NECROSIS, HEMORRHAGE AND COMPLEMENT DEPLETION FOLLOWING BITES BY SPITTING COBRA (NAJA-NIGRICOLLIS)

  • 1 January 1976
    • journal article
    • research article
    • Vol. 45  (177) , 1-22
Abstract
The spitting cobra, N. nigricollis, is widely and densely distributed in Africa. Fourteen patients with proven N. nigricollis bites, who were seen in the savanna region of Nigeria, did not exhibit the neurological signs, such as cranial nerve lesions and respiratory paralysis, expected following elapid poisoning. All had local swelling, in 8 cases involving the entire limb, and 10 developed local tissue necrosis. Spontaneous hemorrhage was detected in 3 cases and was the probable cause of death in one of them; the other death in this series was unexplained. Hematological abnormalities included prolonged clot lysis and failure of clot retraction due to a platet defect. There was no specific deficit in clotting factors and a delayed rise in fibrin degradation products was attributed to extensive tissue damage at the site of the bite. Most patients showed depletion of complement component C3 and glycine-rich .beta.-glycoprotein (GBG), suggesting activation of the alternative pathway of complement fixation. There was evidence of hepatocellular damage in 2 of 6 patients investigated. There was no evidence that specific polyvalent antivenoms, used in doses of up to 80 ml, prevented any of the effects of N. nigricollis venom. Clinical and laboratory diagnosis is discussed. In the past many bites were wrongly classified as viper bites on the basis of clinical findings. Immunodiagnosis is a promising method for assessing the true importance N. nigricollis bite in West Africa.