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Question 1
Incorrect
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An 80-year-old woman with history of hypertension, diabetes, and ischemic stroke, presents with left-sided hemiplegia of the face, tongue, and limbs and right-sided deficits in motor eye activity. A CT scan was ordered and showed a right-sided stroke.
Branches of which of the following arteries are most likely implicated in the case?Your Answer: Posterior cerebral artery
Correct Answer: Basilar artery
Explanation:Weber syndrome is a midbrain stroke characterized by crossed hemiplegia along with oculomotor nerve deficits and it occurs with the occlusion of the median and/or paramedian perforating branches of the basilar artery.
Typical clinical findings include ipsilateral CN III palsy, ptosis, and mydriasis (such as damage to parasympathetic fibres of CN III) with contralateral hemiplegia.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 2
Incorrect
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You suspect that your patient with polycystic kidney disease has developed a berry aneurysm as a complication of his disease. The patient complains of a sudden, severe headache. You are guessing subarachnoid haemorrhage secondary to a ruptured berry aneurysm as the cause of his severe headaches. What is the most likely location of his aneurysm?
Your Answer: Posterior communicating artery
Correct Answer: Anterior communicating artery
Explanation:One of the complications that polycystic kidney disease may cause is the development of a brain aneurysm.
A berry aneurysm is the most common type of brain aneurysm.
The Circle of Willis, where the major blood vessels meet at the base of the brain, is where it usually appears. The most common junctions of the Circle of Willis where an aneurysm may occur include the anterior communicating artery (35%), internal carotid artery (30%), the posterior communicating artery and the middle cerebral artery (22%), and finally, the posterior circulation sites, most commonly the basilar artery tip.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 3
Incorrect
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A patient presents complaining of visual loss. On examination you note a contralateral homonymous hemianopia. Where is the most likely site of the lesion:
Your Answer: Optic nerve
Correct Answer: Optic tract
Explanation:At the optic chiasm, fibres from the medial (nasal) half of each retina crossover, forming the right and left optic tracts.
The left optic tract contains fibres from the left lateral (temporal) retina and the right medial retina.
The right optic tract contains fibres from the right lateral retina and the left medial retina.
Each optic tract travels to its corresponding cerebral hemisphere to reach its lateral geniculate nucleus (LGN) located in the thalamus where the fibres synapse.
A lesion of the optic tract will cause a contralateral homonymous hemianopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 4
Incorrect
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Which of the following clinical features is most suggestive of a lesion of the frontal lobe:
Your Answer:
Correct Answer: Conjugate eye deviation towards the side of the lesion
Explanation:Conjugate eye deviation towards the side of the lesion is seen in damage to the frontal eye field of the frontal lobe. Homonymous hemianopia is typically a result of damage to the occipital lobe (or of the optic radiation passing through the parietal and temporal lobes). Auditory agnosia may been seen in a lesion of the temporal lobe. Hemispatial neglect may be seen in a lesion of the parietal lobe. Receptive dysphasia is seen in damage to Wernicke’s area, in the temporal lobe.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 5
Incorrect
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Regarding CSF (cerebrospinal fluid) production, approximately how much is produced per day?
Your Answer:
Correct Answer: 500 ml
Explanation:CSF fills the ventricular system, a series of interconnected spaces within the brain, and the subarachnoid space directly surrounding the brain. The intraventricular CSF reflects the composition of the brain’s extracellular space via free exchange across the ependyma, and the brain “floats” in the subarachnoid CSF to minimize the effect of external mechanical forces. The volume of CSF within the cerebral ventricles is approximately 30 mL, and that in the subarachnoid space is about 125 mL. Because about 0.35 mL of CSF is produced each minute, CSF is turned over more than three times daily. Approximately 500 mL of CSF is produced per day, at a rate of about 25 mL per hour.
CSF is a filtrate of capillary blood formed largely by the choroid plexuses, which comprise pia mater, invaginating capillaries, and ependymal cells specialized for transport. The choroid plexuses are located in the lateral, third, and fourth ventricles. The lateral ventricles are situated within the two cerebral hemispheres. They each connect with the third ventricle through one of the interventricular foramina (of Monro). The third ventricle lies in the midline between the diencephalon on the two sides. The cerebral aqueduct (of Sylvius) traverses the midbrain and connects the third ventricle with the fourth ventricle. The fourth ventricle is a space defined by the pons and medulla below and the cerebellum above. The central canal of the spinal cord continues caudally from the fourth ventricle, although in adult humans the canal is not fully patent and continues to close with age.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 6
Incorrect
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If a lesion is observed in Broca's area, which function is expected to become affected?
