22 year old male was referred with fever and altered sensorium and seizures with suspicion of brain stem encephalitis. MRI shows enlarged pons with cytotoxic oedema (with reduced ADC values ) and vasogenic oedema with unremarkable vertebra basilar flow voids or bleed or significant 4th ventricle compression, consistent with Rhombencephalitis.
Teaching points by Dr MGK Murthy, Dr GA Prasad & Mr Mahesh
Also referred as Brainstem encephalitis. Infectious, Autoimmune and Paraneopalstic aetiologies are possible
- Infectious causes (100% Abnormal MRI) Listeria (commonest, healthy young adults , biphasic time course with Flu like symptoms, CSF pleocytosis, positive CSF and blood cultures , best treated with Ampicillin), Enterovirus1 (second commonest in Asia-pacific preponderance with no specific treatment available), Herpes Simplex (HSV1 (80%) , HSV2 with 50% showing supratentorial involvement as well , respond well with acycolovir), Epstein Barr virus and Human Herpes virus etc
- Autoimmune (90% abnormal MRI) usually is Behcets disease (CSF pleocytosis) (25% recover with steroids and immune suppression)
- Paraneoplastic varieties (MRI usually normal) (CSF pleocytosis with protein normal) (anti neuronal antibodies positive) (prognosis poor)
Rhombencephalitis-MRI Reviewed by Sumer Sethi on Wednesday, March 18, 2015 Rating: