Microangiopathic Hemolytic Anemia Following Three Different Species of Hump-Nosed Pit Viper (Genus: Hypnale ) Envenoming in Sri Lanka

Long-term health manifestations of hump-nosed pit viper (Genus: Hypnale) bites

INTRODUCTION

The hump-nosed pit viper (Genus: Hypnale) is a highly medically significant snake in Sri Lanka, responsible for the majority of venomous snakebites (22-77%). They are found throughout Sri Lanka and the Western Ghats region of India. The venom can lead to two types of effects: acute and long-term. Acutely, bites often result in local symptoms, with less common systemic effects such as acute kidney injury, venom-induced consumption coagulopathy, and thrombotic microangiopathy.

METHODS

We conducted a prospective observational study at Teaching Hospital Ratnapura, Sri Lanka, spanning six years, starting in June 2015. Patients bitten by hump-nosed pit vipers were followed up for two years, with assessments every three months to identify long-term effects. Data was gathered through interviewer-administered questionnaires.

RESULTS

Out of 728 patients bitten by hump-nosed pit vipers, 22 (3%) were lost to follow-up. Forty-four (6.2%) experienced long-term effects, including chronic kidney disease (24; 3.4%), chronic wounds (five; 0.7%), amputations (five; 0.7%), fasciotomy-related wounds (four; 0.6%), and psychological illnesses (four; 0.6%). There were nine (1.3%) deaths in this group. Among those with chronic effects, 27 (61%) were males, and 17 (39%) were females, with ages ranging from 29 to 82 years (mean 57.6 years). The time it took to diagnose acute kidney injury from the snakebite was 18 h (interquartile range: 15-23.5 h), while the time to diagnose chronic kidney disease was 69 days (interquartile range: 64-74.75 days). In these patients, the estimated glomerular filtration rate was 29.3 mL/min/1.73 m2 (interquartile range: 14-50.75 mL/min/1.73 m2). Among the patients who did not develop long-term complications (662; 91%) 660 (90.7%) experienced local effects, and 82 (11.3%) developed systemic manifestations, including acute kidney injury in 60 (8%) and coagulopathy in 35 (5%).

CONCLUSION

Following hump-nosed pit viper bites, a subset of patients may experience long-term health complications, including chronic kidney disease, chronic ulcers, amputations, fasciotomy-related wounds, and psychological illnesses, with chronic kidney disease being the most frequently observed among these manifestations.

Epidemiology and clinical features of Hypnale nepa (hump-nosed pit viper) envenoming in Sri Lanka

Sri Lanka homes 3 species of hump-nosed pit vipers including Hypnale Hypnale, H. zara and H. nepa from which, latter 2 are endemic to the country. Even though former 2 are the subject of several publications, no major clinical studies have been done regarding H. nepa bites. As these snakes confine only to central hills of the country, their bites are very rare. The objectives of this study were to describe epidemiological and clinical features of H. nepa bites. A prospective observational study was conducted for patients admitted with H. nepa bites to Teaching Hospital, Ratnapura, Sri Lanka for 5 years commencing from June 2015. Species identification was done using a standard key. There were 14 (3.6%) patients with H. nepa bites of which 9 (64%) were males and 5 (36%) were females. Their age ranged from 20 to 73 years (median 37.5). Seven bites (50%) occurred on lower limbs. Majority of bites (10; 71%) happened at daytime [0600-1759 h] in tea estates (8; 57%). Most patients (8; 57%) were admitted within 1-3 h from bite. Hospital stay was 2.5 days (IQR 2-3). Local envenoming was observed in all patients including local pain and swelling [mild (7; 50%), moderate (5; 36%), severe (2; 14%)], local bleeding (1; 7%) and lymphadenopathy (1; 7%). Nonspecific features were observed in 3 (21%). Systemic manifestations were found in 2 (14%) including microangiopathic haemolytic anaemia and sinus bradycardia. Two (14%) had myalgia. H. nepa bites frequently cause local envenoming. But, rarely systemic manifestations may occur.