Your Answer:
Correct Answer: Formation of words
Explanation:The primary functions of the Broca area are both language production and comprehension. While the exact role in the production is still unclear, many believe that it directly impacts the motor movements to allow for speech. Although originally thought to only aid in speech production, lesions in the area can rarely be related to impairments in the comprehension of language. Different regions of the Broca area specialize in various aspects of comprehension. The anterior portion helps with semantics, or word meaning, while the posterior is associated with phonology, or how words sound. The Broca area is also necessary for language repetition, gesture production, sentence grammar and fluidity, and the interpretation of others’ actions.
Broca’s aphasia is a non-fluent aphasia in which the output of spontaneous speech is markedly diminished and there is a loss of normal grammatical structure. Specifically, small linking words, conjunctions, such as and, or, and but, and the use of prepositions are lost. Patients may exhibit interjectional speech where there is a long latency, and the words that are expressed are produced as if under pressure. The ability to repeat phrases is also impaired in patients with Broca’s aphasia. Despite these impairments, the words that are produced are often intelligible and contextually correct. In pure Broca’s aphasia, comprehension is intact.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 7
Incorrect
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The least likely feature expected to be seen in a lesion of the frontal lobe is which of the following?
Your Answer:
Correct Answer: Loss of two-point discrimination
Explanation:Lesions in different areas give rise to different symptoms.
Lesions of the parietal lobe give rise to loss of two-point discrimination.
Lesions to Broca’s area give rise to expressive dysphasia results from damage
Lesions to the primary motor cortex give rise to contralateral weakness of the face and arm.
Lesions to the prefrontal cortex give rise to personality change.
Lesions to the frontal eye field give rise to conjugate eye deviation towards side of lesion. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 8
Incorrect
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Which of the following is a contraindication for aspirin?
Your Answer:
Correct Answer: Children under 16 years
Explanation:Aspirin contraindications include: hypersensitivity to NSAIDs; asthma, rhinitis, and nasal polyps; and usage in children or teens.
There is little evidence of allergic cross-reactivity for salicylates. However, due to similarities in chemical structure and/or pharmacologic activities, the possibility of cross-sensitivity cannot be completely ruled out. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 9
Incorrect
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Which of the following best describes the mechanism of action of aspirin:
Your Answer:
Correct Answer: Cyclo-oxygenase (COX) inhibitor
Explanation:Aspirin is a non-steroidal anti-inflammatory drug (NSAID). Aspirin irreversibly inhibits cyclooxygenase (COX) enzymes and the resulting inhibition of prostaglandin synthesis results in analgesic, antipyretic and to a lesser extent anti-inflammatory actions.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 10
Incorrect
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A 16-year old boy is brought to the emergency room after suffering a traffic accident. Upon examination, there is noted ipsilateral loss of proprioception and vibration, ipsilateral motor loss, and contralateral loss of pain and temperature sensation. A spinal cord injury is given as a diagnosis.
Which of the following is the most probable cause of this manifestation?Your Answer:
Correct Answer: Brown-Séquard syndrome
Explanation:Brown-Sequard Hemicord Syndrome consists of ipsilateral weakness (corticospinal tract) and loss of joint position and vibratory sense (posterior column), with contralateral loss of pain and temperature sense (spinothalamic tract) one or two levels below the lesion. Segmental signs, such as radicular pain, muscle atrophy, or loss of a deep tendon reflex, are unilateral. Partial forms are more common than the fully developed syndrome.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 11
Incorrect
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What type of visual field defect are you likely to see in a lesion of the visual cortex:
Your Answer:
Correct Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:A lesion of the visual cortex will result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 12
Incorrect
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Which of the following is NOT a typical side effect of opioid analgesics:
Your Answer:
Correct Answer: Diarrhoea
Explanation:All opioids have the potential to cause:
Gastrointestinal effects – Nausea, vomiting, constipation, difficulty with micturition (urinary retention), biliary spasm
Central nervous system effects – Sedation, euphoria, respiratory depression, miosis
Cardiovascular effects – Peripheral vasodilation, postural hypotension
Dependence and tolerance -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 13
Incorrect
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Which of the following is most likely to cause a homonymous hemianopia:
Your Answer:
Correct Answer: Posterior cerebral artery stroke
Explanation:A posterior cerebral stroke will most likely result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 14
Incorrect
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Regarding antiemetics, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Of the antiemetics, cyclizine is most commonly associated with acute dystonic reactions.
