Snake venom coagulopathy: use and abuse of blood products in the treatment of pit viper envenomation

An antivenin resistant, IVIg-corticosteroids responsive Viper Induced Thrombocytopenia

In this case report the hospital management of an acute, severe thrombocytopenia in a 57-year-old man in the north-east of Italy is reported. Thrombocytopenia developed immediately after the viper bite, despite the absence of clinical signs of envenomation. No hemorrhage, ecchymoses or other signs of coagulopathy developed during the hospitalization; two doses of antivenin FAB–Fragments had no effect on thrombocytopenia, which instead responded promptly to intravenous immunoglobulins (IVIg) and glucocorticoids. Direct and indirect anti-platelet antibodies against anti-GP IIb/IIIa and Ia/IIa were detected during the treatment and turned negative after 20 weeks. The rationale of such off-label treatment is the interpretation of the thrombocytopenia as a venom-induced immune thrombocytopenia which led to splenic sequestration of platelets. To our knowledge, there is no literature about venom-induced immune thrombocytopenia against GP IIb/IIIa and Ia/IIa protein in European countries and subsequent response to IVIg and corticosteroids.

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Thrombocytopenia is a known effect of viper envenomation.

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Antivenin FAB–Fragments may be ineffective for thrombocytopenia.

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Venom induced immune thrombocytopenia against GP IIb/IIIa and Ia/IIa.

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A treatment based on IVIg and corticosteroids led to a prompt recovery of a severe antivenin-resistant Venom induced thrombocytopenia.

Retrospective Analysis of the Demographic and Clinical Features of Snake Bites Followed in the Intensive Care Unit

Objective Cases of poisoning due to snake bite are a medical condition that requires an emergency treatment approach, which creates serious health problems that can be seen in our country and all over the world. In the Eastern Anatolia Region, poisoning cases due to the bites of viper snakes, especially from the Viperidae family, are frequently seen. The aim of this study is to examine the bite sites, clinical stages, antivenom needs and doses, changes in blood biochemistry, prognostic characteristics of patients treated in our intensive care unit for snake bites in our region, and to present our regional experience with snake bites. Material and Methods Our study included 44 patients who were treated in the intensive care clinic with the complaint of snake bite between August 1, 2018 and August 1, 2021. Symptoms, bite sites, clinical stages, need and doses of antivenom, length of hospital stay, changes in blood biochemistry and mortality of these patients who were exposed to snake bites were retrospectively investigated. Results A total of 44 patients, 13 female (29.55%) and 31 male (70.45%), aged between 18-72 years, who were followed up due to snake bites, were included in the study. In our study, 1 (2.27%) patients in Stage 0, 18 (40.90%) in Stage 1, 21 (47.7%) in Stage 2 and 4 (9.09%) patients in Stage 3 it was found that he was followed up due to snake bite. While total antivenom (4.33±2.18) vials were given to 10 intoxication cases with stage (0-1), vials of total antivenom were given to 25 (7.65±3.03) intoxication cases with stage (2-3). Conclusion We believe that in addition to antivenom treatment in sufficient doses and in an early time, the first correct intervention to snake bite can prevent problems that may develop after poisoning.

Benefits of using heterologous polyclonal antibodies and potential applications to new and undertreated infectious pathogens

BACKGROUND

Passive immunotherapy using polyclonal antibodies (immunoglobulins) has been used for over a century in the treatment and post-exposure prophylaxis of various infections and toxins. Heterologous polyclonal antibodies are obtained from animals hyperimmunised with a pathogen or toxin.

AIMS

The aims of this review are to examine the history of animal polyclonal antibody therapy use, their development into safe and effective products and the potential application to humans for emerging and neglected infectious diseases.

METHODS

A literature search of OVID Medline and OVID Embase databases was undertaken to identify articles on the safety, efficacy and ongoing development of polyclonal antibodies. The search contained database-specific MeSH and EMTREE terms in combination with pertinent text-words: polyclonal antibodies and rare/neglected diseases, antivenins, immunoglobulins, serum sickness, anaphylaxis, drug safety, post marketing surveillance, rabies, human influenza, Dengue, West Nile, Nipah, Hendra, Marburg, MERS, Hemorrhagic Fever Virus, and Crimean-Congo. No language limits were applied. The final search was completed on 20.06.2015. Of 1960 articles, title searches excluded many irrelevant articles, yielding 303 articles read in full. Of these, 179 are referenced in this study.

