of his mouth. Upon examination, you observe facial asymmetry and weakness on the left side. He is unable to hold air under pressure in his mouth and cannot raise his left lip to show his teeth. This complication is likely due to damage to which nerve?

      Your Answer: Mandibular nerve

      Correct Answer: Facial nerve

      Explanation:

      The facial nerve is the seventh cranial nerve and innervates the muscles of facial expression. It runs through the parotid gland and can be injured during parotidectomy. The maxillary nerve is the second division of the trigeminal nerve and carries sensory fibres from the lower eyelid, cheeks, upper teeth, palate, nasal cavity, and paranasal sinuses. The glossopharyngeal nerve is the ninth cranial nerve and has various functions, including carrying taste and sensation from the posterior third of the tongue and supplying parasympathetic innervation to the parotid gland. The mandibular nerve is the third division of the trigeminal nerve and carries sensory and motor fibres, supplying motor innervation to the muscles of mastication. The hypoglossal nerve is the twelfth cranial nerve and supplies the intrinsic muscles of the tongue.

      The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron issues like Bell’s palsy and upper motor neuron issues like stroke.

      The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve’s path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.

    • This question is part of the following fields:

      • Neurological System
      18.7
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  • Question 2 - A 65-year-old woman with chronic kidney disease visits the renal clinic for a...

    Correct

    • A 65-year-old woman with chronic kidney disease visits the renal clinic for a routine examination. Her blood work reveals hypocalcemia and elevated levels of parathyroid hormone.

      What could be the probable reason for her abnormal blood test results?

      Your Answer: Decreased levels of 1,25-dihydroxycholecalciferol (calcitriol, activated vitamin D)

      Explanation:

      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
      23.8
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  • Question 3 - An 80-year-old woman arrives at the emergency department complaining of a severe headache...

    Correct

    • An 80-year-old woman arrives at the emergency department complaining of a severe headache that has persisted for 12 hours. She describes the onset of the headache as sudden and the most intense she has ever experienced. The pain is primarily located at the back of her head, and she denies any history of trauma. Upon examination, she shows no neurological deficits or other symptoms.

      The patient has a history of hypertension, which is being managed with amlodipine, but is otherwise healthy. This is the first time she has experienced a headache of this nature.

      What is the probable underlying diagnosis?

      Your Answer: Subarachnoid haemorrhage

      Explanation:

      The sudden onset of an occipital headache in a 78-year-old patient is a cause for concern, as it may indicate a subarachnoid haemorrhage. This condition occurs when there is bleeding in the space between the arachnoid mater and the pia mater, often due to a ruptured berry aneurysm. Patients typically describe a sudden, severe headache, and risk factors include hypertension, smoking, and autosomal dominant polycystic kidney disease. Urgent investigation with a CT scan is necessary, and treatment may involve medical management and surgical intervention. Acute ischaemic stroke, extradural haemorrhage, and occipital migraine are less likely diagnoses in this scenario.

      There are different types of traumatic brain injury, including focal (contusion/haematoma) or diffuse (diffuse axonal injury). Diffuse axonal injury occurs due to mechanical shearing following deceleration, causing disruption and tearing of axons. Intracranial haematomas can be extradural, subdural or intracerebral, while contusions may occur adjacent to (coup) or contralateral (contre-coup) to the side of impact. Secondary brain injury occurs when cerebral oedema, ischaemia, infection, tonsillar or tentorial herniation exacerbates the original injury.

    • This question is part of the following fields:

      • Neurological System
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  • Question 4 - A 55-year-old man comes in with hyperacousia on one side. What is the...

    Incorrect

    • A 55-year-old man comes in with hyperacousia on one side. What is the most probable location of the nerve lesion?

      Your Answer: Vestibulocochlear

      Correct Answer: Facial

      Explanation:

      If the nerve in the bony canal is damaged, it can lead to a loss of innervation to the stapedius muscle, which can result in sounds not being properly muted.

      The Facial Nerve: Functions and Pathways

      The facial nerve is a crucial nerve that supplies the structures of the second embryonic branchial arch. It is primarily responsible for controlling the muscles of facial expression, the digastric muscle, and various glandular structures. Additionally, it contains a few afferent fibers that originate in the cells of its genicular ganglion and are involved in taste sensation.

