Diagnosis of Amanita Toxicosis in a Dog with Acute Hepatic Necrosis

Hypoadrenocorticism in a Dog Following Recovery from Alpha-Amanitin Intoxication

A 10-year-old, female spayed Labrador Retriever was referred for acute hepatopathy and urinary retention. Blood work from the initial presentation (day 0) revealed a severe, mixed hepatopathy. Over the course of the patient's hospitalization, the patient developed liver insufficiency. Urine was submitted for toxicological screening and revealed detection of a trace concentration of alpha-amanitin. The patient was treated supportively for alpha-amanitin intoxication and was discharged from the hospital on day 8, with most biochemical parameters being markedly improved. The patient was persistently hyporexic at the time of discharge. On day 15, at a recheck appointment, the patient had lost 2.4 kg and liver enzymology revealed improved values. On day 24, the patient was presented for anorexia and vomiting and had lost another 2.3 kg. Blood work and endocrinological testing at that time were consistent with hypoadrenocorticism. The patient was started on glucocorticoids and mineralocorticoids. At day 106, the patient was doing well clinically while receiving monthly mineralocorticoids and daily glucocorticoids. This case report is the first to describe the chronological association between alpha-amanitin-induced liver dysfunction and the subsequent development of adrenal insufficiency in a dog.

A retrospective evaluation of mushroom ingestions in 421 dogs in Norway (2011-2022)

Background

Mushroom poisoning may result in a variety of signs ranging from mild, mostly gastroenteritis, to organ failure and death. To increase the knowledge of prevalence, treatment and outcome in dogs, information regarding mushroom ingestion was collected.

Materials and methods

This retrospective study analysed all inquiries of mushroom ingestion in dogs to the Norwegian Poison Information Center from 2011 to 2022. Mushrooms were identified by a mycologist or Norwegian-certified mushroom expert. Differences in mushroom species, clinical findings, treatments and outcome were evaluated.

Results

A total of 421 mushroom ingestions in dogs were included. The mushrooms were identified as non-poisonous in 45% of cases. The most frequently involved toxin group was gastrointestinal mushrooms, followed by muscarinic mushrooms and mushrooms containing isoxazoles. About 64% of cases were managed at home, 33% were hospitalised and received treatment, and 3% were observed by a veterinarian without treatment. The survival rate was 98.6%, with death occurring after ingestion of Amanita muscaria, Cortinarius rubellus, Amanita virosa, Clitocybe rivulosa and Inocybe sp.

Conclusions

This study demonstrated the importance of rapid and accurate identification of the mushroom. This could prevent delays in therapeutic intervention and avoid unnecessary treatment of these dogs. With early, correct identification of mushrooms, our results demonstrated a good prognosis for dogs after ingestion.

Hepatopathy in Victorian dogs consuming pet meat contaminated with indospicine

BACKGROUND

Indospicine is an arginine analogue and a natural toxin occurring only in Indigofera plant species, including Australian native species. It accumulates in the tissues of grazing animals, persisting for several months after ingestion. Dogs are particularly sensitive to indospicine toxicity and can suffer fatal liver disease after eating indospicine-contaminated pet meat.

METHOD

A disease outbreak investigation was launched following notification to Agriculture Victoria of a cluster of 18 dogs displaying acute, severe, hepatopathy in the East Gippsland Shire in June 2021.

RESULTS

Between June and September 2021, 24 pet dogs died, and 40 others experienced liver disease after eating commercially prepared pet meat found to contain indospicine. The investigation identified the toxin in serum and liver samples from affected dogs and at high levels in some samples of pet meat eaten by the dogs. Twenty-six horses that were moved from the Northern Territory and processed at a Pet Meat Processing facility (knackery) in eastern Victoria over a period of 14 days in late May-early June 2021 were identified as the likely source of the indospicine toxin in the pet meat. Pet meat produced by the knackery and on-sold by several retailers was determined to be the cause of the illness and death in the dogs.

