Abstract              Background: Laboratory parameters such as activated partial thromboplastin time, prothrombin time and serum creatinine are needed to assess snake bite victim. In hospitals or health centres, where the above parameters are not available, platelet count may be useful. Objective: To identify the pattern of association between clinical and laboratory parameters with platelet count among patients admitted and treated for systemic envenomation in the emergency division of one of the tertiary care medical college hospital in South India. Materials and Methods: A prospective hospital based observational study was conducted in patients with history of snake bite and features of systemic envenomation admitted in medicine wards and intensive medical care unit at a tertiary care teaching hospital. Only those patients who witnessed the offending snake and with any one of the following conditions: snake bite patients in whom the WBCT > 20mins, snake bite patients who have features of neuro-paralysis and presence of cellulitis in the area of snake bite were included for the study. The platelet count was estimated at the time of admission, on day 3 and day 5. Patients were followed up during their stay in hospital and final outcome was observed. Results: A total of 78 patients with a history of snake bite were included. Two third of the patients (67.9%) had features of cellulitis. Similarly, three fourth (75.6%) of the patients had WBCT >20 mins. More than one third (38.5%) of the patients had thrombocytopenia (platelet<50,000). Patients with presence of cellulitis, WBCT>20 mins, raised prothrombin time >17 secs and APTT >36 secs were significantly more likely to be presented with day 1 thrombocytopenia. Similarly, patients with abnormal renal function tests such as raised serum creatinine and low albumin had significantly high proportions of thrombocytopenia compared to patients who had normal renal function tests. Platelet count measured on day 3 correlated well with day1 platelet (spearman rank correlation=0.85) compared to day 5 platelet counts (spearman rank correlation 0.59) Conclusion: Platelet count was associated with outcomes in snake bite victims with systemic envenomation and hence can be used as marker for severity of systemic envenomation.

Key Words: snake bite, envenomation, platelet count, thrombocytopenia.