“<i>Bad things come in small packages</i>”: predicting venom-induced coagulopathy in <i>Bothrops atrox</i> bites using snake ontogenetic parameters

The management of snakebite (SB) envenoming in French Guiana (FG) is based on symptomatic measures and antivenom (AV) administration (Antivipmyn Tri®; Instituto Bioclon—Mexico). Our study aimed to assess clinical manifestations, the efficacy, and safety of Antivipmyn Tri® in the management of SB. Our study is a prospective observational work. It was conducted in the Intensive Care Unit (ICU) of Cayenne General Hospital between January 1st, 2016 and December 31, 2019. We included all patients hospitalized for SB envenoming. Our study contained three groups (without AV, three vials, and six vials Antivipmyn Tri®). During the study period, 133 patients were included. The main clinical symptoms were edema (98.5%), pain (97.7%), systemic hemorrhage (18%), blister (14.3%), and local hemorrhage (14.3%). AV was prescribed for 83 patients (62.3%), and 17 of them (20%) developed early adverse reactions. Biological parameters at admission showed defibrinogenation in 124 cases (93.2%), International Normalized Ratio (INR) > 2 in 104 cases (78.2%), and partial thromboplastin time (PTT) > 1.5 in 74 cases (55.6%). The time from SB to AV was 9:00 (5:22–20:40). The median time from SB to achieve a normal dosage of fibrinogen was 47:00 vs. 25:30, that of Factor II was 24:55 vs. 15:10, that of Factor V was 31:42 vs. 19:42, and that of Factor VIII was 21:30 vs. 10:20 in patients without and with AV, respectively, (p < 0.001 for all factors). Patients receiving Antivipmyn Tri® showed a reduction in the time to return to normal clotting tests, as compared to those who did not. We suggest assessing other antivenoms available in the region to compare their efficacy and safety with Antivipmyn Tri® in FG.

Section: Discussionmentioning

confidence: 99%

Clinical Features and Management of Snakebite Envenoming in French Guiana

Résière

Houcke

Pujo

et al. 2020

“…In South America, an important aspect of Bothrops envenomings is that bites by juvenile snakes can cause no local or very mild local manifestations, which can be misdiagnosed as dry bites. However, these cases require a careful examination of the patient’s coagulation parameters, considering the predominance of coagulotoxins in the venom of these immature specimens, which may cause systemic bleeding [ 102 , 103 ]. Figure 2 shows the characteristics of a patient presenting mild, local manifestations and two true dry bites by snakes from the Bothrops genus.…”

Section: Diagnosis Of Snake Dry Bitesmentioning

confidence: 99%

Current Knowledge on Snake Dry Bites

Pucca

Knudsen

Oliveira

et al. 2020

Self Cite

Snake ‘dry bites’ are characterized by the absence of venom being injected into the victim during a snakebite incident. The dry bite mechanism and diagnosis are quite complex, and the lack of envenoming symptoms in these cases may be misinterpreted as a miraculous treatment or as proof that the bite from the perpetrating snake species is rather harmless. The circumstances of dry bites and their clinical diagnosis are not well-explored in the literature, which may lead to ambiguity amongst treating personnel about whether antivenom is indicated or not. Here, the epidemiology and recorded history of dry bites are reviewed, and the clinical knowledge on the dry bite phenomenon is presented and discussed. Finally, this review proposes a diagnostic and therapeutic protocol to assist medical care after snake dry bites, aiming to improve patient outcomes.

“…Differences have been observed in the coagulant activity of venom from B. atrox snakes from distinct locations [21,22], habitats [23], and at different ontogenetic stages [24,25], as well as when compared to the venom of other Bothrops species [26]. There is little information regarding how clotting factors and other components are affected in Bothrops snakebite patients in the Amazon who evolve to systemic or local bleeding.…”

Section: Introductionmentioning

confidence: 99%

Bleeding Disorders in Bothrops atrox Envenomations in the Brazilian Amazon: Participation of Hemostatic Factors and the Impact of Tissue Factor

Oliveira

Alves

Santos

et al. 2020

Bleeding is a common hemostatic disorder that occurs in Bothrops envenomations. We evaluated the changes in coagulation, fibrinolysis components, and platelets in Bothrops atrox envenomations with bleeding. This is an observational study with B. atrox snakebite patients (n = 100) treated in Manaus, Brazilian Amazon. Bleeding was recorded on admission and during hospitalization. We found that the platelet count in our patients presented a weak correlation to tissue factor, factor II, and plasminogen. Tissue factor presented weak correlation to factor V, II, D-dimer, plasminogen, alpha 2-antiplasmin, and moderate correlation to fibrinogen and fibrin/fibrinogen degradation product (FDP). Patients with systemic bleeding (n = 20) presented low levels of factor V, II, fibrinogen, plasminogen, and alpha 2-antiplasmin, and high levels of tissue factor and FDP compared to those without bleeding. Patients with only local bleeding (n = 41) and without bleeding showed similar levels of hemostatic factors. Thrombocytopenia was observed mainly in patients with systemic bleeding and increased levels of serum venom. No association was found between venom levels and systemic bleeding, or between venom levels and clinical severity of envenomation. This is the first report that shows the participation of the extrinsic coagulation pathway in the consumption coagulopathy of B. atrox envenomations with systemic bleeding due to tissue factor release.