A case report of Ovophis monitcola (Mountain pit-viper) envenoming in northeastern India resulting in prolonged coagulopathy

India is home to a diverse spectrum of medically-significant snakes accounting for the world's largest burden of envenoming, morbidity and mortality. Indian polyspecific antivenom is derived from the venom of four snake species (Daboia russelii, Echis carinatus, Naja naja and Bungarus caeruleus), considered to be responsible for the majority of snakebite morbidity and mortality. The treatment of venomous bites from other less-commonly encountered venomous snake species can be challenging. In this report, we describe the case of a 32-year-old male who presented with features of local cytotoxicity and coagulopathy following a bite from Ovophis monitcola (mountain pit-viper) in Nagaland, northeast India. Local and systemic envenoming, confirmed by bedside and laboratory based clotting assays, failed to respond to polyspecific antivenom and venom-induced consumption coagulopathy persisted for 28 days. Remote consultation with a national Poison Control Centre helped establish the responsible snake species and guide appropriate medical management.

Neutrophil-mediated erythrophagocytosis following Russell's viper (Daboia russelii) bite

Snakebite envenomation is regarded as a high-priority neglected tropical disease by the World Health Organisation, as it results in significant loss of lives and permanent disabilities. Russell's viper is one of the snakes that causes morbidities, mortalities and disabilities in India. The clinical presentation of Russell's viper envenomation is characterised by local envenoming effects, tissue damage, venom-induced coagulopathy, neurotoxicity, and kidney injury. However, venom composition and its mechanisms of toxicity are highly variable even within snakes of the same species including Russell's viper. This variation in venom composition results in a broad range of clinical complications. Here we present a previously undocumented case of neutrophil-mediated erythrophagocytosis in a healthy 28-year-old female following Russell's viper bite. Systemic envenomation effects and bleeding abnormalities in this patient were corrected by the administration of polyvalent antivenom. Two days later, the patient developed progressive swelling and ecchymosis in the bitten limb. Observed abnormal limits within blood testing were followed up by a peripheral blood smear where it was found that 30% of neutrophils had phagocytosed erythrocytes as they were found within the cytoplasm. The patient underwent a fasciotomy for compartmental syndrome and received packed red cells and a course of corticosteroids. Following this treatment, the patient made a full recovery. This case report outlines a previously undocumented pathological event induced by Russell's viper envenomation, guiding diagnosis and treatment. Clinicians' knowledge of the mechanisms of toxicity of Russell's viper envenomation and its clinical manifestations are essential for improving the treatment of snakebites to achieve positive outcomes.

Hump-Nosed Pit Viper Envenomation in Western Coastal India: A Case Series

The hump-nosed pit viper (HNPV) has historically been considered less medically significant, causing local envenomation, renal injury, and coagulopathy; however, now, it is known to cause life-threatening complications. We describe the clinical presentation, treatment, and complications of 3 confirmed HNPV bites from the state of Karnataka (southwest coastal India). Patient 1, an 88-y-old woman, reported with the live specimen and developed venom-induced consumption coagulopathy (VICC) and thrombotic microangiopathy leading to acute kidney injury requiring blood product transfusions and dialysis. Patient 2, a 60-y-old woman, reported 3 d after envenomation followed by treatment at another hospital where 30 vials of polyvalent anti-snake venom (ASV) were given. She developed VICC and acute kidney injury requiring dialysis. On Day 9 of treatment, she developed a pontine hemorrhage. She died after a transfer to another treatment center closer to her residence. Patient 3, a 25-y-old man, was brought to our emergency department 6 h after being envenomed. He received topical ayurvedic treatment before arrival. He was unconscious and found to have severe VICC with a massive middle cerebral artery infarct. All 3 patients received Indian polyvalent ASV, which does not cover HNPV envenomation, clearly demonstrating the absence of paraspecificity and neutralization in a clinical setting. To our knowledge, Hypnale hypnale envenomation has not previously been reported from Karnataka state. The diagnosis of HNPV envenomation in a country without snake venom detection kits, under-reporting despite serious complications, financial burdens on rural populations afflicted, and poor outcomes due to the lack of a specific antivenom are discussed.