RESULTS

Serum therapy was first used in the 1890s against diphtheria. Early preparation techniques yielded products contaminated with reactogenic animal proteins. The introduction of enzymatic digestion, and purification techniques substantially improved their safety profile. The removal of the Fc fragment of antibodies further reduces hypersensitivity reactions. Clinical studies have demonstrated the efficacy of polyclonal antibodies against various infections, toxins and venoms. Products are being developed against infections for which prophylactic and therapeutic options are currently limited, such as avian influenza, Ebola and other zoonotic viruses.

CONCLUSIONS

Polyclonal antibodies have been successfully applied to rabies, envenomation and intoxication. Polyclonal production provides an exciting opportunity to revolutionise the prognosis of both longstanding neglected tropical diseases as well as emerging infectious threats to humans.

Crotaline Fab antivenom for the treatment of children with rattlesnake envenomation

OBJECTIVE

There is little data regarding safety or efficacy of Crotalinae polyvalent immune Fab (ovine) antivenom (crotaline Fab) in pediatric patients. Our objective was to provide the first information regarding safety and effectiveness of this new drug in children.

METHODS

Data were collected prospectively and retrospectively for all consecutive pediatric patients bitten by rattlesnakes and treated at 2 urban hospitals during 2001. Cases were included if there were signs of envenomation at presentation, patient age was 13 years or less, and there was administration of crotaline Fab. Cases were excluded if antivenin (Crotalidae) polyvalent (equine origin, the conventional antivenom) was given. Primary outcome variables were snakebite severity scores throughout the course of therapy, number of vials of crotaline Fab administered, occurrence of allergic reactions, adjunct surgical therapy, and the presence of permanent sequelae or serum sickness identified at follow-up.

RESULTS

In the 12 cases studied, ages ranged from 14 months to 13 years (mean: 6.9; standard deviation: 4.2). Presentation snakebite severity scores ranged from 2 to 9 (mean: 5.3; standard deviation: 2.3). Total crotaline Fab doses ranged from 4 to 22 vials (mean: 12.7; standard deviation: 5.4). Initial control of symptoms was achieved with 4 to 16 vials (mean: 7.7; standard deviation: 3.7), and severity scores stabilized or improved within 24 hours in all patients. Recurrence of local swelling occurred in 1 case despite scheduled repeat doses of antivenom. No cases required surgical intervention, and no permanent sequelae were identified. No immediate or delayed hypersensitivity reactions occurred.

CONCLUSION

In this group of pediatric patients treated for rattlesnake envenomation, crotaline Fab antivenom was safe and seemed to be effective.

Epidemiology and hospital course of rattlesnake envenomations cared for at a tertiary referral center in Central Arizona

OBJECTIVE

To describe the demographics and primary inpatient treatment of victims of rattle-snake bites (RSBs) referred to a teritiary referral poison treatment center in central Arizona, and to compare the frequency of local tissue complications and hematologic toxicity during hospitalization in children with those for adults.

METHODS

This was a chart review of patients diagnosed as having RSB by a toxicology service between July 1994 and April 2000. Data collected included: age, sex, date, bite location, time to and length of hospitalization, time to and amount of antivenin, serial hematologic studies, and inpatient complications.

RESULTS

Of 241 patients admitted, 236 charts met inclusion criteria. The majority of RSB victims were male (81%). Children (< or =13 years) represented 22%. Most RSBs (78%) occurred between April and September. Mean time (+/-SEM) to presentation was 1.7 +/- 0.2 hours. Antivenin was administered to 77% of patients, with an average (+/-SEM) of 28.5 +/- 0.9 vials administered. Hematologic abnormalities included: coagulopathy (60%), hypofibrinogenemia (49%), and thrombocytopenia (33%). No statistically significant difference in the above parameters was detected between upper- and lower-extremity envenomations, or between children and adults. Immediate antivenin reactions occurred in 36% of patients. Hemorrhagic bullae formation occurred in 22%, occurring most frequently in upper extremities. Operative procedures were required in 3.4% of patients. Hospitalization averaged 2.5 +/- 0.1 days. There was no fatality.

CONCLUSIONS

In Arizona, RSB victims were typically adult males with upper-extremity bites. Hematologic abnormalities were common. Local tissue complications were more common with upper-extremity envenomations. No statistically significant difference was detected in frequency of hematologic disorders or local tissue complications when children were compared with adults.

Rattlesnake venom-induced thrombocytopenia response to Antivenin (Crotalidae) Polyvalent: a case series

OBJECTIVE

To test the hypothesis that rattlesnake venom-induced thrombocytopenia would improve following Antivenin (Crotalidae) Polyvalent administration, and that the degree of platelet increase would correlate with the dosage of antivenom.

