Gyromitra Mushroom Toxicity - Causes, Symptoms, Diagnosis, and Treatment

Introduction

Gyromitra mushrooms or esculents (edible) are a poisonous mushroom species that can cause toxicity after ingested either raw or cooked. The toxin in these mushroom species is a highly toxic, volatile, colorless, and carcinogenic compound. These mushrooms are found in Europe and North America during the early spring season and are called “brain fungi.”

The Gyromitra mushroom toxicity is mainly caused by consuming the poisonous mushroom while searching for the actual morel mushrooms. These species contain gyromitrin toxins, the leading cause of poisoning. The adverse symptoms usually develop after two to 24 hours, mainly affecting the gastrointestinal system.

How Do Gyromitra Mushrooms Differ From Their Toxic Counterpart?

Actual mushrooms differ from their toxic counterparts in the following ways:

1. True Morels:

• The cap of the mushroom is directly attached to the stem.

• The mushroom cap is uniformly shaped, unlike false morel.

• The top of the mushroom has pits on its surface, which are unique identifiers of natural morel mushroom species.

• The inner part of the true morel is always hallowed lengthwise from the top to the bottom of the stem.

1. False Morels:

• The cap of the false species is attached to the stem at the top, and the remaining part remains hanging.

• The mushroom cap appears irregular and flattened in shape.

• These false mushroom species are wrinkled, smooth, or rigid in appearance but do not have pits on their surface.

• The inner part of the false morel is not hollow but filled with cotton-like tissues.

What Are the Symptoms of Gyromitra Mushroom Toxicity?

Gyromitra mushroom toxicity can cause the following symptoms:

• Initial gastrointestinal symptoms include vomiting, nausea, stomach cramps, and diarrhea with blood stains.

• Severe diarrhea and vomiting can lead to dehydration.

• Vertigo, lethargy, tremors, headaches, dizziness, and ataxia may also develop.

• Neurological dysfunction, liver damage, and kidney failure also occur following initial symptoms and often cause seizures and coma.

• Kidney failure usually occurs rarely, but the toxicity of gyromitra mushrooms can affect the liver to a great extent.

• A person may develop jaundice followed by spleen and liver enlargement.

• Irregular blood sugar levels.

What Is the Mechanism of Action of Gyromitra Mushroom Toxicity?

• Gyromitra mushroom metabolizes in the stomach to form toxic inorganic compounds that can block vitamin B6 in the central nervous system.

• Mushroom toxicity also inhibits the formation of the neurotransmitter GABA (gamma-aminobutyric acid), causing excitation in the central nervous system.

• These inorganic chemical compounds formed by mushroom toxicity can further lead to organ damage and toxicity in the liver.

• Toxins in gyromitra mushrooms can inhibit the histamine hormone, thus elevating the histamine levels and causing abdominal pain, headaches, nausea, and vomiting.

What Is the History of Gyromitra Mushroom Toxicity?

• Gyromitra mushrooms are mainly consumed in Finland and are considered a delicacy in the country. The mushrooms are collected, processed, and sold under proper regulatory control with specific guidelines for preparing the delicacy with gyromitra mushrooms. Although fatalities associated with this mushroom species have been reported to be only four cases in about 100 years, all occurred due to the consumption of raw gyromitra mushrooms.

• Gyromitra mushroom species are widely consumed in Eastern Europe, which has reported the highest number of poisoning cases. At the same time, Western Europe and North America have reported only a few toxicity cases.

• Studies on the toxicity of gyromitra mushrooms suggested that the reactions caused were much similar to those of allergic reactions. Some people had severe symptoms and toxicity, while others showed no signs after eating the same species and amount of mushroom from the same delicacy.

• Many people were found to develop toxicity and ill effects from some mushroom species eaten in the past, and others believed that oil used in preparing mushrooms causes toxicity.

What Is the Pathophysiology of Gyromitra Mushroom?

Gyromitra mushrooms, often mistaken for morels, contain the toxin gyromitrin, which metabolizes into monomethylhydrazine (MMH), a compound with neurotoxic and hepatotoxic effects. The primary mechanism of toxicity involves the inhibition of the enzyme pyridoxine-5’-phosphate (the active form of vitamin B6), which is essential for synthesizing the neurotransmitter gamma-aminobutyric acid (GABA). Depletion of GABA leads to CNS excitation, manifesting as seizures.

