NEUROSURGERY MCQ with Answers (FRCS Neurosurgery/ INI SS – MCh Neurosurgery)

Explanation:

Oligodendroglioma

• slow growing tumor that frequently presents with seizures
• occur primarily in adults, predilection for the frontal lobes
• by definition: a diffusely infiltrating glioma with codeletion of BOTH chromosome arms 1p AND
• 19q, AND mutation of IDH1 OR IDH2
• histology: classic features of “fried egg” cytoplasm (on permanent pathology) & “chicken wire” vasculature are unreliable. Calcifications are common
• recommended treatment: as for WHO grade II astrocytic tumors

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 36

Explanation:

A variety of infectious organisms can cause cavernous sinus thrombosis although the majority are bacterial. Staphylococcus aureus may account for two-thirds of cases, and methicillin resistance should be considered

Ref: https://www.ncbi.nlm.nih.gov/books/NBK448177/

Explanation:

• Acute SDH(Hyperdense on CT): <3 days
• Subacute SDH(Isodense on CT): 4-21 days
• Chronic SDH(Hypodense on CT): >21 days

Chronic SDH

• Chronic SDH: Collection of blood breakdown products that is more than 21 days old
• Chronic SDHs often occur in patients without a clear history of head trauma, as they may arise from minor trauma
• Alcoholics, the elderly, and patients on anticoagulation are at higher risk for developing chronic SDH
• Patients may present with headache, seizure, confusion, contralateral hemiparesis, or coma

Treatment

• A chronic SDH >1 cm or any symptomatic SDH should be surgically drained.
• Chronic SDH typically consists of a viscous fluid, with a texture and dark brown color reminiscent of motor oil.
• A simple burr hole can effectively drain most chronic SDHs.

Reference: Greenberg 9th Edition Chapter 55

Explanation:

• The nerve fibers in the marginal zone of the developing neural tube become myelinated and form the white matter of the spinal cord.
• The wall of the neural tube is formed of a single layer of pseudostratified columnar epithelial cells
• The neuroblasts migrate peripherally to form the Intermediate zone
• The repeated division of the matrix cells of the neural tube results in an increase in the length and diameter of the tube.
• The Intermediate zone of the neural tube will form the gray matter of the spinal cord.

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

Explanation:

• The neural crest cells give rise to the posterior root ganglia.
• The neural crest cells are formed from the lateral margin of the neural plate
• The neural crest cells form the neurons of the autonomic ganglia
• The Schwann cells of peripheral nerves are formed from neural crest cells
• The neural crest cells form the cells of the suprarenal medulla

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

Explanation:

Oligodendroglioma

• slow growing tumor that frequently presents with seizures
• occur primarily in adults, predilection for the frontal lobes
• by definition: a diffusely infiltrating glioma with codeletion of BOTH chromosome arms 1p AND
• 19q, AND mutation of IDH1 OR IDH2
• histology: classic features of “fried egg” cytoplasm (on permanent pathology) & “chicken wire” vasculature are unreliable. Calcifications are common
• recommended treatment: as for WHO grade II astrocytic tumors

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 36

Explanation:

• Brodmann’s area 6: Premotor area or supplemental motor area. Immediately anterior to motor strip, it plays a role in contralateral motor programming.
• Brodmann’s Areas 3, 1, 2: primary somatosensory cortex
• Brodmann’s. area 4: precentral gyrus, primary motor cortex (AKA “motor strip”). Large concentration of giant pyramidal cells of Betz
• Brodmann’s areas 41 & 42: primary auditory areas (transverse gyri of Heschl)

Explanation:

The following agents are considered “broad spectrum” (treat a variety of seizure types):

• valproic acid
• lamotrigine (Lamictal®)
• levetiracetam (Keppra®)

These agents are not considered broad spectrum:

• phenytoin (Dilantin®)
• carbamazepine (Tegretol®)

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 26

Explanation:

• On November 25, 1884, Mr. Rickman J. Godlee performed the first recognized resection of a primary brain tumor. This operation was carried out at the suggestion of Dr. A. Hughes Bennett
• Gliomas initially classified by Bailey and Cushing (1926)

Ref- The first primary brain-tumor operation- https://pubmed.ncbi.nlm.nih.gov/6387062/

Explanation:

Central neurocytoma (WHO grade II)

