A Study of Clinical and Prognostic Forecast in Snake Bite

INTRODUCTION: Snakes are a fascinating part of nature. Their color, movement and secretive habits make them more mysterious than other animals. There are over 300 species of snakes in the world, of which more than 200 ranging in size from 100 mm. Long worm snakes to 6 m long pythons are found in India. In India snakes have been worshipped as gods for thousands of years. Even today in Maharashtra during the harvest festival called “nagapanchami” freshly caught cobras are worshipped with flower, ghee and money. Most of us flee at the site of a snake. However group of people have based their living on these primitive reptiles. AIMS OF THE STUDY: 1. To document the local species of snakes that commonly cause various clinical features. 2. To analyze the time interval between the snakebite and the onset of various clinical features. 3. To find the correlation between the clinical profile and the time interval between bite and starting of treatment. 4. To correlate the clinical severity to the complications encountered by quantitative coagulation and renal function test. 5. To study the time taken for reversal of changes in clinical profile following ASV therapy. 6. To document the incidence of compartment syndrome and the prognosis of the patients with and without fasciotomy. 7. To analyze the complications of ASV therapy. 8. To study the time interval between the administration of ASV. 9. To study cardiovascular and neurological manifestations of snake bite. MATERIALS AND METHODS: Hundred patients with the history of snake bite admitted in Thanjavur Medical College Hospital during the period Jan 2016 to May 2016 was taken up for this study. SELECTION CRITERIA: Patients presenting with the history of snakebite with or without evidence were taken up for the study. Patient with the history and definitive evidence of snakebite in the form of local cellulitis, regional lymph adenitis, and / or prolonged clotting time, taken as suggestive of bite were considered under venomous group. Patient with neurotoxic manifestation like Ptosis, dysphagia external ophthalmoplegia were also included in the study under venomous group. Patient with the history of unknown bite, with or without local swelling with normal clotting time were categorized under non venomous group and included in the study. Patients having local swelling due to tourniquet application and local native treatment were also considered for the study. RESULTS: A total of 100 patients were admitted in Thanjavur Medical College Hospital general medical wards from January to May 2016 with either history or features suggestive of snake bite. Of the 100 patients with snake bite 43 had features suggestive of coagulation abnormality. Six patients presented primarily with neurotoxic manifestation. Two patients has hemostatic and neurotoxic abnormality. Rest of the 49 patients had no features suggestive of snake bite 51% were poisonous and 49% were nonpoisonous which is depicted in figure 1. Of the poisonous bite 84.32% had primary coagulation abnormality and 11.76% had neurotoxic manifestation and 3.92% both. CONCLUSIONS: 1. Hemotoxic envenomation was the commonest form of snake bite poisoning seen in this study. 2. Saw-scaled viper was the commonest snake causing coagulation abnormality while Krait was the most poisonous (in terms of mortality). 3. Onset of coagulation abnormality occurred as early as 3 hours and as late as 13 hours following snake bite. So all patients with history of snake bite should be under medical supervision for at least 24 hours. 4. In the diagnosis of Hemotoxic envenomation the presence of local signs plus a prolonged clotting time had a sensitivity of 100%. 5. Prothrombin time appears to be prolonged earlier than clotting time needs further confirmation. 6. Among the quantitative coagulation tests only fibrinogen level was correlated with the severity of envenomation compared to platelet count. 7. The time interval between the bite and initiation of treatment was not found to be related to time taken for normalization of the coagulation abnormality or to the development of complication in this study. 8. Following ASV therapy, the time taken for normalization of clotting time was found to be around 8 hours in Grade II and 18 hours in Grade III individuals. 9. Direct effect of venom on the kidney was also found to play a role along with disseminated intravascular coagulation and pigment Nephropathy in the causation of renal failure. 10. This Study shows that early and adequate fasciotomy reduces the necrosis of the bitten limb by 100% and acute renal failure by 83%. 11. Since majority of snake bites are in lowerlimbs, farmers and labourers may be advised to wear shoes during work.