Mock Neurology Module 3

A 32-year-old woman presents with a 6-week history of recurrent episodes of severe, migraine-like headache. Each episode is accompanied by transient focal neurological deficits. On separate occasions she has experienced right-sided hemiparaesthesia lasting about an hour, and on another occasion a transient dysphasia, all of which have resolved completely between attacks. She has had four such episodes over this period. She is afebrile (temperature 36.8°C) and systemically well. There is no rash, and she takes no regular medications. She has no significant past history other than occasional migraine without aura in her teens.

Neurological examination between episodes is entirely normal, with no meningism, no papilloedema, and no residual focal deficit.

A non-contrast CT scan of the head reveals no acute haemorrhage, mass lesion, or structural abnormality. MRI brain with diffusion-weighted imaging and MR angiography are normal, with no evidence of acute infarction, demyelination, or vascular abnormality.

A lumbar puncture (performed during an episode) reveals:

• Opening pressure of 18 cmH₂O (reference 10–20 cmH₂O)
• Cerebrospinal fluid (CSF) white cell count of 120 cells/µL (reference <5 cells/µL), with 95% lymphocytes.
• CSF protein is elevated at 0.75 g/L (reference 0.15–0.45 g/L).
• CSF glucose is 3.4 mmol/L with a paired serum glucose of 5.1 mmol/L (CSF:serum ratio 0.67; reference >0.6).
• Gram stain, bacterial culture, and viral PCR (including enterovirus and herpes simplex virus) are negative.

Serial CSF cultures remain sterile, and repeat testing after 3 months shows complete normalisation of CSF parameters with no further episodes.

Which of the following is the most likely diagnosis?

A 68-year-old man presents with sudden onset of left-sided weakness and dysarthria that resolved completely within an hour.

Past history includes hypertension, hyperlipidaemia, and smoking.

On examination, blood pressure is 150/95 mmHg and a right-sided carotid bruit is noted. Urgent carotid Doppler ultrasound shows significant stenosis on one side.

Based on the clinical presentation, which vessel is most likely to have significant stenosis?

A 72-year-old woman presents with recurrent transient neurological deficits, including episodes of right-sided weakness and aphasia.

Brain MRI (including susceptibility-weighted imaging) shows multiple cerebral microbleeds in a lobar (cortical and cortico-subcortical) distribution, with sparing of deep grey structures.

Cognition has declined over the past year with memory impairment and executive dysfunction.

Cerebral amyloid angiopathy (CAA) is suspected.

Which of the following is the most likely serious complication this patient is at risk of developing?

A 42-year-old man presented with diplopia, dysarthria and dysphagia. Over several days he developed weakness of the upper and lower limbs, and by day 4 he was unable to walk unaided. He denied sensory symptoms or bladder disturbance.

Past history is unremarkable; he is a non-smoker, does not drink alcohol excessively, and takes no medications. He was afebrile.

Cranial nerve examination showed bilateral dilated, poorly reactive pupils. He had binocular diplopia. He was dysarthric with a weak cough.

Forced vital capacity was 3.15 L standing and 2.00 L lying. He had a lower motor neuron tetraparesis (power 3/5), was hyporeflexic, with normal sensation. Higher mental function was normal and there were no signs of meningism.

Blood tests (FBC, U&E, LFTs, TFTs, calcium, autoantibody screen, ESR, CRP) were normal. ECG and CXR were unremarkable. CT brain was normal. Initial nerve conduction studies and EMG were normal.

What is the most likely diagnosis?

What best describes the mechanism of action of entacapone?

A 74-year-old man with a 9-year history of idiopathic Parkinson’s disease is reviewed in the movement disorder clinic.

His motor symptoms are well controlled on levodopa/carbidopa, but he has recently developed troublesome nausea and early satiety consistent with gastroparesis, which is limiting his oral intake and the absorption of his Parkinson’s medications.

His treating team wishes to commence an antiemetic with prokinetic properties.

On review of his medications, the team is concerned about worsening his parkinsonism. Two years ago he was prescribed a short course of metoclopramide for nausea by another practitioner and developed a marked deterioration in rigidity and bradykinesia, which resolved on cessation of the drug.

The team wants to select an antiemetic that will control his symptoms without aggravating his motor state or precipitating extrapyramidal side effects.

A baseline ECG shows a normal corrected QT interval (QTc 420 ms; reference <450 ms in men), and there are no other QT-prolonging medications on his chart.

Which of the following antiemetics is most appropriate for this patient?

The aetiology of Parkinson’s disease is multifactorial. Several exogenous factors have been epidemiologically associated with its development.

Which of the following is most consistently associated with a reduced risk of Parkinson’s disease?

A 58-year-old man with a 3-year history of idiopathic Parkinson’s disease is brought to the clinic by his wife, who is distressed and requests an urgent review.

Over the past 6 months she has discovered that he has accumulated more than $40,000 in gambling debts on online poker sites, has been making large impulsive purchases of items they do not need, and has developed a preoccupation with pornography and uncharacteristic sexual demands.

He does not perceive these behaviours as problematic and had concealed them until the financial consequences became apparent.

His motor symptoms have been reasonably controlled.

Eighteen months ago, because of mild wearing-off, his neurologist added a medication to his regimen and progressively up-titrated the dose. The behavioural changes began several months after this change. He has no prior psychiatric history and is not on any antidepressant or antipsychotic.

His current regimen includes levodopa/carbidopa, and one of the following agents was the drug added 18 months ago.

Which of the following medications in his regimen is most likely responsible for his behavioural changes?

A 68-year-old man is referred to the movement disorder clinic with a 14-month history of a progressive gait disorder. His wife reports that he has fallen numerous times, almost always backwards, and that these unexplained falls began within the first year of his symptoms.

He has become increasingly slow and stiff, with a symmetrical akinetic-rigid syndrome affecting the axial muscles more than the limbs. He has no resting tremor.

His wife has also noticed emotional lability, with episodes of involuntary crying and laughing out of proportion to his mood, together with slurred speech and difficulty swallowing.

On examination he has a startled, unblinking facial appearance. There is slowing of vertical saccades and, on formal testing, an impairment of voluntary vertical gaze, particularly downgaze which improves with the oculocephalic (doll’s eye) manoeuvre, consistent with a vertical supranuclear gaze palsy. He has prominent postural instability with a positive pull test.

A trial of levodopa/carbidopa was commenced by his general practitioner and titrated to an adequate dose over the preceding 3 months. The referral notes that his response has been minimal and not sustained.

Which of the following features would be least consistent with a diagnosis of progressive supranuclear palsy and should instead prompt reconsideration of idiopathic Parkinson’s disease?

A 25-year-old nursing student presents with a painless left wrist drop.

Where is the lesion most likely located?

A 30-year-old man presents with numbness of the left fifth digit and the ulnar border of the hand and distal forearm. There is no muscle wasting.

There is weakness of left finger abduction and adduction (4/5), abductor pollicis brevis (4/5), flexor pollicis longus (4/5) and finger extensors (4/5). Other muscle groups are normal.

Sensation is reduced along the ulnar border of the forearm and hand including the fifth digit. Reflexes are symmetrical and preserved.

The remainder of the examination is normal.

What is the most likely diagnosis?

A 55-year-old woman presents with numbness of the left thumb and index finger and the dorsoradial forearm. There is no neck pain. Power is normal. Biceps and triceps reflexes are normal and symmetrical. The brachioradialis reflex is reduced on the left.

Where is the lesion most likely located?

An 18-year-old man wakes after an orthopaedic procedure on his right leg with a right foot drop. There is weakness of ankle dorsiflexion and toe/foot eversion.

Plantar flexion, ankle inversion and knee flexion are normal.

The ankle jerk is preserved. No sensory abnormality is detected other than reduced sensation over the dorsum of the foot and lateral shin.

Which nerve is most likely affected?

An 80-year-old woman with longstanding rheumatoid arthritis complains of neck and occipital pain.

Cervical spine imaging demonstrates atlantoaxial instability with C2 involvement.

What is the most likely clinical finding?

A patient with haemophilia presents with a traumatic right iliacus haematoma.

Examination reveals weak knee extension, an absent knee jerk, and sensory loss over the anteromedial aspect of the thigh and the medial aspect of the leg.

Which nerve is most likely affected?

A 43-year-old man is found collapsed. The following day he has fixed, dilated pupils; absent corneal, gag and cough reflexes; absent vestibulo-ocular (cold caloric) responses; and no response to central painful stimulus. Neuroimaging is unremarkable.

Which test is required before proceeding to formal brain death (brain stem death) testing?

A 28-year-old woman presents with a three-month history of numbness of the hands and feet.

On examination, upper and lower limb reflexes are symmetrically brisk with bilateral extensor (upgoing) plantar responses. Upper limb power and sensation are normal.

There is mild bilateral weakness of ankle dorsiflexion, reduced pinprick to the ankles, normal joint position sense, and vibration impaired to the tibial tuberosities.

MRI shows demyelinating lesions in the cervical and thoracic cord (T2/FLAIR hyperintense).

The most likely diagnosis is:

A 60-year-old woman undergoes a gynaecological procedure in the lithotomy position for 3 hours and sustains a compression injury to the femoral nerve.