      The facial nerve has four main functions, which can be remembered by the mnemonic face, ear, taste, tear. It supplies the muscles of facial expression, the nerve to the stapedius muscle in the ear, taste sensation to the anterior two-thirds of the tongue, and parasympathetic fibers to the lacrimal and salivary glands.

      The facial nerve’s path begins in the pons, where its motor and sensory components originate. It then passes through the petrous temporal bone into the internal auditory meatus, where it combines with the vestibulocochlear nerve. From there, it enters the facial canal, which passes superior to the vestibule of the inner ear and contains the geniculate ganglion. The canal then widens at the medial aspect of the middle ear and gives rise to three branches: the greater petrosal nerve, the nerve to the stapedius, and the chorda tympani.

      Finally, the facial nerve exits the skull through the stylomastoid foramen, passing through the tympanic cavity anteriorly and the mastoid antrum posteriorly. It then enters the parotid gland and divides into five branches: the temporal, zygomatic, buccal, marginal mandibular, and cervical branches. Understanding the functions and pathways of the facial nerve is essential for diagnosing and treating various neurological and otolaryngological conditions.

    • This question is part of the following fields:

      • Neurological System
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  • Question 5 - A 45-year-old woman presents to the clinic with a history of multiple minor...

    Correct

    • 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: 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.

    • This question is part of the following fields:

      • Neurological System
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  • Question 6 - A 78-year-old woman with a history of neurosarcoidosis treated with steroids visits her...

    Correct

    • A 78-year-old woman with a history of neurosarcoidosis treated with steroids visits her GP complaining of intense facial pain. The pain lasts only a few seconds but is unbearable and worsens with exposure to cold air and touch.

      Upon examination, there are no focal neurological signs. However, a few minutes after the examination, she experiences severe pain on her right cheek, which she describes as always being over her right zygoma.

      Through which opening in the skull does the affected cranial nerve pass?

      Your Answer: Foramen rotundum

      Explanation:

      The correct answer is Foramen rotundum, as the maxillary nerve passes through this foramen to exit the skull. This nerve is responsible for the sensory innervation of the upper teeth, gums, and palate. The patient’s trigeminal neuralgia is caused by irritation of the right-sided maxillary nerve.

      Cribriform plate is not the correct answer, as this area of the skull is where the olfactory nerve passes through to enable the sense of smell.

      Foramen ovale is also not the correct answer, as this foramen is where the mandibular nerve exits the skull to provide sensation to the lower face.

      Jugular foramen is not the correct answer, as this foramen is where the accessory nerve passes through to innervate the sternocleidomastoid and trapezius muscles.

      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
      27.7
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  • Question 7 - A 76-year-old man is being discharged from the geriatric ward. He was admitted...

    Incorrect

    • A 76-year-old man is being discharged from the geriatric ward. He was admitted last week for the investigation of recurrent falls. He has a medical history of Parkinson's disease, atrial fibrillation and rheumatoid arthritis.

      The interdisciplinary team has decided to send him home this evening. The doctor in charge of organising his discharge goes through his drug chart to identify any drugs that may be making him more susceptible to having recurrent falls.

      What medication from his drug chart could be contributing to his increased risk of falls?

      Your Answer: Entacapone

      Correct Answer: Selegiline (monoamine oxidase-B inhibitor)

      Explanation:

      The use of monoamine oxidase-B (MAO-B) inhibitors like selegiline may lead to postural hypotension, which can increase the risk of falls, particularly in older individuals. However, fludrocortisone can be utilized to manage postural hypotension that does not respond to conservative treatments, without an associated risk of falls.

      Understanding the Mechanism of Action of Parkinson’s Drugs

      Parkinson’s disease is a complex condition that requires specialized management. The first-line treatment for motor symptoms that affect a patient’s quality of life is levodopa, while dopamine agonists, levodopa, or monoamine oxidase B (MAO-B) inhibitors are recommended for those whose motor symptoms do not affect their quality of life. However, all drugs used to treat Parkinson’s can cause a wide variety of side effects, and it is important to be aware of these when making treatment decisions.

