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Metabolic reasoning
Whole-map thinking. Each case is a chain of cause → effect that ends in the labs: why DKA has ketones and hyperglycemia, why a drinker goes hypoglycemic, why an infant with MCAD deficiency spills no ketones. Walk through the chain on the map, then order it yourself, answer the why questions, or diagnose from the labs.
Ketones without hyperglycemia
A 48-year-old chronic drinker with poor nutrition has been vomiting for 2 days after a binge and has not been able to keep alcohol or food down. He is tachypneic with abdominal pain.
| Glucose | 84 mg/dL | normal |
| Anion gap | 22 | ↑ |
| HCO₃⁻ | 14 mEq/L | ↓ |
| β-Hydroxybutyrate | ↑↑ | ↑↑ |
| Urine ketones (nitroprusside) | trace | misleadingly low |
| Ethanol | undetectable |
Alcoholic ketoacidosis
Starvation + a liver flooded with NADH: lipolysis and ketogenesis with normal or low glucose — no insulin required to treat.
Condition card: Alcoholic ketoacidosis (AKA) →Pathway map →
- Days of vomiting and no food → glycogen depleted, insulin low, glucagon/epinephrine high.
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Pathways involved: Ethanol metabolism, Ketogenesis & ketone body use, Lipolysis, carnitine shuttle & β-oxidation. Drill them one at a time in Metabolic pathways.