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Walnuts (Juglans Regia)

Author: Dr. med. vet. Gisa Löwe | Last modified: 06.11.2025

Walnut poisoning (Juglans regia) represents a serious intoxication in dogs and cats. This is primarily a mycotoxicosis, meaning poisoning by metabolic products of molds that can grow on the nuts. Dogs are particularly affected, as their less selective eating habits make them more likely to ingest walnuts than cats. The main danger does not come from the walnut itself, but from the mycotoxins, especially Penitrem A, which is produced by the mold Penicillium crustosum. These toxins are effective even in small amounts and can lead to severe neurological symptoms. While fresh, un-molded walnuts are generally harmless to pets in small quantities, nuts lying on the ground, damp, or stored nuts with initial mold growth pose a significant risk.

The most important facts at a glance

Walnut poisoning in dogs and cats represents an acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. emergency situation caused by the ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. of mold toxins, particularly Penitrem A. These mycotoxins are found on moldy walnuts and primarily affect the central nervous systemThe CNS (central nervous system) consists of the brain and spinal cord. It is responsible for processing information and controls most functions of the body and behavior. and the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract. Dogs are more frequently affected than cats due to their less selective eating habits.

Clinical symptoms develop rapidly within 15 minutes to 3 hours after ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. and include gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. complaints such as vomiting and diarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., as well as neurological abnormalities like tremor, ataxia, and in severe cases, seizures. DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is primarily based on the historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and characteristic clinical picture, as specific diagnostic tests are not available in routine diagnostics.

TherapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. is symptomatic and includes decontaminationDecontamination refers to the removal of toxic substances or pathogens from a living being, object, or environment to prevent or treat poisoning or infection. measures such as activated charcoalActivated charcoal is a fine-pored, highly adsorbing material commonly used in veterinary medicine to treat poisoning. It binds toxins in the gastrointestinal tract to prevent their absorption into the body. administration, fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. for circulatory stabilization and promotion of toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. eliminationElimination refers to the process by which waste products and toxins are removed from the body. This includes excretion via the kidneys (urine), intestines (stool), lungs (breath), and skin., and pharmacological control of neurological symptoms. Newer approaches such as intravenous lipid emulsion (ILE) can support the binding of lipophilic toxins.

With early and adequate treatment, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is good, with most animals recovering completely within a few days. Aftercare includes a quiet environment, adapted nutrition, and follow-up examinations to monitor organ functions.

Preventive measures such as regularly collecting fallen walnuts in gardens and safe storage in the household are crucial to prevent recurrentRecurrent refers to a disease that repeatedly returns or worsens after a temporary remission or improvement. poisoning cases. Pet owners should be informed about the risks and seek immediate veterinary help if walnut poisoning is suspected.

Causes, development and progression

Many dogs enjoy eating walnuts. However, unripe and fresh walnuts, in particular, can be highly toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. to dogs.
The cause is not visible metabolicMetabolic refers to metabolism, i.e. the entirety of chemical processes that take place in a living organism to enable life processes. Metabolic disorders can cause a variety of Diseases in Dogs and cats. products of molds (mycotoxinMycotoxins are toxic substances produced by molds. Ingestion of mycotoxins can lead to severe poisoning in dogs and cats, especially if contaminated food is consumed. Penitrem A from Penicillium crustosum).
Walnut imports are carefully monitored, so contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. nuts are unlikely to be found in commercial products. The situation is more critical in home gardens, where dogs should not be allowed to eat nuts lying on the ground unchecked.

Supplements

The main cause of walnut poisoning in dogs and cats is the ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. of nuts contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. with mold. These fungi produce highly potent neurotoxinsNeurotoxins are poisons that specifically attack and damage the nervous system. In dogs and cats, they can cause paralysis, seizures, and other severe neurological symptoms. Neurotoxins can be produced in certain plants, toxins, or by bacteria. as secondary metabolites, primarily Penitrem A. ContaminationContamination refers to the pollution of surfaces, objects, water, food, or air with harmful microorganisms, chemicals, or other hazardous substances. of walnuts usually occurs due to improper storage under humid conditions or prolonged lying on the ground, especially during the autumn harvest season. While commercially available walnuts are generally strictly controlled and rarely contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment., there is an increased risk with nuts from private gardens or public places with walnut trees.

ToxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. formation is promoted by various factors:

Humidity above 70% relative humidity
Temperatures between 20-30°C
Damage to the nutshell, facilitating the penetrationPenetration describes the entry or permeation of a substance or organism into a body or material. In medicine, it can refer to the penetration of microorganisms into tissues or the insertion of instruments into the body. of fungal spores
Prolonged storage under suboptimal conditions

Unripe and fresh walnuts that have fallen to the ground and absorbed moisture are particularly at risk. Even nuts that appear outwardly unaffected can already contain significant amounts of mycotoxins. In dogs, ingesting just a few moldy walnuts is enough to triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. clinically relevant poisoning, while cats are less frequently affected due to their more selective eating habits.

Mechanism of action

In dogs, ingesting even a few moldy walnuts can lead to signs of intoxication.
The mycotoxins are rapidly absorbed in the intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. tract. The latency periodThe latency period is the time between exposure to a disease-causing factor and the appearance of the first symptoms of the disease. At this stage, the disease is present but not yet manifest. (time between toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. and the first symptoms of intoxication) is only 15 minutes to 2-3 hours.
They irritate the mucous membrane of the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract and are toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. to the peripheralPeripheral refers to areas located outside the central part of a system or body. In veterinary medicine, this can refer to peripheral nerves, blood vessels, or tissues that are distant from central organs such as the heart or brain. and central nervous systems.
The toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. effect of the mycotoxinMycotoxins are toxic substances produced by molds. Ingestion of mycotoxins can lead to severe poisoning in dogs and cats, especially if contaminated food is consumed. primarily consists of promoting generalizedGeneralized means that a disease or condition affects a large part of the body or multiple organ systems. Generalized diseases can show systemic symptoms and may require more comprehensive treatment. tremors (tremorgenic effect) by increasing the release of excitatory neurotransmitters in the brain and inhibiting the release of inhibitory neurotransmitters in the brain. The result is tremors and seizures.

Supplements

Walnuts are not inherently toxicToxic means "poisonous" and refers to substances that can have harmful effects on the body, including damage to organs, cells, or disruption of metabolic processes. per se, but they can lead to health problems in dogs (less commonly in cats). The potential toxicityToxicity is the measure of a substance's harmfulness or poisonousness. Toxicity can vary depending on the dose, route of exposure, and individual sensitivity. depends on several factors:

Mold contaminationContamination refers to the pollution of surfaces, objects, water, food, or air with harmful microorganisms, chemicals, or other hazardous substances. (production of mycotoxins, especially tremorgenic mycotoxins)
Type of walnut (e.g., black walnut = Juglans nigra)
Rancid or unripe nuts
Fat content and individual intolerance

The actual poisoning problem lies not in the walnut itself, but in microbial or chemical accompanying substances, especially in spoiled or improperly stored nuts.

1. Tremorgenic Mycotoxins (E.G., Penitrem a, Roquefortine C)

Formed by molds (especially Penicillium species) on spoiled walnuts.
NeurotoxicNeurotoxic refers to substances that have harmful effects on the nervous system. Neurotoxic poisonings in dogs and cats can be caused by chemicals, medications, or toxins from the environment and lead to severe neurological symptoms. effect:
- Blockade of GABA-dependent inhibitory synapses
- Result: neuromuscularNeuromuscular refers to the relationship between nerves and muscles, particularly the transmission of nerve impulses that trigger muscle contraction. Neuromuscular disorders can affect movement and coordination in animals. hyperexcitability
Symptoms usually begin within 30 minutes to 6 hours:
- Muscle tremors, seizures, ataxia
- Hypersalivation, hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention.
- In severe cases: status epilepticus, death

2. Damage Due to Oxidative Stress from Black Walnuts

Black walnuts (Juglans nigra) may contain juglone, a phenolic compound with pro-oxidative properties.
In dogs, juglone can lead to:
- GastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. symptoms (vomiting, diarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems.)
- Lethargy, muscle tremors, neurological abnormalities.
Additionally, juglone is associated with lameness or laminitis in horses – in dogs, this is pathophysiologically less relevant.