      Levodopa is nearly always combined with a decarboxylase inhibitor to prevent the peripheral metabolism of levodopa to dopamine outside of the brain and reduce side effects. Dopamine receptor agonists, such as bromocriptine, ropinirole, cabergoline, and apomorphine, are more likely than levodopa to cause hallucinations in older patients. MAO-B inhibitors, such as selegiline, inhibit the breakdown of dopamine secreted by the dopaminergic neurons. Amantadine’s mechanism is not fully understood, but it probably increases dopamine release and inhibits its uptake at dopaminergic synapses. COMT inhibitors, such as entacapone and tolcapone, are used in conjunction with levodopa in patients with established PD. Antimuscarinics, such as procyclidine, benzotropine, and trihexyphenidyl (benzhexol), block cholinergic receptors and are now used more to treat drug-induced parkinsonism rather than idiopathic Parkinson’s disease.

      It is important to note that all drugs used to treat Parkinson’s can cause adverse effects, and clinicians must be aware of these when making treatment decisions. Patients should also be warned about the potential for dopamine receptor agonists to cause impulse control disorders and excessive daytime somnolence. Understanding the mechanism of action of Parkinson’s drugs is crucial in managing the condition effectively.

    • This question is part of the following fields:

      • Neurological System
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  • Question 8 - A 72-year-old male visits the neurology clinic with a complaint of experiencing difficulty...

    Incorrect

    • A 72-year-old male visits the neurology clinic with a complaint of experiencing difficulty in walking over the last three months. During the clinical examination, you conduct the finger-to-nose test and observe that he has a tremor that intensifies as his finger approaches his nose.

      Which part of the brain is the most probable site of damage?

      Your Answer: Basal ganglia

      Correct Answer: Cerebellum

      Explanation:

      An intention tremor can be caused by cerebellar disease, which is evident in this patient’s presentation. Other symptoms associated with cerebellar disease include ataxia and dysdiadochokinesia.

      Resting tremors are more commonly associated with basal ganglia dysfunction.

      Alzheimer’s disease is linked to lesions in the hippocampus.

      Kluver-Bucy syndrome, characterized by hypersexuality, hyperorality, and visual agnosia, is more likely to occur when the amygdala is affected.

      Wernicke and Korsakoff syndrome, which presents with nystagmus, ataxia, ophthalmoplegia, amnesia, and confabulation, is more likely to occur when the hypothalamus is affected.

      Tremor: Causes and Characteristics

      Tremor is a common neurological symptom that can be caused by various conditions. The table below lists the main characteristics of the most important causes of tremor. Parkinsonism is characterized by a resting, ‘pill-rolling’ tremor, bradykinesia, rigidity, flexed posture, short, shuffling steps, micrographia, ‘mask-like’ face, and common depression and dementia. Essential tremor is a postural tremor that worsens if arms are outstretched, but improves with alcohol and rest, and often has a strong family history. Anxiety is often associated with a history of depression, while thyrotoxicosis is characterized by usual thyroid signs such as weight loss, tachycardia, and feeling hot. Hepatic encephalopathy is associated with a history of chronic liver disease, while carbon dioxide retention is associated with a history of chronic obstructive pulmonary disease. Cerebellar disease is characterized by an intention tremor and cerebellar signs such as past-pointing and nystagmus. Other causes of tremor include drug withdrawal from alcohol and opiates. Understanding the characteristics of different types of tremor can help in the diagnosis and management of patients with this symptom.

    • This question is part of the following fields:

      • Neurological System
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  • Question 9 - A 75-year-old woman is involved in a car accident resulting in a complex...

    Incorrect

    • A 75-year-old woman is involved in a car accident resulting in a complex fracture of the distal part of her humerus and damage to the radial nerve. Which movement is likely to be the most affected?

      Your Answer: None of the above

      Correct Answer: Wrist extension

      Explanation:

      Elbow extension will remain unaffected as the triceps are not impacted. However, the most noticeable consequence will be the loss of wrist extension.

      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
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  • Question 10 - Which one of the following is not a direct branch of the facial...

    Incorrect

    • Which one of the following is not a direct branch of the facial nerve?

      Your Answer: Greater petrosal nerve

      Correct Answer: Auriculotemporal

      Explanation:

      The mandibular nerve gives rise to several branches, including the auriculotemporal nerve, lingual nerve, inferior alveolar nerve, nerve to the mylohyoid, and mental nerve.

