Steroid-Responsive Meningitis-Arteritis in Dogs

The meninges are layers of connective tissue that surround the brain, the spinal cord and cerebrospinal fluid (CSF), and the arteries and vessels contained within them. Steroid-responsive meningitis-arteritis results in the presence of white blood cells in the CSF and it is suspected by researchers that the immune system may be mistakenly attacking the meninges. The condition is known by many other names including aseptic suppurative meningitis, Beagle pain syndrome, necrotizing vasculitis, and canine juvenile polyarteritis syndrome. This condition affects young dogs most often with the typical age of onset being 6 to 18 months, but the age range can go up to approximately seven years. Prognosis ranges from excellent to guarded depending on the age of the dog, the pet’s response to the treatment, and the risk of secondary complications like spinal cord compression.

Steroid-responsive meningitis-arteritis (SRMA) is an inflammatory disease of the central nervous system, affecting the meninges (layers of tissue that surround the brain) and the meningeal arteries. This is a well-recognised disease in the field of veterinary medicine and the prognosis can be very positive with prompt treatment and aggressive therapy.

The symptoms for SRMA can be chronic or present as flares of an intermittent nature. Your pet may be showing signs of stiffness and pain only to have the symptoms disappear. It is best to have your canine family member checked by a veterinarian nonetheless because steroid-responsive meningitis-arteritis can lead to serious complications if not attended to.

• Back pain
• Neck pain
• Vocalization of the discomfort
• Fever
• Lowered head
• Arched back
• Stiff gait
• Rigid stance
• Depression
• Lethargy
• Sometimes there may be muscle spasms

Types

Acute

• This is the most common form
• Presents with pain along the back
• Typical signs of fever, stiff gait, and rigid back are seen
• The dog will remain in a hunched position

Chronic

• This can occur as the result of the relapse of an acute attack after treatment
• Secondary complications to chronic SRMA are many, including muscle weakness, seizures, and loss of bodily control

The cause for steroid-responsive meningitis-arteritis is not definitively known but there are concrete suspicions as to why it occurs due to constant research on the condition.

• There may be a genetic predisposition
• All breeds can be affected but there is an over-representation in studies of the following breeds: Boxers, Beagles, Weimaraners, Bernese Mountain Dogs, and the Nova Scotia Duck Tolling Retriever
• The breed disposition may make the prognosis for recovery more guarded for canines of that type
• Studies show there may be an abnormal immune response to the central nervous system
• Researchers think there could be a link between a genetic reaction to the environment
• The condition can accompany immune-mediated polyarthritis suggesting a possible connection
• Some researchers feel there may be a link between vaccinations and the possible desensitization of the dog to viral antigens
• There could be a relation to age as older dogs can be less responsive to treatment

When you bring your canine family member to the clinic the veterinarian will do a physical examination. This will be done with great care as no doubt, your pet is most likely in pain even though he may not display the extent of it to you. Along with taking your dog’s temperature, the veterinarian will do an examination that includes looking for neurological abnormalities in your pet’s behavior and mannerisms. Dogs with advanced SRMA will have dramatically increased signs of weakness and possible indications of impending paralytic effects.

Standard tests that may help in the diagnostic process are urinalysis, complete blood count, and serum chemistry. For instance, in the serum chemistry, your veterinarian may see markers that stand out and could mean SRMA, such as acute phase protein (APP), alpha2 macroglobulin, elevated IgG,  and C-reactive protein (CRP). CRP is a marker that is very indicative of an inflammatory process in the body.

Radiographs and MRI could be the next steps in the search for a diagnosis. The veterinarian will need to investigate the stability of the spine which can be compromised in some diseases. The veterinary team will want to rule out illnesses such as discospondylitis, ascertain whether there has been a trauma to the body that could be causing the arched back and pain, and verify that there are no infections or tumors that could bring on intense fever and discomfort.

Once the stability of the spine and joints has been confirmed, a sample of the cerebrospinal fluid will be taken. In addition to checking for bacteria, fungus, or other inflammatory conditions, the analysis of the CSF could indicate that there is an increase in white blood cells. This factor, along with the physical signs, is very indicative of SRMA.

A dog with a mild case of SRMA can be treated with NSAID’s. Most cases, however, are beyond mild. Young dogs in the acute phase (most commonly seen) are treated with anti-inflammatories and long-term immunosuppressive therapy which lasts between a minimum of 4 months up to 20 months in duration. Prednisolone and prednisone are the usual choices, with a tapering prescription that will be determined in length by follow-up testing and your pet’s clinical response to the medication. A canine who has chronic and recurring SRMA will most likely need a drug therapy given on alternating days which will consist of an immunosuppressive drug and a glucocorticoid. Early in the treatment regimen, pain relief may be necessary also.

Follow-up appointments will be very important and absolutely necessary with a diagnosis of steroid-responsive meningitis-arteritis. Your veterinarian will determine the schedule of the return visits which will depend on how well your furry family member responds to the treatment. The follow-up will mean repeat blood tests and analysis of the CSF until the veterinarian can see that the markers have returned to normal. This could mean appointments every 4 to 6 weeks for several months. It is imperative that you keep the appointments and do not discontinue the medication even though you may think your dog is feeling better. It should be noted that many pets will need a prescription for gastroprotectants; if you see any side effects from the long-term therapy such as blood in the stool or vomiting, or if you are concerned in any way with your pet’s health, contact the clinic without delay. With SRMA there is a potential for relapse, meaning that continued contact with your veterinarian will be recommended.