I85PREP
⌘ K
Arab Board Neurosurgery Final Written study materials
Arab Board Neurosurgery Final Written study resources

Arab Board Neurosurgery Final Written practice questions

One question at a time. Build your Arab Board Neurosurgery Final Written understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Neuroanatomy and Neurophysiology

Which structure passes through the foramen ovale of the sphenoid bone?

  1. The middle meningeal artery
  2. The maxillary division of the trigeminal nerve
  3. The internal carotid artery
  4. The mandibular division of the trigeminal nerve Correct answer.

Explanation

The foramen ovale transmits the mandibular division (V3) of the trigeminal nerve, along with the lesser petrosal nerve and accessory meningeal artery. Each cranial foramen has a defined contents list that must be memorized for localization.

Question 2Neuroanatomy and Neurophysiology

The corticospinal tract descends through which part of the internal capsule?

  1. The posterior limb Correct answer.
  2. The anterior limb
  3. The genu
  4. The retrolenticular part

Explanation

Motor fibers of the corticospinal and corticobulbar tracts concentrate in the posterior limb of the internal capsule, between the thalamus and lentiform nucleus. This compact arrangement explains the dense contralateral hemiparesis seen with small lacunar infarcts at this site.

Question 3Neuroanatomy and Neurophysiology

A lesion of the left oculomotor nerve produces which combination of findings?

  1. Left ptosis with the eye deviated down and out Correct answer.
  2. Right ptosis with a dilated right pupil
  3. Left ptosis with a constricted left pupil
  4. Left ptosis with the eye deviated up and in

Explanation

The oculomotor nerve supplies the levator palpebrae and all extraocular muscles except the superior oblique and lateral rectus. Unopposed action of those two muscles leaves the eye down and out, with ptosis and a dilated unreactive pupil from parasympathetic loss.

Question 4Neuroanatomy and Neurophysiology

The primary somatosensory cortex is located in which region?

  1. The postcentral gyrus of the parietal lobe Correct answer.
  2. The precentral gyrus of the frontal lobe
  3. The superior temporal gyrus
  4. The calcarine cortex of the occipital lobe

Explanation

The primary somatosensory cortex occupies the postcentral gyrus, receiving thalamocortical projections from the ventroposterior nucleus. It lies immediately posterior to the central sulcus, opposite the motor strip.

Question 5Neuroanatomy and Neurophysiology

Which cerebellar region is most concerned with the coordination of limb movements?

  1. The cerebellar hemisphere Correct answer.
  2. The tonsil
  3. The vermis
  4. The flocculonodular lobe

Explanation

The lateral cerebellar hemispheres (neocerebellum) connect with the cerebral cortex via the dentate nucleus and are responsible for the timing and coordination of skilled limb movement. Midline structures instead serve axial and vestibular functions.

Question 6Neuroanatomy and Neurophysiology

Occlusion of the anterior spinal artery at the mid-thoracic level typically spares which modality?

  1. Proprioception and vibration sense Correct answer.
  2. Motor power
  3. Sphincter function
  4. Pain and temperature sensation

Explanation

The anterior spinal artery supplies the anterior two-thirds of the cord, including the corticospinal tracts and spinothalamic fibers, but the posterior columns are supplied by the posterior spinal arteries. Dorsal column modalities are therefore spared in anterior cord infarction.

Question 7Neuroanatomy and Neurophysiology

In a lesion of the right abducens nucleus, which additional finding is expected beyond failure of right eye abduction?

  1. Ipsilateral horizontal gaze palsy Correct answer.
  2. Contralateral hemiparesis
  3. Contralateral hemianopia
  4. Ipsilateral ptosis

Explanation

The abducens nucleus contains internuclear neurons projecting to the contralateral medial rectus subnucleus via the MLF, so its destruction abolishes ipsilateral conjugate gaze rather than only abduction. This distinguishes nuclear from peripheral nerve lesions.

Question 8Neuroanatomy and Neurophysiology

A patient has a left homonymous hemianopia with macular sparing. The lesion most likely involves which structure?

  1. The right optic nerve
  2. The optic chiasm
  3. The right optic radiation with occipital cortex involvement Correct answer.
  4. The left optic tract

Explanation

Homonymous hemianopia reflects a retrochiasmal lesion contralateral to the visual field defect. Macular sparing points to occipital cortex infarction, usually from posterior cerebral artery occlusion, where the macular representation receives collateral supply.

Question 9Neuroanatomy and Neurophysiology

The thalamic nucleus that relays somatosensory information from the face is which of the following?

  1. The ventral posterolateral nucleus
  2. The ventral posteromedial nucleus Correct answer.
  3. The lateral geniculate body
  4. The medial geniculate body

Explanation

Trigeminothalamic fibers carrying facial sensation terminate in the ventral posteromedial nucleus, while body sensation relays in the ventral posterolateral nucleus. The trigeminal lemniscus therefore has a distinct thalamic target.

Question 10Neuroanatomy and Neurophysiology

Which feature best distinguishes a lower motor neuron lesion from an upper motor neuron lesion?

  1. Fasciculations Correct answer.
  2. Hyperreflexia
  3. Extensor plantar response
  4. Spasticity

Explanation

Lower motor neuron lesions cause muscle atrophy, weakness, hypotonia, areflexia, and fasciculations from denervation. Upper motor neuron lesions instead produce spasticity, hyperreflexia, and an extensor plantar response.

Question 11Neuroanatomy and Neurophysiology

Decussation of the corticospinal tract occurs in which part of the neuraxis?

  1. The midbrain
  2. The pons
  3. The caudal medulla Correct answer.
  4. The cervical spinal cord

Explanation

Most corticospinal fibers cross in the pyramidal decussation at the cervicomedullary junction, forming the lateral corticospinal tract. This crossing explains the contralateral motor deficit from a lesion above the decussation.

Question 12Neuroanatomy and Neurophysiology

A lesion at the level of the lateral pontine tegmentum on the left side is most likely to produce which combination?

  1. Ipsilateral facial weakness and contralateral hemiparesis Correct answer.
  2. Contralateral facial weakness and ipsilateral hemiparesis
  3. Ipsilateral facial weakness and ipsilateral hemiparesis
  4. Bilateral facial weakness alone

Explanation

In the pons, facial nerve fibers loop around the abducens nucleus before exiting, so a nuclear or fascicular lesion causes ipsilateral facial palsy. The corticospinal tract, which has not yet reached the medullary decussation, produces contralateral hemiparesis.

Question 13Neuroanatomy and Neurophysiology

The artery of Adamkiewicz most commonly arises from which segmental level?

  1. T8 to L1 on the left Correct answer.
  2. S1 to S3
  3. C5 to C7
  4. T4 to T6

Explanation

The great anterior radiculomedullary artery typically arises from a left lower thoracic or upper lumbar intercostal or lumbar artery, supplying the lower two-thirds of the spinal cord. Its injury during aortic surgery risks anterior cord infarction.

Question 14Neuroanatomy and Neurophysiology

Which finding indicates that a brainstem lesion lies within the medulla rather than the pons?

  1. Contralateral hemiparesis with ipsilateral tongue deviation Correct answer.
  2. Ipsilateral facial palsy
  3. Contralateral hemianopia
  4. Ipsilateral abducens palsy

Explanation

Hypoglossal nerve fibers exit the medulla, so a medullary lesion produces ipsilateral tongue deviation toward the weak side, combined with contralateral hemiparesis from corticospinal involvement. Abducens and facial palsies localize to the pons.

Question 15Neuroanatomy and Neurophysiology

Which neurotransmitter is the principal excitatory mediator at the neuromuscular junction?