      The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron issues like Bell’s palsy and upper motor neuron issues like stroke.

      The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve’s path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.

    • This question is part of the following fields:

      • Neurological System
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  • Question 11 - A 48-year-old man arrives at the Emergency Department with facial drooping and slurred...

    Correct

    • A 48-year-old man arrives at the Emergency Department with facial drooping and slurred speech. You perform a cranial nerves examination and find that his glossopharyngeal nerve has been affected. What sign would you anticipate observing in this patient?

      Your Answer: Loss of gag reflex

      Explanation:

      The correct answer is loss of gag reflex, which is caused by a lesion in the glossopharyngeal nerve (CN IX). This nerve is responsible for taste in the posterior 1/3 of the tongue, salivation, and swallowing. Lesions in this nerve may also result in a hypersensitive carotid sinus reflex.

      Loss of taste on the anterior 2/3 of the tongue is incorrect, as this is controlled by the facial nerve (CN VII), which also controls facial movements, lacrimation, and salivation. Lesions in this nerve may result in flaccid paralysis of the upper and lower face, loss of corneal reflex, loss of taste on the anterior 2/3 of the tongue, and hyperacusis.

      Paralysis of the facial muscles or mastication muscles is also incorrect. The facial nerve controls facial movements, while the trigeminal nerve (CN V) controls the muscles of mastication and facial sensation via its ophthalmic, maxillary, and mandibular branches.

      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 12 - An 80-year-old woman visits her doctor complaining of fatigue, fever and lymphadenopathy. After...

    Correct

    • An 80-year-old woman visits her doctor complaining of fatigue, fever and lymphadenopathy. After a thorough examination and discussion of her recent symptoms, the doctor suspects glandular fever. However, in the following week, she experiences weakness on one side of her occipitofrontalis, orbicularis oculi and orbicularis oris muscles.

      What is the most probable neurological diagnosis for this patient?

      Your Answer: Cranial nerve VII palsy

      Explanation:

      The flaccid paralysis of the upper and lower face is a classic symptom of cranial nerve VII palsy, also known as Bell’s palsy. This condition is often caused by a viral illness, such as Epstein-Barr virus, which results in temporary inflammation and swelling around the facial nerve. The symptoms typically resolve on their own after a period of time.

      While a lacunar stroke can cause unilateral weakness, it would typically affect the arms and/or legs in addition to the facial muscles. Additionally, a lacunar stroke causes upper motor neuron impairment, which would result in forehead sparing.

      Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder that can cause fatigable muscle weakness. However, it would cause global disturbance in neuromuscular junction function rather than isolated unilateral impairment of one nerve, making it an unlikely cause of this presentation.

      Multiple sclerosis causes lesions within the brain and spinal cord, leading to upper motor neuron disturbances and other clinical signs. However, this would not fit with the presence of occipitofrontalis involvement, as forehead sparing is seen in upper motor neuron lesions.

      A partial anterior circulation stroke (PACS) typically presents with two out of three symptoms: unilateral weakness, disturbance in higher function (such as speech), and visual field defects (such as homonymous hemianopia). In this case, there is only unilateral weakness, and a PACS would cause upper motor neuron disturbance, resulting in forehead sparing.

      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 13 - An 80-year-old man arrives at the emergency department accompanied by his wife. According...

    Incorrect

    • An 80-year-old man arrives at the emergency department accompanied by his wife. According to her, he has experienced sudden hearing loss and is currently unable to perceive any sounds. A stroke is suspected, and he is sent for an MRI scan which reveals a thalamic lesion.

      Which specific nucleus of the thalamus is most likely affected by the lesion?

      Your Answer: Ventral anterior nucleus

      Correct Answer: Medial geniculate nucleus

      Explanation:

      Hearing impairment can result from damage to the medial geniculate nucleus of the thalamus, which is responsible for relaying auditory signals to the cerebral cortex. Similarly, damage to other regions of the thalamus can affect different types of sensory and motor functioning, such as visual loss from damage to the lateral geniculate nucleus, facial sensation from damage to the medial portion of the ventral posterior nucleus, and motor functioning from damage to the ventral anterior nucleus.

