Macadamia Nut Poisoning

By Renee Schmid, DVM, DABVT, DABT; Ahna Brutlag, DVM, MS, DABT, DABVT

What is macadamia nut poisoning?

Macadamia nuts are the oily fruit of the macadamia tree. Macadamia trees are native to Australia but now cultivated in other similar climates including Hawaii, South Africa, and California. While macadamia nuts are edible for humans and often found in dessert recipes, ingestion by dogs leads to poisoning. The toxic component within the nut is unknown, but the margin of safety following ingestion is small with just a few nuts leading to intoxication in a small to medium sized dog.

Currently, macadamia nut poisoning is not recognized in other species beyond the dog.

What are the clinical signs of macadamia nut poisoning?

Clinical signs of macadamia nut poisoning occur in stages. Initial clinical signs of vomiting, fever, and lethargy occur within 3 – 6 hours following ingestion of a toxic dose of macadamia nuts. The next stage of clinical signs includes a stumbling gait, reluctance to use the rear limbs, inability to stand, joint stiffness, and muscle tremors; these clinical signs occur 6 – 12 hours post ingestion of a toxic amount.

Pancreatitis or inflammation of the pancreas (a digestive gland located near the small intestine) may be triggered by consumption by high fat diets; macadamia nuts are high in fat. Macadamia nut ingestion increases risk for pancreatitis in susceptible breeds e.g., miniature schnauzer, Yorkshire terrier and other terrier breeds, dachshund, miniature poodle, Cavalier King Charles’s spaniel and Cocker spaniel. Any dog with prior history of pancreatitis as well as obese dogs, are also at a higher risk for pancreatitis after eating macadamia nuts. Severe abdominal pain, dehydration, fever, depression, persistent loss of appetite and vomiting are common clinical signs associated with pancreatitis.

If you believe your pet has ingested macadamia nuts, please call your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, at -800-213-6680 right away.

How is macadamia nut poisoning diagnosed?

There is no specific lab test for macadamia nut poisoning. Diagnosis is supported if a dog has a history of macadamia nut ingestion and is exhibiting clinical signs consistent with poisoning.

Pancreatitis is suspected if a dog is exhibiting the likely clinical signs following recent consumption of macadamia nuts. Your veterinarian will confirm this diagnosis using lab testing for abnormal cell counts along with elevations in liver enzymes. Blood glucose, triglycerides and pancreatic lipase immunoreactivity tests are expected with pancreatitis. Your veterinarian may also recommend an abdominal ultrasound to look for pancreatic abnormalities (enlargement, abscessation); abdominal radiographs may be requested by a veterinarian if an abdominal ultrasound is unavailable and to rule out other potential causes for the dog’s clinical signs.

How is macadamia nut poisoning treated?

Early decontamination including induction of vomiting and activated charcoal administration can be performed by your veterinarian to recover and prevent absorption of macadamia nuts if ingestion is discovered prior to onset of clinical signs. Supportive therapies are provided for symptomatic dogs including intravenous (IV) fluids, pain relievers, muscle relaxants, and anti-nausea medications. Dogs with mild clinical signs can be treated without hospitalization.

Dogs that develop pancreatitis often require hospitalization for 24-hour monitoring of the pet’s vital signs, pain level, and degree of gastrointestinal motility. Treatment includes IV fluids, anti-nausea drugs, and injectable pain medication. Feeding tube placement for nutritional support may be necessary. Severe cases may require surgical intervention.

What is the prognosis for macadamia nut poisoning?

Dogs receiving appropriate veterinary therapy are expected to make a full recovery from macadamia nut poisoning within 24 – 48 hours.

Prognosis for dogs that develop pancreatitis following macadamia nut ingestion is variable. Prognosis for recovery is good for dogs with mild pancreatitis. Unfortunately dogs that develop severe pancreatitis have a guarded prognosis for recovery and increased risk for complications including diabetes mellitus, bile duct obstruction, and chronic pancreatic disease.

Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s fee of $65 per incident includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at www.petpoisonhelpline.com

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