CONCLUSION

This is the first report of severe and frequently fatal hepatopathy in dogs in Victoria relating to consumption of pet meat contaminated with indospicine.

Mammalian Mycophagy: a Global Review of Ecosystem Interactions Between Mammals and Fungi

The consumption of fungi by animals is a significant trophic interaction in most terrestrial ecosystems, yet the role mammals play in these associations has been incompletely studied. In this review, we compile 1 154 references published over the last 146 years and provide the first comprehensive global review of mammal species known to eat fungi (508 species in 15 orders). We review experimental studies that found viable fungal inoculum in the scats of at least 40 mammal species, including spores from at least 58 mycorrhizal fungal species that remained viable after ingestion by mammals. We provide a summary of mammal behaviours relating to the consumption of fungi, the nutritional importance of fungi for mammals, and the role of mammals in fungal spore dispersal. We also provide evidence to suggest that the morphological evolution of sequestrate fungal sporocarps (fruiting bodies) has likely been driven in part by the dispersal advantages provided by mammals. Finally, we demonstrate how these interconnected associations are widespread globally and have far-reaching ecological implications for mammals, fungi and associated plants in most terrestrial ecosystems.

[Acute liver failure in a dog after mushroom intake, presumably of the genus Amanita]

A 4-year-old, neutered male Husky-mix dog weighing 29.4 kg that reportedly ingested a mushroom most likely of the genus Amanita one day prior to presentation exhibited signs of diarrhea, vomitus, inappetence and progressively worsening lethargy. Clinical chemistry revealed hypoglycemia, hyperbilirubinemia, decreased prothrombin and thromboplastin time, as well as increased liver enzyme activities. Despite hospitalization and supportive therapy over a period of 3 days the dog's general condition worsened leading to euthanasia. The pathomorphological findings were characterized by hemorrhage in several organs, hemorrhagic ingesta, icterus, and marked hepatic cellular necrosis.

Physical examination, serum biochemical, and coagulation abnormalities, treatments, and outcomes for dogs with toxicosis from α-amanitin-containing mushrooms: 59 cases (2006-2019)

OBJECTIVE

To report history, physical examination findings, clinicopathologic abnormalities, treatments, and outcomes of dogs with confirmed α-amanitin toxicosis resulting from ingestion of α-amanitin-containing mushrooms, and to report whether any differences were significant between survivors and nonsurvivors.

ANIMALS

59 dogs.

PROCEDURES

Medical records of all dogs with confirmed α-amanitin toxicosis presented to a northern California emergency and specialty veterinary hospital between January 2006 and July 2019 were reviewed for signalment; body weight; history; physical examination findings including rectal temperature at presentation; results of serum biochemical analyses, coagulation tests, and a test for the detection of α-amanitin in urine; treatments; and outcomes. Differences for each were compared between survivors and nonsurvivors.

RESULTS

Among the 59 dogs, 36 were < 1 year of age; 56 had variable clinical signs that included vomiting, diarrhea, anorexia, and weakness or lethargy; and 22 had rectal temperatures > 39.2°C (102.5°F) at presentation. Cases were seen throughout the calendar year. At presentation, alanine aminotransferase activity was mildly to markedly increased in 97% of dogs, hypoglycemia was noted in 78%, and coagulation times were prolonged in 91%. Most dogs that rapidly decompensated died; however, 13 dogs survived to hospital discharge and completely recovered.

CONCLUSIONS AND CLINICAL RELEVANCE

Ability to recognize dogs with α-amanitin toxicosis on the basis of clinical signs, physical examination findings, and clinicopathologic test results is essential because mushroom ingestion is rarely observed and immediate treatment is necessary. Dogs that have marked hypoglycemia or coagulopathy may have a poor prognosis.

Clinical recovery of 5 dogs from amatoxin mushroom poisoning using an adapted Santa Cruz protocol for people

OBJECTIVE

To describe the clinical course, treatment, and outcome of 5 dogs following ingestion of toxic Amanita spp. mushrooms containing amatoxins using an adapted version of the Santa Cruz protocol developed for people.

