Nervous system disorders in dogs can occur in any part of the body, affecting the way a dog moves and behaves. The nervous system comprises the brain and spinal cord, and the nerve pathways that carry signals throughout the body. Signs of a problem can be the followings:

• Seizures
• Disorientation
• Changes in behavior
• Changes in gait
• Head tilt
• Eyes flicking from side to side

Juvenile Epilepsy

Convulsions, or seizures, are caused by electrical disturbances in the brain and can occur in a dog at any age. However, if a dog first has seizures while he is young, then a disorder known as juvenile epilepsy is suspected.

Blood is usually taken to rule out other causes for them such as liver disease. If the blood results are normal, juvenile epilepsy tends to be the diagnosis, especially in breeds known to be prone to the disorder, such as the Beagles, Border Collies, German Shepherds, Golden and Labrador Retrievers, and Irish Setters. 

Antiepileptic drugs will be needed for life.

Wobbler Syndrome

Caused by a malformation of the neck bones putting pressure on the spinal cord, wobbler syndrome makes a dog move in an abnormal way, taking short steps with his front legs and wandering, wobbly steps with his back legs. He may also have neck pain.

There are two forms of wobbler syndrome: one appears at an early age in giant breeds such as Great Danes and gradually worsens; the other form occurs in Dobermans and does not appear until middle age.

The diagnosis is confirmed by X-rays and MRI. Treatment with corticosteroids may help and in some cases, surgery is advised.

Hydrocephalus

This is a congenital problem (present from birth) that occurs in Chihuahuas, Pekingese, and Boston Terriers among others. In hydrocephalus, the fluid that flows round the brain and spinal cord to protect them from injury, is prevented from draining away normally.

The buildup of fluid leads to pressure inside the skull and the risk of brain damage. Severely affected puppies, which often do not survive long after birth, have a markedly domed skull, and fail to grow and develop like their litter mates.

Mild cases of hydrocephalus may not be recognized until a dog is older. MRI or CT scanning, or possibly ultrasound imaging, will confirm the diagnosis. Drug treatment may reduce fluid production; it may also be possible to insert a shunt (tube) in the brain to drain excess fluid.

IVS

Often mistakenly called a stroke by owners, Ideopathic Vestibular Syndrome (IVS) usually occurs in old dogs, affecting the center of balance within the inner ear. The dog suddenly develops a head tilt and may lose his balance.

His eyes flick from side to side as they try to stop the world from spinning. Some dogs are so badly affected that they are nauseous, vomit, and walk around in circles.

IVS usually resolves on its own after a few days. Your vet may give a drug to reduce nausea if your dog cannot keep down food and water. A drug that promotes blood supply to the brain is available and can help to prevent the disease.

CDRM

This distressing disease—chronic degenerative radiculomyelopathy (CDRM)—affects the spinal cord. It causes a dog to gradually lose coordination and movement of his hind limbs, even though he is otherwise well and retains voluntary control over his bladder and bowels.

Breeds in which CDRM occurs include German Shepherds, Boxers, and Corgis. There is no treatment, other than helping the dog to cope.

Syringomyelia

SM, as this disease is known, is characterized by head and neck pain that may be hard to localize. A dog may sleep with his head in a strange position, have pain when being picked up, or have difficulty going up stairs.

The classic sign is for the dog to walk along kicking with a hind leg as if to scratch his ear.

The most common cause of SM is a structural defect in the brain that results in a mismatch between brain size and the space in the skull. This is an inherited disorder in dome-headed breeds such as Spaniels, Chihuahuas, and Petit Basset Griffon Vendeens.

Definitive diagnosis requires an MRI scan, which is also used for screening. Treatment aims at pain control, with lifestyle changes such as feeding from a raised bowl and walking on the lead with a body harness rather than a collar. Surgery is also possible.