Explanation:Cyclizine acts by inhibiting histamine pathways and cholinergic pathways involved in transmission from the vestibular apparatus to the vomiting centre. Metoclopramide is a dopamine-receptor antagonist which acts both peripherally in the GI tract and centrally within the chemoreceptor trigger zone. Prochlorperazine is a dopamine-D2 receptor antagonist and acts centrally by blocking the chemoreceptor trigger zone. Metoclopramide and prochlorperazine are both commonly associated with extrapyramidal effects, such as acute dystonic reaction. Cyclizine may rarely cause extrapyramidal effects.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 15
Incorrect
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A 70-year-old man has a resting tremor, rigidity, bradykinesia, and a shuffling gait. Parkinson's disease is caused by one of the following mechanisms:
Your Answer:
Correct Answer: Loss of dopaminergic neurons in the substantia nigra
Explanation:Parkinson’s disease (PD) is one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years and causing progressive disability that can be slowed but not halted, by treatment. The 2 major neuropathologic findings in Parkinson’s disease are loss of pigmented dopaminergic neurons of the substantia nigra pars compacta and the presence of Lewy bodies and Lewy neurites. See the images below.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 16
Incorrect
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Which of the following statements is correct regarding paracetamol?
Your Answer:
Correct Answer: Liver damage peaks 3 to 4 days after paracetamol ingestion.
Explanation:The maximum daily dose of paracetamol in an adult is 4 grams. Doses greater than this can lead to hepatotoxicity and, less frequently, acute kidney injury. Early symptoms of paracetamol toxicity include nausea, vomiting, and abdominal pain, and usually settle within 24 hours. Symptoms of liver damage include right subcostal pain and tenderness, and this peaks 3 to 4 days after paracetamol ingestion. Other signs of hepatic toxicity include encephalopathy, bleeding, hypoglycaemia, and cerebral oedema.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 17
Incorrect
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The sensation produced by touching the arm with a vibrating tuning fork during a neurological examination is mediated by which of the following spinal tracts:
Your Answer:
Correct Answer: Posterior column
Explanation:Fine-touch, proprioception and vibration sensation are mediated by the posterior column-medial lemniscus pathway.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 18
Incorrect
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Which of the following statements about lithium treatment is FALSE:
Your Answer:
Correct Answer: Concomitant treatment with NSAIDs decreases serum-lithium concentration.
Explanation:Lithium levels are raised by NSAIDs because renal clearance is reduced. Lithium is a small ion (74 Daltons) with no protein or tissue binding and is therefore amenable to haemodialysis. Lithium is freely distributed throughout total body water with a volume of distribution between 0.6 to 0.9 L/kg, although the volume may be smaller in the elderly, who have less lean body mass and less total body water. Steady-state serum levels are typically reached within five days at the usual oral dose of 1200 to 1800 mg/day. The half-life for lithium is approximately 18 hours in adults and 36 hours in the elderly.
Lithium is excreted almost entirely by the kidneys and is handled in a manner similar to sodium. Lithium is freely filtered but over 60 percent is then reabsorbed by the proximal tubules. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 19
Incorrect
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A 70-year old male is taken to the Emergency Room after suffering a traumatic fall while showering. Upon physical examination, the attending physician noted a hyperextended neck, 1/5 muscle strength in both upper extremities, 4/5 muscle strength in both lower extremities, and variable loss in sensation. The patient is placed in the wards for monitoring. For the next 24 hours, anuria is noted.
Which of the following spinal cord injuries is the most likely diagnosis?Your Answer:
Correct Answer: Central cord syndrome
Explanation:Central cord syndrome is the most common type of incomplete cord injury and almost always occurs due to a traumatic injury. It results in motor deficits that are worse in the upper extremities as compared to the lower extremities. It may also cause bladder dysfunction (retention) and variable sensory deficits below the level of injury.
The majority of these patients will be older and present with symptoms after a fall with hyperextension of their neck. On examination, patients will have more significant strength impairments in the upper extremities (especially the hands) compared to the lower extremities. Patients often complain of sensory deficits below the level of injury, but this is variable. Pain and temperature sensations are typically affected, but the sensation of light touch can also be impaired. The most common sensory deficits are in a cape-like distribution across their upper back and down their posterior upper extremities. They will often have neck pain at the site of spinal cord impingement.
Bladder dysfunction (most commonly urinary retention) and priapism can also be signs of upper motor neuron dysfunction. The sacral sensation is usually preserved, but the clinician should assess the rectal tone to evaluate the severity of the compression.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 20
Incorrect
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A well recognised adverse effect of metoclopramide is which of the following?
