Mumps encephalitis with brainstem involvement: significant morbidity and diagnostic dilemmas

• Published in: Archives of disease in childhood 2011-04, Vol.96 (Suppl 1), p.A54-A55
• Main Authors: Atkinson, R E, Kent, S, Fidler, K
• Format: Article
• Language: English
• Subjects: Antibiotics; Lesions; Morbidity
• ISSN: 0003-9888; 1468-2044
• DOI: 10.1136/adc.2011.212563.123

Aims To raise awareness of potentially serious complications of Mumps, and to discuss diagnostic and treatment dilemmas inherent to these complications. Methods An unimmunised 16 year old boy presented to Accident and Emergency with vomiting and unsteadiness 10 days following parotid swelling and suspected mumps. 48 h later he developed clear cerebellar and cranial nerve signs and deteriorated rapidly, raising suspicion of mumps encephalitis. MRI revealed multiple diffuse grey matter lesions, a brainstem lesion and possible white matter involvement with some mass effect. Unfortunately the patient's symptoms continued to progress to a bulbar palsy necessitating intubation and Intensive Care. Results He was treated with Acyclovir, broad spectrum antibiotics, and methylprednisolone to cover the possibility of acute disseminated encephalomyelitis (ADEM). A repeat MRI 1 week following the initial scan showed a significant deterioration with an increase in the number and size of the lesions. After a failed extubation at 1 week the patient had a tracheostomy performed and continued to require help with all activities of daily living. However he remained completely cognitively aware throughout his illness, with no reduction in Glasgow Coma Score (GCS). Investigations revealed positive Mumps IgM serology, and raised cerebrospinal fluid Mumps Immunoglobulin production, but cerebrospinal fluid Mumps PCR was negative. His repeat MRI was not suggestive of ADEM and thus the methylprednisolone was stopped after 3 days. He required multidisciplinary, intensive rehabilitation and made a complete recovery over 4 months. Conclusion With the decline in uptake of the MMR vaccine there has been a recent increase in the number of Mumps cases. Encephalitis is a recognised complication of Mumps. It may present early by direct invasion following initial infection, or late as a post infectious (ADEM) event. The timing of this patient's neurological decline on day 10 made viral invasion or ADEM possible, causing a dilemma as to how best to treat him. Irrespective of the exact mechanism the episode represented significant morbidity. Post mumps bulbar palsy in a child, with no reduction in GCS, has not previously been reported.