Which neurological finding is most likely?

Which of the following is NOT consistent with a diagnosis of Guillain–Barré syndrome (GBS)?

An abnormality in which of the following investigations is most useful in confirming suspected motor neuron disease (amyotrophic lateral sclerosis)?

A 57-year-old man with type 2 diabetes mellitus presents with a right foot drop. There is mild weakness of right ankle dorsiflexion and toe extension, with weak foot eversion but preserved inversion; other muscle groups are normal.

Reflexes are symmetrical with bilateral flexor plantar responses.

Sensation is reduced over the dorsum of the foot only.

Needle EMG shows enlarged (chronic neurogenic) motor unit potentials confined to the right tibialis anterior and peroneus longus, with the short head of biceps femoris, tibialis posterior and gluteus medius normal.

The most likely diagnosis is:

A 39-year-old woman presents with a three-month history of numbness, paraesthesia and pain in the right hand (thumb, index, middle and radial ring finger) that wakes her at night.

Nerve conduction studies show marked prolongation of the median motor distal latency, absent median digital sensory potentials, reduced median mixed nerve amplitude, and normal ulnar nerve conduction.

The most appropriate next step in management is:

A 15-year-old girl presents with a four-month history of progressive, diffuse weakness with inability to run or climb stairs and frequent falls.

Examination shows diffuse 3/5 weakness, absent reflexes with flexor plantar responses, no cranial nerve abnormality, and symmetrical glove-and-stocking sensory loss.

Nerve conduction studies show markedly slowed conduction velocities with conduction block.

The most likely diagnosis is:

A 60-year-old man sustains a large cerebral infarct involving most of the left occipital lobe, with the remainder of the brain unaffected.

Later neurological examination is most likely to reveal:

A patient is referred with a third nerve palsy associated with headache. On examination there is meningism.

Which diagnosis must be excluded most urgently?

A 60-year-old man presents with urinary retention. Examination reveals bilateral brisk lower limb reflexes with extensor (upgoing) plantar responses and a sensory level at the umbilicus. Upper limb examination is normal.

Where is the lesion most likely located?

A 70-year-old man with atrial fibrillation presents with sudden inability to see objects in the right lower quadrant of the visual field in both eyes.

Where is the deficit most likely located?

A 67-year-old right-handed man is brought to the emergency department after his family noticed the sudden onset of “jumbled speech” 2 hours earlier. He is alert and appears untroubled by his difficulties.

His speech is fluent and effortless, produced at a normal rate with normal melody and articulation, but it is largely devoid of meaning and contains invented words and word substitutions: when asked what happened, he replies, “fudden in a hair, still larging OK.”

He is unable to follow simple commands such as “close your eyes” or “point to the window,” and he cannot repeat the phrase “no ifs, ands, or buts.”

He seems unaware that his speech is abnormal. Limb power, tone and reflexes are normal, and there is no facial weakness, but visual field testing suggests a right superior quadrantanopia.

CT brain excludes haemorrhage. MRI with diffusion-weighted imaging confirms an acute infarct in the dominant (left) hemisphere, in the territory of the inferior division of the middle cerebral artery, involving the posterior part of the superior temporal gyrus.

Damage to which Brodmann area is most likely responsible for this patient’s speech abnormality?

A 32-year-old woman at 20 weeks’ gestation presents to the emergency department with a new, severe, progressively worsening headache over 5 days, worse when lying flat and on straining. She has associated nausea and one episode of transient blurred vision. There is no history of seizures.

Examination reveals a right-sided partial ptosis without fatigability on sustained upgaze and no ophthalmoplegia. Pupils are equal and reactive. Fundoscopy shows mild bilateral papilloedema. She is afebrile with no neck stiffness, and there are no focal limb deficits or seizures. Blood pressure is 118/74 mmHg and urinalysis shows no proteinuria.

Non-contrast CT head is normal.

Which of the following interventions is LEAST likely to be beneficial in her acute management?

A 64-year-old man with poorly controlled hypertension, type 2 diabetes mellitus and a 40-pack-year smoking history presents to the emergency department after his wife noticed the sudden onset of a drooping left side of the face and double vision on waking that morning.

He also reports weakness of his right arm and leg, causing him to stumble.

There is no headache, neck pain, vomiting, or reduced level of consciousness, and no preceding trauma or infection.

On examination he is alert and orientated, with a blood pressure of 178/98 mmHg and an irregularly irregular pulse; an ECG confirms atrial fibrillation.

Speech is dysarthric but language (comprehension, naming, repetition) is intact, and there is no neglect or visual field defect.

Cranial nerve examination reveals a left lower motor neuron facial palsy: the entire left side of the face is weak, including the forehead, with an inability to fully close the left eye and loss of the left nasolabial fold.