3. Fat-related Pancreatitis

The high fat content of nuts can triggerA trigger is a stimulus that elicits a specific reaction or state. In veterinary medicine, this can refer to emotional responses, such as fear or aggression, or medical conditions, such as seizures in dogs and cats. reactive or necrotizing pancreatitis in sensitive animals, especially smaller dogs.
Pathomechanism:
- EnzymaticEnzymatic refers to processes catalyzed by enzymes. Enzymes are proteins that accelerate chemical reactions in the body and are essential for metabolism and numerous other vital functions. autodigestion of the pancreasThe pancreas is an organ that produces digestive enzymes and hormones, including insulin. It plays an important role in digestion and blood sugar regulation. due to premature activation of digestive enzymesEnzymes are biological catalysts that accelerate specific chemical reactions in the body without being consumed. They play a crucial role in virtually all physiological processes.
- Release of pro-inflammatory mediators
- Possible systemic reaction: fever, pain, vomiting, circulatory weakness

4. Mechanical Complications

Whole walnuts, if ingested, can lead to foreign bodies in the digestive tract (especially in small dogs).
Risk of intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. obstructionobstruction refers to the blockage or narrowing of a hollow organ or canal, which hinders the normal flow of liquids or gases. In dogs and cats, an obstruction can occur in the digestive tract, airways, or urinary tract and often requires immediate medical treatment. or perforationA perforation is a rupture or hole in the wall of a hollow organ, such as the gastrointestinal tract or bladder, which can lead to the release of contents into the body and severe infection. Perforations are Emergencies that require rapid veterinary intervention in dogs and cats..

Conclusion

Walnut poisoning in dogs and cats is not caused by the nut itself, but by accompanying factors such as mold toxins, rancid fats, or incompatible ingredients. Tremorgenic mycotoxins, in particular, pose a serious neurological risk. Owners should therefore not feed nuts – especially spoiled ones – to pets. Even small amounts of moldy walnuts can lead to life-threatening seizures.

Symptoms of intoxication

Symptoms affect the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract and the nervous system. Mycotoxins can damage the kidneys, so kidney function must be carefully monitored in cases of pre-existing conditions.
The symptoms that may be observed include:

Drooling (salivation)
Vomiting (Vomitus)
DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems. (Diarrhoea)
Weakness
Increased body temperature (hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention.)
Tremor
Tonic-clonic seizures
Ataxia
Hypersensitivity of sensorySensory refers to the senses or perception. Sensory systems in dogs and cats include sight, hearing, smell, taste, and touch, all of which are central to interacting with their environment. nerves (hyperesthesia)
Noise sensitivity (hyperacusis)
Increased respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. rate (tachypnea)
Increased heart rate (tachycardiaTachycardia refers to an unusually fast heartbeat with a resting heart rate of over 100 beats per minute. It can indicate physical exertion, stress, illness, or heart problems.)
Pupil dilationDilation refers to the widening or expansion of a hollow organ or vessel. It can be physiological (normal) or pathological (due to disease). (mydriasis)
Rapid horizontal movement of the pupils (nystagmus)
Seizures

Supplements

The symptoms of walnut poisoning in dogs and cats usually develop rapidly after ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. of contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. nuts. The latency periodThe latency period is the time between exposure to a disease-causing factor and the appearance of the first symptoms of the disease. At this stage, the disease is present but not yet manifest. between ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. and the first symptoms is only 15 minutes to 3 hours, which is due to the rapid absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream. of mycotoxins in the intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. tract. Clinical signs primarily affect two organ systems: the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract and the central nervous systemThe CNS (central nervous system) consists of the brain and spinal cord. It is responsible for processing information and controls most functions of the body and behavior..

GastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. symptoms include:

Increased salivation (hypersalivation)
Vomiting, often repeated and severe
DiarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., which can be watery to bloody
AbdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. pain, recognizable by a tense abdominalThe term "abdominal" refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. wall

The neurological symptoms, caused by the neurotoxicNeurotoxic refers to substances that have harmful effects on the nervous system. Neurotoxic poisonings in dogs and cats can be caused by chemicals, medications, or toxins from the environment and lead to severe neurological symptoms. effect of mycotoxins, can be particularly alarming:

Muscle tremors, often generalizedGeneralized means that a disease or condition affects a large part of the body or multiple organ systems. Generalized diseases can show systemic symptoms and may require more comprehensive treatment. and exacerbated by movement
Coordination disorders (ataxia) with a swaying gait
Hypersensitivity to touch stimuli (hyperesthesia)
Increased noise sensitivity (hyperacusis)
Increased body temperature (hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention.)
Accelerated breathing (tachypneaTachypnea or tachypoe refers to an increased respiratory rate that is above the normal range for the respective living being. It may be a sign of shortness of breath or other respiratory diseases.)
Increased heart rate (tachycardiaTachycardia refers to an unusually fast heartbeat with a resting heart rate of over 100 beats per minute. It can indicate physical exertion, stress, illness, or heart problems.)
Dilated pupils (mydriasis)
Rapid, uncontrolled eye movements (nystagmus)
Tonic-clonic seizures in severe cases

In cats, symptoms may be more subtle, but neurological abnormalities such as ataxia and tremors are also the main symptoms. Particularly small dog breeds, young animals, and animals with pre-existing conditions may show more severe courses. The intensity of symptoms can vary depending on the amount of toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. ingested and the individual sensitivity of the animal.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of walnut poisoning in dogs and cats is primarily based on the historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and clinical presentation. Since no specific diagnostic test for the detection of mycotoxins is available in routine diagnostics, a thorough history-taking is of particular importance.

The diagnostic process includes the following steps:

A detailed historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. is crucial, with the pet owner being asked about possible access to walnuts, especially whether the animal was in a garden with walnut trees or if walnuts were accessible in the household. The temporal correlation between possible ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. and the onset of symptoms provides important clues.

The clinical examination focuses on neurological and gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. abnormalities. The characteristic picture of tremor, ataxia, and hypersalivation, combined with a historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. of possible walnut ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems., strengthens the suspicion. During the neurological examination, reflexes, coordination, and reactions to environmental stimuli are assessed.

Laboratory tests primarily serve to rule out differential diagnoses and assess organ function. A complete blood count, serumSerum is the liquid part of the blood that remains after coagulation. It does not contain blood cells or coagulation factors, but many other proteins, antibody and electrolytes. Serum is used in diagnostics for a variety of blood tests. chemistry with liver and kidney values, and electrolytesElectrolytes are minerals in the body that carry an electric charge and perform vital functions such as regulating fluid balance, acid-base balance, and nerve and muscle activity. The main electrolytes include sodium, potassium, chloride, and magnesium. should be performed. In cases of suspected walnut poisoning, elevated liver enzyme levels may occur, but these changes are non-specific.

In unclear cases, a toxicological analysis of vomit or fecal samples for mycotoxins may be considered in specialized laboratories, but this is rarely necessary and time-consuming in practice.

Therapeutic principles

There is no antidoteAn antidote is a substance used to neutralize or reverse the harmful effects of poisoning or a drug overdose. Antidotes can be specific to certain poisons or have more general detoxifying effects..
DecontaminationDecontamination refers to the removal of toxic substances or pathogens from a living being, object, or environment to prevent or treat poisoning or infection. may involve gastric lavageLavage is a rinsing procedure that uses a liquid to clean a body cavity, organ, or wound. In veterinary medicine, lavage can be used, for example, for gastric lavage or to clean an infected wound. and administration of activated charcoalActivated charcoal is a fine-pored, highly adsorbing material commonly used in veterinary medicine to treat poisoning. It binds toxins in the gastrointestinal tract to prevent their absorption into the body.. Inducing vomiting is not recommended due to the risk of seizures.
Therapy is symptomatic and focuses on:

Intravenous fluid replacement
Controlling vomiting
Controlling tremors and seizures
AnesthesiaAnesthesia refers to the state of insensitivity to pain and can be partial (local anesthesia) or for the entire body (general anesthesia). It is used to keep patients pain-free during surgical procedures. via continuous drip infusion for persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. seizure tendency
Lipid infusion for toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. binding in the blood

The treatment of walnut poisoning in dogs and cats is symptomatic, as no specific antidoteAn antidote is a substance used to neutralize or reverse the harmful effects of poisoning or a drug overdose. Antidotes can be specific to certain poisons or have more general detoxifying effects. exists. The therapeutic management aims to prevent further toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream., eliminate already absorbed toxins, and control symptoms.