  1. Glutamate
  2. Gamma-aminobutyric acid
  3. Glycine
  4. Acetylcholine Correct answer.

Explanation

Motor neurons release acetylcholine, which binds nicotinic receptors on the motor end plate to depolarize muscle. This is why acetylcholinesterase inhibitors and nicotinic blockers act at this synapse.

Question 16Neuroanatomy and Neurophysiology

Destruction of the left medial longitudinal fasciculus produces which clinical sign?

  1. Bilateral ptosis with pupillary dilation
  2. Impaired abduction of the left eye with diplopia
  3. Impaired adduction of the right eye with nystagmus of the left eye on left gaze Correct answer.
  4. Downward deviation of the right eye at rest

Explanation

The MLF carries internuclear fibers from the contralateral abducens nucleus to the medial rectus subnucleus. A left MLF lesion therefore impairs adduction of the right eye during leftward gaze, with abducting nystagmus of the left eye, defining an internuclear ophthalmoplegia.

Question 17Neuroimaging and Diagnostic Evaluation

On a non-contrast CT scan of the head, acute intraparenchymal hemorrhage typically appears as which of the following?

  1. A region of fat density with calcification
  2. A hyperdense region within the brain parenchyma Correct answer.
  3. A hypodense region with mass effect
  4. An isodense region with no mass effect

Explanation

Fresh blood clot retracts and concentrates protein, raising attenuation to roughly 60–80 HU, so acute hemorrhage appears hyperdense relative to brain on non-contrast CT. Density then declines over days to weeks as the clot breaks down, becoming isodense and later hypodense.

Question 18Neuroimaging and Diagnostic Evaluation

Which MRI sequence is most sensitive for detecting acute subarachnoid hemorrhage when CT is negative and the patient presents several days after the ictus?

  1. Susceptibility-weighted imaging
  2. FLAIR Correct answer.
  3. Diffusion-weighted imaging
  4. T1-weighted imaging

Explanation

FLAIR suppresses CSF signal, so blood products in the subarachnoid space stand out as hyperintensity even when they are no longer visible on CT. FLAIR remains sensitive for subarachnoid blood over several days, which is the main reason it is included in the standard brain protocol for suspected hemorrhage.

Question 19Neuroimaging and Diagnostic Evaluation

A patient with a suspected pituitary macroadenoma is being planned for transsphenoidal surgery. Which imaging study best defines the relationship of the tumor to the cavernous sinus and internal carotid arteries?

  1. Contrast-enhanced MRI of the sella with thin slices Correct answer.
  2. Plain skull radiograph
  3. Non-contrast CT of the sella
  4. Carotid Doppler ultrasound

Explanation

Thin-slice gadolinium-enhanced MRI of the pituitary region is the standard for delineating macroadenomas and assessing cavernous sinus invasion and encasement of the internal carotid arteries. The high soft-tissue contrast and multiplanar capability of MRI make it superior to CT for this purpose.

Question 20Neuroimaging and Diagnostic Evaluation

Which finding on CT most strongly suggests that a traumatic epidural hematoma is present?

  1. Bilateral diffuse cerebral edema
  2. A crescent-shaped collection crossing suture lines
  3. A biconvex collection that does not cross suture lines Correct answer.
  4. Subarachnoid blood in the basal cisterns

Explanation

Epidural hematomas are bounded by dural attachments at the cranial sutures, producing a lens-shaped (biconvex) collection that does not cross sutures. Subdural hematomas, in contrast, spread freely under the dura and cross suture lines.

Question 21Neuroimaging and Diagnostic Evaluation

In a patient with acute ischemic stroke, what is the principal advantage of CT perfusion imaging over non-contrast CT alone?

  1. It measures intracranial pressure non-invasively
  2. It directly identifies the site of arterial occlusion
  3. It detects old microhemorrhages
  4. It distinguishes salvageable penumbra from irreversibly infarcted core Correct answer.

Explanation

CT perfusion maps cerebral blood flow, cerebral blood volume, and mean transit time, allowing the ischemic core to be separated from the hypoperfused but potentially salvageable penumbra. This information guides reperfusion decisions, particularly in patients presenting beyond the standard thrombolysis window.

