Immune-mediated brain disorders in pets - meningitis & meningoencephalitis

Immune-mediated brain disorders, such as meningitis and meningoencephalitis, are inflammatory diseases in which the immune system mistakenly attacks the body's own nervous tissue. These conditions often cause severe neurological symptoms such as pain, epileptic seizures, or paralysis. They occur mainly in dogs, particularly in young to middle-aged animals of susceptible breeds. In cats, immune-mediated brain disorders are rare but can occur.

In this article, we discuss the causes, symptoms, diagnosis, treatment, and prognosis of immune-mediated brain disorders in pets.

What are immune-mediated brain disorders?

In immune-mediated brain disorders, the immune system targets the body's own nervous tissue. This leads to inflammation of the meninges (meningitis) and/or the brain tissue itself (encephalitis). There are several forms, including steroid-responsive meningitis-arteritis (SRMA) and granulomatous meningoencephalitis (GME).

Which animals are at risk?

These conditions are most commonly seen in dogs, especially young to middle-aged animals. Certain breeds, such as the Beagle, Bernese Mountain Dog, and Boxer, have an increased susceptibility to SRMA, while the French Bulldog, Chihuahua, Maltese, and Pug are predisposed to developing GME. In cats, immune-mediated brain disorders are relatively rare.

Causes of immune-mediated brain disorders

The exact cause is unknown, but severeal factors play a role:

• Genetic predisposition
• Possible triggering infections
• Environmental factors that activate the immune system

Symptoms in dogs and cats

Symptoms vary depending on the type and severity of the inflammation:

In dogs with SRMA:

• Severe neck pain
• Fever

In dogs with GME:

• Epileptic seizures
• Balance disorders
• Ataxia (unsteady gait)
• Paralysis in severe cases

In cats:

• Very rare
• When present: similar symptoms such as pain, seizures, and neurological deficits

Diagnosis of immune-mediated brain disorders

The diagnosis is made through clinical and neurological examination, combined with imaging and laboratory tests. MRI often shows areas of inflammation in the brain and meninges. Cerebrospinal fluid analysis is essential and reveals an elevated number of inflammatory cells.

Treatment of immune-mediated brain disorders

Medication

The foundation of treatment is long-term suppression/modulation of the immune system. This is usually done with corticosteroids (prednisone) and sometimes in combination with other immunosuppressants such as cytarabine, cyclosporine, or azathioprine.

Supportive therapy

In addition to medication, animals often receive pain relief and sometimes anti-epileptic drugs for epileptic seizures. Physiotherapy can help with the recovery of muscle strength and coordination.

Recovery and prognosis

The prognosis varies greatly depending on the type of immune-mediated disorder and how quickly diagnosis and treatment occur. Many dogs respond well to therapy for SRMA, but relapse is possible if medication is tapered off too quickly. For GME, the prognosis is considerably less favorable. In severe or untreated cases, the condition can be fatal. In cats, the prognosis is harder to assess due to the rarity of the condition.

Want to know more?

Read more about our services in neurology and internal medicine. Our specialized veterinarians at Nesto have experience diagnosing and treating immune-mediated brain disorders and provide intensive guidance to you and your pet throughout the treatment process.

Frequently asked questions (FAQ)

What is immune-mediated meningitis?

An inflammation of the membranes surrounding the brain and spinal cord caused by the body's own immune system, without infection.

Which animals are at risk?

Mainly young to medium-sized dogs of susceptible breeds. In cats, it is very rare.

How is the diagnosis made?

With MRI and cerebrospinal fluid analysis.

How is it treated?

With long-term immunosuppressive medication such as corticosteroids, often combined with other agents.

What is the prognosis?

Many animals improve with treatment, but relapse is possible. Severe cases can be fatal.