Updated: Feb 29, 2008
Thousands of mushroom species are studied and collected by amateur mushroom hunters, but only a handful cause death. False morel mushrooms (eg, Gyromitra esculenta, Gyromitra ambigua, Gyromitra infula) can cause fatal poisonings. These mushrooms are found on the ground or on rotten wood, are orange-brown to brown, have no gills, and have convoluted brainlike caps that are occasionally saddle-shaped. Gyromitra species fruit in the spring, and most poisonings occur during spring or early summer.
Some Gyromitra mushrooms contain hydrazones, including the toxin gyromitrin (N -methyl-N-formylhydrazone). Gyromitrin rapidly decomposes in the stomach to form acetaldehyde and N -methyl-N-formylhydrazine, which is converted to monomethylhydrazine (MMH) by slow hydrolysis. MMH is a water-soluble toxin that causes gastroenteritis, hemolysis, methemoglobinemia, hepatorenal failure, seizures, and coma. MMH is employed in rocket fuel and causes similar toxicity in aerospace industry workers. Cooking can render these mushrooms less toxic, although not reliably so. MMH is volatile and the fumes from cooking may cause toxicity.
Neurotoxicity
MMH exposure is similar to that of isoniazid in that it generates functional pyridoxine deficiency by inhibition of pyridoxine kinase. Pyridoxine kinase inhibition interferes with production of pyridoxal phosphate, an essential cofactor for a number of enzymatic steps, including glutamic acid decarboxylase (GAD).
Gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter of the brain, is produced from glutamate (an excitatory neurotransmitter) by the enzyme GAD. MMH also may inhibit GAD directly. The resultant GABA deficiency, with loss of inhibitory neurotransmission, may lead to seizures.
Gastrointestinal toxicity
Inhibition of diamine oxidase in intestinal mucosa may be responsible for GI effects. Association of individual variability in acetylation rates (eg, slow vs fast acetylators) in hepatotoxicity is not well established.
Hematopoietic toxicity
Hemolysis and methemoglobinemia can occur. Resultant hemoglobinuria may cause renal failure.
In 2004, a total of 2,438,644 toxic substance exposures and 1,183 deaths were reported to the American Association of Poison Control Centers (AAPCC) Toxic Exposure Surveillance System. Mushroom exposures accounted for 8,601 cases and 5 fatalities.1
No adequate international database exists. In the past, gyromitrin-containing mushrooms have been associated with significant mortality in Eastern Europe.
Determining history of mushroom exposure is helpful. Query patients presenting with gastroenteritis about mushroom collecting, cooking, and ingestion.
MMH poisoning may occur after ingestion of fresh, dried, or raw gyromitrin-containing mushrooms or with inhalation of vapors while cooking gyromitrin-containing mushrooms.
| Cholelithiasis | Toxicity, Disulfiram |
| Gastritis and Peptic Ulcer Disease | Toxicity, Iron |
| Gastroenteritis | Toxicity, Isoniazid |
| Giardiasis | Toxicity, Mushroom - Amatoxin |
| Hepatitis | Toxicity, Mushroom - Disulfiramlike
Toxins |
| Methemoglobinemia | Toxicity, Mushroom - Orellanine |
| Pediatrics, Gastroenteritis | Toxicity, Organophosphate and Carbamate |
| Plant Poisoning, Hypoglycemics | Toxicity, Valproate |
| Pregnancy, Hyperemesis Gravidarum | |
| Salmonella Infection | |
| Toxicity, Acetaminophen |
Shigellosis
Initiate supportive care, including intravenous (IV) fluids and seizure control with pyridoxine and benzodiazepines.
The goals of pharmacotherapy are to reduce morbidity, prevent complications, and neutralize the effects of the toxin.
Empirically used to minimize systemic adsorption of toxin. May benefit only if administered within 1-2 hours of ingestion.
Emergency treatment in poisoning caused by drugs and chemicals. Network of pores present in activated charcoal adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water. For maximum effect, administer within 30 min of ingesting poison.
1 g/kg PO (usual dose 30-100 g)
1 g/kg PO (typical dose 12.5-25 g)
<2 years: Use aqueous charcoal without cathartic
May inactivate ipecac syrup if used concomitantly; effectiveness of other medications decreases with coadministration; do not mix with sherbet, milk, or ice cream (decreases adsorptive properties)
Documented hypersensitivity; poisoning or overdosage of mineral acids and alkalies; aspiration risk (consider nasogastric tube and endotracheal intubation)
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Not very effective in poisonings of ethanol, methanol, and iron salts; induce emesis before administering activated charcoal; after emesis with ipecac, patient may not tolerate activated charcoal for 1-2 h; can administer in early stages of gastric lavage; without sorbitol, gastric lavage returns are black; protect airway in patients with depressed level of consciousness; if using multiple doses of charcoal, monitor for presence of bowel sounds to minimize risk of charcoal ileus and vomiting with subsequent pulmonary aspiration
Prevents seizure recurrence and terminates clinical and electrical seizure activity. May be used in conjunction with benzodiazepines.