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.

Purpura fulminans following hump-nosed pit viper (Hypnale hypnale) envenoming: A rare complication of snakebites

Hump-nosed pit vipers of the genus Hypnale are highly venomous and reputed for the commonest venomous snakebites in Sri Lanka. They frequently cause local manifestations and less commonly cause systemic effects such as acute kidney injury and coagulopathy. There is no antivenom currently available in Sri Lanka for their envenoming. However, more and more complications of Hypnale bites are being recently described. Purpura fulminans, one of the rare complications of snakebites that we report following authentic Hypnale hypnale bite. A 58-year-old female was bitten by a hump-nosed viper and developed bilateral toe gangrenes, ultimately ended up with amputations. She got recovered with loss of toes in both feet for 46 days treatment at hospital.

Clinico-epidemiology of Hypnale zara (hump-nosed pit viper) envenoming in Sri Lanka

BACKGROUND

Hump-nosed vipers of the genus Hypnale are the most common cause of venomous snakebites in Sri Lanka. The genus includes three species: Hypnale hypnale, Hypnale zara and Hypnale nepa. Of them, H. hypnale bites are the most common and are the subject of many publications. The epidemiology and clinical features of bites by the other two species have been less investigated.

METHODS

We conducted a prospective observational study of H. zara bites from January 2015 to June 2020 at the Teaching Hospital, Ratnapura, Sri Lanka. Data were collected for 5.5 years in the wet zone of the island, where the principal investigator did assessment of all patients and the data collection.

RESULTS

H. zara envenoming was confirmed through identification of dead or live snake specimens brought with the patients. Of the 480 patients with proven hump-nosed viper bites, H. zara bites accounted for 105 (22%), including dry bites (n=5 [5%]) and envenoming (n=100 [95%]), with gender distribution of 65 (62%) males and a mean age of 43.1 y. Most bites occurred on the lower limbs (n=71 [68%]) in the daytime (n=69 [66%]) in home gardens (n=45 [43%]). A total of 100 (95%) patients had local manifestations, including pain (n=100 [95%]), swelling (n=100 [95%]), bleeding (n=20 [19%]), bruising (n=11 [10%]), lymphadenopathy (n=10 [9%]), necrosis at the bite site (n=9 [9%]) and blistering (n=8 [8%]). Seven (6.7%) patients showed systemic effects, including acute kidney injury (n=2 [2%]), microangiopathic haemolysis (n=2 [2%]), sinus bradycardia (2 [2%]) and one (1%) each had coagulopathy, thrombotic microangiopathy, Kounis syndrome and ischaemic changes on electrocardiography. Eosinophilia was a significant haematological finding (n=26 [25%]) and 16 (15%) had leucocytosis and 15 (14%) had neutrophilia. Ninety six percent of patients (n=101) recovered. Antivenom is not available for hump-nosed viper bites in Sri Lanka and therefore patients were managed conservatively.

CONCLUSIONS

This study shows that H. zara bites mainly cause local envenoming and rarely systemic effects.

