A Rare Case of Dengue Encephalitis with Raised Procalcitonin

BACKGROUND Dengue virus is a common arbovirus with uncertain neurotropism. Dengue encephalitis is a rare but fatal manifestation of severe dengue. Diagnosis requires high clinical suspicion. It should be routinely considered in patients with encephalopathy, especially in countries where dengue virus is endemic. Unlike other forms of severe dengue, the typical warning signs and biochemical derangements are not reliable markers for dengue encephalitis. Alternative biochemical markers of dengue encephalitis are needed. CASE REPORT We present a case of dengue encephalitis with distinctly raised procalcitonin (13.2 μg/L), in the absence of the typical warning signs and biochemical derangements of severe dengue. The patient was a 65-year-old man with fever and sudden loss of consciousness in the absence of other localizing signs/symptoms. Inflammatory markers were raised, with findings of leptomeningeal enhancement on brain computed tomography suggestive of meningoencephalitis. Septic workup was unremarkable (normal renal and liver functions, negative blood and urine cultures). The typical neurotropic microorganisms were not detected in the cerebrospinal fluid. On day 4 of admission, the patient reported abdominal pain and hematuria with a new onset of bicytopenia. Subsequent investigations for dengue infection were positive for serum dengue NS1 antigen and dengue RNA (type 2 strain) in cerebrospinal fluid, confirming the diagnosis of dengue encephalitis. The patient was managed supportively and experienced full clinical recovery. CONCLUSIONS Dengue encephalitis is a rare condition with nonspecific biochemical and imaging abnormalities. We demonstrated that a raised procalcitonin level can occur in the setting of dengue encephalitis. In endemic countries, this finding may prompt further investigations for dengue encephalitis in patients with meningoencephalitis.