      The Thalamus: Relay Station for Motor and Sensory Signals

      The thalamus is a structure located between the midbrain and cerebral cortex that serves as a relay station for motor and sensory signals. Its main function is to transmit these signals to the cerebral cortex, which is responsible for processing and interpreting them. The thalamus is composed of different nuclei, each with a specific function. The lateral geniculate nucleus relays visual signals, while the medial geniculate nucleus transmits auditory signals. The medial portion of the ventral posterior nucleus (VML) is responsible for facial sensation, while the ventral anterior/lateral nuclei relay motor signals. Finally, the lateral portion of the ventral posterior nucleus is responsible for body sensation, including touch, pain, proprioception, pressure, and vibration. Overall, the thalamus plays a crucial role in the transmission of sensory and motor information to the brain, allowing us to perceive and interact with the world around us.

    • This question is part of the following fields:

      • Neurological System
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  • Question 14 - A 45-year-old woman arrives at the emergency department complaining of a sudden headache....

    Correct

    • A 45-year-old woman arrives at the emergency department complaining of a sudden headache. The doctor is evaluating her condition. Her BMI is 33 kgm2.

      During the cranial nerve examination, the doctor observes papilloedema on fundoscopy. The patient also reports a loss of taste in the back third of her tongue. Which of the following nerves could be responsible for this loss?

      Your Answer: Glossopharyngeal nerve

      Explanation:

      The glossopharyngeal nerve mediates taste and sensation from the posterior one-third of the tongue, while the anterior two-thirds of the tongue receive taste input from the chorda tympani branch of the facial nerve and sensation input from the lingual branch of the mandibular division of the trigeminal nerve. The base of the tongue receives taste and sensation input from the internal branch of the superior laryngeal nerve, which is a branch of the vagus nerve.

      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
      19.8
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  • Question 15 - A 75-year-old male visits his GP accompanied by his wife who is anxious...

    Incorrect

    • A 75-year-old male visits his GP accompanied by his wife who is anxious about his recent memory decline. The patient's wife is worried as her mother had Alzheimer's disease and she fears her husband may be developing it too. Among the following causes of cognitive decline, which one is potentially reversible?

      Your Answer: HIV

      Correct Answer: Brain tumour

      Explanation:

      Normal pressure hydrocephalus can be a reversible cause of dementia, while Pick’s disease is a degenerative form of frontotemporal dementia that cannot be reversed. Lewy body dementia is a progressive condition that is linked to parkinson’s and visual hallucinations. Multi-infarct dementia is associated with cardiovascular risk factors like smoking, diabetes, and atrial fibrillation, but the damage caused by infarcts is irreversible. A brain tumor is a potential cause of dementia that can be reversed.

      Understanding the Causes of Dementia

      Dementia is a condition that affects millions of people worldwide, and it is caused by a variety of factors. The most common causes of dementia include Alzheimer’s disease, cerebrovascular disease, and Lewy body dementia. These conditions account for around 40-50% of all cases of dementia.

      However, there are also rarer causes of dementia, which account for around 5% of cases. These include Huntington’s disease, Creutzfeldt-Jakob disease (CJD), Pick’s disease, and HIV (in 50% of AIDS patients). These conditions are less common but can still have a significant impact on those affected.

      It is also important to note that there are several potentially treatable causes of dementia that should be ruled out before a diagnosis is made. These include hypothyroidism, Addison’s disease, B12/folate/thiamine deficiency, syphilis, brain tumours, normal pressure hydrocephalus, subdural haematoma, depression, and chronic drug use (such as alcohol or barbiturates).

      In conclusion, understanding the causes of dementia is crucial for effective diagnosis and treatment. While some causes are more common than others, it is important to consider all potential factors and rule out treatable conditions before making a final diagnosis.

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      • Neurological System
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  • Question 16 - A 67-year-old female comes to the GP after a recent fall resulting in...

    Incorrect

    • A 67-year-old female comes to the GP after a recent fall resulting in a right knee injury. She reports difficulty in lifting her right foot. During the clinical examination, you observe a lack of sensation on the dorsum of her right foot and the lower lateral area of her right leg.

      What nerve is most likely to have been affected by the injury?

