Bites due to Russell's Viper (Daboia russelii) are common in Sri Lanka. Commonest haematological manifestation is consumptive coagulopathy and bleeding. Commonest neurological manifestations are ptosis, ophthalmoplegia and rarely respiratory failure which are due to presynaptic inhibition of neuromuscular transmission. There are no authenticated reports of acute ischemic strokes following bites by D. russelii. We report the first authenticated case series of ischemic strokes following bites by D. russelii in Sri Lanka.
Methods: This was a prospective observational study of all atypical neurological manifestations following bites by D. russelii admitted to a hospital in Sri Lanka. We documented clinical features of all atypical neurological manifestations of D. russelii bites and recorded the findings of brain imaging.
Results: During a period of 18 months, at one centre, 9 patients out of an estimated 500 victims of D. russelii bites were found to have Computerized Tomographic evidence of single or multiple ischemic (non-haemorrhagic) strokes of medium to large vessel territories of the brain. These patients had either low Glasgow coma scale or hemiparesis within minutes to 4 days following bites. One patient died and another had gross neurological deficit, while others had mild or no neurological deficit at three months.
Discussion: This report confirms that ischemic strokes can occur following envenoming by D. russelii. Involvement of multiple medium to large vessel territories and absence of watershed infarctions points to prothrombotic properties of the venom as the putative mechanism.