Long-term Effects of Snake Envenoming

Abstract

Long-term effects of envenoming compromise the quality of life of the survivors of snakebite. We searched MEDLINE (from 1946) and EMBASE (from 1947) until October 2018 for clinical literature on the long-term effects of snake envenoming using different combinations of search terms. We classified conditions that last or appear more than six weeks following envenoming as long term or delayed effects of envenoming. Of 257 records identified, 51 articles describe the long-term effects of snake envenoming and were reviewed. Disability due to amputations, deformities, contracture formation, and chronic ulceration, rarely with malignant change, have resulted from local necrosis due to bites mainly from African and Asian cobras, and Central and South American Pit-vipers. Progression of acute kidney injury into chronic renal failure in Russell’s viper bites has been reported in several studies from India and Sri Lanka. Neuromuscular toxicity does not appear to result in long-term effects. Endocrine anomalies such as delayed manifestation of hypopituitarism following Russell’s viper bites have been reported. Delayed psychological effects such as depressive symptoms, post-traumatic stress disorder and somatisation have been reported. Blindness due to primary and secondary effects of venom is a serious, debilitating effect. In general, the available studies have linked a clinical effect to a snakebite in retrospect, hence lacked accurate snake authentication, details of acute management and baseline data and are unable to provide a detailed picture of clinical epidemiology of the long-term effects of envenoming. In the future, it will be important to follow cohorts of snakebite patients for a longer period of time to understand the true prevalence, severity, clinical progression and risk factors of long-term effects of snake envenoming.

Effect of Traditional Chinese Medicine on Long-Term Outcomes of Snakebite in Taiwan

“…A case report described a 49-year-old woman who developed acute cerebral infarction following a T. stejnegeri snakebite in Taiwan [45]. Both cerebral infarction and intracranial hemorrhage can result in brain injuries that cause long-term sequelae such as hemiplegia or cerebellar ataxia [36,49].…”

Amplification of Snake Venom Toxicity by Endogenous Signaling Pathways

“…Inflammation is sustained for long duration, failure of serotherapy to address [4] No specific evidence against…”

“…Current standard of care therapy for snakebite is focused on the use of antibody-based treatments (here termed "serotherapies") intended to intercept, neutralize and remove venoms present in the circulation before they produce long-term effects [4]. The basic concepts and methodology underlying serotherapy were developed more than a century ago: stimulated by Pasteur's and Behring's work on rabies and diphtheria, Albert Calmette produced antisera effective against cobra venom [5].…”

Current research into snake antivenoms, their mechanisms of action and applications

“…In humans these result in a number of different acute envenoming syndromes, including local tissue damage at the bite site due to the spread of venom locally, and effects due to systemic spread of venom such as venom-induced consumption coagulopathy, neuromuscular paralysis, acute kidney injury, cardiovascular collapse and myotoxicity [7][8][9][10][11]. Some of the acute effects may lead to permanent effects such as amputations, blindness and hypopituitarism, while the traumatic experience of the snakebite can lead to psychological effects [12]. Many factors such as the venom composition, injected venom amount, characteristics of the bite, first-aid and co-morbidities of the snakebite patient determine the severity of envenoming syndromes.…”