• rare, WHO Grade II neuronal tumor
• primarily seen in young adults. Typically intraventricular, attached to septum pellucidum
• gross total resection can be curative (but some recur even after GTR)
• if MIB-1 labeling index > 2–4%, there is an increased risk of recurrence after subtotal resection
• if MIB-1 labeling is elevated, radiation therapy after subtotal resection can reduce the risk of recurrence

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 38

Explanation:

• The carotid siphon is the S-shaped part of the ICA which begins at the posterior bend of the cavernous ICA and ends at the ICA bifurcation.
• The intracavernous and the supraclinoid segments of the ICA make up the carotid siphon.
• Begins at the posterior bend of the cavernous ICA and ends at the ICA bifurcation

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 2.

Answer: A

Explanation

• MC cause is hypertension, causing rupture of small perforating arteries or arterioles
• MC site: Basal ganglia (Putamen)

• Intracerebral Hemorrhage is the second most common form of stroke (15–30% of strokes), but the most deadly
• unlike ischemic infarct: smooth progressive onset over minutes to hours, often with severe headache, vomiting, and alterations in level of consciousness
• unenhanced CT scan of the brain is the initial diagnostic study of choice
• the volume of the hematoma correlates highly with morbidity and mortality
• ICH enlarges in > 33% of cases within the first 3 hours of onset
• worse prognosis for patient on anticoagulants or with elevated cardiac troponins
• additional diagnostics (e.g. CTA, catheter angiogram, MRV…) if suspicion of underlying abnormality (e.g. AVM, dural sinus thrombosis, neoplasm…)
• hypertension (SBP > 150 mm Hg): reduce SBP to 140
• surgery

1. a) supratentorial ICH: still controversial. Surgery does not improve neurologic outcome, but may reduce length of ICU stay and mortality
2. b) cerebellar ICH with neurologic deterioration, or brainstem compression, or obstructive hydrocephalus from intraventricular clot: surgical evacuation ASAP (initial treatment with EVD is not recommended)

Reference: Greenberg 9th Edition Chapter 84

Explanation:

Causes of hyperintensity on TI are paramagnetic effect of hemorrhage (subacute or chronic), paramagnetic material melanin ion, very high protein content, fat (teratoma, dermoid lipoma) and in flow related enhancement in tumor vessels.

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 13

Explanation:

CEREBRAL CORTEX STRUCTURE

• Made up of six identifiable layers.
• In the motor cortex in the precentral gyrus, the second and fourth layers lack granular cells.
• Third and Fifth layers in the somesthetic cortex in the postcentral gyrus lack pyramidal cells.
• The motor cortex is thicker than the sensory cortex.

Topic : Introduction and Organization of the Nervous System| Neuroanatomy

Reference: Snell’s Anatomy 8^th Edition, Chapter 1

Answer: A

Explanation:

Berry aneurysms: MC intracranial aneurysm, saccular in appearance, arising at the bifurcation of intracranial arteries.

About 85% aneurysms occur in the anterior circulation

Following 3 most common locations:

• ACoA (single most common): 30%
• P-comm: 25%
• Middle cerebral artery (MCA): 20%

5–15% in posterior circulation (vertebro-basilar)

≈ 10% on basilar artery: basilar bifurcation, AKA basilar tip, is the most common in basilar, followed by

BA-SCA, BA-VA junction, AICA

≈ 5% on vertebral artery: VA-PICA junction is the most common in vertebral art

20–30% of aneurysm patients have multiple aneurysms

Reference: Greenberg 9th Edition Chapter 74

Explanation:

• The precentral gyrus (face area) is supplied by the middle cerebral artery
• The face area of the postcentral gyrus is supplied by the middle cerebral artery.
• The cuneus is supplied by the posterior cerebral artery
• The Inferior temporal gyros is supplied by the posterior cerebral artery
• The Wernicke area is supplied by the middle cerebral artery

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 17

Explanation:

Middle meningeal artery (MMA) embolization is a minimally invasive potential option for treating chronic SDH (CSDH). Membranes of the CSDH contain friable neovasculature that may be responsible for repeated rebleeding into the subdural space and may contribute to recurrence after surgical evacuation. It has been shown to be safe and effective in small series as treatment for recurrent CSDH as well as for primary treatment, and larger trials are anticipated.

