Treatment of amatoxin poisoning: 20-year retrospective analysis

Advances in the use of milk thistle (Silybum marianum)

Milk thistle (Silybum marianum) is an herbal supplement used to treat liver and biliary disorders. Silymarin, a mixture of flavanoid complexes, is the active component that protects liver and kidney cells from toxic effects of drugs, including chemotherapy. Although milk thistle has not significantly altered the course of chronic liver disease, it has reduced liver enzyme levels and demonstrated anti-inflammatory and T cell-modulating effects. There is strong preclinical evidence for silymarin's hepatoprotective and anticarcinogenic effects, including inhibition of cancer cell growth in human prostate, skin, breast, and cervical cells. Milk thistle is considered safe and well-tolerated, with gastrointestinal upset, a mild laxative effect, and rare allergic reaction being the only adverse events reported when taken within the recommended dose range. More clinical trials of rigorous methodology, using standardized and well-defined products and dosages, are needed to evaluate the potential of silymarin against liver toxicity, chronic liver disease, and human cancers.

Clinical applications of Silybum marianum in oncology

Milk thistle (Silybum marianum) is an herb that is increasingly used in oncology research and treatment settings. Historically, it has been used to treat liver and biliary disorders and has been used in detoxification and cleansing protocols. However, milk thistle is increasingly being investigated for its use in adult and pediatric populations for oncology indications. Possible indications during cancer treatment include cleansing and detoxification after chemotherapy, preventing hepatotoxicity during chemotherapy, treating hepatotoxicity after chemotherapy, and potentiating chemotherapy and radiation therapy as an adjunctive treatment. Milk thistle may also have applications in ameliorating long-term hepatic and cardiovascular effects of cancer treatment. Preliminary studies are investigating its use as a chemopreventive agent and possibly to treat cancer directly. Much of milk thistle's current clinical use grows out of historical uses but is informed by an increasing number of clinical trials and animal studies. This article provides an overview of the current clinical applications of milk thistle in the oncology setting, including guidelines on commonly used forms and doses.

Determination of alpha-amanitin in serum and liver by multistage linear ion trap mass spectrometry

This paper describes a rapid LC-MS/MS/MS method for the analysis of alpha-amanitin in serum and liver. Serum was initially prepared by precipitation of proteins with acetonitrile and subsequent removal of acetonitrile with methylene chloride. Liver was prepared by homogenization with aqueous acetonitrile and subsequent removal of acetonitrile using methylene chloride. For both matrices, the aqueous phase was then extracted using mixed-mode C18/cation exchange SPE cartridges and analyzed on a linear ion trap LC-MS system. Standards were prepared in extracts of control matrix. Seven replicate fortifications of serum at 0.001 mug/g (1 ng/g) of alpha-amanitin gave a mean recovery of 95% with 8.8% CV (relative standard deviation) and a calculated method detection limit of 0.26 ng/g. Seven replicates of control liver fortified at 1 ng/g gave a mean recovery of 98% with 17% CV and a calculated method detection limit of 0.50 ng/g. This is the first report of a positive mass spectrometric identification and quantitation of alpha-amanitin in serum and liver from suspect human and animal intoxications.

Amanita phalloides poisoning: reassessment of prognostic factors and indications for emergency liver transplantation

BACKGROUND/AIMS

Amanita phalloides poisoning is an uncommon cause of acute liver failure with an especially rapid course. The aim of this study was to re-assess transplantation criteria in patients with mushroom poisoning.

METHODS

Twenty-seven patients admitted for Amanita phalloides poisoning were studied. Previously reported transplantation criteria, including the recent Ganzert's criteria, were tested retrospectively.