Furthermore, monomethylhydrazine interferes with other enzymatic processes in the liver and kidneys, leading to oxidative stress and damage. The hepatotoxic effects can lead to hepatic necrosis, while renal involvement may result in acute kidney injury (AKI).

What Is the Toxicokinetics of Gyromitra Mushroom?

Upon ingestion, gyromitrin is absorbed from the gastrointestinal tract and rapidly metabolized in the liver to produce MMH. MMH is lipid-soluble, allowing for rapid diffusion across cellular membranes, including the blood-brain barrier. This accounts for the swift onset of neurological symptoms, typically 6 to 12 hours after ingestion. MMH is then further metabolized in the liver, generating reactive oxygen species (ROS) that contribute to cellular damage, especially in the liver and kidneys.

MMH is primarily excreted by the kidneys, and its half-life is dependent on the severity of renal impairment. Patients with pre-existing liver or kidney conditions may experience prolonged and exacerbated toxicity due to impaired detoxification and excretion processes.

How Is Gyromitra Mushroom Toxicity Diagnosed?

Gyromitra mushroom toxicity is diagnosed in the following ways:

• Laboratory tests include lactate dehydrogenase, elevated transaminase, and total bilirubin levels.

• Diagnosis is made based on the central nervous system, liver, and kidney test report findings.

• Tests show elevated levels of creatinine cause acute kidney injury.

• No findings can be seen in CT and MRI if seizures are present.

How Is Gyromitra Mushroom Toxicity Treated?

• Initial treatment mainly supports maintaining the electrolyte and fluid balance in the body. In addition, the doctor continuously monitors kidney output, liver function tests, creatinine levels, and blood urea nitrogen.

• Seizures are treated effectively with benzodiazepines.

• Activated charcoal therapy is done for gastric decontamination during early detection of toxicity.

• Intravenous fluids are given to a person having severe diarrhea and vomiting.

• Kidney dysfunction cases are treated with dialysis, and the lost blood cells are replaced through blood transfusion.

• If a person develops methemoglobinemia, methylene blue treatment is given intravenously.

• Vitamin B6 or pyridoxine is used to treat neurological symptoms like refractory seizures.

• Refractory hepatic failure is treated with a liver transplant.

What Are the Major Complications Caused by Gyromitra Mushroom Toxicity?

The complications caused by gyromitra mushroom toxicity include:

• Gyromitra syndrome.

• Acute liver injury.

• Acute kidney injury.

• Central nervous system toxicity.

• Refractory seizures.

• Red blood cell hemolysis.

• Methemoglobinemia.

What Is the Differential Diagnosis for Gyromitra Mushroom Toxicity?

• Iron toxicity.

• Gallstones.

• Isoniazid toxicity.

• Stimulant abuse.

• Organophosphorus toxicity.

• Giardiasis.

• Gastroenteritis.

• Pediatric gastroenteritis.

What Is the Prognosis of Gyromitra Mushroom?

Gyromitra mushroom poisoning outcomes are mainly defined by the degree of exposure, the patient’s age, and the time elapsed to receive medical assistance. The evidence also shows that early diagnosis of the disease and initiation of treatment greatly affect the prognosis of a patient with the disease. In mild cases, a patient can be treated with adequate rest, proper nutrition, and hydration and be cured in three to five days.

However, the serious cases that can occur when treatment is delayed or when gyromitrin ingestion is in higher doses are hepatotoxicity, renal failure, and neurological involvement in the form of seizures or coma. Mortality is low but increases with severe hepatic or renal involvement, with the former being worse if treatment is not initiated promptly. Patients with underlying liver or kidney disease are considered to have a poor prognosis in the case of infection.

Conclusion

Mushroom poisoning cases are witnessed worldwide because people consume them without correctly identifying suitable species. These poisonous species lead to adverse signs and symptoms and cause a gyromitra syndrome in a person almost after five hours of mushroom consumption. Accidental mushroom poisoning can occur because people do not know mushrooms can cause toxicity in the body. The only way to reduce toxicity through mushrooms is to recognize edible species that are safe for consumption. Gyromitra mushrooms have carcinogenic properties and can cause toxicity even when taking less amount over a prolonged period. Therefore, a person should take medical advice immediately if any incident takes place.