DecontaminationDecontamination refers to the removal of toxic substances or pathogens from a living being, object, or environment to prevent or treat poisoning or infection. is the first step in treatment. If presented within the first one to two hours after ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems., gastric lavageLavage is a rinsing procedure that uses a liquid to clean a body cavity, organ, or wound. In veterinary medicine, lavage can be used, for example, for gastric lavage or to clean an infected wound. under anesthesia may be considered. Inducing vomiting with emetics such as apomorphine in dogs or xylazine in cats is controversially discussed due to existing or impending neurological symptoms with a tendency to seizures and should only be done under strict veterinary supervision.

The administration of activated charcoalActivated charcoal is a fine-pored, highly adsorbing material commonly used in veterinary medicine to treat poisoning. It binds toxins in the gastrointestinal tract to prevent their absorption into the body. (1-4 g/kg body weight) is an important part of therapy to bind toxins still in the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients.. In severe cases, activated charcoalActivated charcoal is a fine-pored, highly adsorbing material commonly used in veterinary medicine to treat poisoning. It binds toxins in the gastrointestinal tract to prevent their absorption into the body. administration can be repeated every 4-6 hours for 24-48 hours to also capture enterohepatically circulating toxins.

Intravenous fluid therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. with crystalloid solutions (e.g., Ringer’s lactate) is essential to stabilize circulatory function and promote renal eliminationElimination refers to the process by which waste products and toxins are removed from the body. This includes excretion via the kidneys (urine), intestines (stool), lungs (breath), and skin. of toxins. The dosage depends on the patient’s hydration status, typically 2-4 ml/kg/h.

Neurological symptoms are controlled with anticonvulsantsAnticonvulsants, also called antiepileptic drugs, are medications used to control or prevent seizures. They are used in dogs and cats with epilepsy or other conditions that cause seizures.. For tremors and mild seizures, diazepam (0.5-2 mg/kg i.v.) is the drug of choice. For persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. seizures, phenobarbital (2-4 mg/kg i.v.) or levetiracetam (20 mg/kg i.v.) can be used. In therapy-resistant cases, a continuous propofol drip infusion (0.1-0.4 mg/kg/min) or even general anesthesia may be necessary.

A promising newer therapeutic option is intravenous lipid emulsion (ILE). This can help bind lipophilic toxins like mycotoxins in the blood. The dosage is 1.5 ml/kg as a bolus, followed by 0.25-0.5 ml/kg/min over 30-60 minutes.

SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. measures include antiemeticsAntiemetics are medications used to prevent or treat Nausea and Vomiting. In dogs and cats, they are used in various situations, including after surgery, for motion sickness, or for certain conditions that cause Nausea. such as maropitant (1 mg/kg s.c.) for persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. vomiting, temperature management for hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention., and creating a calm environment to avoid additional stimulation.

Prognosis & follow-up care

The prognosis for walnut poisoning is generally good with early and adequate treatment. Most dogs and cats recover completely within 24 to 72 hours, although mild neurological symptoms such as intermittentIntermittent refers to something that occurs at intervals or starts and stops temporarily, such as intermittent Pain that comes and goes. tremors may persist for up to a week in individual cases. The timing of treatment initiation is crucial for treatment success – the earlier treatment begins, the better the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop..

Factors that can negatively influence the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. are:

Pre-existing liver or kidney diseases
IngestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. of large quantities of moldy walnuts
Delayed start of treatment (>6 hours after ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems.)
Severe neurological symptoms such as persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. seizures
Very young, old, or small animals with less physiological reserve

Aftercare plays an important role in complete recovery. After discharge from inpatient treatment, the following aspects should be considered:

Create a calm, stress-free environment for the animal to promote neurological recovery. Activity should be restricted in the first few days, with a slow increase as symptoms improve.

