Cat scratch disease encephalitis: New insights into rate, clinical features, and long-term outcomes

OBJECTIVE: Encephalitis, is a rare manifestation of cat scratch disease (CSD). We aimed to characterize CSD encephalitis/meningoencephalitis rate, diagnosis, clinical features, and outcome. METHODS: Patients with encephalitis/meningoencephalitis were identified through a national CSD surveillance registry active since 1991. Clinical data were collected. Long-term follow-up was performed, including neurological/cognitive assessments. Outcome was assessed using the Extended Glasgow Outcome Scale (GOSE). RESULTS: Nineteen patients, 0.5% of the CSD cohort, were identified. Cat contact (84%), fever (79%), and lymphadenopathy (68%) were common. Seizures occurred in 13 patients (68%), including 5 with status epilepticus; 6 requiring mechanical ventilation. Two clinical patterns were identified: an acute form (63%), with rapid onset and shorter recovery, and a subacute form (37%), occurring in older patients (median age of 35 vs 12.5 years), with progressive neurologic manifestations and longer recovery. CSF findings varied. Neuroimaging was normal in 79%. All patients had favorable outcomes: 11 (58%) fully recovered (GOSE 8) while 8 (42%) reported persistent cognitive complaints (GOSE 7) after a median follow-up of 58 months, (range 1-185). CONCLUSION: CSD encephalitis/meningoencephalitis presents in two forms: acute and subacute. Prognosis is generally favorable, but recovery may take months and cognitive complaints often persist. Antibiotic and corticosteroid use warrants further investigation.