CASE SERIES SUMMARY

Five dogs were presented with clinical signs compatible with amanitin toxicity with witnessed ingestion noted in 3 of 5 dogs. Clinical findings included acute onset vomiting and diarrhea, lethargy, and hepatopathy including signs of fulminant hepatic failure (increased liver enzyme activities, hyperbilirubinemia, prolonged clotting times, and hypoglycemia were noted among these cases). Urine toxicological screening confirmed the presence of Amanita toxins in 4 cases with expert mycologist speciation in the fifth. Core interventions included percutaneous biliary drainage, use of octreotide, and early nil per os orders. All dogs survived to discharge with this treatment strategy.

NEW OR UNIQUE INFORMATION PROVIDED

This case series describes the use of a modified version of the Santa Cruz protocol to address amatoxin-induced fulminant hepatic failure in dogs. The protocol was safe, well tolerated, and all patients made a full clinical recovery.

Clinical and histologic outcome in a dog surviving massive hepatic necrosis

This report describes the clinical and histologic recovery of a 2‐year‐old mixed‐breed dog presented with hypovolemic shock, markedly increased serum alanine amino transferase activity, and hemoabdomen. Emergency exploratory surgery revealed a friable liver with multiple capsule hemorrhages necessitating removal of the left lateral lobe. Histologic evaluation showed acute massive hepatic necrosis with centrilobular and midzonal distribution. The dog survived, and all monitored laboratory values normalized within 7 weeks. A liver biopsy taken 8 weeks after presentation revealed normal hepatic architecture with a few, randomly distributed neutrophilic foci. Follow‐up included intermittent determination of liver variables including liver function tests for a period of 7 years. The dog's health status, and all test results remained normal during this time. Complete recovery and good long‐term quality of life after life‐threatening acute liver failure secondary to massive hepatic necrosis is possible in dogs.

Acute liver failure in two dogs following ingestion of cheese tree (Glochidion ferdinandi) roots

OBJECTIVE

To describe the management and resolution of acute liver failure (ALF) in two dogs following ingestion of cheese tree (Glochidion ferdinandi) roots.

CASE SUMMARIES

A 2-year-old male entire Bullmastiff and a 5-year-old female neutered German Shepherd dog were presented for acute-onset lethargy and vomiting after chewing on tree roots of a cheese tree. Both dogs developed clinical abnormalities consistent with ALF, including hepatic encephalopathy, marked increase in alanine aminotransferase activity and bilirubin concentration, and prolonged coagulation times. Treatment included administration of intravenous fluids, hepatoprotectants, vitamin K₁ , antibiotics, lactulose, antacids, antiemetics, and multiple fresh frozen plasma transfusions. Follow-up examinations performed 30 days after initial presentation revealed the dogs to be clinically healthy with serum biochemical and coagulation profiles within reference intervals.

NEW OR UNIQUE INFORMATION

This is the first report describing ALF in two dogs following ingestion of cheese tree (G. ferdinandi) roots. In this clinical setting, despite a poor prognosis, survival and recovery of adequate liver function were possible with medical management.

Mushroom Poisoning Cases in Dogs and Cats: Diagnosis and Treatment of Hepatotoxic, Neurotoxic, Gastroenterotoxic, Nephrotoxic, and Muscarinic Mushrooms

Ingestion of poisonous mushrooms by small animals can lead to liver failure, neurotoxicity, or gastrointestinal irritation. Although amanita poisoning can be lethal, ingestion of other toxic mushrooms is generally self-limiting and not life threatening. Most cases are undiagnosed, as routine diagnostic tests only exist for amanitins and psilocin. Early detection of amanitin exposure can greatly aid in the therapeutic intervention by allowing veterinarians to make timely decisions regarding patient management. Treatment is generally supportive, but specific therapeutic measures exist for amanitin and psilocin exposures.

