Post encephalitic parkinsonism following dengue viral infection

Background Incidence of dengue fever as well as dengue hemorrhagic fever is increasing in Sri Lanka especially among elderly population. As the number of cases is rising, rare complications of dengue illness also can be seen in clinical practice when compared to the past few years. Prompt identification and treatment of such complications is challenging due to lack of awareness and unavailability of standard treatment. Case presentation 69 years old man presented with acute onset fever and was diagnosed as having dengue illness. On the 4th day of illness, the disease was progressed into dengue haemorrhagic fever and recovered uneventfully. Although he recovered from primary illness, his general condition continued to deteriorate due to new onset of features of parkinsonism. Cerebrospinal fluid analysis and electro encephalogram showed evidence of encephalitis. Cerebrospinal fluid analysis also revealed positive IgM antibodies against dengue virus. Then the diagnosis of post encephalitic parkinsonism following dengue viral infection was made and started on. He was started on SINEMET (carbidopa 10 mg and levodopa 100 mg) half tablet 6 hourly started. After 1 week of treatment he showed marked improvement and then patient was discharged with further follow up plan. Conclusion Although the management of dengue illness and dengue haemorrhagic fever is straightforward, recognition and treatment of rare complications like post encephalitic parkinsonism following dengue viral infection is difficult without great clinical suspicion.