Technique (summary): angiography of the common and external carotid arteries is performed on the affected side. The distal MMA vasculature may exhibit irregular wispiness. The MMA is selectively catheterized using a microcatheter, and 150–250 micron diameter polyvinyl alcohol particles100 or 15–20% n-butyl-2-cyanoacrylate98 is injected under fluoro roadmap until there is flow stasis. Post-injection angio confirms effective MMA embolization. Branches to avoid: potential ophthalmic collaterals and branches supplying cranial nerves.

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 102.

Explanation:

• The p53 protein is coded by a tumor suppressor gene on chromosome 17p 13.1.

Li-Fraumeni syndrome

• Rare (< 400 families identified) inherited autosomal dominant disorder of children and young adults with predominat soft-tissue sarcomas, osteosarcomas, breast cancer brain tumors and adrenocortical carcinoma.
• Usually caused by a germline mutation in the TP53 tumor suppressor gene on chromosome 17p13.
• There are 3 main sets of criteria for diagnosing Li-Fraumeni-like syndrome: LFL-E2 definition, LFL-B definition & the Chompret criteria.
• CNS tumors show a bimodal age distribution: 1) in children (primarily medulloblastomas & related embryonal tumors), and 2) in age 20–40 (primarily astrocytic neoplasms).

All except D affect the 3rd nerve. But when pilocarpine is instilled, it acts directly on the muscarinic receptor (M3) found on the iris sphincter muscle, causing the muscle to contract and engage in miosis. If miosis does not occur with pilocarpine, it indicates that the muscarinic receptor on the the iris sphincter muscle is blocked – hence pharmacologic blockade is the answer.

A pharmacologically dilated pupil is very large (7–8 mm), and is larger than typical mydriasis due to third nerve compression (5–6 mm).

To differentiate pharmacologic pupil from a third nerve lesion: instill 1% pilocarpine (a parasympathomimetic) in both eyes (for comparison). A pharmacologic pupil does not constrict, whereas the normal side and a dilated pupil from a third nerve palsy will.

Explanation:

Drugs indicated for Absence Seizures

• ethosuximide – Drug of Choice
• valproic acid (VA)
• clonazepam
• methsuximide

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 26

Explanation:

• AKA Originally known as the Bernhardt-Roth syndrome, and sometimes called “swashbuckler’s disease,” meralgia paresthetica (MP
• caused by entrapment of the lateral femoral cutaneous nerve (LFCN) of the thigh (a purely sensory branch with contributions from L2 and L3 nerve roots,
• Location: where it enters the thigh through the opening between the inguinal ligament and its attachment to the anterior superior iliac spine (ASIS).

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 30

Explanation:

• A deviation of the mouth on smiling, which disappear on voluntary movement, constitute the so called ‘Emotional Facial Weakness’. This occurs in deep seated lesions of the opposite thalamus, or its connection with frontal lobe

Explanation:

Velocity-dependent resistance to passive muscle stretch usually due to upper motor neuron lesion. Symptoms include muscle tightness, cramping/pain, and fatigue. It is due to a loss of descending GABA inhibition of muscle groups resulting in hypertonia (coactivation of agonist and antagonist muscles during volitional movement).

Spasticity results from lesions in upper motor neuron pathways, causing absence of inhibitory influence on alpha motor neurons (αMN) (alpha spasticity) as well as on gamma motor neurons (intrafusal fibers) (gamma spasticity). Result: uninhibited reflex arc between αMN and Ia afferents from muscle spindles, resulting in a hypertonic state of muscles with clonus, and sometimes with involuntary movements. Etiologies include: injury to cerebrum (e.g. stroke) or spinal cord (spasticity is an expected sequelae of spinal cord injury rostral to the conus medullaris), multiple sclerosis, and congenital abnormalities (e.g. cerebral palsy, spinal dysraphism)

Ref:

• https://www.frontiersin.org/articles/10.3389/fneur.2010.00149/full
• Greenberg 9^th Ed, Ch 98

Head trauma is the most common cause of SAH. In patients without head trauma, SAH is most commonly caused by a brain aneurysm.

Berry aneurysms: MC intracranial aneurysm, saccular in appearance, arising at the bifurcation of intracranial arteries.