RESULTS

The rate of fatal intoxication (death and/or transplantation) was 8/27 (30%). An interval between ingestion and diarrhea <8h was a very early predictor of a fatal outcome (accuracy of 78%). Later on, non-paracetamol and paracetamol King's College criteria were superior to Clichy's and Ganzert's criteria (accuracy of 100% compared to 85% and 85%, respectively). Encephalopathy and renal insufficiency were not constant in the fatal intoxication group. Prothrombin index below 10% 4 days or more after ingestion had a 100% accuracy for predicting a fatal outcome.

CONCLUSIONS

Liver transplantation should be strongly considered in patients with an interval between ingestion and diarrhea <8h. Encephalopathy should not be an absolute prerequisite for deciding transplantation. From day 4 after ingestion, prothrombin index lower than 10% ( approximately INR of 6) alone is a reliable tool for deciding emergency transplantation.

The organic anion transport polypeptide 1d1 (Oatp1d1) mediates hepatocellular uptake of phalloidin and microcystin into skate liver

Organic anion transporting polypeptides (rodent Oatp; human OATP) mediate cellular uptake of numerous organic compounds including xenobiotic toxins into mammalian hepatocytes. In the little skate Leucoraja erinacea a liver-specific Oatp (Oatp1d1, also called sOatp) has been identified and suggested to represent an evolutionarily ancient precursor of the mammalian liver OATP1B1 (human), Oatp1b2 (rat), and OATP1B3 (human). The present study tested whether Oatp1d1 shares functional transport activity of the xenobiotic oligopeptide toxins phalloidin and microcystin with the mammalian liver Oatps/OATPs. The phalloidin analogue [(3)H]-demethylphalloin was taken up into skate hepatocytes with high affinity (Km approximately 0.4 microM), and uptake could be inhibited by phalloidin and a variety of typical Oatp/OATP substrates such as bromosulfophthalein, bile salts, estrone-3-sulfate, cyclosporine A and high concentrations of microcystin-LR (Ki approximately 150 microM). When expressed in Xenopus laevis oocytes Oatp1d1 increased uptake of demethylphalloin (Km approximately 2.2 microM) and microcystin-LR (Km approximately 27 microM) 2- to 3-fold over water-injected oocytes, whereas the alternative skate liver organic anion transporter, the dimeric Ostalpha/beta, exhibited no phalloidin and only minor microcystin-LR transport. Also, the closest mammalian Oatp1d1 orthologue, the human brain and testis OATP1C1, did not show any phalloidin transport activity. These results demonstrate that the evolutionarily ancient Oatp1d1 is able to mediate uptake of cyclic oligopeptide toxins into skate liver. The findings support the notion that Oatp1d1 is a precursor of the liver-specific mammalian Oatps/OATPs and that its transport properties are closely associated with certain forms of toxic liver injury such as for example protein phosphatase inhibition by the water-borne toxin microcystin.

Intoxication-related fatalities in northern Germany

BACKGROUND

Knowing what substances cause death in intoxicated patients is of medical, legal, and political relevance. Harmonized data documentation like TESS (Toxic Exposure Surveillance System) in the United States does not exist yet in Germany. However, the GIZ-Nord Poison Center in Göttingen issues an annual report that includes fatalities. The aim of this study was to obtain an overview of the substances resulting in fatal poisoning and to define risk factors.

METHODS

In a retrospective study, all fatalities due to poisoning from January 1996 until March 2003 were analyzed.

RESULTS

From 1996 to 2003, the GIZ-Nord Poison Center was consulted in 168,000 cases. There were 142 fatalities due to poisoning (0.08% of all consultations). In 79 cases, the lethal substance was a medical drug, mostly tricyclic antidepressants and cardiovascular drugs. Two immigrants of German origin from the former Soviet Union died after consuming Amanita mushrooms. Five elderly, disorientated patients died of respiratory failure due to aspiration of detergent products from soap or shampoo.

CONCLUSION

Three groups of patients with a high risk of dying from intoxication can be defined: (1) suicidal patients with access to tricyclic antidepressants or cardiovascular drugs, (2) immigrants from the former Soviet Union who mistake toxic German mushrooms for edible species, and (3) elderly, disorientated patients who ingest large amounts of soap or shampoo.

