This study was designed to document clinical and epidemiological aspects and intensive care management of patients bitten by the common krait, Bungarus caeruleus. The study was started on 1st of January 1996 and all the admissions of common krait bites to General Hospital, Anuradhapura in 1996 were included.
Out of 42 patients, 25(60%) were severely envenomed and needed mechanical ventilation, 11 (26%) mild to moderatly envenomed, did not require ventilation and 6(14%) were nonenvenomed inspire of proven bites. All the patients were from poor farming communities living in villages who had been bitten at night while sleeping on the floor. The majority of bites took place between 2200 and 0400hrs. In 29(69%) offending snakes were killed and available for identification. Commonest age group was 10 - 30 years (57%) and the majority of bites (83%) took place in the rainy season of the year, especially in October and November. The cardinal symptom was abdominal pain developing within hours, and other symptoms were dysphagia, dysphonia, drooping of eye lids, paresis of limbs and respiratory difficulties. Most patients [31(78%)] were admitted within 7 hr, and 17(40%) needed ventilator support in 10 hr (range 3 to 50 hr), after the bite. In the ventilated group, duration of assisted ventilation ranged from 12 hr to 9 days (mode 4 days). 15(60%) went into total respiratory paralysis ("0" tidal volume) and 3(12%) within one hour after admission. The level of consciousness (LOC) was normal in 2, drowsy in 15, semiconscious in 1, and deep coma in 7. LOC had a direct significant correlation to the duration of ventilation (r = 0. 6386, p < 0.01). Autonomic disturbance (AD) with hypertension, arrhythmia, tearing, sweating and salivation was seen in most patients. The deep coma mimicked brain death, but had a very good prognosis despite the associated complications (ARDS, AD, lung collapse, shock). Incidence of hypokalemia in the first 48 hours was 71%. Recovery of neck flexion (power Gr 2-3) had significant correlation to onset of recovery of respiration (r = 0.491, p < 0.05) and it was used as a parameter in weaning off ventilation. Retrograde memory loss was observed in all recovered patients for variable duration (mode 3 days) which had no significant correlation to LOC and duration of ventilation. Doses of polyvalent anti venom above 10 - 20 ampoules had no significant benefit (p < 0.05) in reversing respiratory paralysis. Seven (17%) patients died due to ARDS in 4, arrhythmia in 1, poor resuscitation before admission in 2. At post mortem submucosal haemorrhage in stomach was a frequent finding.
Mortality in krait bites could be minimized with early and free access to ventilation. Evidence such as deep coma and retrograde memory loss suggest possible encephalopathic effect of krait venom, in addition to proven neuromuscular paralysis.