About 85% aneurysms occur in the anterior circulation

Following 3 most common locations:

• ACoA (single most common): 30%
• P-comm: 25%
• Middle cerebral artery (MCA): 20%

5–15% in posterior circulation (vertebro-basilar)

≈ 10% on basilar artery: basilar bifurcation, AKA basilar tip, is the most common in basilar, followed by

BA-SCA, BA-VA junction, AICA

≈ 5% on vertebral artery: VA-PICA junction is the most common in vertebral art

20–30% of aneurysm patients have multiple aneurysms

Reference: Greenberg 9th Edition Chapter 74

Explanation: 8 to 12 vessels course over the disc margin and the darker arterioles are approx 2/3rd the size of the light-colored venules

AKA choked (optic) disc. Thought to be caused by axoplasmic stasis. One theory: elevated ICP is transmitted through the subarachnoid space of the optic nerve sheath to the region of the optic disc.

Elevated ICP will usually obliterate retinal venous pulsation if the pressure is transmitted to the point where the central retinal vein passes through the subarachnoid space (≈ 1 cm posterior to the globe).

Papilledema (PPD) may also be dependent on the ratio of retinal arterial to retinal venous pressure, with ratios < 1.5:1 more commonly associated with papilledema than higher ratios.

Elevated ICP generally causes bilateral papilledema.

Papilledema may appear similar to optic neuritis on funduscopy, but the latter is usually associated with more severe visual loss and tenderness to eye pressure over the eye.

Pseudopapilledema may mimic papilledema in that the optic disc may appear swollen, but, unlike true papilledema, the peripapillary vessels are not obscured. It may be unilateral or bilateral. There are a number of benign conditions that can cause pseudopapilledema (including a small optic cup, buried disc drusen…), and extensive workup is generally not indicated.

Papilledema typically takes 24–48 hours to develop following a sustained rise in ICP. It is rarely seen as early as ≈ 6 hours after onset, but not earlier. Papilledema does not cause visual blurring or reduction of visual fields unless very severe and prolonged.

Answer:D

Explanation:

• Acute SDH(Hyperdense on CT): <3 days
• Subacute SDH(Isodense on CT): 4-21 days
• Chronic SDH(Hypodense on CT): >21 days

Chronic SDH

• Chronic SDH: Collection of blood breakdown products that is more than 21 days old
• Chronic SDHs often occur in patients without a clear history of head trauma, as they may arise from minor trauma
• Alcoholics, the elderly, and patients on anticoagulation are at higher risk for developing chronic SDH
• Patients may present with headache, seizure, confusion, contralateral hemiparesis, or coma

Treatment

• A chronic SDH >1 cm or any symptomatic SDH should be surgically drained.
• Chronic SDH typically consists of a viscous fluid, with a texture and dark brown color reminiscent of motor oil.
• A simple burr hole can effectively drain most chronic SDHs.

Reference: Greenberg 9th Edition Chapter 55

Explanation:

• Histologically benign tumor of cranial nerve VIII located in the cerebellopontine angle (CPA)
• Usually arises from inferior division of the vestibular portion of the VIII nerve
• 3 most common early symptoms (clinical triad): hearing loss (insidious and progressive), tinnitus (high pitched) and dysequilibrium (true vertigo is uncommon)
• Histology: comprised of Antoni A (narrow elongated bipolar cells) and Antoni B fibers (loose reticulated)

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 40

Answer: B

Explanation:

Berry aneurysms: MC intracranial aneurysm, saccular in appearance, arising at the bifurcation of intracranial arteries.

About 85% aneurysms occur in the anterior circulation

Following 3 most common locations:

• ACoA (single most common): 30%
• P-comm: 25%
• Middle cerebral artery (MCA): 20%

5–15% in posterior circulation (vertebro-basilar)

≈ 10% on basilar artery: basilar bifurcation, AKA basilar tip, is the most common in basilar, followed by

BA-SCA, BA-VA junction, AICA

≈ 5% on vertebral artery: VA-PICA junction is the most common in vertebral art

20–30% of aneurysm patients have multiple aneurysms

Reference: Greenberg 9th Edition Chapter 74

Explanation:

The most common histopathological type of membrane was the inflammatory membrane (Type II) seen in 42.30% of cases followed by hemorrhagic inflammatory membrane (Type III) seen in 34.62% of cases while scar inflammatory type of membrane (Type IV) was seen in 23.08% of cases. No case with noninflammatory type (Type I) was encountered.

