Bite-to-hospital time and morbidity in victims of viper bite in a rural hospital in Nigeria

BACKGROUND: Mortality amongst in-hospital patients bitten by carpet viper in northern Nigeria has reduced, related to use of a monospecific ovine Fab snake antivenom. However, many victims survive with temporary or permanent morbidity. OBJECTIVES: Study objectives were to: (1) determine and score the morbidity caused by carpet viper bite; and (2) find the relationship between bite-to-hospital time and morbidity amongst victims of carpet viper bite. METHOD: A prospective study was conducted in a rural hospital in north-central Nigeria. The morbidities scored were oedema, tenderness, prolonged whole-blood clotting time, blister, ulcer, need for blood transfusion, coma, hypotension, convulsion, length of hospital stay, need for disarticulation, and need for skin graft. A score of one was given to each objective sign. The bite-to-hospital time of 233 subjects was obtained. Descriptive and inferential statistical analysis was done. RESULTS: Most of the subjects (150 or 64%) came to the hospital within 6 hours of the snake bite, with 2 (1%) arriving within 1 hour. The median bite-to-hospital time was 5 hours, with a range of 0.5–216 hours. Major morbidities were oedema, seen in 212 (91.0%; 95% CI 86.6–94.3%); incoagulable blood, seen in 205 (88%; 95% CI 83.1–91.9%), and tenderness, seen in 201 (86.3%; 95% CI 81.2–90.4%). The mean morbidity score was 8 ± 4. For every unit increase in logged bite-to-hospital time, the morbidity score increased by 1.85 (p < 0.001). CONCLUSION: Morbidity caused by carpet viper bite is high in Zamko, north-central Nigeria, and correlates with increasing bite-to-hospital time.