Brain Abscesses in Cats

In some cases the abscess may be seen initially external to the skull, but in others there is only abscessation within the cranial cavity, making them very difficult to detect.

These cats are often, but not always, pyrexic at presentation with progressive forebrain signs which vary from mild behaviour changes to ataxia, circling and blindness. In addition to creating a space-occupying lesion within the skull, these abscesses generate a marked inflammatory response and secondary meningitis and oedema which can often lead to concurrent brain herniation.

Diagnosis necessitates a CT or ideally an MRI scan and treatment centres around surgical drainage and lavage of the abscess. In the two cases we have seen recently, a craniectomy was performed to remove necrotic bone and access the abscess for drainage of purulent material and copious lavage. The skull defect is often small and can be left open.

Brain abscess in cats can often be misdiagnosed as a brain tumour if MRI is not available and for a pyrexic cat with rapidly developing forebrain signs it is an important differential to consider. Brain abscesses can be fatal if not treated promptly, however the prognosis is very good when treated surgically.