How to tell Thimble morel from False morel

GYROMITRIN POISONING is life-threatening.

Active toxin: GYROMITRIN (acetaldehyde N-methyl-N-formylhydrazone); concentration in fruit bodies is 50-300 mg/kg fresh weight (highly variable!).

Metabolism: in the stomach, gyromitrin is hydrolyzed to N-methyl-N-formylhydrazine, and then to MONOMETHYLHYDRAZINE (MMH) — a hydrazine compound used as rocket fuel.

How MMH acts: LIVER TOXIN — damages the liver HEMOLYTIC — destroys red blood cells, causes hemoglobinuria NEUROTOXIN — affects the central nervous system, causes seizures CARCINOGEN (IARC Group 2B — "possibly carcinogenic to humans") Inhibits pyridoxine (vitamin B6)-dependent enzymes — hence the antidote: IV pyridoxine

Heat breakdown is NOT COMPLETE: Gyromitrin PARTLY evaporates with the steam during boiling (boiling point 87°C) Not all molecules are destroyed — some remain in the flesh The steam from boiling is toxic too — cooks have been poisoned by inhaling it Drying (for months to years) — better, but not a complete method No method guarantees safety

Cumulative toxicity: Small doses eaten repeatedly build up in the liver Regular eaters risk cirrhosis and hepatocellular cancer Deaths have been reported in people who ate "small portions every spring for several years"

Individual sensitivity: Some people can eat a lot without visible symptoms (once) Others are fatally poisoned by a single 100-200 g portion Genetic variability in N-acetyltransferase 2 (NAT2): "fast acetylators" partly detoxify it, "slow" ones do not

LATENCY PERIOD: 6-12 hours (sometimes up to 24 h). This is what makes false morels so treacherous: by the time symptoms start, people no longer connect them with the mushroom they ate that morning.

Symptoms by phase:

Phase I (6-24 h): Nausea, repeated vomiting Diarrhea (often bloody) Cramping abdominal pain Headache, dizziness Fever

Phase II (12-72 h): — critical Jaundice (yellowing of the whites of the eyes and skin) Dark urine (hemoglobinuria from destroyed red blood cells) Transaminases raised 10-100 times (severe hepatitis) Anemia (hemolysis) Azotemia (raised urea and creatinine) — kidney failure Methemoglobinemia

Phase III (3-7 days): — lethal Hepatic coma Multiple organ failure Seizures (MMH neurotoxicity) Death from liver failure or complications

Mortality up to 10-15% in significant poisoning without timely treatment. With timely medical care (pyridoxine, hemodialysis, rehydration), mortality is <5%.

FIRST AID — IMMEDIATELY: 1. CALL 112 or your local emergency number RIGHT AWAY, even if there are no symptoms but you know false morels were eaten. DO NOT WAIT for symptoms — the latency period is 6-12 h. 2. Keep a sample of the mushroom (fresh or from vomit) for the toxicologist 3. ACTIVATED CHARCOAL within the first 1-2 h after eating 4. IN HOSPITAL — INTRAVENOUS PYRIDOXINE (vitamin B6) — the antidote for hydrazine poisoning. Dose: 25 mg/kg slowly IV, repeated if needed. This is the absolute priority. 5. IV fluid therapy — rehydration, electrolyte correction 6. Liver monitoring — transaminases, bilirubin, prothrombin time, checked every 4-6 h 7. Blood monitoring — hemoglobin, reticulocytes, hemolysis markers 8. If hemolysis occurs — blood transfusion, urine alkalinization (to prevent kidney damage from hemoglobin) 9. Hemodialysis if there are signs of kidney failure or high MMH levels in the blood

PREVENTION: DO NOT EAT. No processing method guarantees safety. Modern mycology's rule is a complete ban on eating it. If false morels are part of your culinary tradition, gradually replace them with safe spring mushrooms (morels, St George's mushroom, button mushrooms).