Acute Inocybe mushroom toxicosis in dogs: 5 cases (2010-2014)

OBJECTIVE

To describe the clinical course, treatment, and outcome of 5 dogs following ingestion of mushrooms belonging to the Inocybe genus.

CASE SERIES SUMMARY

Five dogs with witnessed Inocybe ingestions were presented with clinical signs compatible with poisoning. Vomiting, ptyalism, diarrhea, depression, and tachycardia were common clinical findings in the dogs in this case series. The prognosis with Inocybe toxicosis appears to be excellent as all dogs fully recovered following supportive care.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first reported case series of Inocybe mushroom ingestions in dogs where identification of the mushrooms were confirmed by an expert mycologist.

A novel orellanine containing mushroom Cortinarius armillatus

Orellanine (3,3',4,4'-tetrahydroxy-2,2'-bipyridine-1,1'-dioxide) is a tetrahydroxylated di-N-oxidized bipyridine compound. The toxin, present in certain species of Cortinarius mushrooms, is structurally similar to herbicides Paraquat and Diquat. Cortinarius orellanus and Cortinarius rubellus are the major orellanine-containing mushrooms. Cortinarius mushrooms are widely reported in Europe where they have caused human poisoning and deaths through accidental ingestion of the poisonous species mistaken for the edible ones. In North America, Cortinarius orellanosus mushroom poisoning was recently reported to cause renal failure in a Michigan patient. Cortinarius mushroom poisoning is characterized by delayed acute renal failure, with some cases progressing to end-stage kidney disease. There is debate whether other Cortinarius mushroom contain orellanine or not, especially in North America. Currently, there are no veterinary diagnostic laboratories in North America with established test methods for detection and quantitation of orellanine. We have developed two diagnostic test methods based on HPLC and LC-MSMS for identification and quantitation of orellanine in mushrooms. Using these methods, we have identified Cortinarius armillatus as a novel orellanine-containing mushroom in North America. The mean toxin concentration of 145 ug/g was <1% of that of the more toxic C. rubellus. The HPLC method can detect orellanine at 17 μg g(-1) while the LC-MSMS method is almost 2000 times more sensitive and can detect orellanine at 30 ng g(-1). Both tests are quantitative, selective and are now available for veterinary diagnostic applications.

Production of (15)N-labeled α-amanitin in Galerina marginata

α-Amanitin is the major causal constituent of deadly Amanita mushrooms that account for the majority of fatal mushroom poisonings worldwide. It is also an important biochemical tool for the study of its target, RNA polymerase II. The commercial supply of this bicyclic peptide comes from Amanita phalloides, the death cap mushroom, which is collected from the wild. Isotopically labeled amanitin could be useful for clinical and forensic applications, but α-amanitin has not been chemically synthesized and A. phalloides cannot be cultured on artificial medium. Using Galerina marginata, an unrelated saprotrophic mushroom that grows and produces α-amanitin in culture, we describe a method for producing (15)N-labeled α-amanitin using growth media containing (15)N as sole nitrogen source. A key to success was preparing (15)N-enriched yeast extract via a novel method designated "glass bead-assisted maturation." In the presence of the labeled yeast extract and (15)N-NH4Cl, α-amanitin was produced with >97% isotope enrichment. The labeled product was confirmed by HPLC, high-resolution mass spectrometry, and NMR.

Acute liver failure in dogs and cats

OBJECTIVE

To define acute liver failure (ALF), review the human and veterinary literature, and discuss the etiologies and current concepts in diagnostic and treatment options for ALF in veterinary and human medicine.

ETIOLOGY

In veterinary medicine ALF is most commonly caused by hepatotoxin exposure, infectious agents, inflammatory diseases, trauma, and hypoxic injury.

DIAGNOSIS

A patient may be deemed to be in ALF when there is a progression of acute liver injury with no known previous hepatic disease, the development of hepatic encephalopathy of any grade that occurs within 8 weeks after the onset of hyperbilirubinemia (defined as plasma bilirubin >50 μM/L [>2.9 mg/dL]), and the presence of a coagulopathy. Diagnostic testing to more specifically characterize liver dysfunction or pathology is usually required.