Your Answer:
Correct Answer: Acute dystonic reaction
Explanation:Side effects of metoclopramide are commonly associated with extrapyramidal effects and hyperprolactinemia. Therefore its use must be limited to short-term use. Metoclopramide can induce acute dystonic reactions which involve facial and skeletal muscle spasms and oculogyric crises. These dystonic effects are more common in the young girls and young women, and in the very old. These symptoms usually occur shortly after starting treatment with this drug and subside within 24 hours of stopping it. Abortion of dystonic attacks can be carried out by injection of an antiparkinsonian drug like procyclidine.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 21
Incorrect
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A 29-year-old man has been complaining about his recent headaches. Detailed history was taken and a neurological examination was performed.
Which of the following cranial nerves is correctly paired with its lesion?Your Answer:
Correct Answer: The oculomotor nerve: the eye appears to look ‘down and out’
Explanation:The following are the lesions of the cranial nerves:
1. Olfactory nerve (I)
Reduced taste and smell, but not to ammonia which stimulates the pain fibres carried in the trigeminal nerve2. Optic nerve (II)
Manifested by visual field defects, pupillary abnormalities, optic neuritis, optic atrophy, papilledema3. Oculomotor nerve (III)
A fixed, dilated pupil which doesn’t accommodate, ptosis, complete internal ophthalmoplegia (masked by ptosis), unopposed lateral rectus causes outward deviation of the eye. If the ocular sympathetic fibres are also affected behind the orbit, the pupil will be fixed but not dilated.4. Trochlear nerve (IV)
Diplopia due to weakness of downward and inward eye movement. The most common cause of a pure vertical diplopia. The patient tends to compensate by tilting the head away from the affected side.5. Trigeminal nerve (V)
Reduced sensation or dysesthesia over the affected area. Weakness of jaw clenching and side-to-side movement. If there is a lower motor neuron (LMN) lesion, the jaw deviates to the weak side when the mouth is opened. There may be fasciculation of temporalis and masseter.6. Abducens nerve (VI)
Inability to look laterally. The eye is deviated medially because of unopposed action of the medial rectus muscle.7. Facial nerve (VII)
Facial weakness. In an LMN lesion the forehead is paralysed – the final common pathway to the muscles is destroyed; whereas the upper facial muscles are partially spared in an upper motor neurone (UMN) lesion because of alternative pathways in the brainstem. There appear to be different pathways for voluntary and emotional movement. CVAs usually weaken voluntary movement, often sparing involuntary movements (e.g., spontaneous smiling). The much rarer selective loss of emotional movement is called mimic paralysis and is usually due to a frontal or thalamic lesion.8. Vestibulocochlear nerve (VIII)
Unilateral sensorineural deafness, tinnitus. Slow-growing lesions seldom present with vestibular symptoms as compensation has time to occur.9. Glossopharyngeal nerve (IX)
Unilateral lesions do not cause any deficit because of bilateral corticobulbar connections. Bilateral lesions result in pseudobulbar palsy. These nerves are closely interlinked.10. Vagus nerve (X)
Palatal weakness can cause ‘nasal speech’ and nasal regurgitation of food. The palate moves asymmetrically when the patient says ‘ahh’. Recurrent nerve palsy results in hoarseness, loss of volume and ‘bovine cough’.11. Accessory nerve (XI)
Weakness and wasting of sternocleidomastoid and trapezius muscles12.Hypoglossal nerve (XII)
An LMN lesion produces wasting of the ipsilateral side of the tongue, with fasciculation; and on attempted protrusion the tongue deviates towards the affected side, but the tongue deviates away from the side of a central lesion. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 22
Incorrect
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In the emergency room, a 28-year-old woman complains of wobbly and slurred speech, is unable to do the heel-shin test, and has nystagmus. The following signs are most likely related to damage to which of the following areas:
Your Answer:
Correct Answer: Cerebellum
Explanation:Cerebellar injury causes delayed and disorganized motions. When walking, people with cerebellar abnormalities sway and stagger.
