Introduction
Canine meningitis is a condition of swelling and inflammation of the tissues covering the brain and spinal cord that leads to neurological symptoms, fever and pain. Regardless of the cause of the condition (of which there are many), meningitis is very serious; early and accurate diagnosis is crucial to achieving a successful outcome. A conclusive diagnosis of meningitis cannot always be based solely upon a dog’s clinical signs. Additional tests are necessary to rule out other causes of the same symptoms in order to reach a correct and conclusive diagnosis.
Diagnosing Meningitis
The signs of meningitis often are easy to spot. If a veterinarian sees a dog with fever, stiffness, painful spasms in the back, rigidity of the muscles of the neck and forelimbs and extreme sensitivity to touch (called “hyperesthesia”), she probably will begin her diagnostic process by running blood and urine tests to rule out other possible causes of these signs. If the results of these tests are normal, the veterinarian may prescribe medications on the assumption that the signs are caused by meningitis. This is called diagnosis by “response to treatment.” If the medications work, then the dog probably indeed was suffering from meningitis.
In some cases, the veterinarian or owner wants at least a tentative diagnosis before treatment begins. Very few tests are available to diagnose meningitis. These include a computed tomography (CT) scan, magnetic resonance imaging (MRI) and a cerebrospinal fluid tap. These tests are expensive, and they are not widely available. Even these tests normally are not completely conclusive. The only way to truly definitively diagnose canine meningitis is by histopathologic examination of affected brain and/or spinal cord tissue, which is not normally done in a clinical setting.
A CT scan or MRI, if available, will allow a veterinarian to visualize any inflammation of the tissue layers surrounding the brain and spinal cord. If inflammation is not seen, this will rule out meningitis as a cause of the dog’s clinical signs. A sample of the cerebrospinal fluid which coats the brain and spinal cord can also help with the diagnosis. This procedure involves collection of fluid through a needle inserted between several of the vertebrae in the back. The fluid is then analyzed microscopically for evidence suggestive of meningitis. During this procedure, the dog will be under general anesthesia.
Meningitis can be a life-threatening condition. If your dog displays signs consistent with meningitis, please make an immediate visit to a veterinarian. Early diagnosis is essential for successful treatment and recovery.