THERAPY

Supportive care to aid the failing liver and compensate for the lost functions of the liver remains the cornerstone of care of patients with ALF. Advanced therapeutic options such as extracorporeal liver assist devices and transplantation are currently available in human medicine.

PROGNOSIS

The prognosis for ALF depends upon the etiology, the degree of liver damage, and the response to therapy. In veterinary medicine, the prognosis is generally poor.

Feasibility of flotation concentration of fungal spores as a method to identify toxigenic mushrooms

Purpose

Mushroom poisoning is a recurring and challenging problem in veterinary medicine. Diagnosis of mushroom exposure in animals is hampered by the lack of rapid diagnostic tests. Our study evaluated the feasibility of using flotation concentration and microscopic evaluation of spores for mushroom identification. Evaluation of this method in living animals exposed to toxigenic mushrooms is limited by ethical constraints; therefore, we relied upon the use of an in vitro model that mimics the oral and gastric phases of digestion.

Methods

In our study, mycologist-identified toxigenic (poisonous) and nontoxigenic fresh mushrooms were collected in North Carolina, USA. In phase 1, quantitative spore recovery rates were determined following magnesium sulfate, modified Sheather’s sugar solution, and zinc sulfate flotation (n=16 fungal species). In phase 2, mushrooms (n=40 fungal species) were macerated and digested for up to 2 hours in a salivary and gastric juice simulant. The partially digested material was acid neutralized, filtered, and spores concentrated using zinc sulfate flotation followed by microscopic evaluation of spore morphology.

Results

Mean spore recovery rates for the three flotation fluids ranged from 32.5% to 41.0% (P=0.82). Mean (± standard error of the mean) Amanita spp. spore recovery rates were 38.1%±3.4%, 36.9%±8.6%, and 74.5%±1.6% (P=0.0012) for the magnesium sulfate, Sheather’s sugar, and zinc sulfate solutions, respectively. Zinc sulfate flotation following in vitro acid digestion (phase 2) yielded spore numbers adequate for microscopic visualization in 97.5% of trials. The most common spore shapes observed were globose, spiked, elliptical, smooth and reticulate.

Conclusion

Flotation can concentrate mushroom spores; however, false negative results can occur. Spore morphology could not be used to differentiate species of mushroom-forming fungi since the spore shape and surface characteristics seen in the present study were often observed with multiple species of mushroom-forming fungi.

Establishment of a simple living donor liver transplantation dog model using a two-step nonvenous bypass hepatectomy

AIM

Dogs are an ideal model for studying living donor liver transplantation (LDLT). However, due to their poor tolerance to congestion and acidosis during portal vein blockage, current LDLT dog models with long operation times have high mortality. To address the issue, we designed a novel simplified operation with two-step nonvenous bypass (NVB) hepatectomy.

METHODS

Eighty dogs were evenly randomized to the living liver donor (LLD) or the recipient (LLR) groups. A standard lobectomy of I, II, and III lobes was performed in the LLD group. In the LLR group, first only I, II, and III lobes were resected using NVB; the residual lobes were resected off just after donor lobes were implanted.

RESULTS

For the LLD group, the operation time was 172.67 ± 20.98 minutes, amount of blood loss was 71.39 ± 13.59 mL, and 2-week survival rate was 85.00%. For the LLR group, the operation time was 251.61 ± 22.87 minutes, amount of blood loss was 220.00 ± 96.40 mL, amount of blood transfusion was 163.89 ± 44.74 mL, and 48-hour survival rate was 77.14%. In the LLR group, the mean arterial and central venous pressures decreased after organ implantion, but gradually recovered to normal levels after surgery. The liver function biochemical parameters recovered to preoperational levels after 14 days in the LLD group; in the LLR group, they gradually increased during 48 hours after operation.

