Bilateral blindness following Russell's viper bite - a rare clinical presentation: a case report

Long-term disability after cerebral ischemic stroke following a Bothrops atrox snakebite in the Brazilian Amazon

Bothrops atrox envenomations in the Brazilian Amazon are responsible for a number of local and systemic effects. Among these, stroke presents the worst prognosis for the patient since it may evolve into disabilities and/or premature death. This complication is caused by coagulation disorders and generates hemorrhagic and thrombotic conditions. This study presents a case report of a 54-year-old female patient who presented extensive cerebral ischemia after a B. atrox envenomation that occurred in the state of Amazonas, Brazil. The patient was hospitalized for 102 days, which included a stay in the intensive care unit. Clinical and laboratory findings indicated a thrombogenic coagulopathy. On discharge, the patient had no verbal response, partial motor response, and right hemiplegia. The assessment carried out four years after discharge evidenced incapacitation, global aphasia and bilateral lower and upper limbs showed hypotrophy with a global decrease in strength. Ischemic stroke is a possible complication of B. atrox snakebites even after antivenom treatment, with the potential to cause debilitating long-term consequences.

From birth to bite: the evolutionary ecology of India's medically most important snake venoms

BACKGROUND

Snake venoms can exhibit remarkable inter- and intraspecific variation. While diverse ecological and environmental factors are theorised to explain this variation, only a handful of studies have attempted to unravel their precise roles. This knowledge gap not only impedes our understanding of venom evolution but may also have dire consequences on snakebite treatment. To address this shortcoming, we investigated the evolutionary ecology of venoms of Russell's viper (Daboia russelii) and spectacled cobra (Naja naja), India's two clinically most important snakes responsible for an alarming number of human deaths and disabilities.

METHODOLOGY

Several individuals (n = 226) of D. russelii and N. naja belonging to multiple clutches (n = 9) and their mothers were maintained in captivity to source ontogenetic stage-specific venoms. Using various in vitro and in vivo assays, we assessed the significance of prey, ontogeny and sex in driving venom composition, function, and potency.

RESULTS

Considerable ontogenetic shifts in venom profiles were observed in D. russelii, with the venoms of newborns being many times as potent as juveniles and adults against mammalian (2.3-2.5 ×) and reptilian (2-10 ×) prey. This is the first documentation of the ontogenetic shift in viperine snakes. In stark contrast, N. naja, which shares a biogeographic distribution similar to D. russelii, deployed identical biochemical cocktails across development. Furthermore, the binding kinetics of cobra venom toxins against synthetic target receptors from various prey and predators shed light on the evolutionary arms race.

CONCLUSIONS

Our findings, therefore, provide fascinating insights into the roles of ecology and life history traits in shaping snake venoms.

Cortical Blindness and Thrombotic Microangiopathy Following a Hemotoxic Snake Envenomation: An Unusual Presentation

Snake envenomation leads to significant morbidity and mortality with local, hematological, renal, and neurological complications. Hemotoxic envenomation activates a hemorrhagic cascade, leading to many manifestations ranging from skin bleeds to major organ bleeds and fatal intracranial hemorrhage. Although rare, ischemic manifestations are possible following a hemotoxic envenomation, and they may present as cortical blindness, an unusual ocular symptom. Snake envenomation is also known to cause multifactorial acute kidney injury (AKI), precipitated by hemodynamic disturbances secondary to rhabdomyolysis, hemoglobinuria, direct tubular toxicity, and thrombotic microangiopathy. Thrombotic microangiopathy (TMA) is often overlooked in snake bites, as the hematological manifestations are often conveniently attributed to venom-induced consumptive coagulopathy (VICC). The distinct clinical entity of thrombotic microangiopathy should factor into one's differential diagnosis in patients presenting with microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury following a snake bite. We report a patient who developed cortical blindness and thrombotic microangiopathy following snake envenomation, which are uncommon sequelae.

Peripheral Arterial Thrombosis following Russell's Viper Bites

Envenomings by Russell's viper ( Daboia russelii ), a species of high medical importance in India and other Asian countries, commonly result in hemorrhage, coagulopathies, necrosis, and acute kidney injury. Although bleeding complications are frequently reported following viper envenomings, thrombotic events occur rarely (reported only in coronary and carotid arteries) with serious consequences. For the first time, we report three serious cases of peripheral arterial thrombosis following Russell's viper bites and their diagnostic, clinical management, and mechanistic insights. These patients developed occlusive thrombi in their peripheral arteries and symptoms despite antivenom treatment. In addition to clinical features, computed tomography angiography was used to diagnose arterial thrombosis and ascertain its precise locations. They were treated using thrombectomy or amputation in one case that presented with gangrenous digits. Mechanistic insights into the pathology through investigations revealed the procoagulant actions of Russell's viper venom in standard clotting tests as well as in rotational thromboelastometry analysis. Notably, Russell's viper venom inhibited agonist-induced platelet activation. The procoagulant effects of Russell's viper venom were inhibited by a matrix metalloprotease inhibitor, marimastat, although a phospholipase A 2 inhibitor (varespladib) did not show any inhibitory effects. Russell's viper venom induced pulmonary thrombosis when injected intravenously in mice and thrombi in the microvasculature and affected skeletal muscle when administered locally. These data emphasize the significance of peripheral arterial thrombosis in snakebite victims and provide awareness, mechanisms, and robust strategies for clinicians to tackle this issue in patients.