[Phalloidin syndrome: role of Elisa-based assay for the detection of alpha- and gamma-amanitins in urine. Preliminary results]

After consumption of mushrooms containing amatoxins (Amanita, Lepiota, and Galerina species), symptoms usually develop after a long delay (>6 h). Initial symptoms start as severe gastroenteritis, progressing to liver failure and possibly death as a result of hepatic coma. Since the survival rate of poisoned patients is claimed to depend on the time of beginning of efficient treatment, fast and reliable assays for amatoxins in biological fluids are essential. Described analytical methods for amatoxins include high performance liquid chromatography and radioimmunoassay (RIA). Recently, a new enzyme-linked immunosorbent assay (Bühlmann Amanitin ELISA kit) has been introduced as an alternative method to RIA. This ELISA-based assay offers several advantages: no complex extraction procedure is required (vs. HPLC) and no safety precautions concerning radioactivity have to be taken (vs. RIA). From August 2004 to October 2005, a pilot study was performed to test the practicability and the clinical utility of this method in emergency situations.

RESULTS

ten urines, 9 serums and 1 faeces from 10 patients suffering from acute gastroenteritis after mushroom ingestions (7 contaminated meals) were analyzed. Definitive diagnosis of amatoxin poisoning was made in 4 cases (3 contaminated meals) on the basis of the anamnesis, laboratory results, and clinical course. A patient developed a severe amatoxin poisoning with urinary amanitins level < 1.5 microg/L (urines were collected more than 72 h after mushroom ingestion). Two patients were paucisymptomatic with urinary amanitins levels >10 microg/L (urines were collected before the 36th hour).

CONCLUSION

Urine is the sample of choice for the determination of amatoxins. The most critical factor to invalidate the usefulness of this analysis is time. After 36 h, the sensitivity is unreliable.

Molecular characterization and inhibition of amanitin uptake into human hepatocytes

Amatoxins are the main poison of the green death cap (Amanita phalloides) and among the most dangerous natural toxins causing hepatic failure. A possible therapeutic approach is the inhibition of the transporting systems mediating the uptake of amatoxins into human hepatocytes, which, however, have yet to be identified. In the current study we tested whether members of the organic anion-transporting polypeptide (OATP) family, localized in the sinusoidal membranes of human hepatocytes, are involved in amatoxin uptake. For this, Madin Darby canine kidney strain II (MDCKII) cells stably expressing human OATP1B3, OATP2B1, or OATP1B1, were assayed for the uptake of 3H-labeled O-methyl-dehydroxymethyl-alpha-amanitin. Under our conditions, only OATP1B3 was able to transport amanitin with a K(m) value of 3.7 microM +/- 0.6 microM. Accordingly, toxin uptake was inhibited by OATP1B3 substrates and inhibitors (cyclosporin A, rifampicin, the quinoline derivatives MK571 ([(3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)((3-dimethylamino-3-oxopropyl)thio)methyl)thiopropanoic acid]) and montelukast, the cholecystokinin octapeptide (CCK-8), paclitaxel, and bromosulfophthalein), as well as by some antidotes used in the past for the treatment of human amatoxin poisoning (silibinin dihemisuccinate, penicillin G, prednisolone phosphate, and antamanide). These transport studies are in line with viability assays monitoring the toxic effect of amanitin on the transfected MDCKII cells. Further support for amatoxin transport was found in primary human hepatocytes, expressing OATP1B3, OATP2B1, and OATP1B1, where CCK-8, a substrate specific for OATP1B3, prevented the fragmentation of nucleoli, a lesion typical for amanitin action. In conclusion, we have identified OATP1B3 as the human hepatic uptake transporter for amatoxins; moreover, substrates and inhibitors of OATP1B3, among others rifampicin, may be useful for the treatment of human amatoxin poisoning.