Damage to the cerebellum can cause asynergia, the inability to judge distance and when to stop, dysmetria, the inability to perform rapid alternating movements or adiadochokinesia, movement tremors, staggering, wide-based walking or ataxic gait, a proclivity to fall, weak muscles or hypotonia, slurred speech or ataxic dysarthria, and abnormal eye movements or nystagmus.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 23
Incorrect
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All of the following predisposes to lithium toxicity in patients taking long-term therapy EXCEPT:
Your Answer:
Correct Answer: Hypernatraemia
Explanation:A common complication of long term lithium therapy results in most cases of lithium intoxication. It is caused by reduced excretion of the drug which can be due to several factors including deterioration of renal function, dehydration, hyponatraemia, infections, and co-administration of diuretics or NSAIDs or other drugs that may interact.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 24
Incorrect
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Regarding codeine, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: There is a reduced risk of toxicity in patients who are ultra-rapid metabolisers of codeine.
Explanation:Codeine phosphate is a weak opioid and can be used for the relief of mild to moderate pain where other painkillers such as paracetamol or ibuprofen have proved ineffective.Codeine is metabolised to morphine which is responsible for its therapeutic effects. Codeine 240 mg is approximately equivalent to 30 mg of morphine. The capacity to metabolise codeine can vary considerably between individuals; there is a marked increase in morphine toxicity in people who are ultra rapid metabolisers, and reduced therapeutic effect in poor codeine metabolisers. Codeine is contraindicated in patients of any age who are known to be ultra-rapid metabolisers of codeine (CYP2D6 ultra-rapid metabolisers).Codeine is also contraindicated in children under 12, and in children of any age who undergo the removal of tonsils or adenoids for the treatment of obstructive sleep apnoea due to reports of morphine toxicity.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 25
Incorrect
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Which of the following is NOT a typical cerebellar sign:
Your Answer:
Correct Answer: Hypertonia
Explanation:Hypotonia means decreased muscle tone. It can be a condition on its own, called benign congenital hypotonia, or it can be indicative of another problem where there is progressive loss of muscle tone, such as muscular dystrophy or cerebral palsy. It is usually detected during infancy. Hypotonia is characteristic of cerebellar dysfunction.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 26
Incorrect
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Which of the following is NOT an adverse effect of amitriptyline:
Your Answer:
Correct Answer: Hypokalaemia
Explanation:Adverse effects include:
Antimuscarinic effects: Dry mouth, Blurred vision, Constipation, Urinary retention, Sedation, Confusion
Cardiovascular effects: Heart block, Arrhythmias, Tachycardia, Postural hypotension, QT-interval prolongation, Hepatic impairment, Narrow-angle glaucoma -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 27
Incorrect
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At which opioid receptors do opioid analgesics act primarily?
Your Answer:
Correct Answer: Mu
Explanation:Opioid receptors are widely distributed throughout the central nervous system. Opioid analgesics mimic endogenous opioid peptides by causing prolonged activation of these receptors, mainly the mu(μ)-receptors which are the most highly concentrated in brain areas involved in nociception.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 28
Incorrect
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What type of visual field defect are you most likely to see in a lesion of the parietal optic radiation:
Your Answer:
Correct Answer: Contralateral homonymous inferior quadrantanopia
Explanation:A lesion of the parietal optic radiation will result in a contralateral homonymous inferior quadrantanopia.
A lesion of the temporal optic radiation will result in a contralateral homonymous superior quadrantanopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 29
Incorrect
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After what time period should intravenous phenytoin be used as second-line treatment of status epilepticus?
Your Answer:
Correct Answer: 25 minutes
Explanation:If seizures recur or fail to respond after initial treatment with benzodiazepines within 25 minutes of onset, phenytoin sodium, fosphenytoin sodium, or phenobarbital sodium should be used.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 30
Incorrect
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A 70-year-old man presents with right-sided hemiplegia and loss of joint position sense, vibratory sense, and discriminatory touch. Upon further physical examination, it was observed that her tongue deviates to the left-hand side. An MRI and CT scan was ordered and results showed that he was suffering a left-sided stroke.
Branches of which of the following arteries are most likely implicated in the case?Your Answer:
Correct Answer: Anterior spinal artery
Explanation:Medial medullary syndrome is a form of stroke that affects the medial medulla of the brain. It is caused by a lesion in the medial part of the medulla, which is due to an infraction of vertebral arteries and/or paramedian branches of the anterior spinal artery.
It is characterized by contralateral paralysis of the upper and lower limb of the body, a contralateral decrease in proprioception, vibration, and/or fine touch sensation, paresthesias or less commonly dysesthesias in the contralateral trunk and lower limb, and loss of position and vibration sense with proprioceptive dysfunction. Ipsilateral deviation of the tongue due to ipsilateral hypoglossal nerve damage can also be seen.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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SESSION STATS - PERFORMANCE PER SPECIALTY