Involved in synthesis of GABA within CNS. Administer with benzodiazepines.
25 mg/kg IV over 15-30 min to 5 g IV initial; may be repeated for recurring seizures; not to exceed 15-20 g/d
25 mg/kg IV over 15-30 min to 5 g IV initial; initial doses of >70 mg/kg may be associated with greater toxicity
May decrease levodopa, phenytoin, and phenobarbital serum levels
Documented hypersensitivity
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
>200 mg/d may precipitate withdrawal effects when medication is discontinued; risk of peripheral neuropathy increases with increasing dose; ataxia, incoordination, and seizures reported
Prevents seizure recurrence and terminates clinical and electrical seizure activity. May be used in conjunction with pyridoxine (vitamin B-6).
Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA.
5-10 mg IV q10-15min until symptoms resolve; not to exceed 30 mg
30 days to 5 years: 0.2-0.5 mg IV (slowly) q2-5min until symptoms resolve; not to exceed 5 mg
>5 years: 1 mg IV (slowly) q2-5min until symptoms resolve; not to exceed 10 mg
Increased CNS depression if coadministered with phenothiazines, barbiturates, alcohols, or other sedative medications
Documented hypersensitivity; hypotension; acute narrow-angle glaucoma
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Even though classified as Category D in pregnancy, remains DOC along with pyridoxine for initial treatment of status seizures in this specific case; caution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity); intubation may be necessary
Sedative hypnotic with short onset of effects and relatively long half-life. May depress all levels of CNS, including limbic and reticular formation, by increasing action of GABA, which is a major inhibitory neurotransmitter in the brain. Monitoring patient's blood pressure after administering dose is important. Adjust prn.
2-8 mg slow IVP; not to exceed 2 mg/min; may repeat prn
0.05-0.1 mg/kg IV over 1-2 min; may repeat prn
Increased CNS depression when used with alcohol, phenothiazines, or barbiturates
Documented hypersensitivity; preexisting CNS depression; hypotension; narrow-angle glaucoma
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Caution in renal or hepatic impairment, myasthenia gravis, organic brain syndrome, or Parkinson disease; intubation may be necessary
Used as alternative in termination of refractory status epilepticus. Because water soluble, takes approximately 3 times longer than diazepam to peak EEG effects. Thus clinician must wait 2-3 min to fully evaluate sedative effects before initiating procedure or repeating dose. Has twice the affinity for benzodiazepine receptors than diazepam. May be administered IM if unable to obtain vascular access.
0.01-0.05 mg/kg (usually 0.5-4 mg, not to exceed 10 mg) IV given slowly over several min; may repeat q10-15min until adequate response achieved
<32 weeks: 0.5 mcg/kg/min IV infusion
>32 weeks: 1 mcg/kg/min IV infusion
Children: 0.05-0.2 mg/kg IV over 2-3 min, followed by 1-2 mcg/kg/min continuous infusion
Status epilepticus (refractory to standard therapy), >2 months and children: 0.15 mg/kg followed by continuous infusion of 1 mcg/kg/min, titrating dose upward q5min until seizures controlled
Sedative effects may be antagonized by theophyllines; narcotics, cimetidine, ethanol, and erythromycin may accentuate sedative effects because of decreased clearance; reduce dose of thiopental by 15% when using together
Documented hypersensitivity; preexisting hypotension; narrow-angle glaucoma; sensitivity to propylene glycol (diluent)
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Caution in congestive heart failure, pulmonary disease, renal impairment, hepatic failure, neuromuscular disease, hypotension, and in patients >60 y; monitor for respiratory depression with high or repeated doses; consider lower dosages in patients with organic brain syndrome and those who may have inhibition of benzodiazepine metabolism and clearance (eg, using nicotine, taking cimetidine)
In reduced form, leukomethylene blue is an electron donor to reduce methemoglobin. Reduction of methylene blue is by NADPH generated by G-6-PD.
Used to convert ferrous iron of reduced hemoglobin to ferric form that is the basis for antidotal action.
1-2 mg/kg (0.1-0.2 mL/kg of 1% solution) IV over 5 min; may repeat q4h prn; not to exceed 7 mg/kg total IV dose
1-2 mg/kg IV over 5 min; not to exceed 7 mg/kg total IV dose
None reported
Documented hypersensitivity; renal insufficiency
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Can cause profound hemolytic anemia in G-6-PD deficiency; do not inject into CNS; high doses can induce methemoglobinemia; IV infiltration can cause tissue necrosis
Watson WA, Litovitz TL, Rodgers GC, et al. 2004 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2005;23(5):589-666. [Medline].
Watson WA, Litovitz TL, Klein-Schwartz W, et al. 2003 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2004;22(5):335-404. [Medline].
Watson WA, Litovitz TL, Rodgers GC, et al. 2002 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2003;21(5):353-421. [Medline].