A Rare Case of Micro-Angiopathic Hemolytic Anemia Due to Envenoming by Giant Asian Honey Bee (Apis dorsata)

Giant Asian honey bee sting envenoming is a recognized cause of morbidity and mortality in rural Sri Lanka. Mass envenoming causes clinical effects, either as allergic and anaphylactic reactions or bee sting toxin-induced multiorgan damage. We report a patient who had mass envenoming from more than 1000 stingers who subsequently developed hematologic features suggestive of thrombotic microangiopathy-related hemolytic anemia. The transient acute kidney injury and acute hepatic failure seen in the patient were also considered to be secondary to thrombotic microangiopathy. A normal clotting profile and a high proportion of schistocytes in blood film ruled out disseminated intravascular coagulation as the underlying cause of the microangiopathic hemolytic anemia. The normal platelet count raised the possibility of a "partial" thrombotic microangiopathy, as has previously been reported in association with Shiga toxin-related hemolytic uremic syndrome and hump-nosed pit viper envenoming. Venom-induced direct toxicity on red cells was another possible explanation for the hemolysis, but the high proportion of schistocytes made it less likely. The place of therapeutic plasma exchange for venom-associated thrombotic microangiopathy is controversial. The patient recovered with symptomatic treatment and meticulous fluid management, without needing therapeutic plasma exchange as an adjunct treatment.

Kounis Syndrome Following Hypnale zara (Hump-Nosed Pit Viper) Bite in Sri Lanka

A 47-y-old man was bitten by a hump-nosed viper (Hypnale zara) and gradually developed retrosternal chest pain associated with ST segment elevation on electrocardiogram. He had normal troponin I levels and no evidence of coagulopathy. Initially, he was managed as having anterior ST elevation myocardial infarction with thrombolysis. Later, because troponin levels were normal, he was suggested to have the type I variant of Kounis syndrome (allergic coronary artery spasm). This was supported by high eosinophil counts in peripheral blood. He was successfully managed with supportive treatment and discharged 6 d after the snakebite. Cardiac complications are rarely reported after hump-nosed viper bites, and clinical reports of coronary vasospasm after snakebites are extremely rare in the literature. This is the first known report of Kounis syndrome after a hump-nosed viper bite.

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.

Severe acute kidney injury following Sri Lankan Hypnale spp. envenoming is associated with thrombotic microangiopathy

CONTEXT

Acute kidney injury (AKI) is the most serious clinical manifestation of the Sri Lankan hump-nosed pit viper (Hypnale spp.) bites. Thrombotic microangiopathy (TMA) is increasingly recognized in association with AKI in cases of Hypnale spp envenomation. We investigated AKI in a cohort of cases of Hypnale envenomation, its association with TMA and the early diagnostic value of common biomarkers for AKI occurring.

MATERIALS AND METHODS

We conducted a prospective observational study of suspected viper bites and included 103 confirmed cases of Hypnale envenomation, based on venom specific enzyme immunoassay of blood. AKI was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Thrombotic microangiopathy was diagnosed based on thrombocytopenia (platelet count < 150,000 × 10³/μL) and microangiopathic haemolytic anaemia (MAHA). We investigated the diagnostic performance of creatinine, platelet count and INR for AKI within 4 h and 8 h post-bite by area under the receiver operator characteristic curve (AUC-ROC).

RESULTS

Ten patients developed AKI: seven AKI stage 1 and three AKI stage 3. Ten patients (10%) developed thrombocytopaenia while 11 (11%) had MAHA. All three AKI stage 3 had thrombocytopaenia and MAHA fulfilling the criteria for TMA. Two of them presented with oliguria/anuria and all three required haemodialysis. Serum creatinine within 4 h post-bite was the best predictor of AKI with AUC-ROC of 0.83 (95% CI: 0.67-0.99) and was no better within 8 h of the bite.

CONCLUSIONS

We found that AKI is uncommon in Hypnale spp. envenomation, but an important serious complication. Severe AKI was associated with TMA. A creatinine within 4 h post-bite was the best predictor of AKI.

Kidney injury following envenoming by hump-nosed pit viper (Genus: Hypnale) in Sri Lanka: proven and probable cases

BACKGROUND

Hump-nosed pit vipers (Hypnale hypnale) are highly venomous snakes found in Sri Lanka and the Western Ghats region of India. They are the most common cause of venomous snakebites in Sri Lanka, mainly causing local envenoming leading to pain, swelling and necrosis. Systemic envenoming causing acute kidney injury and coagulopathy are more commonly recognized following their bites.