METHODS

The authors conducted a retrospective review of all patients admitted for rattlesnake envenomation at two southern California hospitals between 1980 and 1998. Patients were included if platelet count was less than 150 x 10(9)/L following a rattlesnake bite. Patients were excluded if they received platelet transfusion. The relationship between Antivenin (Crotalidae) Polyvalent administration and venom-induced thrombocytopenia was evaluated by linear regression and paired t-test.

RESULTS

The authors identified 103 cases of rattlesnake envenomation. Seventeen cases met inclusion criteria for thrombocytopenia. Two patients were excluded because they received platelet transfusions. One additional patient was excluded from paired t-test only because no antivenom was given. Thrombocytopenia usually improved between presentation and discharge (mean difference, 44 x 10(9)/L), although complete resolution was often not achieved. A statistically significant partial improvement in platelet counts immediately after antivenom administration was observed in a subset of patients with severe thrombocytopenia (platelet count <100 x 10(9)/L) (mean difference, 64 x 10(9)/L). Using regression analysis, the authors did not detect a linear relationship between the amount of Antivenin (Crotalidae) Polyvalent administered and the degree of improvement.

CONCLUSIONS

Although rattlesnake venom-induced thrombocytopenia usually improves immediately after Antivenin (Crotalidae) Polyvalent administration and by the time of discharge, the degree of improvement is frequently incomplete and of uncertain clinical significance in the absence of life-threatening bleeding. The authors found no correlation between the degree of improvement and the dosage of Antivenin (Crotalidae) Polyvalent.

Antivenom therapy in the Americas

Envenomations are an important cause of injury in the Americas. While supportive care alone may result in an acceptable outcome, antivenom offers a specific therapy that can significantly reduce the injury and symptoms of the envenomation. Antivenoms are hyperimmune sera collected from animals immunised with venom. The antibodies contained in the serum bind and inactive venom components. This leads to cessation or reversal of the toxic effects of the venom. The serum is often processed to increase the level of antibodies directed against venom components and decrease the amount of inactive proteins that may cause allergic reactions. The processing may include precipitation of inactive proteins, chromatographic methods and cleavage of the immunoglobulins to form antibody fragments known as Fab or F(ab)2. In the Americas, antivenoms are produced to treat crotalid and Micrurus snake envenomations. Latrodectus and Loxosceles spider envenomations and Centruroides and Tityus scorpion envenomations. The indications, method of administration and incidence of adverse reactions differ greatly for each antivenom. The adverse effects encountered when using antivenoms are primarily allergic in nature. Anaphylaxis, which may be life threatening, is a major concern. Preparations to treat anaphylaxis must be made before initiating antivenom therapy. Serum sickness is also common with many of the antivenom preparations.

Envenomations

Envenomations are uncommon, challenging causes of critical care admissions. This article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the United States. Most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.

Intravascular hemolysis associated with North American crotalid envenomation

CASE REPORT

This is a case of severe intravascular hemolysis, without significant coagulopathy, following envenomation by a North American crotalid. A MEDLINE search from 1966-1997, and a review of older literature, revealed no similar cases. A 4-year-old girl was envenomated in her right foot by a 2.5 foot-long rattlesnake whose description matched that of the Hopi rattlesnake (Crotalus viridis nuntius). The snake was not captured. Her initial hematocrit was 45%. In spite of treatment with antivenin and improvement in her lower extremity pain and swelling, her hematocrit decreased to 20.4%. Laboratory tests and clinical exam showed a Coombs positive hemolytic anemia without significant signs of coagulopathy.

Thrombocytopenia following timber rattlesnake envenomation

STUDY OBJECTIVE

To better characterize timer rattlesnake venom--induced thrombocytopenia and coagulopathy and the response to therapy with Antivenin (Crotalidae) Polyvalent.

METHODS

We conducted a retrospective multicenter review of timber rattlesnake envenomation.

RESULTS

We reviewed 18 cases at two institutions. Restoration of normal prothrombin time and partial thromboplastin time was achieved in all cases with antivenom therapy. In contrast, complete reversal of thrombocytopenia was not achieved, despite antivenom therapy.

CONCLUSION

Antivenom (Crotalidae) Polyvalent was less effective in reversing thrombocytopenia than coagulopathy after timber rattlesnake envenomation, suggesting that a component of timber rattlesnake venom persists in the blood despite antivenom therapy. Persistent thrombocytopenia may be due to a venom factor that the antivenom does not neutralize or to inadequate dosing of antivenom. Prompt reversal of thrombocytopenia following treatment of timber rattlesnake envenomation with this antivenom appears unlikely.