You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Bacterial meningitis is not commonly reported in cats or dogs, but it does occur from time to time.

Infection of the central nervous system (CNS) may be by haematogenous spread, spread from an adjacent structure eg the ear, or by direct invasion through a wound. Bacteria that manage to gain access to the CNS produce a widespread inflammatory reaction and signs associated with the area of brain or spinal cord involved. When the leptomeninges are involved the clinical signs of meningitis may develop, including :

• Anorexia
• Cervical rigidity
• Depression
• Generalised pain
• High body temperature
• Hyperaesthesia
• Opisthotonos
• Photophobia
• Spinal pain
• Vomiting

Bacteria that have been associated with meningitis in dogs and cats include the following, and virulence is enhanced in organisms that have neurotropism, or produce a capsule or a toxin :

• Actinomyces viscosus
• Bacteroides spp
• b Haemolytic streptococci
• Fusobacteria
• Listeria monocytogenes
• Nocardia asteroides
• Pasteurella spp
• Peptostreptococcus
• Staphylococcus aureus
• Staphylococcus intermedius

These infectious agents do not represent a human health hazard.

Diagnosis can be difficult based upon clinical signs alone. Other aids to diagnosis include :

• Bacteria in CSF smears
• Increased protein in CSF (100-5000mg/dl)
• Increased numbers of neutrophils in CSF (>500/ml)
• Concurrent bacteraemia on blood cultures
• MRI or CT scans may show up a space-occupying lesion eg abscess

Treatment :

• Antibiotics - Ampicillin, Trimethoprim-sulphonamide combinations, chloramphenicol or metronidazole (for anaerobes)
• Fluid therapy
• Anticonvulsants
• Diuretics (if oedema present)

Antibiotic treatment needs to be given for up to 12 weeks and abscesses may not respond adequately.

Updated January 2016