Ref: Histopathological study of the outer membrane of the dura mater in chronic sub dural hematoma: Its clinical and radiological correlation- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4732239/

Explanation:

• It’s not subconjunctival haemorrhage, its periorbital ecchymosis or bruising.
• Signs of Base of Skull fracture are –
  • Battle’s sign (bruising over the mastoid)
  • Racoon’ or ‘panda’ eyes (bilateral periorbital bruising).
  • Haemotympanum, or overt bleeding from the ear if the tympanic membrane has ruptured, and CSF rhinorrhoea or otorrhoea

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2850869/

The representation of the arm and face are draped over the convexity of the brain, while the foot and leg areas are located along the upper aspect of the medial surface. Areas with fine motor or sensory function (e.g. fingers, tongue) have a larger area of representation.

Reference: Greenberg 9^th Edition Chapter 1

Explanation:

Superior Oblique

Attachments: Originates from the body of the sphenoid bone. Its tendon passes through a trochlea and then attaches to the sclera of the eye, posterior to the superior rectus.

Actions: Depresses, abducts and medially rotates the eyeball.

Innervation: Trochlear nerve (CN IV)

Explanation:

• The middle frontal gyrus (MFG) is usually more sinuous than the IFG or SFG, and it often connects to the pre-central gyrus via a thin isthmus.
• The central sulcus joins the Sylvian fissure in only 2% of cases (i.e., in 98% of cases there is a “subcentral” gyrus).
• The intraparietal sulcus (ips) separates the superior and inferior parietal lobules.
• The IPL is composed primarily of the AG and SMG.
• The Sylvian fissure terminates in the Superior Marginal Gyrus (Brodmann’s area 40). The superior temporal sulcus terminates in the Angular Gyrus.’

Reference: Greenberg 9^th Edition Chapter 1

Explanation:

Hyperalgesia: Exaggerated response to noxious stimulus

Allodynia: Sensation of pain in response to an innocuous stimulus

Hyperpathia: Nociceptive stimuli evoke exaggerated level of pain

Causalgia: Type of Neuropathic pain

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Ch 99

Explanation:

Treatment should adhere to thetreatment options as in nonpregnant women. The optimal time to perform the procedure during pregnancy is still a matter of debate. It is recommended to delay surgery if possible until after the first trimester to reduce the miscarriage risk—surgery during the second and third trimesters surgery is considered safe. Delay can cause progressive neurologic deterioration and increasing risk of urgent intervention (resection and cesarean section). Due to the significant complications of prematurity (e.g. respiratory diseases, bradycardia, necrotizing enterocolitis, intraventricular hemorrhage, hypoglycemia and feeding problems, sepsis and seizures) iatrogenic preterm birth should be avoided whenever possible by postponing or continuing treatment until a term delivery can be achieved. The decision of performing an elective cesarean section preterm is often based upon the risk of increased intracranial pressure associated with bearing-down efforts during the second stage of labor. Nonetheless, if patients are clinically stable and carefully discussed, and the individual risk of rapid tumor growth has been evaluated, gestational advancement until fetal maturity should be considered, as well as the attempt to have a vaginal delivery. Balance between waiting for fetal maturation and risk of intrauterine death (secondary to maternal death) remains difficult in patients with highly malignant tumors. A recent study summarized long-term data of children after antenatal exposure to chemotherapy (and/or radiotherapy) found a cardiac outcome equal to the general population, and no adverse effects of treatment on the general health  and age-appropriate neurocognitive (IQ, attention, behavior, memory) development. Estimations of the absorbed fetal dose were between 0.01 and 0.1 Gy (10-100 mGy) for patients who received whole brain RT by a 3D conformal technique and many of the toxic effects will only be induced above the deterministic threshold of 0.1 Gy. Most studies reporting on the administration of radiotherapy to brain tumors showed that the fetal exposure never exceeded this threshold dose. These radiotherapy schedules are therefore considered safe. Still, proper shielding should always be used to further reduce the fetal dose and it is recommended to discuss treatment with a radiation physicist and to use a phantom to estimate the fetal dose as accurate as possible in order to counsel parents on the potential risks of radiation-induced toxicity.

Ref

Tewari KS, Cappuccini F, Asrat T, et al. Obstetric emergencies precipitated by malignant brain tumors. Am J Obstet
Gynecol 2000;182:1215-21

Verheecke M, Halaska MJ, Lok CA, et al. Primary brain tumours, meningiomas and brain metastases in pregnancy: report on 27 cases and review of literature. Eur J Cancer 2014;50(8):1462-71; Amant F, Van Calsteren K, Halaska MJ, et al.

Long-term cognitive and cardiac outcomes after prenatal exposure to chemotherapy in children ged 18 months or older: An observational study. Lancet Oncol 2012;13(3)

Explanation:

• The middle frontal gyrus (MFG) is usually more sinuous than the IFG or SFG, and it often connects to the pre-central gyrus via a thin isthmus.
• The central sulcus joins the Sylvian fissure in only 2% of cases (i.e., in 98% of cases there is a “subcentral” gyrus).
• The intraparietal sulcus (ips) separates the superior and inferior parietal lobules.
• The IPL is composed primarily of the AG and SMG.
• The Sylvian fissure terminates in the Superior Marginal Gyrus (Brodmann’s area 40). The superior temporal sulcus terminates in the Angular Gyrus.’

AC-PC line

The “AC-PC line” connects the anterior commissure (AC) and the posterior commissure (PC) on a midline sagittal image. The AC is the horizontally positioned white matter tract that crosses in front of the fornix. The PC is the white-matter band at the level of the pineal that crosses at the posterior third ventricle. The AC-PC line is used in functional neurosurgery and is also used as the baseline for axial MRI scans (and for recent CT scanners). In the more entrenched Talairach definition, it passes through the superior edge of the AC and the inferior edge of the PC .

Alternative Schaltenbrand definition: a line passing through the midpoint of the AC & PC, allowing both AC & PC to be imaged on a single thin axial MRI slice. These definitions differ by 5.81° ± 1.07°.5

The orbitomeatal line (p.243) (used in older CT scanners) is ≈ 9° steeper than the Talairach AC-PC line.

Explanation:

• The posterior spinal artery arises from the vertebral artery
• The ophthalmic artery is a branch of the cerebral portion of the internal carotid artery.
• The pontine arteries are branches of the basilar artery
• The posterior communicating artery is a branch of the internal carotid artery
• The posterior inferior cerebellar artery is a branch of the vertebral artery

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 17

Explanation:

Carbamazepine is the drug of choice and is effective initially in 75% of patients. It should be started gradually as a daily dose of 100 mg and increased to 200 mg qid

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 98

Explanation:

The hypothalamus lies directly above the pituitary gland and occupies approximately 2 per cent of the brain volume. It is composed of a number of cell groups as well as fiber tracts that are symmetric about the third ventricle. In saggital section, the hypothalamus extends from the optic chiasm, lamina terminalis and anterior commissure rostrally to the cerebral peduncle and interpeduncular fossa caudally . The cavity of the third ventricle lies in the midline. In coronal section , each of the two symmetric walls of the hypothalamus can be divided into four surfaces: a lateral surface contiguous with the thalamus, subthalmus and internal capsule, the latter dividing the hypothalamus from the corpus striatum; a medial surface extending to the wall of the third ventricle, covered by ependymal cells; a superior surface corresponding to the hypothalamic sulcus that separates the hypothalamus from the central mass of the thalamus; and an inferior surface that is in continuity with the floor of the third ventricle. The external surface of the hypothalamic floor gives rise to a median protuberance called the tuber cinereum (or gray swelling due to the pale bluish color of the blood vessels seen in the postmortem human brain), whose central part extends anteriorly and downward into a funnel-like process, the infundibulum or median eminence. The infundibulum is in direct continuity with the infudibular stem of the posterior pituitary gland, and together with the pars tuberalis of the anterior pituitary, forms the pituitary stalk . Two additional symmetric eminences, the lateral eminences, corresponding to the most lateral portion of the hypothalamic wall and the postinfundibular eminence, as well as the symmetric mammillary bodies, complete the macroscopic morphology of the hypothalamic floor.