CONCLUSION

The present method with two-step NVB hepatectomy can be used efficiently and safely for establishing LDLT dog model.

Retrospective study of cattle poisonings in California: recognition, diagnosis, and treatment

In this retrospective study all suspect bovine intoxications submitted to the California Animal Health and Food Safety Laboratory between January 1, 2000 and December 31, 2011 were reviewed. A total of 1199 cases were submitted, but a diagnosis of intoxication was only established in 13.5% of cases. In these cases, overexposures to minerals, metals, and poisonous plants were determined as the most commonly diagnosed poisonings in cattle in California. Nitrate/nitrite poisoning was the most commonly diagnosed plant-associated intoxication, followed by gossypol and oleander. This study details the diagnostic challenges and treatment options for the most commonly diagnosed intoxications. To ensure proper treatment and prevention of new cases, accurate diagnosis is necessary, and therefore this review provides an essential tool for the food animal practitioner. Available toxicological analyses are offered at select laboratories, which can be time consuming and expensive, yet the potential for residues in consumed animal products and implications for human health necessitate testing and consultation. Any potential exposure to a toxicant in cattle should be reviewed to determine whether a residue hazard exists. Therapy focuses on immediate removal of the toxicant from the environment and from the gastrointestinal tract. With few antidotes available, most are cost prohibitive to treat numerous affected cattle. In addition, most antidotes will require extra-label drug use and establishment of meat and milk withdrawal times.

Amanitin Toxicosis in Two Cats with Acute Hepatic and Renal Failure

Amanitin is a toxic cyclopeptide present in several species of poisonous mushrooms. Amanitin toxicosis was diagnosed in 2 cats from separate premises. Both cats initially had lethargy and vomiting, and they rapidly developed depression and neurological signs over 24–48 hours. Marked elevation of alanine aminotransferase was the primary finding, with subsequent serum chemistry values compatible with hepatic and renal failure. Histopathological findings consisted of submassive to massive acute hepatic necrosis, renal proximal tubular epithelial necrosis, and foci of necrosis and inflammation in the gastrointestinal tract. Amanitin exposure was confirmed postmortem by detection of α-amanitin in the kidney by liquid chromatography–mass spectrometry. A similar clinical course and pathological changes are reported in human and canine amanitin intoxication; however, gastrointestinal lesions are not typically described.

Amanitin intoxication in two beef calves in California

Two 2- and 3-month-old beef calves from 2 separate herds, locations, and times were found dead and were submitted to the veterinary diagnostic laboratory for diagnostic work-up. In both cases, no premonitory signs were seen by the owners. Histopathology revealed acute panlobular hepatic necrosis in both calves. In addition, calf A had copper and selenium deficiency, and calf B had oxalate nephrosis, and selenium and zinc deficiencies. Alpha-amanitin was detected in the urine from calf A, and in the liver and rumen contents from calf B using liquid chromatography–mass spectrometry. The cause of panlobular hepatic necrosis and death of both calves was determined to be amanitin toxicosis from ingestion of amanitin-containing mushrooms based on microscopic changes and toxicological analysis of tissues. In cases of sudden death in cows with histopathological findings of panlobular hepatic necrosis, toxicological analysis for amanitin is needed for a definitive diagnosis of poisoning by amanitin-containing mushrooms.

Pet bird toxicity and related environmental concerns

Birds may be exposed to toxins through various sources in their everyday environment. Toxicity may occur through inhalation or oral or dermal exposures. Clinicians diagnose and treat these toxicities in an effort to correct the disease of the individual patient. Recognition of toxicity in the avian patient has further significance as it relates to the patient's environment, including the health of other animals, humans, and the ecosystem. While some toxicities, such as lead and zinc toxicosis, are well-documented in avian species, others are limited to anecdotal reports and extrapolation from other species. Continued research is needed in this area of avian medicine to expand our knowledge and improve our ability to diagnose and treat toxic conditions in birds.