Development of renal function abnormalities following bites by Russell's vipers (Daboia russelii siamensis) in Myanmar

Sodium oleate, arachidonate, and linoleate enhance fibrinogenolysis by Russell's viper venom proteinases and inhibit FXIIIa; a role for phospholipase A2 in venom induced consumption coagulopathy

Life-threatening symptoms produced by Russell's viper (RV, Daboia russelii) envenomation result largely from venom induced consumption coagulopathy (VICC). VICC is thought to be mediated to a large degree by venom serine and metalloproteinases, as well as by snake venom phospholipase A2 (svPLA2), the most abundant constituent of RV venom (RVV). The observation that the phenolic lipid anacardic acid markedly enhances proteolytic degradation of fibrinogen by RVV proteinases led us to characterize the chemical basis of this phenomenon with results indicating that svPLA2 products may be major contributors to VICC. RESULTS: Of the chemical analogs tested, the anionic detergents sodium dodecyl sulfate, sodium deoxycholate, N-lauryl sodium sarcosine, and the sodium salts of the fatty acids arachidonic, oleic and to a lesser extend linoleic acid were able to enhance fibrinogenolysis by RVV proteinases. Enhanced Fibrinogenolysis (EF) was observed with various venom size exclusion fractions containing different proteinases, and also with trypsin, indicating that conformational changes of the substrate and increased accessibility of otherwise cryptic cleavage sites are likely to be responsible for EF. In addition to enhancing fibrinogenolysis, sodium arachidonate and oleate were found to partially inhibit thrombin induced, factor XIIIa (FXIIIa) mediated ligation of fibrin chains. In clotting experiments with fresh blood RVV was found to disrupt normal coagulation, leading to small, partial clot formation, whereas RVV pretreated with the PLA2 inhibitor Varespladib induced rapid and complete clot formation (after 5 min) compared to blood alone. CONCLUSION: The observations that fatty acid anions and anionic detergents induce conformational changes that render fibrin(ogen) more susceptible to proteolysis by RVV proteinases and that RVV-PLA2 activity (which produces FFA) is required to render blood incoagulable in clotting experiments with RVV indicate a mechanism by which the activity of highly abundant RVV-PLA2 promotes degradation and depletion of fibrin(ogen) resulting in incoagulable blood seen following RVV envenomation (VICC).

Bedside Coagulation Tests in Diagnosing Venom-Induced Consumption Coagulopathy in Snakebite

Venom-induced consumption coagulopathy is the most important systemic effect of snake envenoming. Coagulation tests are helpful to accurately and promptly diagnose venom-induced consumption coagulopathy and administer antivenom, which is the only specific treatment available. However, bedside clotting tests play a major role in diagnosing coagulopathy in low-income settings, where the majority of snakebites occur. We conducted a literature search in MEDLINE^® from 1946 to 30 November 2019, looking for research articles describing clinical studies on bedside coagulation tests in snakebite patients. Out of 442 articles identified, 147 articles describing bedside clotting assays were included in the review. Three main bedside clotting tests were identified, namely the Lee–White clotting test, 20-min whole blood clotting time and venous clotting time. Although the original Lee–White clotting test has never been validated for snake envenoming, a recently validated version has been used in some South American countries. The 20-min whole blood clotting time test is the most commonly used test in a wide range of settings and for taxonomically diverse snake species. Venous clotting time is almost exclusively used in Thailand. Many validation studies have methodological limitations, including small sample size, lack of case-authentication, the inclusion of a heterogeneous mix of snakebites and inappropriate uses of gold standard tests. The observation times for bedside clotting tests were arbitrary, without proper scientific justification. Future research needs to focus on improving the existing 20-min whole blood clotting test, and also on looking for alternative bedside coagulation tests which are cheap, reliable and quicker.