A follow-up examination after 24-48 hours and, if necessary, after one week is recommended to monitor the healing process. On this occasion, blood parameters can be checked to assess liver and kidney function.

The diet should initially consist of easily digestible food in small, frequent portions to protect the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract. Adequate fluid intake must be ensured.

Preventive measures to avoid renewed exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. should be discussed with the pet owner, especially for animals living in gardens with walnut trees. This includes regularly collecting fallen nuts and safely storing walnuts in the household.

Research outlook

Research in the field of mycotoxicoses in small animals has gained importance in recent years. Current studies focus on several promising areas that could improve the management of walnut poisoning in dogs and cats.

One focus is on the development of rapid diagnostic tests for the detection of Penitrem A and other tremorgenic mycotoxins in blood or urine. Chromatographic methods combined with massIn pathology, the term "mass" is used to describe an abnormal lump or growth in the body. A mass can form in the skin or subcutaneous tissue, or even inside the body. The causes can be benign (not cancer) or malignant (cancer). spectrometry show promising results for the sensitive detection of even low toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. concentrations. These could, in the future, refine and accelerate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients..

Intravenous lipid emulsion (ILE) therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. is being intensively researched. Recent studies investigate optimized dosing protocols and the efficacy of various lipid emulsions in binding mycotoxins. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. results suggest that ILE can shorten recovery time and reduce the severity of neurological symptoms.

In the field of antidoteAn antidote is a substance used to neutralize or reverse the harmful effects of poisoning or a drug overdose. Antidotes can be specific to certain poisons or have more general detoxifying effects. development, specific toxin binders are being investigated that could selectively bind to mycotoxins and prevent their absorption in the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients.. Modified activated charcoalActivated charcoal is a fine-pored, highly adsorbing material commonly used in veterinary medicine to treat poisoning. It binds toxins in the gastrointestinal tract to prevent their absorption into the body. preparations with increased binding capacity for mycotoxins are in the preclinical testing phase.

The role of the microbiome in mycotoxinMycotoxins are toxic substances produced by molds. Ingestion of mycotoxins can lead to severe poisoning in dogs and cats, especially if contaminated food is consumed. detoxification is increasingly coming into focus. Studies are investigating whether certain probiotic bacterial strains can metabolize mycotoxins or reduce their absorptionAbsorption refers to the uptake of substances by living cells or tissues. In the context of veterinary medicine, it often refers to the absorption of nutrients, drugs, or toxins from the digestive tract into the bloodstream.. This could enable new preventive approaches.

Epidemiological studies analyze regional and seasonal clusters of poisoning cases in relation to climatic factors. This data could help to better predict risk periods and develop targeted preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies.

The identification of genetic factors influencing individual susceptibility to mycotoxins could enable personalized treatment approaches in the future. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. studies indicate breed-specific differences in mycotoxinMycotoxins are toxic substances produced by molds. Ingestion of mycotoxins can lead to severe poisoning in dogs and cats, especially if contaminated food is consumed. metabolism.

These research approaches promise improved diagnostic and therapeutic options for the future, which could lead to even more targeted and effective treatment of walnut poisoning in dogs and cats.

Frequently asked questions (FAQs)

