DHA Neurosurgery exam questions

6 worked Neurosurgery practice questions

Original exam-style questions from the bank, spread across the blueprint domains. They are not real or recalled exam questions. Try each one, then open the answer for the rationale and reference. None of them appear in the free mock exam, so reading them will not spoil it.

1. Question 1 · Cerebrovascular Neurosurgery

   For a ruptured aneurysm judged equally suitable for clipping or coiling, what did the International Subarachnoid Aneurysm Trial show?

   1. AClipping reduced death or dependency at 1 year
   2. BCoiling reduced death or dependency at 1 year
   3. CBoth had identical outcomes and rebleed rates
   4. DCoiling had a lower late rebleeding rate
   Show answer and explanation

   Correct answer: B. Coiling reduced death or dependency at 1 year

   ISAT found an absolute reduction of about 7% in death or dependency at 1 year with endovascular coiling. Late rebleeding was slightly more frequent after coiling, so the claim of a lower late rebleed rate is wrong.

   Reference: Molyneux A, et al. ISAT, Lancet 2002

2. Question 2 · Neuroanatomy, Neurophysiology and Neuroimaging

   A 50-year-old has sudden headache with ptosis, a dilated unreactive pupil and the eye turned down and out. Which lesion is most likely?

   1. ADiabetic microvascular third nerve palsy
   2. BPosterior communicating artery aneurysm
   3. CCavernous sinus meningioma
   4. DMidbrain lacunar infarct
   Show answer and explanation

   Correct answer: B. Posterior communicating artery aneurysm

   A painful third nerve palsy involving the pupil suggests compression by a posterior communicating artery aneurysm, because the pupillomotor fibres run on the outer surface of the nerve. Diabetic microvascular palsy usually spares the pupil.

   Reference: Greenberg, Handbook of Neurosurgery, 10th ed.

3. Question 3 · Neuroanatomy, Neurophysiology and Neuroimaging

   After a stab wound to the left side of the thoracic spine, a patient has left leg weakness and loss of proprioception, with loss of pain and temperature in the right leg. What is the diagnosis?

   1. ACentral cord syndrome
   2. BAnterior cord syndrome
   3. CBrown-Sequard syndrome
   4. DConus medullaris syndrome
   Show answer and explanation

   Correct answer: C. Brown-Sequard syndrome

   Hemisection of the cord causes ipsilateral motor and dorsal column loss with contralateral spinothalamic loss, because spinothalamic fibres cross within a segment or two of entry. Anterior cord syndrome causes bilateral motor loss with preserved proprioception.

   Reference: ASIA International Standards for Neurological Classification of SCI

4. Question 4 · Neurocritical Care, Perioperative Care and Safety

   Six days after aneurysmal SAH, a patient's sodium falls to 127 mmol/L with high urine sodium, rising urine output, weight loss and low central venous pressure. What is the best management?

   1. AStrict fluid restriction to 800 mL per day
   2. BStart oral tolvaptan
   3. CGive furosemide with free water
   4. DIsotonic or hypertonic saline replacement
   Show answer and explanation

   Correct answer: D. Isotonic or hypertonic saline replacement

   Hyponatraemia with volume depletion and natriuresis after SAH suggests cerebral salt wasting, which is treated with sodium and volume replacement. Fluid restriction, the SIADH treatment, causes hypovolaemia and raises the risk of delayed cerebral ischaemia.

   Reference: Neurocritical Care Society: Management of SAH, Neurocrit Care 2011

5. Question 5 · Neurotrauma

   A 45-year-old with a GCS of 9 after an assault has an acute subdural haematoma 12 mm thick with 7 mm midline shift. What is the best management?

   1. AICP monitor and serial CT
   2. BTwist-drill drainage
   3. CRepeat CT in 6 hours
   4. DCraniotomy and evacuation
   Show answer and explanation

   Correct answer: D. Craniotomy and evacuation

   An acute subdural haematoma thicker than 10 mm or with midline shift over 5 mm should be evacuated surgically regardless of GCS. Twist-drill or burr-hole drainage suits liquefied chronic collections, not acute clotted blood.

   Reference: Brain Trauma Foundation: Surgical Management of TBI, Neurosurgery 2006

6. Question 6 · Neurotrauma

   A patient with severe traumatic brain injury is started on phenytoin. What benefit is supported by the evidence?

   1. AFewer late seizures after 1 week
   2. BLower overall mortality at 6 months
   3. CBetter functional outcome at 1 year
   4. DFewer seizures in the first 7 days
   Show answer and explanation

   Correct answer: D. Fewer seizures in the first 7 days

   Prophylactic phenytoin reduces early post-traumatic seizures (within 7 days) but does not prevent late seizures or improve mortality or functional outcome. Continuing prophylaxis long term to prevent late epilepsy is not supported.

   Reference: Temkin NR, et al. NEJM 1990; Brain Trauma Foundation 4th ed.