Free UKMLA neurosciences questions with explanations

D. Aspirin 300 mg now and stroke clinic review within 24 hours

Anyone with a suspected TIA should be given aspirin 300 mg immediately (unless contraindicated) and assessed by a specialist stroke service within 24 hours of symptom onset, because early antiplatelet therapy substantially reduces the high early risk of recurrent stroke. The ABCD2 score is no longer used to stratify urgency. All TIAs are treated as high-risk. Brain imaging is arranged by the specialist service and does not delay aspirin.

E. Cardioembolism

In atrial fibrillation, loss of coordinated atrial contraction causes blood stasis in the left atrial appendage and thrombus formation; embolisation to the cerebral circulation typically produces sudden, large-territory cortical infarcts such as this left MCA stroke. Anticoagulation based on CHA2DS2-VASc is recommended to prevent such events, and absence of anticoagulation here makes cardioembolism the most likely mechanism.

E. Therapeutic dose low molecular weight heparin

Anticoagulation is the treatment of cerebral venous thrombosis, and a haemorrhagic venous infarct does not change that, because the bleeding is a consequence of venous congestion and the way to stop it worsening is to reopen the venous outflow. Trials showed that heparin improves outcomes even in patients presenting with haemorrhage, and low molecular weight heparin is the usual initial agent, followed by oral anticoagulation for several months. Withholding treatment allows the thrombus to propagate into further sinuses and cortical veins. Thrombolysis and surgery are reserved for patients who deteriorate despite anticoagulation, and antiplatelet therapy is not effective for venous thrombosis.

E. IV thiamine before glucose

The triad of confusion, ophthalmoplegia and ataxia in a malnourished alcohol-dependent patient indicates Wernicke's encephalopathy, and parenteral thiamine (Pabrinex) must be given before any glucose because glucose metabolism is thiamine-dependent and can precipitate or worsen Wernicke's encephalopathy, which if untreated progresses to irreversible Korsakoff's syndrome. Parenteral thiamine is recommended for any suspected case in alcohol misuse with malnutrition or decompensation.

D. Electromyography

Electromyography (EMG) is the key investigation in suspected motor neurone disease (MND), demonstrating widespread active denervation (fibrillation potentials, positive sharp waves) and chronic reinnervation (large polyphasic motor unit potentials) across multiple body regions, fulfilling the revised El Escorial/Awaji criteria. Normal sensory nerve conduction alongside these findings supports MND by excluding a sensorimotor neuropathy, but pure motor mimics such as multifocal motor neuropathy with conduction block must still be excluded.

E. Weight loss

Idiopathic intracranial hypertension is driven by obesity, and sustained weight loss (up to about 15% of body weight was needed in one cohort; the amount required is not established) is the only disease-modifying intervention shown to induce lasting remission, normalising intracranial pressure and resolving papilloedema; bariatric surgery achieves this more reliably than dieting in severe obesity. Acetazolamide lowers CSF production and is used to protect vision while weight is lost, particularly with more than mild papilloedema, but it controls rather than cures and is often poorly tolerated. Topiramate is an alternative with the side benefit of weight loss, but in a woman of childbearing potential it can be used only within the Pregnancy Prevention Programme. Serial lumbar punctures give only hours of relief, and surgery (shunting or optic nerve sheath fenestration) is reserved for vision at risk despite medical treatment.

A. Thyroid function tests

A new fine symmetrical action tremor with weight loss, heat intolerance, palpitations, and loose stools points to thyrotoxicosis, a reversible secondary cause of tremor that must be excluded before labelling a tremor as essential. Thyroid function tests showing suppressed TSH with raised free T4 confirm the diagnosis, and treating the thyroid disease resolves the tremor. Identifying secondary causes is a routine step in tremor assessment.

A. Exclude vestibular schwannoma

MRI of the internal auditory meatus in suspected Meniere's disease is performed mainly to exclude a retrocochlear lesion, particularly a vestibular schwannoma, which can mimic the unilateral audiovestibular symptoms. Meniere's remains a clinical diagnosis supported by audiometry, so imaging is about ruling out dangerous alternatives rather than confirming the condition. This is standard UK practice before settling on a Meniere's label.

D. Lung cancer

Lung cancer is the single most common primary source of brain metastases, accounting for approximately 40 to 50% of cases, reflecting both its high population incidence and strong propensity for early haematogenous spread. Multiple ring-enhancing lesions at the grey-white matter junction in an older patient with new seizures and progressive headache is the classic presentation of metastatic disease, and lung primary is the statistically most likely source.

A. 12-lead ECG

Amitriptyline has class Ia-like sodium-channel blocking activity that prolongs the QT and QRS intervals and can precipitate arrhythmia in patients with structural heart disease. A baseline 12-lead ECG is advised before prescribing a tricyclic in elderly patients or those with established cardiac disease to detect pre-existing conduction abnormalities (prolonged QTc, bundle branch block) that would contraindicate its use.