Question 22Neuroimaging and Diagnostic Evaluation

Which MRI finding is characteristic of a cerebral abscess cavity on post-contrast imaging?

  1. A thin smooth enhancing wall with central low T1 signal
  2. A ring of enhancement with a complete, thin, uniform wall and restricted central diffusion Correct answer.
  3. A hyperintense lesion on T1 without enhancement
  4. A heterogeneous mass with calcification and no enhancement

Explanation

A pyogenic abscess classically shows a thin, complete, uniform enhancing rim with a necrotic center that restricts diffusion (low apparent diffusion coefficient). The restricted diffusion of pus helps distinguish abscess from a necrotic tumor, whose center usually does not restrict as strongly.

Question 23Neuroimaging and Diagnostic Evaluation

A patient has a suspected cerebral aneurysm with a negative CT angiogram but continued clinical concern. Which study is the reference standard for detecting a small aneurysm?

  1. Radionuclide cisternography
  2. Magnetic resonance venography
  3. Digital subtraction angiography Correct answer.
  4. Transcranial Doppler

Explanation

Digital subtraction angiography remains the reference standard for cerebral aneurysm detection because of its high spatial resolution and ability to show small or complex aneurysms that may escape non-invasive studies. It also permits immediate endovascular treatment when an aneurysm is found.

Question 24Neuroimaging and Diagnostic Evaluation

Which sequence best demonstrates the extent of a spinal epidural abscess and its relationship to the spinal cord and nerve roots?

  1. Non-contrast CT of the lumbar spine
  2. Contrast-enhanced MRI of the whole spine Correct answer.
  3. Bone scan
  4. Plain radiographs of the spine

Explanation

Gadolinium-enhanced MRI is the study of choice for spinal epidural abscess because it shows the collection, its craniocaudal extent, cord compression, and associated discitis or osteomyelitis. Imaging the whole spine is important because epidural abscesses can be multifocal.

Question 25Neuroimaging and Diagnostic Evaluation

A patient with a known glioblastoma is being assessed for tumor recurrence versus treatment-related change after chemoradiation. Which imaging approach is most useful?

  1. Perfusion MRI and MR spectroscopy Correct answer.
  2. Non-contrast CT
  3. Plain skull radiograph
  4. Carotid ultrasound

Explanation

Perfusion MRI (relative cerebral blood volume) and MR spectroscopy help separate true tumor progression, which shows increased perfusion and altered metabolite ratios such as elevated choline, from radiation necrosis, which is relatively hypoperfused. These advanced techniques are commonly used when conventional contrast-enhanced imaging is ambiguous.

Question 26Neuroimaging and Diagnostic Evaluation

Which imaging modality is preferred for the initial evaluation of a suspected cervical spine fracture in an awake, hemodynamically stable trauma patient?

  1. CT of the cervical spine Correct answer.
  2. MRI of the cervical spine
  3. Plain radiographs in three views
  4. Flexion-extension radiographs

Explanation

CT of the cervical spine is the preferred initial study in stable trauma patients because of its high sensitivity for fractures and rapid acquisition. MRI is reserved for suspected ligamentous injury, cord injury, or when the patient cannot be clinically cleared.

Question 27Neuroimaging and Diagnostic Evaluation

A patient has a suspected spontaneous intracranial hypotension with postural headache. Which MRI finding supports the diagnosis?

  1. Enlarged ventricles with transependymal edema
  2. Multiple ring-enhancing parenchymal lesions
  3. Diffuse pachymeningeal enhancement with sagging of the brain Correct answer.
  4. Hyperdense basal cisterns

Explanation

Spontaneous intracranial hypotension produces low CSF volume, leading to diffuse dural enhancement, brain sagging, subdural collections, and venous engorgement. These findings reflect the Monro-Kellie principle, in which loss of CSF volume is compensated by vascular and meningeal changes.