      Your Answer: Lateral cutaneous nerve of the thigh

      Correct Answer: Common peroneal nerve

      Explanation:

      A common peroneal nerve lesion can result in the loss of sensation over the lower lateral part of the leg and the dorsum of the foot, as well as foot drop. In contrast, a femoral nerve lesion would cause sensory loss over the anterior and medial aspect of the thigh and lower leg, while a lateral cutaneous nerve of the thigh lesion would cause sensory loss over the lateral and posterior surfaces of the thigh. An obturator nerve lesion would result in sensory loss over the medial thigh, and a tibial nerve lesion would cause sensory loss over the sole of the foot.

      Understanding Common Peroneal Nerve Lesion

      A common peroneal nerve lesion is a type of nerve injury that often occurs at the neck of the fibula. This condition is characterized by foot drop, which is the most common symptom. Other symptoms include weakness of foot dorsiflexion and eversion, weakness of extensor hallucis longus, sensory loss over the dorsum of the foot and the lower lateral part of the leg, and wasting of the anterior tibial and peroneal muscles.

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      • Neurological System
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  • Question 17 - A 21-year-old male visits the GP complaining of a sore and itchy eye...

    Incorrect

    • A 21-year-old male visits the GP complaining of a sore and itchy eye upon waking up. Upon examination, the right eye appears red with a discharge of mucopurulent nature. The patient has a medical history of asthma and eczema and is currently using a salbutamol inhaler. Based on this information, what is the most probable diagnosis?

      Your Answer: Allergic rhinitis

      Correct Answer: Bacterial conjunctivitis

      Explanation:

      A mucopurulent discharge is indicative of bacterial conjunctivitis, which is likely in this patient presenting with an itchy, red eye. Although the patient has a history of asthma and eczema, allergic rhinitis would not produce a mucopurulent discharge. Viral conjunctivitis, the most common type of conjunctivitis, is associated with a watery discharge. A corneal ulcer, on the other hand, is characterized by pain and a watery eye.

      Infective conjunctivitis is a common eye problem that is often seen in primary care. It is characterized by red, sore eyes that are accompanied by a sticky discharge. There are two types of infective conjunctivitis: bacterial and viral. Bacterial conjunctivitis is identified by a purulent discharge and eyes that may be stuck together in the morning. On the other hand, viral conjunctivitis is characterized by a serous discharge and recent upper respiratory tract infection, as well as preauricular lymph nodes.

      In most cases, infective conjunctivitis is a self-limiting condition that resolves on its own within one to two weeks. However, patients are often offered topical antibiotic therapy, such as Chloramphenicol or topical fusidic acid. Chloramphenicol drops are given every two to three hours initially, while chloramphenicol ointment is given four times a day initially. Topical fusidic acid is an alternative and should be used for pregnant women. For contact lens users, topical fluoresceins should be used to identify any corneal staining, and treatment should be the same as above. It is important to advise patients not to share towels and to avoid wearing contact lenses during an episode of conjunctivitis. School exclusion is not necessary.

    • This question is part of the following fields:

      • Neurological System
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  • Question 18 - A 32-year-old female patient comes to your clinic complaining of double vision that...

    Incorrect

    • A 32-year-old female patient comes to your clinic complaining of double vision that has been present for 2 days. After taking a thorough medical history, she reports no other visual changes. During the examination, you observe that she is unable to abduct her left eye. Which cranial nerve is most likely affected?

      Your Answer: Cranial nerve 4

      Correct Answer: Cranial nerve 6

      Explanation:

      The muscle responsible for abduction of the eye is the lateral rectus, which is controlled by the 6th cranial nerve (abducens).

      The optic nerve (cranial nerve 2) provides innervation to the retina.
      The oculomotor nerve (cranial nerve 3) controls the inferior oblique, medial superior and inferior rectus muscles.
      The trochlear nerve (cranial nerve 4) controls the superior oblique muscle.
      The trigeminal nerve (cranial nerve 5) provides sensory input to the face and controls the muscles used for chewing.

      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 19 - A 61-year-old male comes to the emergency department with sudden onset double vision....

    Incorrect

    • 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: Middle cerebral artery stroke

      Correct 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.

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      • Neurological System
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  • Question 20 - 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: Middle cerebral artery stroke

      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.

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      • Neurological System
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