Are all walnuts toxic to dogs and cats?
Not all walnuts are toxic. The danger mainly comes from moldy walnuts that contain mycotoxins. Fresh, unmoldy walnuts in small quantities are generally harmless, but due to their high fat content, they can cause gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. upset.
How quickly do symptoms appear after ingesting moldy walnuts?
The first symptoms usually appear within 15 minutes to 3 hours after ingestion. The rapid development of symptoms is characteristic of this poisoning and underscores the need for prompt veterinary treatment.
Can cats also get walnut poisoning?
Yes, cats can also be poisoned by moldy walnuts. However, due to their more selective eating habits, they are less frequently affected than dogs. The symptoms and treatment are similar in both animal species.
How can I tell if a walnut is contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. with mold?
Mold contaminationContamination refers to the pollution of surfaces, objects, water, food, or air with harmful microorganisms, chemicals, or other hazardous substances. is not always visible to the naked eye. Outwardly, mold can appear as whitish, greenish, or bluish discoloration. However, nuts can also be internally contaminatedContaminated describes something that has been polluted by harmful microorganisms, chemicals, or other dangerous substances. In veterinary medicine, this can affect food, water, toys, or the environment. without being outwardly visible. Moist, musty-smelling, or unusually looking walnuts should generally not be fed.
What should I do if my pet has eaten moldy walnuts?
Seek veterinary attention immediately, even if no symptoms are yet visible. If possible, take any remaining walnuts that were eaten with you to allow for a better assessment of the situation. Do not attempt to induce vomiting without veterinary instruction.
Are there long-term consequences after recovering from walnut poisoning?
With timely and adequate treatment, long-term consequences are rare. Most animals recover completely. In very severe cases with persistentPersistent means lasting or continuing for an extended period. In veterinary medicine, it can refer to chronic diseases or symptoms that do not subside. seizures, permanent neurological deficits could theoretically occur, but this is an exception.
Which dog and cat breeds are particularly susceptible to walnut poisoning?
There are no specific breeds that are particularly susceptible. However, small breeds and young animals may show more severe courses due to the unfavorable ratio of body weight to the amount of toxinA toxin is a poison produced by living cells or organisms that can be harmful to the body upon contact or ingestion. Toxins can originate from bacteria, plants, animals, or fungi. ingested. Animals with pre-existing liver or kidney diseases also have an increased risk of complications.
How can I protect my pet from walnut poisoning?
Regularly collect fallen nuts in gardens with walnut trees. Store walnuts safely out of reach of pets in the household. When out walking, make sure your pet does not eat any nuts lying on the ground. Train a reliable “leave it” command for emergency situations.
Are other types of nuts as dangerous for pets as walnuts?
Different types of nuts pose different risks. Macadamia nuts can lead to weakness, tremors, and hyperthermiaHyperthermia refers to an elevated body temperature beyond the normal range. In dogs and cats, this can be caused by overheating, Fever, or certain diseases, and often requires urgent medical attention. in dogs. Almonds and pistachios can cause gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. upset due to their high fat content. In general, nuts should only be given in very small quantities and under supervision.
Is intravenous lipid emulsion an effective treatment method for walnut poisoning?
Intravenous lipid emulsion (ILE) shows promising results in the treatment of poisoning with lipophilic toxins such as mycotoxins. InitialInitial means beginning or at the start. In medicine, it can refer to the first symptoms of a disease or the first phase of a treatment process. clinical experience suggests faster recovery and milder neurological symptoms. However, the method is still being researched and is not available in every veterinary practice.

Literature

https://www.vetpharm.uzh.ch/GIFTDB/PFLANZEN/0198_tvm.htm
Fritz, L., Miklis, A., Bitter, V., & Neiger, R. (2020). Suspected intoxication by tremorgenic mycotoxins in twelve dogs after ingestionIngestion refers to the intake of substances through the mouth and their delivery to the digestive tract. In dogs and cats, the ingestion of toxic substances, foreign objects, or incompatible foods can lead to health problems. of moldy walnuts. Kleintierpraxis, 65(9), 476-481.
Manwaring, G., Graves, T., & Schott, H. (2021). Intravenous lipid emulsion therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. for treatment of mold toxicosis in dogs: A retrospective case series (2010-2020). Journal of Veterinary Emergency and Critical Care, 31(3), 345-352. https://doi.org/10.1111/vec.13058
Peterson, M. E., & Talcott, P. A. (2022). Small Animal Toxicology (4th ed.). Elsevier Health Sciences, 612-615.
Puschner, B., & Reimschuessel, R. (2021). Toxicosis caused by tremorgenic mycotoxins in companion animals. Veterinary Clinics of North America: Small Animal Practice, 51(6), 1299-1315. https://doi.org/10.1016/j.cvsm.2021.06.006
Löwe G, Löwe O. Poisoning in Dogs and Cats – A Veterinary Guide. 2nd edition. Kreuztal: Kynos-Verlag. 2021; 208 p.