Idiopathic intracranial hypertension, also known as pseudotumor cerebri, is a clinical syndrome that mimics brain tumors and is characterized by the following EXCEPT

Correct Answer: C

Rationale: Pseudotumor cerebri featurhigh ICP , normal CSF , papilledema , and normal ventricl. Slightly decreased ventricular size is not typical; ventriclare normal or slit-like, not reduced. This imaging nuance makes C the exception and correct answer.

Correct Answer: A

Rationale: Megalocephaly (large head) results from chronic subdural effusions , hydrocephalus , Canavan disease (D in original), congenital CMV , and familial traits , all increasing brain or skull size via fluid, tissue, or genetics. Thalassemia , a hemoglobinopathy, causmarrow hyperplasia and skull thickening (e.g., frontal bossing), but not true megalocephaly, which involvbrain or CSF volume. Subdurals expand skull space, hydrocephalus enlargventricles, and familial casreflect benign inheritance. Thalassemias skeletal focus, not brain enlargement, makes A the exception and correct answer, per differential diagnostic criteria.

Correct Answer: D

Rationale: Arteriovenous malformation (AVM) fits severe headache, seizure, coma, and nuchal rigidity from subarachnoid hemorrhage (SAH). Prior right-sided headachsuggest vascular irritability; acute collapse indicatrupture. Afebrile state rulout bacterial or tuberculous meningitis , which present with fever. Brain tumor grows slowly, lacking sudden coma. Pott puffy tumor involvsinusitis, not coma. AVMs bleeding risk, per stroke literature, makes D the correct answer, aligning with acute vascular catastrophe.

Correct Answer: B

Rationale: Maternal serum α-fetoprotein (MSAFP) screens for neural tube defects (NTDs) like spina bifida at 16-18 weeks, per ACOG. Elevated AFP indicatopen defects leaking into amniotic fluid. Chromosomdetect aneuploidy, not NTDs. Estriols and prolactin assess fetal well-being or lactation, not defects. Fibronectin predicts preterm labor. MSAFPs specificity for NTDs, validated by screening programs, make B the correct answer.

Correct Answer: D

Rationale: Hypoxic-ischemic encephalopathy (HIE) is the most common neonatal seizure cause (~50-60%), per Volpe, from perinatal asphyxia disrupting brain metabolism. Febrile seizuroccur later (6 months-5 years). Pre-eclampsia affects mothers, indirectly fetuses. Hypocalcemia is less frequent (~10%). Aicardi syndrome is rare. HIprevalence in term infants makes D the correct answer.