Internal Medicine Practice MCQs (FCPS, USMLE, PLAB, MRCP)

A 29-year-old man is brought to the emergency department in a comatose state a few hours after complaining of sudden onset of excruciating headache. Neurologic examination reveals dilated pupils poorly responsive to light. A CT scan of the head without contrast demonstrates hyperdensity within the suprasellar cistern, while MRI is unremarkable. Lumbar puncture shows hemorrhagic cerebrospinal fluid. Which of the following is the most likely diagnosis?
a)Amyloid angiopathy-related hemorrhage
b)Cavernous sinus thrombosis
c)Hemorrhagic infarction
d)Pituitary apoplexy
e)Ruptured berry aneurysm

Explanation:
The correct answer is E.
Headache of sudden onset ("thunderclap" headache), rapid deterioration of mental status and blood in the CSF are virtually diagnostic of ruptured berry aneurysms. Note the characteristic hyperdensity on CT of the suprasellar cistern, indicating blood in the subarachnoid space. Rupture of a berry aneurysm is the most common cause of subarachnoid bleeding. Berry aneurysms develop as a result of congenital weakness at branching points of the arteries in the circle of Willis. These outpouchings tend to expand progressively, but in most cases they remain asymptomatic. Hypertension facilitates development and rupture of berry aneurysm. One third of patients recover, one third die, and one third develop re-bleeding. Rapid onset of coma is an ominous sign.

Amyloid angiopathy-related hemorrhage (choice A) would manifest as a cortical-based hematoma in a lobar distribution. It is due to accumulation of Aβ amyloid in blood vessel walls.

Cavernous sinus thrombosis (choice B) is a rare complication of conditions leading to coagulation abnormalities, such as sepsis, antiphospholipid antibody syndrome, and leukemias. It leads to hemorrhagic infarction of large areas of hemispheric gray and white matter.

Hemorrhagic infarction (choice C) usually develops as a result of embolic occlusion of an intraparenchymal artery. It gives rise to a hyperdense wedge-shaped area in a cortical field corresponding to a specific vascular territory.

Pituitary apoplexy (choice D) refers to hemorrhage in the pituitary gland. It may occur in the setting of a large pituitary adenoma or in pregnancy. It manifests with rapid onset of panhypopituitarism.