Effect of high-dose methyl-prednisolone on brainstem encephalopathy and basal ganglia impairment complicating cat scratch disease

Abstract

Cat scratch disease (CSD) is a zoonotic illness caused by the Gram negative bacillus Bartonella henselae characterized by a small skin lesion at the site of a bite, lick or scratch by a cat, commonly followed by regional lymphadenopathy 1 or 2 weeks later. We report herein on severe neurological complications of CSD combining brainstem encephalopathy and basal ganglia impairment. This 12-year-old female acutely presented to a local hospital with profound coma and a prolonged tonic posturing of extremities. On the neurological examination she was deeply comatose with pin-point pupils and lack of vestibulo-ocular responses, suggestive of brainstem encephalopathy, along with marked rigid hypertonicity suggestive also of basal ganglia impairment. Initially suspecting Herpes simplex encephalitis or acute disseminated encephalomyelitis she was promptly started with high-dose methyl-prednisolone and acyclovir. Her parents apparently reported that she was scratched by a kitten some 4 weeks prior to her present admission and as such, suspecting CSD, she was begun with doxycycline and rifampicin. Her serology had proven positive for IgM antibodies to Bartonella henselae establishing the diagnosis. She regained consciousness after 4 days and the signs of brainstem and extra-pyramidal impairment also gradually abated and disappeared after 10 days. A follow-up exam after a month disclosed mild extra-pyramidal abnormalities which disappeared after 3 months. Although extremely rare, CSD should be also considered in a patient presenting with a severe encephalopathy and associated basal ganglia impairment. The prompt administration of high-dose methyl-prednisolone upon admission may have contributed to the favorable outcome in our patient and therefore should be advocated in any patient presenting with profound encephalopathy regardless the underlying etiology recovered later.