Litovitz TL, Klein-Schwartz W, Rodgers GC, et al. 2001 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2002;20(5):391-452. [Medline].
Litovitz TL, Klein-Schwartz W, White S, et al. 2000 Annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2001;19(5):337-95. [Medline].
Litovitz TL, Klein-Schwartz W, White S, et al. 1999 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 2000;18(5):517-74. [Medline].
Litovitz TL, Klein-Schwartz W, Caravati EM, et al. 1998 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 1999;17(5):435-87. [Medline].
Litovitz TL, Klein-Schwartz W, Dyer KS, et al. 1997 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 1998;16(5):443-97. [Medline].
Litovitz TL, Smilkstein M, Felberg L, et al. 1996 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System. Am J Emerg Med. Sep 1997;15(5):447-500. [Medline].
Hoppe-Roberts JM, Lloyd LM, Chyka PA. Poisoning mortality in the United States: comparison of national mortality statistics and poison control center reports. Ann Emerg Med. May 2000;35(5):440-8. [Medline].
Braun R, Greeff U, Netter KJ. Liver injury by the false morel poison gyromitrin. Toxicology. Feb 1979;12(2):155-63. [Medline].
Brent J, Kulig K. Mushrooms. In: Haddad LM, et al, eds. Clinical Management of Poisoning and Drug Overdose. 3rd ed. WB Saunders; 1998:365-74.
Karlson-Stiber C, Persson H. Cytotoxic fungi--an overview. Toxicon. Sep 15 2003;42(4):339-49. [Medline].
Leathem AM, Dorran TJ. Poisoning due to raw Gyromitra esculenta (false morels) west of the Rockies. CJEM. Mar 2007;9(2):127-30. [Medline].
Michelot D, Toth B. Poisoning by Gyromitra esculenta--a review. J Appl Toxicol. Aug 1991;11(4):235-43. [Medline].
Schneider A, Attaran M, Meier PN, Strassburg C, Manns MP, Ott M. Hepatocyte transplantation in an acute liver failure due to mushroom poisoning. Transplantation. Oct 27 2006;82(8):1115-6. [Medline].
Trestrail JH. Monomethylhydrazine-containing mushrooms. In: Spoerke DG, Rumack BH, eds. Handbook of Mushroom Poisoning: Diagnosis and Treatment. CRC Press LLC; 1994:279-87.
Yildirim C, Bayraktaroglu Z, Gunay N, Bozkurt S, Köse A, Yilmaz M. The use of therapeutic plasmapheresis in the treatment of poisoned and snake bite victims: an academic emergency department's experiences. J Clin Apher. Dec 2006;21(4):219-23. [Medline].
mushroom poisoning, false morel mushrooms, Gyromitra esculenta, Gyromitra ambigua, Gyromitra infula, mushroom toxicity, gyromitra toxin, gyromitra poisoning, hydrazones, N -methyl-N-formylhydrazone, mushroom exposure, gyromitrin-containing mushrooms, poisonous mushrooms
Reed Brozen, MD, Director of Air Transport, Associate Professor, Department of Emergency Medicine, Dartmouth Medical School, Dartmouth-Hitchcock Medical Center
Reed Brozen, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, New Hampshire Medical Society, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
Marcus J Hampers, MD, MBA, Instructor, Department of Medicine, Dartmouth Medical School; Consulting Staff, Department of Internal Medicine, Section of Hospital Medicine, Department of Anesthesiology, Section of Critical Care Medicine, and Department of Emergency Medicine, Dartmouth Hitchcock Medical Center
Marcus J Hampers, MD, MBA is a member of the following medical societies: American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians, American Medical Association, New Hampshire Medical Society, Society of Critical Care Medicine, and Undersea and Hyperbaric Medical Society
Disclosure: Nothing to disclose.
B Zane Horowitz, MD, FACMT, Professor, Fellowship Director, Department of Emergency Medicine, Oregon Health and Sciences University; Medical Director, Oregon Poison Center; Medical Director, Alaska Poison Control System
B Zane Horowitz, MD, FACMT is a member of the following medical societies: American Academy of Clinical Toxicology and American College of Medical Toxicology
Disclosure: Nothing to disclose.
John T VanDeVoort, PharmD, ABAT, Director of Pharmacy, Sacred Heart Hospital
John T VanDeVoort, PharmD, ABAT is a member of the following medical societies: American Academy of Clinical Toxicology and American Society of Health-System Pharmacists
Disclosure: Nothing to disclose.
Michael Hodgman, MD, Assistant Clinical Professor of Medicine, Department of Emergency Medicine, Bassett Healthcare
Michael Hodgman, MD is a member of the following medical societies: American College of Medical Toxicology, American College of Physicians, Medical Society of the State of New York, and Wilderness Medical Society
Disclosure: Nothing to disclose.
John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
Asim Tarabar, MD, Assistant Professor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital
Disclosure: Nothing to disclose.
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