Of thistles and mushrooms

In the last few days a woman has died in hospital in Melbourne after eating poisonous mushrooms. Cases of death from eating these mushrooms are rare but notable for the difficulty in treatment. That is why it is interesting that just two weeks ago the Georgetown University Medical Centre has reported success in treating four cases of mushroom poisoning using an extract from the seeds of a common thistle.

On June 8th 2012 it was reported that a woman who was admitted to a Melbourne hospital after eating poisonous mushrooms had died. The woman, aged in her 50s, picked the death-cap mushrooms in the suburb of Box Hill. She was admitted to the Austin Hospital in a critical condition and then subsequently passed away. It is believed she was visiting from China.

In January 2012 two people who ate death cap mushrooms at a New Year’s Eve party in Canberra later died at a Sydney hospital. Two people who ate smaller portions survived the poisoning. It is believed that all four of the people poisoned were Chinese nationals.

The nationality of the people involved in these incidents is relevant because the mushroom involved in these cases is the Death Cap (Amanita phalloides) which looks similar to Straw Mushrooms that grow widely throughout Asia and are consumed safely. Death Cap mushrooms however, contain a substance called amatoxin which impacts enzymes involved in cellular DNA. When Death Cap mushrooms are consumed death results in about 50 per cent of cases.

The Death Cap is a large mushroom with white gills and the base of the stem is surrounded by a cup-shaped sack. Death Caps may be white but are usually pale green to yellow in colour, with white gills and a white or pale green stalk up to 15cm long. The entire mushroom is poisonous and cooking or peeling the mushroom does not remove toxicity.

Death Caps are said to taste pleasant and symptoms can occur six to 24 hours after consumption. Initial symptoms can include abdominal pain, diarrhoea, vomiting, hypotension and jaundice, with acute hepatitis potentially followed by seizures, coma, renal failure and cardiac arrest. The liver involvement is why the seeds of the herb Milk Thistle (Silybum marianum) have been used in cases of mushroom poisoning.

Milk Thistle has been used for at least 2000 years as a herbal remedy for a variety of ailments, particularly liver, kidney, and gall bladder problems. Many studies have shown that substances in Milk Thistle (especially a flavonoid called silymarin) protect the liver from toxins. Silymarin itself is a mixture of chemicals including silibinin, silidianin, and silichristine (and yes, it is all a bit too “sili” for words). Based on this Milk Thistle has been used as an emergency antidote to poisoning by Death Cap mushroom. Animal studies have found that milk thistle extract completely counteracts the toxic effects of the mushroom when given within ten minutes of ingestion. If given within 24 hours, it significantly reduces the risk of liver damage and death. This has been supported in the recent experience coming out of Georgetown.

In the latest incident a man who had eaten poisonous mushrooms was taken to Georgetown University Medical Centre. The physicians contacted a California researcher who is the chief researcher for a study on using silibinin from Milk Thistle seeds intravenously to treat amatoxin poisoning. They were given emergency permission to use the intravenous (IV) silibinin to treat the man.

A week later another patient with mushroom poisoning arrived at Georgetown. To allow further use of the silibinin IV, the Medical Centre constituted a formal “clinical trial” which was then extended to include two more patients who presented with mushroom poisoning two days later.

The treatment with the IV extract of Milk Thistle seeds was accompanied in two of the cases by nasobiliary drainage to remove toxins from the liver. Aggressive hydration was also pursued as a way to reduce liver damage.

In all four cases liver failure was prevented and all patients fully recovered.

Much more needs to be known about silibinin, this chemical from the seeds of Milk Thistle, such as exactly how much is needed and exactly when to deliver it. Anyone who thinks that they may have eaten a Death Cap should seek immediate medical attention but it is fascinating that this ancient liver treatment is finding some very modern applications.