Ischemic brain infarcts and intracranial haemorrhages following Russell's viper (Daboia russelii) bite in Sri Lanka

Acute Myocardial Infarction After Russell's Viper (Daboia russelii) Bite

Russell's viper (Daboia russelii) is a deadly venomous snake that causes most snakebite deaths in Sri Lanka. It is widely distributed all over the country, and it commonly causes venom-induced consumption coagulopathy and neuroparalysis. Cardiotoxic manifestations after Russell's viper bites are rare. We report a 60-year-old man diagnosed with ST-elevation myocardial infarction after a proved Russell's viper bite.

Cerebral Complications of Snakebite Envenoming: Case Studies

There are an estimated 5.4 million snakebite cases every year. People with snakebite envenoming suffer from severe complications, or even death. Although some review articles cover several topics of snakebite envenoming, a review of the cases regarding cerebral complications, especially rare syndromes, is lacking. Here, we overview 35 cases of snakebite by front-fanged snakes, including Bothrops, Daboia, Cerastes, Deinagkistrodon, Trimeresurus, and Crotalus in the Viperidae family; Bungarus and Naja in the Elapidae family, and Homoroselaps (rare cases) in the Lamprophiidae family. We also review three rare cases of snakebite by rear-fanged snakes, including Oxybelis and Leptodeira in the Colubridae family. In the cases of viper bites, most patients (17/24) were diagnosed with ischemic stroke and intracranial hemorrhage, leading to six deaths. We then discuss the potential underlying molecular mechanisms that cause these complications. In cases of elapid bites, neural, cardiac, and ophthalmic disorders are the main complications. Due to the small amount of venom injection and the inability to deep bite, all the rear-fanged snakebites did not develop any severe complications. To date, antivenom (AV) is the most effective therapy for snakebite envenoming. In the six cases of viper and elapid bites that did not receive AV, three cases (two by viper and one by elapid) resulted in death. This indicates that AV treatment is the key to survival after a venomous snakebite. Lastly, we also discuss several studies of therapeutic agents against snakebite-envenoming-induced complications, which could be potential adjuvants along with AV treatment. This article organizes the diagnosis of hemotoxic and neurotoxic envenoming, which may help ER doctors determine the treatment for unidentified snakebite.

Acute ischemic stroke: a rare complication of hump-nosed pit viper (Hypnale spp.) bite: a case report

Background

Hump-nosed pit viper is a medically important deadly venomous snake in Sri Lanka and is the commonest cause of venomous snakebites in the country. It frequently causes local effects and systemic manifestations such as acute kidney injury and coagulopathy that occur in less than 10% of all bites. This also includes some atypical presentations such as thrombotic microangiopathy and myocardial infarction. Currently, no antivenom is available for hump-nosed pit viper bites in Sri Lanka, and patients are managed with supportive treatment. This case illustrates an acute ischemic stroke following a hump-nosed viper bite, which is the second case in the literature.

Case presentation

A 71-year-old a Sinhalese male patient presented with left-sided hemiparesis with mouth deviation on day 2 of hump-nosed viper (Hypnale spp.) bite on the right foot. Non-contrast computed tomography of brain showed right ischemic stroke in internal capsule. He was given antiplatelets and statins and continued supportive treatment including limb physiotherapy and speech therapy. He recovered completely and was discharged on day 4 with clinic follow-up.

Conclusions

Physicians should be aware that ischemic cerebral infarcts may occur following hump-nosed pit viper bites.

Snakebite associated thrombotic microangiopathy: a systematic review of clinical features, outcomes, and evidence for interventions including plasmapheresis

