Polyneuropathy In Dogs

A polyneuropathy is a heterogeneous group of nerve disorders characterized by the malfunction of several peripheral nerves (those outside the brain and spinal cord). Canine Polyneuropathy is the predominant contributor to peripheral neuropathy cases.

Polyneuropathy has a wide range of etiologies; it may occur in cases of autoimmune or inherited conditions or infectious, or connected with neoplasm, chemical intoxication, or endocrinopathy.

The primary role of the peripheral nerves is to connect the central nervous system to the organs, limbs, and skin as they extend to the outermost areas of the body. They spread ll over the entire body, and are responsible for conscious, automatic physical responses (autonomic), the movement of the digestive system (enteric), and coordinated movement (somatic).

The peripheral nerves don’t have the protective features of the central nervous system (the vertebrae of the spine and the skull bone protects it). Peripheral nerves are more exposed to foreign substances that come into contact with the body and they are more susceptible to toxic damage and physical injury.

Myelin is a sleeve of fatty, white, lipid insulating layer (also called a sheath) that wraps around some nerve fibers. This is basically a greatly modified plasma membrane and this can also be lost through a process called demyelination, a condition that makes the myelin worn away or damaged, resulting in the loss of electrical signals in the nerves and impairing function. Or, when the actual nerve fibers within the myelin sheath deteriorate (Axonal degeneration), there will be secondary demyelination.

• Sensory nerve disorders(pain/pleasure nerve receptors):
• Spatial disorientation (Problems with positional awareness)
• Pain/sensitivity
• The pet scratched the area due to a burning sensation
• No muscle deterioration/ No muscle tremors

• Motor and sensorimotor nerve disorders:
• Lack of reflexes or Weak reflexes(automatic physical responses)
• Weakness or paralysis in all four legs
• Muscle deterioration (atrophy)
• Muscle tremors, trembling
• Weak to no muscle tone

• Dysfunctioning autonomic nervous system (No conscious control):
• Dry mouth and nose
• Low tear production (dry eyes)
• Lack of an anal reflex
• Slow heartbeat rate

• Under-active thyroid gland:
• Paralysis of the esophagus/throat affects ability to drink and eat
• Facial paralysis
• Paralysis of the voice box
• Instability
• Dizziness

• The prognosis of peripheral neuropathies in dogs will depend on the primary disorder that was diagnosed. The majority of these disorders have to be treated for life.
• To monitor the dog’s progress, follow-up visits will be necessary, and regular blood tests will be required to monitor thyroid and glucose levels.
• Arthritic dogs may need to continue steroid medications and physical therapy.
• Dogs that underwent surgery will be restricted to minimal exercise/activity.
• Dogs that have peripheral nerve damage may benefit from regular visits to physical, aquatic therapy, and massage.

There are no home remedies as this is basically an inherited disease. The only way of prevention is by eliminating affected dogs from the gene pool.

When dogs are diagnosed with inherited types of polyneuropathies, it is important to take measures to avoid breeding or neutering the dogs (if they does survive to adulthood) to remove affected dogs from the gene pool.

Neospora parasite-infected female dogs should not be bred, since the parasite can reach the foetus by transmitting itself through the placenta.

Coonhound paralytic Dogs (polyradiculoneuritis) should be protected from frequent raccoons exposure as the preliminary infection does not pass on any immunity.

Chesapeake Bay Retriever, Saint Bernard, Great Dane, Newfoundland, Collie, Labrador Retriever

1. Causes:

• Congenital/inherited
• Dysautonomia: Malfunction of the autonomic nervous system, which causes hyperpyrexia, diaphoresis, lack of coordination, and lack of reflexes.
• Immune-mediated:
• Metabolic disease
• Pancreatic tumors
• Hypothyroidism

• Infectious
• Neospora caninum parasite - deteriorates muscles (atrophy), impairs the immune system, and affects the hind legs, possibly with paralysis.
• Acute canine idiopathic polyradiculoneuritis (Coonhound paralysis) - is similar to Guillain–Barre syndrome in humans and mainly affects hunting dogs that come into close contact with infected raccoons; affecting the muscles that control breathing and barking as well as the limbs.

• Medications: some antibiotics, anticonvulsants, and sedatives

• Toxins
• Carbon Tetrachloride - used in refrigerants and insecticides
• Thallium - used in electronic devices, camera lenses, rodent poison, etc
• Lindane - used for killing scabies, insects, and lice
• Organophosphates- used in pesticides, fertilizers, and flame retardants

• Idiopathic neuropathies: Unknown cause

2. Types:

Acute polyneuropathy

• Acute forms occur when the dogs get the condition abruptly with severe symptoms.
• This type is common when the dogs have an infection causing nerve damage or an autoimmune reaction.
• Acute polyneuropathy can often be treated successfully.

Chronic polyneuropathy

• Chronic forms arise when the symptoms last for a longer duration and take time for the treatment to show results.
• This type can be caused by underlying conditions, such as kidney failure or diabetes.
• It’s not always easy to figure out the cause as there can be many different causes of chronic polyneuropathy and some can be idiopathic.

3. Morbidity:

Causes of acute type:

• Certain insecticides
• Some antibiotics, anticonvulsants, and sedatives
• Autoimmune disorders in which a dog’s own defense mechanism attacks the myelin in their nerve cells
• Cancer, especially those that directly affect the nervous system, such as multiple myeloma

Chronic polyneuropathy is typically idiopathic, but sometimes it can be caused by:

• Some cancers, including lung cancer
• Diabetes
• Nutritional or vitamin deficiencies
• Hypothyroidism
• kidney failure
• Certain heavy metals

4. Mortality:

Polyneuropathy itself is not usually considered to cause death but is typically more of a contributing factor to other health complications that can lead to death

5. Diagnosis:

• Complete blood count (CBC), an electrolyte panel, and a urinalysis
• Erythrocyte sedimentation rate
• Ultrasound
• Electrophysiology
• A tissue sample (biopsy)

6. Prognosis:

It is really difficult to predict chances for recovery as the nature and extent of the disease varies so greatly from dog to dog. While your dog may unexpectedly clear of clinical signs, within a short period, it may present with a new set of symptoms.

Most of the polyneuropathies primary causes can never be determined, the peripheral nerves will continue to worsen and your dog's disease will deteriorate.

Contact your vet right away, if you notice any of the following:

1. Spatial disorientation (Problems with positional awareness)
2. Lack of reflexes or Weak reflexes(automatic physical responses)

Antioxidants: Blueberries, Strawberries, Raspberries, Cranberries, Red cabbage, Cooked yellow squash, steamed broccoli, spinach, kale, and green beans.

Omega-3 fatty acids: Mackerel, Salmon, cod, herring, oysters, Sardines, Anchovies, etc.

B vitamins: Salmon, Liver and organ meats, Leafy greens, legumes, beef, oysters, clam, mussels, etc.

Vitamin E: Salmon; Avocado, Trout, Eggs, Spinach, Safflower Oil, Sunflower Oil, etc.

L-Carnitine: Red meat - Ground beef, chicken breast, fish and shellfish, avocados, and peanut butter.

Alpha-lipoic acid: Broccoli, tomatoes, spinach, Brussels sprout, red meat, and organ meats.

Medium-Chain Triglycerides: Milk, butter, yogurt, cheese, etc.

Whatever the course of the condition, your pet will never completely come again to the original condition or pre-onset state. So vets recommend monitoring the symptoms continually and assess your pet’s quality of life.