Syndromic diagnosis and management of confirmed mushroom poisonings

OBJECTIVE

To assess the evolving global epidemiology of mushroom poisoning and to identify new and emerging mushroom poisonings and their treatments, a descriptive analysis and review of the world's salient scientific literature on mushroom poisoning was conducted.

DATA SOURCE

Data sources from observation studies conducted over the period 1959-2002, and describing 28,018 mushroom poisonings since 1951, were collected from case reports, case series, regional descriptive studies, meta-analyses, and laboratory studies of mushroom poisonings and the toxicokinetics of mycotoxins.

STUDY SELECTION

Studies included in the review were selected by a MEDLINE search, 1966-2004, an Ovid OLDMEDLINE search, 1951-1965, and a medical library search for sources published before 1951.

DATA EXTRACTION

To better guide clinicians in establishing diagnoses and implementing therapies, despite confusing ingestion histories, data were extracted to permit an expanded syndromic classification of mushroom poisoning based on presentation timing and target organ systemic toxicity.

DATA SYNTHESIS

The final 14 major syndromes of mushroom poisoning were stratified first by presentation timing and then by target organ systemic toxicity and included early (<6 hrs), late (6-24 hrs), and delayed syndromes (> or =1 day). There were eight early syndromes (four neurotoxic, two gastrointestinal, two allergic); three late syndromes (hepatotoxic, accelerated nephrotoxic, erythromelalgia); and three delayed syndromes (delayed nephrotoxic, delayed neurotoxic, rhabdomyolysis). Four new mushroom poisoning syndromes were classified including accelerated nephrotoxicity (Amanita proxima, Amanita smithiana), rhabdomyolysis (Tricholoma equestre, Russula subnigricans), erythromelalgia (Clitocybe amoenolens, Clitocybe acromelalgia), and delayed neurotoxicity (Hapalopilus rutilans). In addition, data sources were stratified by three chronological time periods with >1,000 confirmed mushroom ingestions reported and tested for any statistically significant secular trends in case fatalities from mushroom ingestions over the entire study period, 1951-2002.

CONCLUSIONS

Since the 1950s, reports of severe and fatal mushroom poisonings have increased worldwide. Clinicians must consider mushroom poisoning in the evaluation of all patients who may be intoxicated by natural substances. Since information on natural exposures is often insufficient and incorrect, a new syndromic classification of mushroom poisoning is recommended to guide clinicians in making earlier diagnoses, especially in cases where only advanced critical care, including organ transplantation, may be life saving.

Indication of liver transplantation following amatoxin intoxication

BACKGROUND/AIMS

Indication of liver transplantation in acute liver failure following amatoxin intoxication is still uncertain.

METHODS

One hundred and ninety-eight patients were studied retrospectively. The laboratory parameters alanine-aminotransferase, serum bilirubin, serum creatinine and prothrombin index were analyzed over time. Predictors of fatal outcome and survival were determined by receiver-operating-characteristic and sensitivity-specificity analysis.

RESULTS

Twenty-three patients died in the median 6.1 days (range, 2.7-13.9 days) after ingestion. Using a single parameter as predictor of fatal outcome the area under the receiver-operating-characteristic curve of prothrombin index (0.96) and serum creatinine (0.93) were both significantly greater (P<0.05) compared with serum bilirubin (0.82) and alanine-aminotransferase (0.69). Prediction of fatal outcome had an optimum, if a prothrombin index less than 25% was combined with a serum creatinine greater than 106 micromol/l from day 3 after ingestion onwards (sensitivity 100%, 95% confidence interval 87-100; specificity 98%, 95% confidence interval 94-100). The median time period between the first occurrence of this predictor in non-survivors and death was 63h (range, 3-230h).

CONCLUSIONS

A decision model of liver transplantation following amatoxin intoxication using prothrombin index in combination with serum creatinine from day 3 to 10 after ingestion enables an early and reliable assessment of outcome.

