Sir,Infective origins of mental illness were hypothesized as early as 1845 by Esquirol. Patients with encephalitis lethargica had features schizophrenia and affective disorders.[1] Although there are reports of encephalitis associated with dengue psychiatric manifestations are under-reported.[2]During the 2017 dengue outbreak in India, the highest number of dengue cases was reported in Kerala. Here, we report three cases of the first episode of mania following serologically confirmed dengue fever and discuss etiological possibilities of mania following dengue.
Case 1
18-years-old lady, temperamentally easy child with no past or family history of mental illness was brought to psychiatry outpatient department (OPD) after a week of resolution of dengue with decreased sleep, overtalkativeness, easy irritability, over religiosity, and grandiose delusion. She was diagnosed with organic mood disorder mania and improved with olanzapine 15 mg and sodium valproate 1500 mg/day.
Case 2
38-years-old man with no past or family history was brought to OPD. His symptoms started 5 days after resolution of dengue as decreased sleep, increased energy, and over socialization. He had an excessive talk, irritable mood, and expansive ideas. He was diagnosed to have an organic mood disorder mania. He improved within a week on haloperidol 10 mg/day.
Case 3
48-years-old lady with no past or family history was brought 4 days after resolution of dengue fever. She had insomnia, overtalkativeness, over-religiosity, increased psychomotor activity and elated mood. She was diagnosed to have organic mania and improved on olanzapine 5 mg/day in a week.
DISCUSSION
In the cases discussed, there was a temporal relationship between dengue fever and the emergence of mania which aroused suspicion whether a causal relationship existed between dengue and mania.Dengue virus is a nonneurotropic virus, but in a recent study, the virus could be isolated from brain tissue and cerebrospinal fluid (CSF) of lethal cases of dengue.[3] In our cases, demonstration of dengue virus in CSF would have been confirmatory, but was not undertaken. There was no suspicion of encephalitis rendering this as sensorium was intact. There are reports that dengue encephalopathy may have no CSF changes.[2] No reports of mania following dengue have demonstrated structural changes in the brain.[45]In our cases, absence of previous affective episodes, family history, and psychosocial stressors strongly supported organic etiology. All the cases recovered rapidly unlike that of typical mania. The homotypical manifestation of cases also suggested organicity. Follow-up of cases looking at course of illness would help to delineate it from an independent mood disorder.There are a few indicators against organic etiology as well. Dengue outbreak is a traumatic event with thanatophobia and trauma of witnessing death.[6] Hence in the aftermath of outbreak, the possibility of reactive psychosis also needs to be considered. A few argue that dengue and psychiatric disorders are only accidental co-occurrence mentioning Thailand's database where dengue prevalence is the highest.[7]The case series suggests that research on psychiatric disorders in patients affected with such infective outbreaks may shed light on the infective etiology of psychiatric disorders.
Declaration of patient consent
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