We are just recovering from the SARS CoV2 pandemic and the dengue season is upon us! The wards and the out-patients are full of patients with Dengue. It appears there are many more children with serious complications this year than we usually see.
A 12 year old boy came in with fever and body aches for 5 days and altered sensorium for 2 days. The Dengue NS1 antigen was positive, platelet count was low and his transaminases were mildly elevated.
His MRI Brain had the classic splenial hyper intensity on T2/ FLAIR and also showed diffusion restriction.
For a long time it was debated whether the dengue virus actually infects the central nervous system. However documentation of the RNA virus in the CSF in the absence of serum viral copies suggests that the dengue virus can occasionally be neurotropic.
Of course, encephalopathy due to shock, metabolic derangements like hyponatremia, hepatic and renal dysfunctions are certainly commoner than actual encephalitis.
Other neurological manifestations include myositis, immune mediated disorders ( eg ADEM, GBS, transverse myelitis and the Miller Fischer syndrome) and neuro-ophthalmic manifestations ( eg uveitis, maculopahty, optic neuritis).https://doi.org/10.1016/S1474-4422(13)70150-9
The transient splenic hyper intensity is thought to be due to intramyelinic edema and is seen in many other conditions such as influenza related encephalopathy, seizures, demyelination and hypoglycaemia.
There are no specific antivirals available for dengue though pulse methyl prednisolone and IVIG have been used for the immune mediated neurological dysfunctions due to dengue.
Mortality can be as high as 30%.
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