Mycotoxins revisited: Part I

Mushrooms are ubiquitous in nature. They are an important source of nutrition; however, certain varieties contain chemicals that can be highly toxic to humans. Industrially cultivated mushrooms are historically very safe, but foraging for mushrooms or accidental ingestion of mushrooms in the environment can result in serious illness and death. The emergency department is the most common site of presentation for patients suffering from acute mushroom poisoning. Although recognition can be facilitated by identification of a characteristic toxidrome, the presenting manifestations can be variable and have considerable overlap with more common and generally benign clinical syndromes. The goal of this two-part article is to review the knowledge base on this subject and provide information that will assist the clinician in the early consideration, diagnosis and treatment of mushroom poisoning. Part I, presented in this issue of the Journal, reviews the epidemiology and demographics of mushroom poisoning, the physical characteristics of the most toxic varieties, the classification of the toxic species, and an overview of the cyclopeptide-containing mushroom class. Part II, to be published in the next issue of the Journal, will be focused on the presentation of the other classes of toxic mushrooms along with an up-to-date review of the most recently identified poisonous varieties.

Acute Liver Failure

Acute liver failure (ALF) is an uncommon medical emergency whose rapid progression and high mortality demand early diagnosis and expert management, including immediate transfer of any potential case to facilities for intensive care and orthotopic liver transplantation (OLT). All patients with ALF must be screened aggressively for acetaminophen toxicity (history, serum levels, "hyperacute" presentation with renal failure), for other drugs, and viral hepatitis; rare causes of ALF should also be considered. After an acetaminophen overdose, N-acetylcysteine must be given as early as possible, preferably in the emergency room, but any patient with ALF should promptly receive N-acetylcysteine if there is suspicion of acetaminophen toxicity irrespective of the time of ingestion. Supportive care for all patients with ALF includes adequate enteral nutrition, aggressive screening and treatment of infection, prophylactic broad-spectrum antibiotics, and antifungal agents. Sedation with propofol is given for severe agitation or mechanical ventilation. With advanced coma grades, intensive care is needed with hemodynamic monitoring, ventilatory support, continuous renal replacement for renal failure, and intracranial pressure monitoring. Intracranial hypertension is treated with mannitol and/or acute short-term hyperventilation, but if the patient is refractory to treatment, mild-moderate hypothermia is achieved by a cooling blanket that is continued throughout OLT. Barbiturate coma is only used in refractory cases as the last treatment modality. Seizures are aggressively treated with phenytoin, with additional diazepam as needed. Candidacy and activation for OLT should be completed as early as possible in the course of ALF, especially in "hyperacute" cases such as acetaminophen toxicity. The final decision to proceed with OLT is made when a donor organ becomes available. King's College Hospital criteria for OLT are still the best prognostic assessment for fatal outcome in ALF, but the criteria fail to identify some patients who will die.

Diagnostic accuracy of urinary amanitin in suspected mushroom poisoning: a pilot study

BACKGROUND

Amatoxin-containing species are responsible for the most severe cases of mushroom poisoning, with high mortality rate. Therefore, this poisoning should be ruled out in all patients presenting gastrointestinal symptoms after wild mushroom ingestion.

OBJECTIVE

To determine sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic efficacy (DE) of urinary amanitin analysis in cases of suspected mushroom poisoning.

METHODS

All cases of mushroom ingestion referred to a Poison Center during a one-month period were analyzed. Amanitin measurements were performed by ELISA method (functional least detectable dose 1.5 ng/ml; cut-off value not clearly established). Gastrointestinal symptoms latency and initial clinical assessment were considered alternative diagnostic tools. Definitive diagnosis was used as the reference standard.