Massive acute ischemic stroke after Bothrops spp. envenomation in southwestern Colombia: Case report and literature review

Bothrops spp. envenomation and its relationship with ischemic stroke has complex pathogenesis. Local effects such as edema, pain, redness, necrosis, and systemic manifestations like coagulation disorders, thrombosis, renal failure, and hemorrhage have been reported. Hemorrhagic stroke is a common neurological complication but ischemic stroke is poorly understood. We present here the case of a 50-year-old male with no comorbidities referred from a rural area in southwest Colombia with a Bothrops spp. snakebite on the left hand. On admission, the patient presented with a deterioration of consciousness and required mechanical ventilation assistance. The MRI showed multiple ischemic areas in the bilateral frontaltemporal and occipital regions. Two months later, the patient had a favorable resolution, although central paresis in the III and VI cranial nerves and positive Babinski's sign persisted. As already mentioned, the pathophysiology of ischemic stroke due to snakebite is complex but the procoagulant activity of the venom components, the hypovolemic shock, the endothelial damage, and the thromboinflammation can explain it, and although it rarely occurs, it should be considered as a complication of ophidian accidents caused by Bothrops spp.

Rapid development of a salivary calculus in submandibular gland and its potential causes in a young victim following Russell's viper bite

Russell's viper bites are known to cause a range of haemotoxic, neurotoxic, myotoxic, cytotoxic and nephrotoxic complications. However, the impact of Russell's viper bites as well as bites from other venomous snakes on sialolithiasis has not been previously reported. Here, we present an interesting case where a Russell's viper bite induced the rapid development of a calculus in submandibular gland in a 10-year-old boy. Upon admission, the victim did not show any symptoms of swelling and/or pain around his oral cavity. He received antivenom treatment to normalise his coagulation parameters, however, on day three he developed swelling and extreme pain around his right mandibular region. An ultrasound investigation revealed the presence of a calculus in his submandibular gland, which was removed using a minor surgical procedure. The histopathological examination revealed this as a poorly calcified salivary calculus, which is composed of cell debris, mucopolysaccharides and lipids. The mechanisms behind its rapid development following a snakebite are unclear although this could be linked to excessive inflammation or modifications to the composition of saliva induced by venom toxins or other unknown factors. This report reveals an unusual complication induced by a Russell's viper bite and alerts clinicians who treat snakebites to be aware of such envenomation effects. Moreover, this will lead to novel research to explore the relationship between venom toxins and functions of salivary glands.

Acute cerebral infarction following a Trimeresurus stejnegeri snakebite: A case report

RATIONALE

Acute cerebral infarction after snake bites is rare. The underlying mechanism causing the thrombotic process remains complex and unknown.

PATIENT CONCERNS

We herein describe a 49-year-old female who was bitten by a Trimeresurus stejnegeri. After 4 days of biting, she developed acute ischemic infarct.

DIAGNOSIS

The patient exhibited right side weakness and speech disturbances. Brain computed tomography (CT) scan showed no sign about cerebral hemorrhage symptoms, and brain magnetic resonance imaging (MRI) showed acute ischemic infarct in the left territory. The patient confirmed a diagnosis of acute cerebral infarction following a T. stejnegeri bite.

INTERVENTIONS

The patient received an injection of polyvalent anti-snake venom serum, neuroprotective therapy, and anti-platelet aggregate treatment.

OUTCOMES

At the 3-month follow-up visit, the patient's left lower extremity swelling disappeared, the right limb muscle strength recovered, and the modified Rankin scale (mRS) score was 4 points.

LESSONS

The patient was diagnosed with acute ischemic infarct interrelated to snake bite; further investigations were needed to ascertain mechanism. The clinicians should pay more attention to identify potential victims of neurologic complications, to reduce the mortality rate of snake bite.

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 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.

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

Snakebite is an important medical problem in Sri Lanka. Of the deadly venomous snakes, Russell's viper (Daboia russelii) is widely distributed and responsible for most of the fatalities of snakebite in the country. It is not uncommon to see atypical manifestations in Russell's viper bite. We report the events of intracranial haemorrhages and multiple ischemic brain infarcts following Russell's viper (Daboia russelii) bite of a previously healthy 43-years-old male who succumbed to envenoming.

Brainstem ischemic stroke after to Bothrops atrox snakebite

We report case of a 48 years old woman bitten on her right foot by a Bothrops atrox viper. As a result, she developed a severe coagulopathy which improved with application of polyvalent antivenom. Four days after bite she suffered a devastating brainstem ischemic stroke. Possible pathogenetic mechanisms are discussed.