Cycad Plant Toxicity in Cats

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(Last Updated On: December 7, 2018)

Common names: Sago palm, king sago, sago cycad, Japanese sago palm, fern palm, coontie palm, cardboard palms, queen sago

Scientific name: Bowenia, Ceratozamia, Cycas, Dioon, Encephalartos, Macrozamia, Microcycas, Stangeria, and Zamia.

Toxic parts: All parts of the plant, seeds contain the highest amount of toxin

Toxic properties: Cycasin, methylazoxymethanol (MAM), B-N-methylamino-L-alanine (L-BMAA) and unidentified

About:

Cycads are an ancient cone-bearing plant which comprise of nine genera and approximately 100 species. Their natural habitat is tropical and sub-tropical regions.

All parts of cycads are toxic, however the seeds and roots contain the highest concentration of toxins. The toxic properties are neurotoxic, hepatotoxic (liver) and has been shown to be a carcinogenic in rats (page 7). Following ingestion, bacteria in the gastrointestinal tract metabolise cycasin into its active compound methylazoxymethanol (MAM), which is toxic to the liver. L-BMAA is a neurotoxin, affecting the nerve tissues.

Cycad toxicosis has been described in  dogs, sheep, cattle and humans. In fact, cycad toxicosis  struck Captain James Cook’s crew (and pigs) in 1770 during their voyage to Australia. Seventy three years prior, in 1697, members of Dutch explorer Willem de Vlamingh’s crew were poisoned when they consumed the seeds while visiting the Swan River in Western Australia.

Symptoms:

Due to the highly toxic nature of cycads, even a small amount of ingested plant can lead to serious and life-threatening symptoms.

Gastrointestinal signs typically develop within 24 hours of ingestion and include:

  • Drooling (due to nausea)
  • Vomiting which may contain blood
  • Diarrhea which may contain blood
  • Weakness
  • Depression
  • Loss of appetite (anorexia)
  • Increased thirst and urination

As damage to the liver progresses, additional symptoms relating to liver failure, coagulopathy (bleeding disorders) and neurological signs can develop which may include:

Liver failure:

  • Abdominal pain
  • Ascites (build up of fluid in the abdomen)
  • Jaundice (yellow skin, sclera/whites of the eyes and mucus membranes)
  • Bleeding from the nose, mouth, anus, in the urine and feces (due to the development of blood clotting disorders)
  • Bruising
  • Spots under the skin (petechiae)
  • Dark, tarry stools (melena)

Neurological:

Neurological signs can develop as a result of cycad neurotoxins or secondary to liver failure and may include:

  • Seizures
  • Wobbly gait (ataxia)
  • Tremors
  • Behavioural changes (circling, aggression)
  • Encephalopathy

Diagnosis:

There is no test for cycad poisoning and diagnosis is made by a history of ingestion and identification of the plant in the cat’s vomit. The veterinarian will perform a complete physical examination of your cat and obtain a medical history from you including the, the age and weight of your cat and any underlying medical conditions, when ingestion occurred and how much.

Tests may be necessary to evaluate the overall health of your cat, these include:

Baseline tests: Complete blood count, biochemical profile and urinalysis. These can provide helpful information on liver and kidney function as well as the level of dehydration if the cat has been vomiting or has diarrhea.

When the liver is damaged, it spills its enzymes (ALT and AST) into the blood and therefore it is common to see high levels of ALT and AST as well as elevated  bilirubin levels. Other abnormalities due to liver failure include hypoglycemia (low blood sugar), hypoalbuminemia (low blood albumin) and hyperammonemia (elevated ammonia).

Coagulation profiles: Prothrombin time (PT) or activated partial thromboplastin time (APTT) to determine how fast it takes for the blood to clot.

Treatment:

If you suspect your cat has ingested any part of a cycad, seek urgent veterinary care immediately. The sooner treatment begins, the better the outcome.

Unfortunately there is no antidote to cycad toxicosis, the goal of treatment is to prevent further absorption as well as manage symptoms.

Gastric decontamination: If ingestion is recent, the veterinarian can induce vomiting with ipecac or pump the stomach (gastric lavage).

Gastric protectants: Sucralfate, cimetidine or famotidine to coat the lining of the stomach and decrease stomach acid production.

Activated charcoal: This binds to the toxin and prevents further absorption.

Aggressive fluid therapy: This helps to maintain hydration, which is particularly important if the cat has lost fluids due to vomiting or diarrhea, and increase urinary excretion of the toxin.

Liver protectants: Such as s-adenosylmethionine (SAMe), N-acetylcysteine (NAC), Ursodeoxycholic acid and silymarin. These products are converted into antioxidants which protect the liver cells from waste products, helps move bile out of the liver, stabilises cell membranes and reduces inflammation.

Vitamin K: This fat soluble vitamin is necessary for the the formation of certain clotting factors, as the liver fails, clotting factors decrease, which can lead to coagulopathy (blood clotting disorders). Administration of Vitamin K may help to restore normal blood clotting.

Anti-nausea medications: To control nausea and prevent vomiting.

Anti-seizure medications: Diazepam for cats experiencing tremors or seizures.

Blood or plasma transfusions: If gastrointestinal tract bleeding is severe or blood clotting disorders are present.

The veterinarian will monitor the cat’s liver enzymes, electrolytes and coagulation profiles until normal parameters return.

Prognosis:

If treatment begins before clinical signs develop, the prognosis is good, however it is guarded once clinical signs develop which highlights the importance of prompt veterinary attention.

Prevention:

The only way to prevent cycad toxicity is to keep cycads out of the house and garden (if your cat is goes outdoors). This page contains an extensive list of plants which are toxic to cats. It is important that all pet owners are familiar with the dangers of toxic plants to cats and dogs.

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