Question 28Neuroimaging and Diagnostic Evaluation

Which MRI sequence is most useful for detecting small deposits of hemosiderin, such as after multiple prior hemorrhages?

  1. T2-weighted imaging
  2. T1-weighted imaging
  3. Susceptibility-weighted imaging Correct answer.
  4. Proton density imaging

Explanation

Susceptibility-weighted imaging exploits the magnetic properties of hemosiderin and other blood breakdown products, producing marked signal loss (blooming) that makes even small deposits conspicuous. This makes it valuable for detecting microbleeds and superficial siderosis.

Question 29Neuroimaging and Diagnostic Evaluation

On CT, which feature favors a diagnosis of a colloid cyst over a simple arachnoid cyst at the foramen of Monro?

  1. Calcification of the cyst wall
  2. Marked enhancement after contrast
  3. Hyperdensity relative to CSF with a location at the foramen of Monro Correct answer.
  4. CSF density and no enhancement

Explanation

Colloid cysts typically contain viscid material and appear hyperdense relative to CSF on non-contrast CT, characteristically at the foramen of Monro. Arachnoid cysts follow CSF density and do not restrict or obstruct in the same way.

Question 30Neuroimaging and Diagnostic Evaluation

A patient has a suspected dural arteriovenous fistula. Which study best demonstrates the arterial supply, venous drainage, and cortical venous reflux?

  1. Catheter cerebral angiography Correct answer.
  2. Transcranial Doppler
  3. MR venography
  4. CT of the head without contrast

Explanation

Catheter cerebral angiography is the definitive study for dural arteriovenous fistulas because it shows the arterial feeders, the fistula site, and the pattern of venous drainage, including cortical venous reflux that determines hemorrhage risk. Non-invasive studies may suggest the diagnosis but cannot fully characterize the angioarchitecture.

Question 31Neuroimaging and Diagnostic Evaluation

Which imaging finding on MRI is most characteristic of a Chiari I malformation?

  1. Absence of the corpus callosum
  2. Cerebellar tonsillar descent below the foramen magnum Correct answer.
  3. Enlargement of the fourth ventricle with a cystic posterior fossa
  4. Upward herniation of the cerebellar vermis

Explanation

Chiari I malformation is defined by downward displacement of the cerebellar tonsils through the foramen magnum, often with a peg-like appearance and crowded posterior fossa. Associated findings include syringomyelia and impaired CSF flow at the craniovertebral junction.

Question 32Neuroimaging and Diagnostic Evaluation

A patient with a suspected cerebral venous sinus thrombosis has an equivocal non-contrast CT. Which study is most appropriate to confirm the diagnosis?

  1. Non-contrast MRI of the brain
  2. MR venography or CT venography Correct answer.
  3. Carotid Doppler ultrasound
  4. Radionuclide perfusion scan

Explanation

Venous imaging with MR venography or CT venography directly demonstrates absent flow or filling defects in the dural sinuses and is the appropriate confirmatory study. Non-contrast MRI may show indirect signs such as venous infarction but does not reliably exclude thrombosis.

Question 33Neurotrauma and Critical Care

A 24-year-old man is brought in after a motorcycle crash with a Glasgow Coma Scale score of 5. According to Advanced Trauma Life Support principles, which manoeuvre is the most appropriate first step to secure his airway?

  1. Awake fibreoptic intubation in the sitting position
  2. Insertion of an oropharyngeal airway alone
  3. Urgent cricothyroidotomy
  4. Orotracheal intubation with in-line cervical stabilisation Correct answer.

Explanation

Definitive airway control in a patient with a GCS of 8 or less requires intubation, and in trauma this is performed with manual in-line cervical stabilisation to protect a potentially injured spine. Simple airway adjuncts do not protect against aspiration or provide definitive ventilation. Surgical airway is reserved for failed intubation or an obstructed airway that cannot be bypassed.

