Dysautonomia in dogs (Key-Gaskell syndrome)

What is dysautonomia in dogs (Key-Gaskell syndrome)?

Key-Gaskell syndrome, also known as canine dysautonomia, is a neurological disorder that affects the autonomic nervous system in dogs. The autonomic nervous system controls many of your dog's bodily functions, such as:

• Drooling
• Pupil size
• Heart rate
• Breathing
• Digestion
• Bowel movement
• Blood pressure
• Urination
• Body temperature

Dysautonomia causes dysfunction of the nerves of the autonomic system. This can affect a dog's eyes, digestive system, or urinary tract. Although this condition is usually fatal, it is relatively rare in dogs.

Symptoms of Dysautonomia in Dogs

Symptoms can appear quickly, within hours or over several weeks. Signs of dysautonomia can vary but often include:

• Loss of appetite and weight loss
• Dry vomiting and retching
• Vomiting and diarrhea
• Constipation
• Difficulty swallowing
• Dilated (enlarged) pupils and decreased tear production
• Fear/avoidance of light
• Protrusion of the third eyelids
• Keratoconjunctivitis sicca (dry eye)
• Changes in heart rate and blood pressure
• Dry nose and mouth
• Cough
• Difficulty breathing
• Difficulty urinating
• Poor control of bladder and bowel movements
• Overall weakness

Symptoms such as difficulty urinating and difficulty breathing warrant an immediate trip to the veterinarian.

Causes of Dysautonomia in Dogs

The exact cause of dysautonomia in dogs is not fully understood. Key-Gaskell syndrome can be triggered by exposure to certain environmental factors. Eating plants, toxins, or contaminated food or water can contribute to the development of the disease. However, the specific agents have not yet been determined.

How Vets Diagnose Dysautonomia in Dogs

Diagnosing Key-Gaskell syndrome usually involves your veterinarian performing a physical exam on your dog, identifying its symptoms, and running diagnostic tests.

Your veterinarian will ask you several questions to obtain a complete history of your dog's health, a timeline of his symptoms and possible incidents that may have led to dysautonomia. This history may provide clues about which organs are affected. Although there is no specific test for dysautonomia, the following procedures can be used:

Eye exam results

Your veterinarian will perform a Schirmer tear test on your dog. This painless test allows you to see if your dog is producing enough tears. Your veterinarian will place a strip of special paper in your dog's lower eyelid. Moisture and tears from your dog's eyes will flow onto the paper for 60 seconds and your veterinarian will analyze the results.

Imaging

X-rays may show signs of aspiration pneumonia (food or fluid in the lungs), a dilated (enlarged) esophagus, enlarged intestines, and a swollen bladder. Esophageal dysfunction can be confirmed with fluoroscopy (an imaging procedure that shows real-time moving images of your dog's esophagus).

An abdominal ultrasound allows your veterinarian to see your dog's organs. If the symptom is present, this test can confirm the slow movement of your dog's intestines.

An echocardiogram, or ultrasound of the heart, may reveal enlargement of the left atrium (upper chamber) and ventricle (main chamber).

The enlargement can cause a decrease in the functions of the heart. This may cause weakness, inability to exercise, heart murmur (a whistling or whistling sound present in the heartbeat), or abnormal heart rhythm. Most dogs only show certain symptoms.

Pharmacological tests

Key-Gaskell syndrome can cause loss of control of the iris of the eye. This can make your dog sensitive to certain medications.

Pilocarpine is a medication used in animals with eye diseases. When applied to the eye of a dog with dysautonomia, the pupil shrinks within 45 to 60 minutes. In a healthy dog, the size of the pupils will not change.

Your veterinarian may also perform an atropine challenge test, which will check your dog's heart health. If you give a healthy dog ​​atropine, their heart rate will increase. However, when a dog suffers from Key-Gaskell syndrome, its levels remain the same.

Biopsy/necropsy/histopathology

To diagnose this disease, veterinary pathologists can examine tissue samples from the intestines and assess the condition of the mesenteric plexus, a complex network of nerves found in the intestine.

In some cases, Key-Gaskell syndrome can only be confirmed after death by analyzing nerve cells in the spinal cord and base of the brain. In acute cases, there is a noticeable degeneration of nerve cells, while in chronic cases, there is both a loss of nerve cells and an increase in a specific type of supporting cells.

Treatment of dysautonomia in dogs

Unfortunately, there is no cure for dysautonomia. Your veterinarian will focus on supportive care, symptom management, and your dog's comfort. This may include:

• Replenishing your dog's water intake, also known as fluid therapy
• Drugs
• Placement of a nasogastric feeding tube (a tube that carries food and medicine to your dog's stomach through the nose)

These treatments aim to relieve your dog's symptoms and improve his quality of life. Some dogs may be able to live with this condition, while others may not.

Dogs with symptoms such as KCS (dry eye) and constipation tend to live longer with this condition because they are easier to manage with medications like eye drops and stool softeners. Dogs that develop aspiration pneumonia or suffer from heart abnormalities have a shorter survival time.

Here are the most common therapies offered to dogs with Key-Gaskell syndrome:

• Fluid therapy: Dysautonomia can cause dehydration due to decreased saliva and tear production. Intravenous (into the vein) or subcutaneous (under the skin) fluid therapy may be recommended to keep your dog hydrated.
• Nutritional support: Some dogs may have difficulty eating, which may require a feeding tube. Your veterinarian may also recommend foods that are easy to digest, such as Hill's® Science Diet a/d. These treatments can be used until your dog no longer gags and weight loss has stopped.
• Gastrointestinal support: Your veterinarian may prescribe medications to relieve vomiting, nausea, and other gastrointestinal (GI) symptoms. Medications that help with your dog's gastrointestinal movement can help alleviate any problems. Stool softeners may also be given to stop constipation.
• Eye and nose support: Eye drops such as Optimmune can help treat dry eye. Humidifying the air and using artificial tears and lubricants can also keep your dog's eyes and nose moist. Products include Optixcare Eye Lube, Bag Balm or Dermoscent BioBalm.
• Urinary support: Your veterinarian may also suggest medications or place a urinary catheter in your dog's bladder at the start of treatment.
• Treatment of infection:Antibiotics may be given to treat or prevent secondary bacterial infections in your dog.

Recovery and management of dysautonomia in dogs

The course of dysautonomia can vary and the disease cannot be cured, but only managed. If a dog receives treatment for its symptoms, improvement may be seen as early as 24 hours or as late as three to four weeks.

The severity of symptoms, disease progression, and response to treatment all play a role in determining your dog's quality of life.

Dogs with Key-Gaskell syndrome should be monitored closely. Your veterinarian will regularly monitor his vital signs (temperature, breathing and heart rate), water intake, urination, weight and bowel movements.