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.

Cat-eyed snake (Genus: Boiga) bites in Sri Lanka: First authentic case series

Cat snakes (Genus: Boiga) are considered to be of lesser medical important in Sri Lanka, as their bites are known to cause only mild local effects such as local pain and swelling at the site of the bite. Five species of cat snakes are found in Sri Lanka, of which three are endemic. They are widely distributed all over the country. Out of seven cases of cat snake bites, including six adults and one child, five developed only mild local effects and two did not have any symptoms. Any of them did not develop systemic manifestations. The snakes responsible were the Sri Lanka cat snake (Boiga ceylonensis), Forsten's cat snake (Boiga forsteni), and also Ranawana's cat snake (Boiga ranawanei) which is the first report in Sri Lanka.

Epidemiological and clinical features of hump-nosed pit viper (Hypnale hypnale and Hypnale zara) envenoming in children

BACKGROUND

Bites by the hump-nosed pit vipers (HNPV) of the genus Hypnale are the commonest type of venomous snakebites in Sri Lanka. Their bites frequently cause local effects while rarely causing systemic envenoming, that may include acute kidney injury and coagulopathy. There are 3 species of genus Hypnale including H. hypnale, H. zara and H. nepa from which latter two are endemic to Sri Lanka. Virtually all studies on HNPV bites in Sri Lanka are focused on adults except two studies in paediatric group. The aims of this study were to describe the epidemiology and clinical manifestations of HNPV bites in a group of children admitted to a tertiary care hospital in Sri Lanka.

METHODOLOGY/PRINCIPAL FINDINGS

This was a prospective observational study carried out in Teaching Hospital Ratnapura, Sri Lanka over 27 months commencing from May 2020 including all children aged up to 14 years with the history of HNPV bites. There were 40 (56%) HNPV bites, of them 28 (70%) were males. The age was 84 months (50.2-120 months). Majority (n = 21;52.5%) were bitten during day-time (06:00-17:59) in home gardens (n = 20; 50%) on lower limbs (n = 24;60%). Most children (n = 30;75%) were admitted to the medical facility < 4 hours after the snakebite [90 min (40-210 min)] and the hospital stay was 4 days (3-5 days). Local envenoming was observed in 38 patients (95%) and systemic effects developed in 4 patients (10%) as mild coagulopathy. Local effects include local pain (n = 30; 94%), swelling (n = 38;95%), blistering (n = 11;27.5%), necrosis at the site of bite (n = 11; 27.5%), regional lymph node enlargement (n = 8;20%) and local bleeding (n = 4;10%). For the local effects, surgical interventions were needed in 10 children (25%) and 3 (7.5%) of them developed acute compartment syndrome leading to fasciotomy. Leucocytosis (n = 28;78%) and eosinophilia (n = 9;27%) were the prominent laboratory findings. All got recovered except in patients with fasciotomy who got permanent scar.

CONCLUSIONS/SIGNIFICANCE

Hump-nosed pit viper bites mostly cause local effects and rarely systemic envenoming in children. Compartment syndrome is common in children following their bites.

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.

Venom-Induced Consumption Coagulopathy Following Hump-Nosed Pit Viper (Genus: Hypnale) Envenoming in Sri Lanka: Uncertain Efficacy of Fresh Frozen Plasma

INTRODUCTION

Hump-nosed pit vipers (Hypnale spp) cause the highest number of venomous snakebites in Sri Lanka. Bites commonly cause local envenoming leading to local pain, swelling, and necrosis of the site of the bite. Acute kidney injury is the most common systemic manifestation, and some patients develop venom-induced consumption coagulopathy (VICC). Genus Hypnale comprises 3 species. Of them, H hypnale is found in Sri Lanka and the Western Ghats region of India. The other 2 (H nepa and H zara) are endemic species in Sri Lanka.

METHODS

This study included 500 patients with hump-nosed viper bites studied prospectively over 4.5 y starting June 2014. All patients were assessed and the data were collected by the principal investigator (primary data). A subgroup of patients who developed VICC is described. There were 2 groups, including proven (patients with the specimen of the snake) and probable (specimen of snake not available) bites.

RESULTS

Thirty (n=500; 6%) patients developed VICC; of them, 17 (3%) were proven cases, and 13 (2%) were probable cases. In both groups, 24 (80%) recovered, 2 (7%) progressed to chronic kidney disease, 1 (3%) died of severe hemostatic dysfunction, and 3 (10%) were lost to follow-up. Systemic bleeding was observed in 16 patients (53%), including hematuria (microscopic and gross) in 8 (27%) and venipuncture bleeding in 5 (17%). Eleven (37%) developed local bleeding at the site of the bite. Fresh frozen plasma was administered to 20 patients (67%), among whom only 11 (55%) experienced early correction of VICC. In both groups, 15 (50%) developed acute kidney injury, and 2 (7%) progressed to chronic kidney disease. Microangiopathic hemolysis was observed in 18 patients (60%) and thrombocytopenia in 16 (53%). Thrombotic microangiopathy was detected in 13 patients (43%), of whom 10 (33%) developed hemolytic uremic syndrome and 2 (7%) had thrombotic thrombocytopenic purpura. Of patients with VICC in the proven group, 94% (n=16) was caused by H hypnale and 1 (6%) was caused by H zara. In the proven group, median international normalized ratio was 3.7 (interquartile range 1.6-5.0); in the probable group, it was 5.0 (interquartile range 2.1-5.4).

CONCLUSIONS

We found that 6% of patients develop hemostatic dysfunction after hump-nosed viper bites. However, which patients will develop coagulopathy or die of envenoming is unpredictable. Reliable and accessible treatments are unmet essential needs because antivenoms for these bites are currently not available in the country. Therapy with fresh frozen plasma has doubtful efficacy in early correction of VICC and needs further evaluation.

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.

Epidemiology and clinical features of Green pit viper (Trimeresurus trigonocephalus) envenoming in Sri Lanka

Green pit viper is a venomous endemic snake in Sri Lanka. But little is known regarding its envenoming in the country. This study was carried out in order to find out epidemiology and clinical profile of its bites. A series of 17 patients with Sri Lankan Green pit viper (Trimeresurus trigonocephalus) bites was prospectively studied over 4 years. The mean age was 36 ½ years (range 12-61 years) and comprised 14 (82%) males. Except one case, all bites occurred during day time (0600 h-1800 h) due to inadvertent provocation. In 13 cases (76%) bite took place in estates (tea or cinnamon) and 8 patients (47%) were estate workers. The bitten sites were upper limbs in 11 cases (65%) and lower limbs in 6 cases (35%). Ten patients (59%) brought the offending snake to the hospital and one patient was asymptomatic. Sixteen (94%) developed local envenoming features- 16 (94%) local pain and swelling, 6 (35%) local bleeding and lymphadenopathy and blistering in 4 (24%) patients. Systemic envenoming developed in 4 (24%) patients including 3 (18%) with coagulopathy that was treated with fresh frozen plasma. One (6%) patient developed bradycardia. Sri Lankan Green pit viper bites commonly occurs in estates and causes local envenoming frequently and coagulopathy occasionally.

Coagulopathy and extensive local swelling following Green pit viper (Trimeresurus trigonocephalus) envenoming in Sri Lanka

Trimeresurus trigonocephalus (Sri Lankan Green pit viper) is a moderately venomous arboreal snake endemic to Sri Lanka. Even though, its bites are not uncommon, published reports of such cases are limited to three in literature. We report three cases of coagulopathy following Green pit viper bites and treatment with fresh frozen plasma.