Question 34Neurotrauma and Critical Care

Which finding on a computed tomography scan of the head most strongly indicates the need for urgent surgical evacuation in a patient with a traumatic intracranial haematoma?

  1. An acute subdural collection exceeding 10 mm in thickness with midline shift Correct answer.
  2. A punctate traumatic subarachnoid haemorrhage in the basal cisterns
  3. A thin crescent of hyperdensity over the convexity with no mass effect
  4. A small contusion in the frontal pole measuring 8 mm

Explanation

Acute subdural haematoma thickness greater than 10 mm or midline shift greater than 5 mm are established operative indications regardless of the patient's neurological status. Small convexity collections without mass effect, isolated traumatic subarachnoid blood, and small polar contusions are typically managed conservatively with observation.

Question 35Neurotrauma and Critical Care

A patient with a severe traumatic brain injury has an intracranial pressure of 26 mmHg and a mean arterial pressure of 80 mmHg. What is the cerebral perfusion pressure, and what is the recommended lower target for it in adults?

  1. 54 mmHg; target at least 60 mmHg Correct answer.
  2. 54 mmHg; target at least 80 mmHg
  3. 106 mmHg; target at least 60 mmHg
  4. 106 mmHg; target at least 80 mmHg

Explanation

Cerebral perfusion pressure equals mean arterial pressure minus intracranial pressure, giving 54 mmHg here. Current adult guidelines recommend maintaining a cerebral perfusion pressure of at least 60 mmHg, with avoidance of aggressive attempts to exceed 70 mmHg in most patients.

Question 36Neurotrauma and Critical Care

Which cervical spine clearance statement is correct for an alert, asymptomatic trauma patient with no distracting injury?

  1. A normal plain radiograph series alone is sufficient for clearance
  2. Magnetic resonance imaging is mandatory before removing a collar in every patient
  3. Dynamic flexion-extension views are required in all patients before clearance
  4. Clinical clearance can be performed if the patient is fully alert with no midline tenderness and a normal neurological examination Correct answer.

Explanation

In the awake, asymptomatic patient without distracting injury, clinical clearance using validated criteria such as the NEXUS or Canadian C-spine rule is appropriate and avoids unnecessary imaging. Imaging is reserved for patients who fail clinical criteria. Flexion-extension views and routine MRI are not required in this low-risk group.

Question 37Neurotrauma and Critical Care

A 30-year-old pedestrian is hypotensive after a head injury. Which statement best reflects the relationship between systemic hypotension and outcome in traumatic brain injury?

  1. A single episode of systolic blood pressure below 90 mmHg worsens neurological outcome Correct answer.
  2. Hypotension has little effect provided the intracranial pressure is controlled
  3. Hypertension should be avoided because it always worsens haemorrhage
  4. Permissive hypotension is the preferred strategy to reduce bleeding

Explanation

Systemic hypotension, defined as systolic blood pressure below 90 mmHg, is a powerful independent predictor of poor outcome after traumatic brain injury and must be corrected promptly. Maintaining adequate perfusion takes priority because secondary ischaemic injury compounds the primary insult.

Question 38Neurotrauma and Critical Care

Which clinical sign is the earliest reliable indicator of transtentorial herniation in a patient with an expanding supratentorial mass?

  1. A deteriorating level of consciousness with an ipsilateral dilated pupil Correct answer.
  2. Bilateral fixed dilated pupils
  3. Decerebrate posturing in all four limbs
  4. Papilloedema on fundoscopy

Explanation

Early uncal herniation compresses the third nerve, producing an ipsilateral dilated pupil, while progressive brainstem compression causes declining consciousness. Bilateral fixed pupils and decerebrate posturing indicate advanced, often irreversible brainstem compromise. Papilloedema reflects chronically raised pressure rather than acute herniation.

Question 39Neurotrauma and Critical Care

Which of the following best describes the recommended initial management of a patient with a Glasgow Coma Scale score of 13 after a minor head injury and a normal computed tomography scan?