Twelve month prospective study of snakebite in a major teaching hospital in Mandalay, Myanmar; Myanmar Snakebite Project (MSP)

The Myanmar Snakebite Project is an Australian government (Department of Foreign Affairs and Trade) supported foreign aid project in collaboration with the Myanmar government with the aim of improving outcomes for snakebite patients in Myanmar. As part of the project a case record database was established to document prospective cases of snakebite presenting to Mandalay General Hospital, in Upper Myanmar. The study period was 12 months (1-2-2016 to 31-1-2017). Snake identity was based on a mixture of identified dead snakes brought with patients, doctor's clinical opinion and patient identification. 965 patients were enrolled during the 12 month period, of whom 948 were included for analysis. The male: female ratio was 1.58:1. Most cases involved bites to the lower limbs (82.5%) and adults involved in farm work, confirming snakebite as an occupational disease in this community. Motorised transport was by far the most common form of transport to health care and most patients sought care from the health system (87.7%), not traditional healers (11.5%) as their first point of contact. The officially promoted application of a pressure pad, bandage and immobilisation as first aid for snakebite was almost never used, while most patients used some form of tourniquet (92.0%). 85.4% of cases where a snake ID was listed were bitten by Russell's vipers. Russell's viper bites were responsible for all fatalities (9.8% of cases) and all cases of Acute Kidney Injury (AKI). For all cases, clinical features included local swelling (76.5%), local pain (62.6%), AKI (59.8%), incoagulable blood (57.9%), regional lymphadenopathy (39.8%), nausea/vomiting (40.4%), thrombocytopenia (53.6%), abdominal pain (28.8%), shock (11.8%), secondary infection (8.6%), panhypopituitarism (2.1%). AKI required renal replacement therapy (RRT) in 23.9% of cases, all ascribed to Russell's viper bite. Green pit viper bites were the next most common cause of bites (7.6%) and were associated with incoagulable blood (29%) and occasionally shock (5%) and local necrosis (3%), and in one case AKI not requiring RRT. In contrast to Russell's viper bites, green pit viper bite was most likely to occur in the home (49%). Some green pit viper patients were treated with Russell's viper antivenom (15%), presumably because they had incoagulable blood, although this antivenom is not effective against green pit viper envenoming. For the entire patient group, antivenom was given in 80.5% of cases. The most common indications were presence of coagulopathy/non-clotting blood (59.8%), local swelling (47.4%), oliguria/anuria (19.8%), heavy proteinuria (19.4%). A febrile reaction to antivenom was reported in 47.9% of cases, while anaphylaxis, occurred in 7.9% of cases.

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Reports 12 month prospective observational study of snakebite patients at Mandalay General Hosp.

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Snakebite was an occupational disease of farm workers, tourniquets the most common first aid.

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Russell's viper (RV) responsible for most bites, causing coagulopathy, thrombocytopenia, AKI.

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Green pit viper bites were the next most common, potentially causing diagnostic confusion with RV.

Venom proteomics and antivenom neutralization for the Chinese eastern Russell's viper, Daboia siamensis from Guangxi and Taiwan

The eastern Russell's viper (Daboia siamensis) causes primarily hemotoxic envenomation. Applying shotgun proteomic approach, the present study unveiled the protein complexity and geographical variation of eastern D. siamensis venoms originated from Guangxi and Taiwan. The snake venoms from the two geographical locales shared comparable expression of major proteins notwithstanding variability in their toxin proteoforms. More than 90% of total venom proteins belong to the toxin families of Kunitz-type serine protease inhibitor, phospholipase A2, C-type lectin/lectin-like protein, serine protease and metalloproteinase. Daboia siamensis Monovalent Antivenom produced in Taiwan (DsMAV-Taiwan) was immunoreactive toward the Guangxi D. siamensis venom, and effectively neutralized the venom lethality at a potency of 1.41 mg venom per ml antivenom. This was corroborated by the antivenom effective neutralization against the venom procoagulant (ED = 0.044 ± 0.002 µl, 2.03 ± 0.12 mg/ml) and hemorrhagic (ED50 = 0.871 ± 0.159 µl, 7.85 ± 3.70 mg/ml) effects. The hetero-specific Chinese pit viper antivenoms i.e. Deinagkistrodon acutus Monovalent Antivenom and Gloydius brevicaudus Monovalent Antivenom showed negligible immunoreactivity and poor neutralization against the Guangxi D. siamensis venom. The findings suggest the need for improving treatment of D. siamensis envenomation in the region through the production and the use of appropriate antivenom.

Clinical and laboratory parameters associated with acute kidney injury in patients with snakebite envenomation: a prospective observational study from Myanmar

Background

Snakebite-related acute kidney injury (AKI) is a common community-acquired AKI in tropical countries leading to death and disability. The aims of this study were to (1) determine the occurrence of snakebite-related AKI, (2) assess factors at presentation that are associated with snakebite-related AKI, and (3) determine the outcomes of patients with snakebite-related AKI.

Methods

We conducted a prospective observational study of patients with snake envenomation at the three academic tertiary care hospitals in Yangon, Myanmar between March 2015 and June 2016. Patient data including baseline characteristics, clinical and laboratory findings, hospital management, and outcomes were recorded in a case report form. A stepwise multivariate logistic regression analysis using a backward selection method determined independent factors significantly associated with AKI.

Results

AKI was observed in 140 patients (54.3%), the majority of whom were AKI stage III (110 patients, 78.6%). AKI occurred at presentation and developed during hospitalization in 88 (62.9%) and 52 patients (37.1%), respectively. Twenty-seven patients died (19.3%), and 69 patients (49.3%) required dialysis. On multivariate logistic regression analysis, (1) snakebites from the Viperidae family (odds ratio [OR]: 9.65, 95% confidence interval [CI]: 2.42–38.44; p = 0.001), (2) WBC >10 × 10³ cells/μL (OR: 3.55, 95% CI: 1.35–9.34; p = 0.010), (3) overt disseminated intravascular coagulation (OR: 2.23, 95% CI: 1.02–4.89; p = 0.045), (4) serum creatine kinase >500 IU/L (OR: 4.06, 95% CI: 1.71–9.63; p = 0.001), (5) serum sodium <135 mmol/L (OR: 4.37, 95% CI: 2.04–9.38; p < 0.001), (6) presence of microscopic hematuria (OR: 3.60, 95% CI: 1.45–8.91; p = 0.006), and (7) duration from snakebite to receiving antivenom ≥2 h (OR: 3.73, 95% CI: 1.48–9.37; p = 0.005) were independently associated with AKI. Patients bitten by Viperidae with normal renal function who had serum sodium <135 mmol/L had a significantly higher urine sodium-to-creatinine ratio than those with serum sodium ≥135 mmol/L (p < 0.001).

Conclusions

Identifying factors associated with snakebite-related AKI might help clinicians to be aware of snakebite patients who are at risk of AKI, particularly patients who demonstrate renal tubular dysfunction after Viperidae bites.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0510-0) contains supplementary material, which is available to authorized users.

Role of biomarkers of nephrotoxic acute kidney injury in deliberate poisoning and envenomation in less developed countries

Acute kidney injury (AKI) has diverse causes and is associated with increased mortality and morbidity. In less developed countries (LDC), nephrotoxic AKI (ToxAKI) is common and mainly due to deliberate ingestion of nephrotoxic pesticides, toxic plants or to snake envenomation. ToxAKI shares some pathophysiological pathways with the much more intensively studied ischaemic AKI, but in contrast to ischaemic AKI, most victims are young, previously healthy adults. Diagnosis of AKI is currently based on a rise in serum creatinine. However this may delay diagnosis because of the kinetics of creatinine. Baseline creatinine values are also rarely available in LDC. Novel renal injury biomarkers offer a way forward because they usually increase more rapidly in AKI and are normally regarded as absent or very low in concentration, thereby reducing the need for a baseline estimate. This should increase sensitivity and speed of diagnosis. Specificity should also be increased for urine biomarkers since many originate from the renal tubular epithelium. Earlier diagnosis of ToxAKI should allow earlier initiation of appropriate therapy. However, translation of novel biomarkers of ToxAKI into clinical practice requires better understanding of non-renal factors in poisoning that alter biomarkers and the influence of dose of nephrotoxin on biomarker performance. Further issues are establishing LDC population-based normal ranges and assessing sampling and analytical parameters for low resource settings. The potential role of renal biomarkers in exploring ToxAKI aetiologies for chronic kidney disease of unknown origin (CKDu) is a high research priority in LDC. Therefore, developing more sensitive biomarkers for early diagnosis of nephrotoxicity is a critical step to making progress against AKI and CKDu in the developing world.

