Learn / FMK
Every FMK condition
299 diseases, deficiencies, toxicities and drug mechanisms harvested from every FMK deck — the ones sprinkled through a single bullet as much as the ones with their own slide. Pick what you're given and what you have to name, or let it cycle; distractors come from the same category so you have to discriminate (hypoketotic vs. ketotic hypoglycemia, which GSD, which urea-cycle enzyme…). Every answer shows the whole card with the lecture and slide.
Amino acid · FMK 07.1
Hyperammonemia Acquired / not inherited
Defect / target: Acquired: liver disease (viral hepatitis, hepatotoxins, liver failure with gut urease-derived ammonia reabsorption); Congenital: deficiency of any urea cycle enzyme or NAG synthase
Mechanism: Ammonia the liver cannot convert to urea accumulates and is neurotoxic; astrocytes swell as they buffer ammonia via glutamine synthesis (osmotic stress) → cerebral edema.
↑ Accumulates: Ammonia (normal 5–35 µmol/L, can exceed 1,000), brain glutamine· ↓ Deficient: Urea synthesis capacity
Presentation: Tremor, slurred speech, drowsiness, vomiting, blurred vision, lethargy, poor feeding, tachypnea, seizures → cerebral edema, coma, death; medical emergency
Labs: Blood ammonia > 35 µmol/L; normal glucose, no infection
Treatment: ↓ dietary protein; replace missing enzyme; nitrogen scavengers — phenylbutyrate (→ phenylacetylglutamine) or benzoate (→ hippurate via glycine)
Brain has no urea cycle — glutamine synthetase is its only ammonia sink, so hyperammonemia hits the brain hardest
acquired or genetic (see individual UCDs)
Learn the mechanism: Urea cycle (+ the CPS-II collision) →
FMK 07.1 Amino Acid Metabolism I · slide 2, 13, 17, 18