  1. Immediate discharge without observation
  2. Observation for a period with written head injury advice Correct answer.
  3. Admission for intracranial pressure monitoring
  4. Urgent decompressive craniectomy

Explanation

A patient with a GCS of 13 and a normal scan is at low but non-zero risk of deterioration and should be observed with clear return precautions. Intracranial pressure monitoring and surgery are reserved for significant intracranial pathology. Discharge without observation risks missing delayed deterioration.

Question 40Neurotrauma and Critical Care

Which factor is the strongest predictor of outcome after severe traumatic brain injury in adults?

  1. Initial haemoglobin concentration
  2. Time from injury to arrival at hospital
  3. Presence of a scalp laceration
  4. Age of the patient Correct answer.

Explanation

Increasing age is one of the most consistent and powerful independent predictors of poor outcome after severe traumatic brain injury, alongside the motor component of the Glasgow Coma Scale and pupillary reactivity. Scalp laceration, haemoglobin level, and transport time are not established independent prognostic factors of comparable weight.

Question 41Neurotrauma and Critical Care

A patient with a severe head injury develops diabetes insipidus with high urine output and rising serum sodium. Which abnormality is most likely responsible?

  1. Deficiency of antidiuretic hormone Correct answer.
  2. Deficiency of atrial natriuretic peptide
  3. Excess antidiuretic hormone secretion
  4. Excess aldosterone secretion

Explanation

Diabetes insipidus after head injury results from damage to the hypothalamic-pituitary axis with deficient antidiuretic hormone release, producing dilute urine and hypernatraemia. Excess antidiuretic hormone causes the opposite picture of fluid retention and hyponatraemia. Aldosterone and atrial natriuretic peptide do not produce this pattern.

Question 42Neurotrauma and Critical Care

Which statement about the use of hypertonic saline in raised intracranial pressure is correct?

  1. It is contraindicated in all patients with hyponatraemia
  2. It acts by increasing serum osmolality and drawing water from brain tissue Correct answer.
  3. It has no role when mannitol has failed
  4. It lowers serum osmolality to reduce cerebral oedema

Explanation

Hypertonic saline raises serum osmolality, creating an osmotic gradient that moves water out of brain tissue and reduces intracranial pressure. It can be used when mannitol fails and is sometimes preferred in haemodynamically unstable patients. Its effect depends on raising, not lowering, osmolality.

Question 43Neurotrauma and Critical Care

A patient with a depressed skull fracture over the frontal sinus is being assessed. Which feature most strongly indicates the need for surgical elevation?

  1. A fracture depressed by 3 mm with no neurological deficit
  2. A fracture with associated pneumocephalus and cerebrospinal fluid leak Correct answer.
  3. A closed fracture with overlying scalp haematoma
  4. A linear fracture extending into the orbital roof

Explanation

Depressed fractures associated with dural breach, pneumocephalus, or cerebrospinal fluid leak require elevation and dural repair to prevent infection. Small depressions without deficit or dural breach may be managed conservatively. Linear extensions and overlying haematoma alone do not mandate surgery.

Question 44Neurotrauma and Critical Care

Which physiological target is recommended during the ICU management of a patient with severe traumatic brain injury?

  1. Permit hyperthermia to reduce infection risk
  2. Maintain hyperventilation with carbon dioxide around 25 mmHg throughout
  3. Maintain normocapnia with arterial carbon dioxide around 35 to 38 mmHg Correct answer.
  4. Maintain mean arterial pressure below 60 mmHg to reduce oedema

Explanation

Normocapnia is the standard target because both hypo- and hypercapnia alter cerebral blood flow adversely; hyperventilation is reserved for brief rescue of impending herniation. Hyperthermia worsens outcome and should be treated. Hypotension reduces cerebral perfusion and must be avoided.

Question 45Neurotrauma and Critical Care

A patient with a traumatic acute subdural haematoma is being prepared for surgery. Which factor most strongly influences the decision to operate regardless of the initial Glasgow Coma Scale score?