Effect of purified Russell's viper venom-factor X activator (RVV-X) on renal hemodynamics, renal functions, and coagulopathy in rats

Acute renal failure (ARF) is the most frequent and a serious complication in victims of Russell's viper snakebites. Russell's viper venom-factor X activator (RVV-X) has been identified as a main procoagulant enzyme involving coagulopathy, which might be responsible for changes in renal hemodynamics and renal functions. Here, we purified RVV-X from crude Russell's viper venom to study renal hemodynamics, renal functions, intravascular clot, and histopathological changes in Sprague-Dawley rats. Changes in renal hemodynamics and renal functions were evaluated by measuring the mean arterial pressure, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), effective renal blood flow (ERBF), renal vascular resistance (RVR), and fractional excretion of electrolytes. After 10 min, rats receiving both crude venom and purified RVV-X decreased GFR, ERPF, and ERBF and increased RVR. These changes correlated to renal lesions. Along with the determination of intravascular clot, rats injected with purified RVV-X increased the average D-dimer level and reached a peak at 10 min, declined temporarily, and then reached another peak at 30 min. The temporal association between clots and renal dysfunction was observed in rats within 10 min after the injection of purified RVV-X. These findings suggested RVV-X as a major cause of renal failure through intravascular clotting in the renal microcirculation.

Emergency treatment of a snake bite: Pearls from literature

Snake bite is a well-known occupational hazard amongst farmers, plantation workers, and other outdoor workers and results in much morbidity and mortality throughout the world. This occupational hazard is no more an issue restricted to a particular part of the world; it has become a global issue. Accurate statistics of the incidence of snakebite and its morbidity and mortality throughout the world does not exist; however, it is certain to be higher than what is reported. This is because even today most of the victims initially approach traditional healers for treatment and many are not even registered in the hospital. Hence, registering such patients is an important goal if we are to have accurate statistics and reduce the morbidity and mortality due to snakebite. World Health Organization/South East Asian Region Organisation (WHO/SEARO) has published guidelines, specific for the South East Asian region, for the clinical management of snakebites. The same guidelines may be applied for managing snakebite patients in other parts of the world also, since no other professional body has come up with any other evidence-based guidelines. In this article we highlight the incidence and clinical features of different types of snakebite and the management guidelines as per the WHO/SEARO recommendation.

Ability of a small, basic protein isolated from Russell's viper venom (Daboia russelli russelli) to induce renal tubular necrosis in mice

Russell's viper venom (RVV) induced acute renal failure involves both direct and indirect nephrotoxic actions where the specific component/s are yet to be identified. A basic cytotoxin of 7.2kDa (RVV-7) has been identified as potential nephrotoxin. Autoradiographic experiments demonstrated that only RVV-7 among RVV toxins binds specifically to mice kidney membrane. Homogeneous preparation of RVV-7 confirmed its necrotic cell killing property having EC(50) of 4.79+/-3.28microM. Tissue distribution kinetics of RVV-7 in mice showed its higher localization in kidney compared to blood and liver. Role of inherent factor responsible for its localization in kidney was assessed after chemical inactivation of its cytotoxic activity. Cytotoxicity was neutralized by histidine modification but consequent alteration of in vivo distribution was insignificant. Classical concept of glomerular capillary wall (GCW) permselectivity barrier denotes that apart from size selectivity, GCW also restricts anionic proteins from filtration. Reducing the pI of RVV-7 by chemical manipulation of its surface positive charges resulted to decreased accumulation in kidney. Histological observations of kidney from mice treated in vivo with RVV-7 showed degenerated tubular epithelium. These findings indicate that basic character and small size of RVV-7 are favorable for its rapid accumulation in kidney leading to necrotic destruction of tubular epithelium.