Ref: https://www.ncbi.nlm.nih.gov/books/NBK279126/

Explanation:

Intracranial Ependymomas

• usually benign tumors, often fibrillary with epithelial appearance.
• Perivascular pseudorosettes or true rosettes may be seen in classic (papillary) form
• most often occur in the floor of the 4th ventricle, presenting with hydrocephalus (increased ICP) and cranial nerve VI & VII palsies
• evaluation: includes imaging the entire neuraxis (usually with enhanced MRI: cervical, thoracic, lumbar & brain) because of potential for seeding through CSF
• worse prognosis the younger the patient (especially age < 24 months)
• treatment: the best outcomes are associated with gross total removal (no enhancing tumor on post-op MRI) followed by XRT. XRT may be withheld for age < 3
• do LP ≈ 2 weeks post-op to send ≈ 10 cc of CSF for cytology for prognostication

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 38

Explanation:

• Surgical treatment and natural history are associated with high morbidity and mortality. Adjuvant ventricular shunting is not necessary unless definitive endovascular treatment is unavailable immediately.
• Emergency embolization is indicated in infants with refractory cardiac failure, acute or symptomatic hydrocephalus, rapid neurological deterioration or when parenchymal calcifications appear on follow up scanning of brain.
• Neonates or infants having encephalomalacia or severe brain damage or severe
  parenchymal loss do not need any aggressive treatment because of poor clinical outcome in spite of successful closure of the shunt by embolization.
• Transarterial embolization is employed when the diagnostic angiogram demonstrates accessible feeding arterial branches from the choroidal and perforator arteries having sufficient caliber to permit navigation of the microcatheters.
• Transvenous technique is particularly employed when the perforating arteries are not of sufficient caliber to permit negotiation of the microcatheters.
• If the shunt is very large with extremely high flow the venous approach
  is preferred to avoid migration of the embolic material when delivered by the transarterial route.
• Occasionally it is necessary to use a combination of both techniques.
• In high flow choroidal malformations with no accessible femoral approach, occipital bone
  over the torcular is penetrated with a large bore needle for catheterization of the varix in neonates. However it is necessary to make a burr-hole in older children. The goal of treatment is to reduce the volume load initially and attempt to finally obliterate the shunt completely.
• In the majority of infantsand children, it becomes necessary to stage theembolization ranging from a few weeks to a fewmonths based on the angioarchitecture and clinical
• The follow-up endovascular approach isbased on the residual shunt and the architecture of
  the malformation.
• Occlusive venopathy is a well known delayed event causing progressive neurological deterioration

Ref:

• https://pubmed.ncbi.nlm.nih.gov/14691640/
• Greenberg 9^th Ed, Ch 79

Explanation:

The pituitary gland, situated within the sella turcica derives its name from the Greek ptuo and Latin word pītuītārius pertaining to or secreting phlegm.

Galen hypothesized that nasal phlegm originated from the brain and drained via the pituitary gland

Ref: https://en.wikipedia.org/wiki/Pituitary_gland

Explanation:

This is a case of chronic subdural haematoma

These patients are elderly, mostly on antiplatelets with recent history of fall. Mass effect is produced over a period of days to weeks.

Symptoms

• Pressure symptoms
• Seizures
• Neurological deficit

Acute subdural haematoma is associated with forceful and high impact head injuries. Conscious level is altered right from the beginning

Extra dural haematoma has contralateral hemiparesis, ipsilateral pupillary dilatation and altered conscious levels

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 55

Explanation:

• Superior Oblique – depress the eye when it is turned inwards
• Inferior oblique – elevates the eye when it is turned inwards
• Superior Rectus – Main movement is elevation. Also contributes to adduction and medial rotation of the eyeball.
• Inferior Rectus – Main movement is depression. Also contributes to adduction and lateral rotation of the eyeball
• Medial Rectus- Adducts the eyeball
• Lateral Rectus- Abducts the eyeball

Answer: A

Explanation:

Causes of Cerebrovascular Accidents

• Ischemic (85%)
  • Embolic (75%)
  • Thrombotic (25%)
• Hemorrhage (15%)
  • Parenchymal (10%)
  • Subarachnoid (1-2%)
  • Epidural (<1%)
  • Subdural (<1%)

Reference: Greenberg 9th Edition Chapter 80

Explanation

Epidural Hematoma

• EDH is a neurosurgical emergency
• Nearly always associated with a skull fracture
• More common in young male patients
• Associated with tearing of a meningeal artery
• Hematoma accumulates in the space between bone and dura.
• Source of bleeding: 85% = arterial bleeding (the middle meningeal artery is the most common source of middle fossa EDHs).
• Not always arterial: disruption of a major dural venous sinus can result in an EDH.
• Many of the remainder of cases are due to bleeding from middle meningeal vein or dural sinus.
• 70% occur laterally over the hemispheres with their epicenter at the pterion, the rest occur in the frontal, occipital, and posterior fossa (5–10% each).

