Can Dogs Have Nystagmus When Excited?

Nystagmus is an involuntary rapid motion of the eyes attributed to stimuli of the vestibular system, which governs your dog's visual acuity. Rhythmic motion is normal for your dog's eyes; nystagmus is an interruption or exaggeration of this natural occurrence. Nystagmus is part of your dog's physiological makeup and is triggered by overstimulation. Abnormal nystagmus is associated with a more serious disorder.

  1. Types

    • The two most common types of nystagmus are vertical and horizontal. Nystagmus can be a response to stimulation or the result of a malignant pathological problem. Vertical nystagmus, rarer than horizontal, often a symptom of serious brain damage. Horizontal nystagmus is often seen with disease of the vestibular system; vertical nystagmus is exclusively apparent with central vestibular disease. Veterinarians describe your dog's eye movement with phases, and in horizontal nystagmus, the fast phase occurs from the same direction in which the dog's head tilts. When central vestibular disease (particularly of the cerebellum) is present, the fast phase of the nystagmus eye movement is directed toward the lesion. Vertical nystagmus suggests a lesion is present in the central nervous system, and neurological testing is indicated.

    Symptoms

    • Because eye movement is directly linked to your dog's vestibular system, signs that he cannot perceive his orientation properly may indicate abnormal nystagmus. Your dog may not be able to tell which way is up. If your dog suffers with this disorder, he will show signs of being uncertain whether he is standing or leaning, and he may appear dizzy. The onset of symptoms can be sudden. Continual head tilt, circling and staggering may also be symptoms of abnormal nystagmus.

    Common Causes and Diagnosis

    • The vestibular system, sometimes called the "balance system," is your dog's sensory system responsible for maintaining balance of the head and body. Diseases that may lead to abnormal nystagmus include hypothyroidism, traumatic injuries and neoplastic tumors. Nystagmus from central vestibular disorders includes tumors, thiamine deficiency, viral infections, heart attacks, hemorrhages of the heart and exposure to toxins. Your veterinarian will diagnose abnormal nystagmus by analyzing cerebrospinal fluid, which will also reveal inflammation associated with this disorder. Brain imaging tests such as MRIs or CT scans are also used to identify potential brain abnormalities. Your veterinarian may also analyze urine and bacterial cultures to check for infection in the dog's body.

    Treatment

    • The treatment and prognosis for central vestibular disease linked to abnormal nystagmus depends upon the cause. All courses of treatment are lengthy. Because abnormal nystagmus is an immune disease, antioxidant steroids will decrease symptoms. During the early stages, anti-vertigo drugs will make your dog more comfortable. For this, veterinarians use diphenhydramine, an antihistamine.