Antivenom treatment and renal dysfunction in Russell's viper snakebite in Taiwan: a case series

Formosan Russell's viper (Daboia russelli siamensis) is the sixth most frequent cause of snakebites in Taiwan. Its bite induces greater kidney injury than other Russell's vipers in Southeast Asia. Poor availability of antivenom might be the major reason. To enhance treatment, we supplied the antivenom to the teaching hospitals that are near the areas where D. r. siamensis is found. We also used an ELISA in diagnosis. From June 1999 to December 2001, a total of 13 cases of D. r. siamensis snakebite were diagnosed with serum venom level of 10-98 ng/ml, 1-6 hours after being envenomed. Abnormal coagulation function and acute renal failure occurred early and were the two most important clinical features. Early specific antivenom treatment, 3-6 hours after systemic envenoming, restored the coagulation function in 1-2 days and seemed to be statistically effective in reducing the severity of renal damage compared with the historical and delayed group by the Wilcoxon rank-sum test. Two to four vials of antivenom were needed to block the systemic toxicity and produced few side effects. The antivenom should be administered as early as possible to prevent systemic dysfunction.

Renal involvement in Russell's viper bite patients without disseminated intravascular coagulation

We measured urinary beta-N-acetylglucosaminidase (NAG: EC 3.2.1.30), blood urea, serum creatinine, albuminuria index and creatinine clearance in 16 patients bitten by Russell's viper (Daboia russelii siamensis) without disseminated intravascular coagulation (DIC) at the time of admission and then once daily for 5 d. Urinary NAG activity and the albuminuria index showed considerable variation whereas the other standard indicators of renal function revealed no abnormality. It is concluded that structural damage to the kidney occurred in these victims in the absence of DIC, indicating a direct toxic effect of Russell's viper venom on the kidney.

Effects of Russell's viper venom on renal lysosomal functions in experimental mice

The lysosome-enriched fraction of mice kidney was isolated by homogenization and differential centrifugation. Lysosomal functions, namely lysosomal enzyme activities and membrane integrities were investigated in (a) the renal lysosome-enriched fraction, incubated with different concentrations of Russell's viper venom (RVV) for various time intervals (in vitro test) and (b) the kidney homogenate of mice, which had been envenomed with different dosages of RVV and been sacrificed after various time intervals post-envenomation (in vivo test). Three typical marker enzymes for lysosome were used, namely N-acetyl-beta-D-glucosaminidase (NAG), cathepsin D and acid phosphatase. It was found that, with increasing dosages of RVV and increasing time intervals after RVV treatment, the activities of all lysosomal enzymes generally increased and the lysosomal membrane integrities apparently reduced in in vitro and in vivo conditions, respectively. Among the three typical marker enzymes, NAG was found to be the most specific, sensitive and informative marker enzyme for the study of lysosomal functions in the kidney of mice treated with RVV.

Urinary NAG as an early indicator of renal damage in Russell's viper bite envenomation

Urinary N-acetyl-beta-D-glucosaminidase (NAG; beta-N-acetylglucosaminidase; EC 3.2.1.30), blood urea, serum creatinine and creatinine clearance were measured in 23 patients bitten by Russell's viper (Daboia russelii siamensis), with systemic envenomation, at different time intervals after the bite during clinical observation for 5 d. Activities of urinary NAG were compared with these indicators of renal function in 3 clinical conditions: non-oliguric acute renal failure (ARF), oliguric ARF not requiring peritoneal dialysis, and oliguric ARF requiring peritoneal dialysis. Cut-off values to identify the 3 conditions were established. When the times of onset of the conditions, indicated by the cut-off values, were compared, urinary NAG was generally found to be the earliest indicator of renal damage. In each type of ARF, the urinary NAG level was abnormal before changes in the values of the other indicators of renal function. It may be possible to predict the types of ARF within 2 h after the bite by measurement of urinary NAG.