“Textbook” presentation with Lucid interval has following features (Only < 10%-27% have this classic presentation):

• brief posttraumatic loss of consciousness (LOC): from initial impact
• followed by a “lucid interval” for several hours
• then, obtundation, contralateral hemiparesis, ipsilateral pupillary dilatation as a result of mass effect from hematoma

Other presenting findings:

• H/A, vomiting, seizure (may be unilateral), hemi-hyperreflexia + unilateral Babinski sign, and elevated CSF pressure (LP is seldom used any longer).
• Bradycardia is usually a late finding.
• In peds, EDH should be suspected if there is a 10% drop in hematocrit after admission.
• Contralateral hemiparesis is not uniformly seen, especially with EDH in locations other than laterally over the hemisphere.
• Shift of the brainstem away from the mass may produce compression of the opposite cerebral peduncle on tentorial notch which can produce ipsilateral hemiparesis (so called Kernohan’s phenomenon or Kernohan’s notch phenomenon),9 a false localizing sign.
• 60% of patients with EDH have a dilated pupil, 85% of which are ipsilateral. No initial loss of consciousness occurs in 60%. No lucid interval in 20%. NB: a lucid interval may also be seen in other conditions (including subdural hematoma).
• MC site: Temporal (pterion is thinnest part of skull and overlies middle meningeal artery)
• Force required to sustain a skull fracture can be surprisingly small – a fall from standing or a single blow to the head.
• Early recognition and treatment is likely to result in full recovery
• Delays in diagnosis and treatment can result in death from secondary brain injury.
• EDH on CT scan: Lentiform (lens shaped or biconvexQ) hyperdense lesion between the skull and brain.
• Treatment of EDH: Immediate surgical evacuationQ via a craniotomy.
• Overall mortality for all cases of EDH is about 18% but for isolated EDH it is about 2%.

Reference: Greenberg 9th Edition Chapter 55

Explanation:

Ependymoma. RELA fusion-positive (WHO grade II or III)

• A supratentorial ependymoma characterized by presence of an RELA fusion gene.
• Comprise ≈ 70% of supratentorial childhood ependymomas, and almost none of the infratentorial tumors
• Grading: These tumors are graded based on histology as either grade II or III (no grade I ependymomas have been found with this gene).
• Based on the only study available at the time of the classification, this group has the worst prognosis of the 3 supratentorial varieties

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 38

Explanation

The femoral route is used most. Most feared complication is stroke. 4 percent risk for TIA and stroke 1 percent permanent deficit and very low < 0.1 percent for death

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 12

Explanation:

Epidural Hematoma

• Source of bleeding: 85% = arterial bleeding (the middle meningeal artery is the most common source of middle fossa EDHs).
• Many of the remainder of cases are due to bleeding from middle meningeal vein or dural sinus.
• 70% occur laterally over the hemispheres with their epicenter at the pterion, the rest occur in the frontal, occipital, and posterior fossa (5–10% each).

“Textbook” presentation with Lucid interval has following features (Only < 10%-27% have this classic presentation):

• brief posttraumatic loss of consciousness (LOC): from initial impact
• followed by a “lucid interval” for several hours
• then, obtundation, contralateral hemiparesis, ipsilateral pupillary dilatation as a result of mass effect from hematoma

Other presenting findings:

• H/A, vomiting, seizure (may be unilateral), hemi-hyperreflexia + unilateral Babinski sign, and elevated CSF pressure (LP is seldom used any longer).
• Bradycardia is usually a late finding.
• In peds, EDH should be suspected if there is a 10% drop in hematocrit after admission.
• Contralateral hemiparesis is not uniformly seen, especially with EDH in locations other than laterally over the hemisphere.
• Shift of the brainstem away from the mass may produce compression of the opposite cerebral peduncle on tentorial notch which can produce ipsilateral hemiparesis (so called Kernohan’s phenomenon or Kernohan’s notch phenomenon),9 a false localizing sign.
• 60% of patients with EDH have a dilated pupil, 85% of which are ipsilateral. No initial loss of consciousness occurs in 60%. No lucid interval in 20%. NB: a lucid interval may also be seen in other conditions (including subdural hematoma).

Reference: Greenberg 9th Edition Chapter 55