Snakebite is a neglected tropical disease with significant morbidity and mortality. Thrombotic microangiopathy (TMA) is an important but poorly understood complication of snakebite associated with acute kidney injury (AKI). Numerous treatments have been attempted based on limited evidence. We conducted a systematic review of TMA following snakebite using a pre-determined case definition of blood film red cell schistocytes or histologically diagnosed TMA. The search strategy included major electronic databases and grey literature. We present a descriptive synthesis for the outcomes of AKI, dialysis free survival (DFS), other end-organ damage, overall survival, and interventions with antivenom and therapeutic plasmapheresis (TPE). This study was prospectively registered with PROSPERO (CRD42019121436). Seventy-two studies reporting 351 cases were included, predominantly small observational studies. Heterogeneity for study selection, design, reporting and outcomes were observed. The commonest envenoming species were hump-nosed vipers (Hypnale spp.), Russell's viper (Daboia russelii) and Australian brown snakes (Pseudechis spp.). The prevalence of TMA was at least 5.4% in proven and probable Hypnale bites, and 10-15% of Australian elapid envenomings, AKI occurred in 94% (293/312) of TMA cases, excluding case reports. The majority of cases with AKI required dialysis. Included prospective and retrospective cohort studies reporting interventions and renal outcomes showed no evidence for benefit from antivenom or TPE with respect to DFS in dialysis dependant AKI. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) assessment for quality of accumulated evidence for interventions was low. The major complication of TMA following snakebite is AKI. AKI improves in most cases. We found no evidence to support benefit from antivenom in snakebite associated TMA, but antivenom remains the standard of care for snake envenoming. There was no evidence for benefit of TPE in snakebite associated TMA, so TPE cannot be recommended. The quality of accumulated evidence was low, highlighting a need for high quality larger studies.

Snakebite Envenoming a Challenging Diagnosis for the Forensic Pathologist: A Systematic Review

Snakebite envenoming (SBE) is a public health issue in developing countries. The estimated annual global incidence of snakebites is about 5.4 million snakebites per year, resulting from 1.8 to 2.7 million cases of SBE and from 81,000 to 138,000 deaths with 400,000 survivors suffering permanent physical and psychological disabilities. There are more than 3000 species of snakes around the world: 600 are venomous and over 200 are considered to be medically important because of their clinical effects. The severity of SBE depends on several factors among which bite localization, snake's size, condition of glands and teeth, bite angle and bite duration, the microflora of the snake's mouth and victim's skin, age of the victim, weight, health status, and victim's activity after a bite. Snake venoms are mixtures of protein families, and each of these families contains many different toxins or toxin isoforms. Based on their effects, snake venoms can be classified as hemotoxic, neurotoxic, or cytotoxic and they can all act together involving multiple tissues and organs. When the bite is fatal, the mechanism of death is primarily related to the paralysis of respiratory muscles, which causes asphyxia and hypoxic-ischemic encephalopathy, but also anaphylactic shock, hemorrhagic shock, cardiomyopathy, acute tubular necrosis (ATN). The purpose of this literature review is to evaluate epidemiological and post-mortem examination findings in fatal SBEs in order to better understand the pathophysiological mechanisms, thus helping pathologists in defining the correct diagnosis.

Identifying the snake: First scoping review on practices of communities and healthcare providers confronted with snakebite across the world

BACKGROUND

Snakebite envenoming is a major global health problem that kills or disables half a million people in the world's poorest countries. Biting snake identification is key to understanding snakebite eco-epidemiology and optimizing its clinical management. The role of snakebite victims and healthcare providers in biting snake identification has not been studied globally.

OBJECTIVE

This scoping review aims to identify and characterize the practices in biting snake identification across the globe.

METHODS

Epidemiological studies of snakebite in humans that provide information on biting snake identification were systematically searched in Web of Science and Pubmed from inception to 2nd February 2019. This search was further extended by snowball search, hand searching literature reviews, and using Google Scholar. Two independent reviewers screened publications and charted the data.

RESULTS

We analysed 150 publications reporting 33,827 snakebite cases across 35 countries. On average 70% of victims/bystanders spotted the snake responsible for the bite and 38% captured/killed it and brought it to the healthcare facility. This practice occurred in 30 countries with both fast-moving, active-foraging as well as more secretive snake species. Methods for identifying biting snakes included snake body examination, victim/bystander biting snake description, interpretation of clinical features, and laboratory tests. In nine publications, a picture of the biting snake was taken and examined by snake experts. Snakes were identified at the species/genus level in only 18,065/33,827 (53%) snakebite cases. 106 misidentifications led to inadequate victim management. The 8,885 biting snakes captured and identified were from 149 species including 71 (48%) non-venomous species.

CONCLUSION

Snakebite victims and healthcare providers can play a central role in biting snake identification and novel approaches (e.g. photographing the snake, crowdsourcing) could help increase biting snake taxonomy collection to better understand snake ecology and snakebite epidemiology and ultimately improve snakebite management.