RESULTS

Among 61 patients included in the study, amatoxin poisoning was diagnosed in 10 cases. Urine samples were collected 5.5 to 92 hours after mushroom ingestion. Urinary amanitin DE was 91.8%, 93.4%, and 80.3%, based on the cut-off value considered (1.5, 5.0, and 10.0 ng/ml, respectively). Symptoms latency longer than 6 hours and initial clinical assessment DE were 70.5% and 67.2%, respectively. To identify amatoxin poisoning, initial clinical assessment resulted more sensitive and urinary amanitin analysis more specific.

CONCLUSIONS

Urinary amanitin analysis is a valuable diagnostic tool and may significantly contribute to the management of suspected mushroom poisoning. At present, the best diagnostic accuracy can be obtained taking advantage of both the high sensitivity and negative predictive value of the clinical assessment performed by an experienced toxicologist, and the high specificity and positive predictive value that characterize urinary amanitin analysis.

Acute liver failure

Acute liver failure is a rare and life-threatening clinical syndrome following severe hepatic injury. Depending on the rapidity of its development, two distinct complications contribute to a high mortality: in hyperacute liver failure, rapid development of massive hepatic necrosis and apoptosis gives rise to severe hyperammonemia, hepatic encephalopathy and life-threatening cerebral edema. The high risk of cerebral herniation requires early listing for emergency liver transplantation. Patients with hyperacute liver failure surviving the initial episode of cerebral edema have a substantial potential for hepatic recovery. If progressive hepatic failure develops more slowly, astrocytic osmoregulation prevents cerebral herniation in most instances. Unfortunately, these patients have a small potential of hepatic regeneration and transplantation should be performed before renal failure, sepsis or multiorgan failure emerge. Experimental treatment methods including detoxification by artificial or bioartificial liver support or by stimulating hepatic regeneration are currently evaluated. Recognition of ammonia toxicity has stimulated the search for early ammonia-lowering strategies and strongly renewed the interest in dialytic therapies. Anti-apoptotic interventions are among the most promising pharmacological options for the near future.

Successful treatment of a child with fulminant liver failure and coma caused by Amanita phalloides intoxication with albumin dialysis without liver transplantation

FLF is a life-threatening disease. Hepatic coma exerts dramatic impact on patient survival. At present, LTx is the treatment modality of choice that provides significant improvement in outcome of most patients with FLF. Multiple attempts have been made to reduce mortality and improve the patient's condition. One of the new options is AD - MARS. We present the case of a 11-yr-old boy with FLF and hepatic coma who avoided the scheduled LTx because of rapid neurological and biochemical improvement immediately after three MARS sessions.

Cytotoxic fungi—an overview

Among fungal toxins causing organ damage in the human body, amatoxins and orellanine remain exceptional. Amatoxins, a group of bicyclic octapeptides occurring in some Amanita, Galerina and Lepiota species, induce deficient protein synthesis resulting in cell death, but might also exert toxicity through inducing apoptosis. Target organs are intestinal mucosa, liver and kidneys. Poisoning will result in dehydration and electrolyte derangement, liver necrosis and possibly kidney damage. In established poisoning the mainstay of treatment is optimum symptomatic and supportive care. No specific treatment is available, but some pharmaceuticals, like silibinin, benzylpenicillin and acetylcysteine, might have a role in limiting the extent of hepatic damage. Orellanine is a nephrotoxic bipyridine N-oxide found in some Cortinarius species. Its mechanism of action is not fully understood, but it has been shown to inhibit protein synthesis and to generate free oxygen radicals. As early symptoms often are lacking or vague, poisoning may initially be overlooked or misinterpreted and the patients usually present with established renal damage. Supportive care is the only therapeutic option. Tricholoma equestre might contain a myotoxin and repeated ingestion may cause significant rhabdomyolysis. Ingestion of Amanita smithiana and A. proxima has been reported to result in kidney damage. Gyromitrin, a toxic compound that is converted to hydrazines in the stomach, occurs in some Gyromitra species. It is mainly neurotoxic, but may also induce moderate hepatic damage and haemolysis.