METHOD

A series of 465 patients with hump-nosed viper bites was prospectively studied over four years from January 2014. All patients were assessed and the data were collected by the principal investigator (primary data).

RESULTS

Forty-four (9.5%) patients developed acute kidney injury, of which 23 (5%) were proven cases and 21 (4.5%) were probable cases. Of the proven cases, 4 (17%) progressed to chronic kidney disease and 12 (52%) had thrombotic microangiopathy, from which 11 (48%) developed haemolytic uremic syndrome and 1 (4%) had thrombotic thrombocytopenic purpura. Twelve (52%) showed microangiopathic haemolysis and 15 (65%) had thrombocytopenia. Oliguria was observed in 10 (43%) whereas 7 (30%) each had anuria and normal urine output. Ten patients (43%) developed haematuria, from which 6 had microscopic haematuria and 4 had macroscopic haematuria. Proteinuria was observed in 8 (35%). Coagulopathy developed in 3 (13%) patients. In probable cases, 3 (14%) died due to complications of kidney injury.

CONCLUSION

A significant proportion of patients develop acute kidney injury following hump-nosed pit viper bite. Who will develop acute kidney injury or succumb to the venom is unpredictable. Reliable and accessible treatments are a critical unmet need.

Thrombotic Microangiopathy Following Hypnale zara (Hump-Nosed Pit Viper) Envenoming: The First Known Case Report from Sri Lanka

A 65-y-old previously healthy farmer developed thrombotic microangiopathy (TMA) comprising the triad of acute kidney injury, microangiopathic haemolysis, and thrombocytopenia after a proven Hypnale zara (hump-nosed pit viper) bite. He developed coagulopathy, which was treated with fresh frozen plasma, and underwent 8 cycles of hemodialysis. He is being followed up in the nephrology clinic for acute kidney injury. TMA caused by Hypnale hypnale, the commonest species of genus Hypnale, has previously been reported, but this is the first known case of TMA following a bite by H zara, the endemic species in Sri Lanka.

Nephrotoxicity induced by the venom of Hypnale hypnale from Sri Lanka: Studies on isolated perfused rat kidney and renal tubular cell lines

The hump-nosed pit viper Hypnale hypnale is responsible for a high number of snakebite cases in southwestern India and Sri Lanka. Although most patients only develop local signs and symptoms of envenoming, there is a growing body of evidence indicating that these envenomings may be associated with systemic alterations, including acute kidney injury. In this study we evaluated the renal toxicity of H. hypnale venom by using a perfused isolated rat kidney system and by assessing cytotoxicity in two different renal tubular cell lines in culture. The venom caused alterations in several renal functional parameters, such as reduction on perfusion pressure, renal vascular resistance, and sodium and chloride tubular transport, whereas glomerular filtration rate and urinary flow initially decreased and then increased after venom perfusion. In addition, this venom was cytotoxic to proximal and distal renal tubular cells in culture, with predominance of necrosis over apoptosis. Moreover, the venom affected the mitochondrial membrane potential and induced an increment in reactive oxygen species in these cells. Taken together, our results demonstrate a nephrotoxic activity of H. hypnale venom in these experimental models, in agreement with clinical observations.

Cardiac arrest and atrial fibrillation in a patient after hump-nosed pit viper (Hypnale hypnale) bite

A 42-year-old previously healthy male patient died 16 days after a proven hump-nosed pit viper (Hypnale hypnale) envenoming due to multi-organ failure. On admission he had cardiac arrest that recovered from cardiopulmonary resuscitation then developed atrial fibrillation which was reverted to normal rhythm by application of synchronized electrical cardioversion. He also had persistent coagulopathy and thrombotic microangiopathy comprising the triad of microangiopathic haemolysis, acute kidney injury and thrombocytopenia. This is the second reported case with cardiac complications following hump-nosed pit viper bites in Sri Lanka.