Amanita phalloides (death cap) contains highly toxic amanitins. Dosages of 0.1-0.5 mg/kg may be lethal, whereas the average death cap contains 80 mg. Classically the first symptoms of abdominal pain, (bloody) diarrhoea, nausea and vomiting emerge 6 to 24 hours after ingestion. With appropriate care the patient may soon improve. However, amanitins entering the hepatocyte will continue to inhibit RNA polymerase II, leading to a stop in protein synthesis and subsequent hepatic failure. This generally occurs 24 to 36 hours after ingestion and is accompanied by a rapid elevation of liver transaminases, often complicated by renal tubular necrosis.1 The reference standard test for detection of amanitin is ELISA urinalysis (sensitivity 60%, specificity 100%) performed 6 to 24 hours after intoxication.2 However, this test was not readily available and a bedside test, known as the Meixner test, was performed.3 Based on the history in combination with the positive test, we started treatment promptly with activated charcoal and N-acetylcysteine (150 mg/ kg in the first 15 minutes followed by 150 mg/kg/day). Moreover, silibinin was urgently ordered and administered intravenously at 5 mg/kg during the first hour, followed by 20 mg/kg/day. Silibinin, derived from milk thistles, inhibits uptake of amanitin in human hepatocytes and was successfully used in several case reports.4,5 Two days later, the presence of amanitins was confirmed by urinalysis. During this period, the patient’s liver tests deteriorated rapidly. Fortunately, on day 3 all the tests improved (table 2) and our patient recovered well without the need of a liver transplantation.
The blue colour arises from a reaction with lignin (present in most poor-quality paper, such as newspaper); false-positives resulting from this reaction are reported to be rare. However, blue pigments in a mushroom may yield false-positive results. Therefore, a negative control test on lignin-free (office) paper may increase the specificity. Findings should always be confirmed with a urinary ELISA test.6,7 This case clearly illustrates how the Meixner test may expedite the diagnosis of Amanita intoxication; patients should be treated as soon as possible with N-acetylcysteine and activated charcoal, as well as silibinin.