  1. Presence of a small contralateral contusion
  2. Thickness of the haematoma greater than 10 mm or midline shift greater than 5 mm Correct answer.
  3. The mechanism of injury
  4. The patient's age

Explanation

Haematoma thickness greater than 10 mm or midline shift greater than 5 mm are independent operative indications in acute subdural haematoma, irrespective of the initial Glasgow Coma Scale. Age, mechanism, and small contralateral contusions influence prognosis but are not the primary operative criteria.

Question 46Neurotrauma and Critical Care

Which finding on a computed tomography scan is most consistent with diffuse axonal injury?

  1. A large extradural haematoma at the vertex
  2. A depressed parietal fracture with underlying contusion
  3. An isolated temporal epidural collection
  4. Punctate haemorrhages at the grey-white junction and corpus callosum Correct answer.

Explanation

Diffuse axonal injury characteristically produces small haemorrhagic lesions at the grey-white matter junction, corpus callosum, and brainstem after rotational acceleration-deceleration forces. Extradural collections and focal contusions under a fracture reflect different, focal injury mechanisms.

Question 47Neurotrauma and Critical Care

A patient with a severe traumatic brain injury is being monitored with jugular venous oxygen saturation. A value persistently below 50 percent most likely indicates which physiological state?

  1. Global cerebral ischaemia with inadequate blood flow Correct answer.
  2. Complete brain death
  3. Normal cerebral oxygen metabolism
  4. Cerebral hyperaemia with luxury perfusion

Explanation

Jugular venous oxygen saturation below 50 percent indicates that the brain is extracting an increased fraction of delivered oxygen, consistent with inadequate cerebral blood flow or global ischaemia. Values above 75 percent suggest hyperaemia or, in the extreme, absent metabolism. Normal values lie approximately between 55 and 75 percent.

Question 48Neurotrauma and Critical Care

Which statement about decompressive craniectomy for severe traumatic brain injury is correct?

  1. It reliably improves functional outcome in all patients with raised intracranial pressure
  2. It should replace medical management of raised intracranial pressure
  3. It is contraindicated in patients under 40 years of age
  4. It reduces intracranial pressure but may increase the proportion of survivors with severe disability Correct answer.

Explanation

Decompressive craniectomy effectively lowers intracranial pressure and reduces mortality, but randomised evidence shows an increased proportion of survivors with severe disability compared with medical management. It is therefore a second-tier option after medical therapy fails, not a universal or first-line treatment.

Question 49Neurotrauma and Critical Care

A patient with a traumatic brain injury develops a fixed dilated pupil and arterial hypertension with bradycardia. Which physiological sequence best explains these findings?

  1. Increased intracranial pressure causing brainstem compression with sympathetic surge and vagal bradycardia Correct answer.
  2. Hypovolaemia producing reflex tachycardia and hypotension
  3. Acute adrenal insufficiency with loss of vasomotor tone
  4. Primary cardiogenic shock with cerebral hypoperfusion

Explanation

The Cushing reflex results from raised intracranial pressure compressing brainstem structures, producing hypertension from sympathetic activation and bradycardia from vagal response. This triad signals impending herniation and requires urgent decompression. The other options describe states that produce hypotension or tachycardia rather than this pattern.

Question 50Neurotrauma and Critical Care

Which measure is most effective for preventing ventilator-associated pneumonia in a patient with a severe head injury who is mechanically ventilated?

  1. Continuous deep sedation
  2. Daily chest radiographs
  3. Routine prophylactic broad-spectrum antibiotics
  4. Elevating the head of the bed and maintaining cuff pressure with subglottic suction Correct answer.

Explanation

A ventilator care bundle including head-of-bed elevation, cuff pressure control, and subglottic secretion drainage reduces ventilator-associated pneumonia. Routine prophylactic antibiotics promote resistance, daily radiographs do not prevent pneumonia, and deep sedation without interruption prolongs ventilation.