Hemotoxic Snakebite Presenting with Bilateral Blindness Due to Ischemic Occipital Infarcts

Cerebrovascular complications are rare following a Viperidae snake envenomation, let alone ischemic ones. This catastrophic hemorrhaging cascade is widely known to cause a wide array of manifestations. Its manifestations can range from skin bleeds to fatal intracranial or organ hemorrhages. Our patient had cortical blindness secondary to an ischemic occipital infarct following a hemotoxic snakebite - a seemingly distinct oxymoron. The physician should be mindful of the fact that a hemotoxic snakebite can deceptively bring in ischemic attacks as well. Toxic vasculitis, thrombotic angiopathies, widespread vasospasm and endothelial damage are believed to shoulder a part of the disease process that can bring about tissue ischemia.

Key Messages

Hemotoxic snake envenomation can have devastating effects. Apart from dealing with the threat of coagulopathy, the physician must also be alert to the ironical ischemic aftermath that can equally bring in misery. Our patient had one such complication-bilateral cortical blindness resulting from bilateral occipital ischemic infarcts. The physician must be aware that a hemotoxic snakebite can even instigate ischemic dilemmas, i.e. cerebrovascular infarcts, as well.

How to cite this article

Kodiatte Abraham A, Livingston J. Hemotoxic Snakebite Presenting with Bilateral Blindness Due to Ischemic Occipital Infarcts. Indian J of Crit Care Med 2019;23(2): 99-101.

Cerebrovascular Accident and Snake Envenomation: A Scoping Study

BACKGROUND

Snake envenomation is associated with serious complications including infections, bleeding and, in rare occasions, thrombosis. Previous work by our group examined the association of snakebite and acute myocardial infarction. In this systematic review we aim to assess the clinical characteristics and outcomes of acute cerebrovascular accidents that are reported to be extremely rare complications of snake envenomation.

METHODS

We performed a literature search for reports on stroke associated with snake envenomation between Jan 1995 to Oct 2018, and summarized their characteristics.

RESULTS

Eighty-three published cases were reviewed. 66.3% of the cases were younger than 50 years of age. The mean time for the onset of the symptoms is 23.8±10.9 hours after exposure. 77.1% of the cases found to have ischemic stroke, 20.5% with intra-cranial hemorrhage and both infarction and hemorrhage in 2.4%. Mortality was reported in 16.9% with mean time between onset of the symptoms and death is 4.2 days.

CONCLUSION

Stroke secondary to snake envenomation is a rare but serious complication. Once stroke is suspected, initiating appropriate management is crucial in reducing morbidity and mortality associated with this potentially fatal complication of snake envenomation.

Cerebrovascular Injury Following Scorpion Sting and Snake Envenomation: A Case Series

BACKGROUND

Neurological complications following snake and scorpion bite are diverse. Literature regarding patterns of cerebrovascular injury (CVI) and outcomes among these patients is scarce. This is a descriptive study of the clinical profile, brain imaging findings, mechanisms of injury, vascular territory involvement and outcomes of CVI following scorpion and snake envenomation, in a tertiary care center in South India.MethodologyPatients with scorpion sting- and snake envenomation-related complications were retrospectively enrolled. Neuroimaging was performed on five patients with each envenomation, and they were found to have neurological involvement. On imaging, three patients were found to have a CVI. Clinical, radiological parameters and outcomes of these patients were studied. We also performed a review of the literature and analyzed the finding of all the cases.ResultIn all, three patients each had evidence of CVI in imaging. An additional 32 reports of scorpion sting-related CVI and 35 reports of snake envenomation-related CVI were identified from the literature. There was a male predominance among these patients. Mean age of the patients with scorpion sting was 42.8 years as compared with 33 years for the patients with snake envenomation. Features of severe envenomation were present in all patients. Persistently depressed sensorium and new-onset focal neurological deficits were seen in 70% of all patients. Infarcts were seen in 88% of patients with snake envenomation and 53% of patients with a scorpion sting. Mortality was 28% among patients with a scorpion sting as compared with 8% with snake envenomation.

CONCLUSION

Cerebrovascular injuries are uncommon neurological manifestations following scorpion and snake envenomation. These tend to occur in younger patients. Infarcts are more common than bleeds.