Probable sepsis-associated encephalopathy as a component of multiple organ dysfunction syndrome in a cat with pyothorax.

A 2-year-old male neutered domestic shorthair cat with bacterial pyothorax was referred to a tertiary hospital for treatment of sepsis. He met criteria for multiple organ dysfunction syndrome and developed new-onset neurological dysfunction subsequent to the development of sepsis. Neurological changes included generalised seizures, coma and proprioceptive and cranial nerve deficits. The cat additionally had pulmonary, hepatobiliary and gastrointestinal dysfunction. Diagnostic findings included a normal brain MRI and a normal cerebrospinal fluid (CSF) total cell count (0.6 cells/μL, reference interval 0-8 cells/μL) with a relative increase in neutrophils (35%) and mast cells (31%). Exclusion of other aetiologies and a consistent clinical progression prompted a diagnosis of probable sepsis-associated encephalopathy (SAE). Treatment followed guideline recommendations for sepsis, including prompt broad-spectrum intravenous antimicrobial therapy, source control, intravenous fluid therapy and vasoactive agents to normalise perfusion, mechanical ventilation, and support for other organ dysfunctions. Treatment for seizures included multiple anticonvulsant medications (midazolam, levetiracetam, propofol and phenobarbital). The cat had a good long-term functional outcome; however, generalised seizures persisted up to 2 years post-discharge. This is the first report of a syndrome of neurological dysfunction in a cat consistent with SAE in humans.