The epidemiology of snake bite in Central Province and National Capital District, Papua New Guinea

Snake bite is an important medical problem in some areas of Papua New Guinea and appears to be most common in the Central Province and National Capital District. The overall incidence for Central Province is 215.5 per 100,000 population, but Kairuku subprovince has an incidence of 526 per 100,000, which is amongst the highest in the world. The clinical pattern of envenoming also varies within the Province, suggesting that different species of snake may be responsible for bites in different areas. Most envenomed patients are bitten during daylight on the lower limb and are rarely able to describe the snake. The mortality rate in Central Province is 7.9 per 100,000; most patients die from ventilatory failure due to severe neurotoxicity. Mortality might be reduced by increased use of compression bandaging as a first aid measure, earlier treatment with antivenom and earlier referral to hospital.

In vitro nephrotoxicity of Russell's viper venom

To assess direct nephrotoxicity of Russell's viper venom (RVV; Daboia russelii siamensis), isolated rat kidneys were perfused in single pass for 120 min. Ten micrograms/ml and 100 micrograms/ml RVV were administered 60 minutes and 80 minutes, respectively, after starting the perfusion. Furthermore, cultured mesangial cells and renal epithelial LLC-PK1 and MDCK cells were exposed to RVV (100 to 1000 micrograms/ml) for 5 minutes up to 48 hours. The IPRK dose-dependently exhibited reductions of renal perfusate flow (RPF, 7.7 +/- 2.4 vs. 16.5 +/- 0.7 ml/min g kidney wt in controls, experimental values given are those determined 10 minutes after termination of 100 micrograms/ml RVV admixture), glomerular filtration rate (GFR 141 +/- 23 vs. 626 +/- 72 microliters/min g kidney wt) and absolute reabsorption of sodium (TNa 8 +/- 1.7 vs. 79 +/- 9 mumol/min g kidney wt), and an increased fractional excretion of sodium (FENa 60 +/- 7 vs. 8 +/- 0.8%) and water (FEH2O 68 +/- 3.2 vs. 13 +/- 1.2%). Urinary flow rate (UFR) showed both oliguric and polyuric phases. Functional alterations of this type are consistent with ARF. Light and electron microscopy of perfusion fixed IPRK revealed an extensive destruction of the glomerular filter and lysis of vascular walls. Various degrees of epithelial injury occurred in all tubular segments. In cell culture studies RVV induced a complete disintegration of confluent mesangial cell layers, beginning at concentrations of 200 micrograms/ml. In epithelial LLC-PK1 and MDCK cell cultures only extremely high doses of RVV (> 600 and 800 micrograms/ml, respectively) led to microscopically discernible damage. These results clearly demonstrate a direct dose dependent toxic effect of RVV on the IPRK, directed primarily against glomerular and vascular structures, and on cultured mesangial cells.

Renal ischaemia, transient glomerular leak and acute renal tubular damage in patients envenomed by Russell's vipers (Daboia russelii siamensis) in Myanmar

Fifty-two patients who had been bitten by Russell's vipers in Myanmar developed acute renal failure (serum creatinine exceeding 1.3 mg/dL). Thirty-four of them (65%) became oliguric, but the other 18 (35%) maintained a urine output of more than 400 mL/24 h. In oliguric patients, gastrointestinal haemorrhages, renal angle tenderness and conjunctival oedema occurred more commonly, and peak serum creatinine, blood urea nitrogen and the fractional excretion of sodium were significantly higher (P < 0.01) than in non-oliguric patients, indicating a greater degree of renal damage. Urinary concentrations of beta 2 microglobulin and retinol binding protein were raised in most of the patients indicating failure of proximal tubular reabsorption of these proteins, while high urinary N-acetyl glucosaminidase concentrations were consistent with renal tubular damage. Plasma concentrations of active renin were very high, suggesting that renal ischaemia, associated with activation of the renin-angiotensin system, was involved in the development of renal dysfunction.