On testing eye movements, there is a failure of abduction of the left eye, with diplopia that is maximal on left lateral gaze; adduction, elevation and depression of both eyes are otherwise preserved, and the pupils are equal and reactive with no ptosis.

Limb examination shows a right-sided hemiplegia (power 2/5 in the right arm and leg) with increased tone, hyperreflexia and an extensor (upgoing) right plantar response, consistent with an upper motor neuron pattern.

Crucially, the right side of the face is spared. Sensation is grossly intact, and there is no limb ataxia or nystagmus.

Non-contrast CT brain excludes haemorrhage.

Where is the lesion?

Bilateral posterior cerebral artery (PCA) infarction is most likely to present with which of the following?

A 38-year-old man reports difficulty reading while commuting. On right gaze, his right (abducting) eye develops nystagmus and his left (adducting) eye is slow to reach the midline. Convergence is preserved.

This is most likely due to a lesion in which structure?

A 58-year-old man with poorly controlled hypertension and atrial fibrillation (recently non-adherent with anticoagulation) is brought to the emergency department after collapsing at home. His wife reports that over the preceding hour he complained of sudden severe dizziness, slurred speech and difficulty swallowing, then became progressively unresponsive and unable to move.

On arrival he appears awake, with his eyes open, but is completely mute and does not move his limbs. Blood pressure is 190/105 mmHg and the pulse is irregularly irregular. He is breathing spontaneously.

The concerning initial impression is of a comatose patient, but careful examination reveals preserved awareness.

When addressed, he consistently opens and closes his eyes to command and looks up and down to command, but is unable to generate any horizontal eye movements.

There is a quadriplegia with flaccid then increasing tone, hyperreflexia and bilateral extensor plantar responses. There is a bilateral lower facial weakness, an inability to move the tongue, and absent gag and cough reflexes with anarthria (he cannot phonate or articulate). Horizontal gaze is impaired bilaterally, but vertical eye movements and blinking are preserved and voluntary.

When asked yes/no questions, he answers appropriately by blinking and by vertical eye movements, demonstrating intact consciousness, comprehension and cognition. Pupils are equal and reactive. There is no decorticate or decerebrate posturing.

An EEG (performed because of the initial suspicion of coma) shows a normal, reactive waking background, confirming preserved cortical activity and wakefulness. Non-contrast CT brain excludes haemorrhage but a CT angiogram demonstrates occlusion of the basilar artery.

Where is the lesion?

A 66-year-old man with a long history of hypertension, type 2 diabetes mellitus and hyperlipidaemia presents to the emergency department with the sudden onset of clumsiness and heaviness of his right arm and leg, noticed on waking that morning, together with slurred speech. He also reports that his tongue feels “off” and that food is catching on the left side of his mouth. There is no headache, vertigo, hearing loss, facial numbness or difficulty swallowing, and he denies chest pain or palpitations.

On examination he is alert and fully orientated, with a blood pressure of 172/96 mmHg and a regular pulse. Language (comprehension, naming, repetition) and higher cognitive function are intact, and there is no visual field defect or neglect.

Motor examination reveals a right-sided upper motor neuron hemiparesis affecting the arm and leg (power 3/5) with increased tone, hyperreflexia and an extensor right plantar response. Importantly, the face is spared. Sensory testing shows loss of vibration sense and proprioception on the right side of the body, with relatively preserved pain and temperature sensation (a dissociated sensory loss).

On cranial nerve examination, the striking finding is of the tongue: at rest there is wasting (atrophy) and fasciculation of the left half of the tongue, and on protrusion the tongue deviates to the left, indicating a left lower motor neuron twelfth (hypoglossal) nerve palsy. There is no ptosis, no pupillary abnormality, no Horner syndrome, no nystagmus, no facial sensory loss and no limb ataxia.

Non-contrast CT brain excludes haemorrhage. 

Where is the lesion?

A 60-year-old woman presents with a 3-month history of diplopia and progressive visual loss in the left eye, without pain. She smokes 20 cigarettes daily and drinks alcohol in moderation.

Visual acuity is 6/6 right and 6/36 left. There is left partial ptosis with mild proptosis and conjunctival injection. The left pupil is smaller than the right but reacts normally to light. There is limitation of abduction of the left eye and a pale left optic disc. The left corneal reflex is reduced. The remainder of the neurological examination is normal.

Routine bloods (FBC, U&E, LFTs, TFTs, calcium, creatine kinase, autoantibody screen) are normal. ECG and CXR are unremarkable. Slit-lamp examination and intraocular pressures are normal.

Where is the most likely site of the causative lesion?