Coagulation abnormalities following brown recluse spider (Loxosceles reclusa) envenomation: A description of 2 cases and review of the literature.

OBJECTIVE

Hemostatic abnormalities, including disseminated intravascular coagulation (DIC), are often cited as a common finding in patients following Loxosceles spider envenomation (ie, loxoscelism). The prevalence and severity of coagulopathy, however, particularly following L reclusa (ie, brown recluse) envenomation, is not well described. This study aimed to characterize coagulation laboratory parameters and coagulopathy in patients following L reclusa envenomation.

METHODS

We evaluated the coagulation laboratory parameters (eg, prothrombin time, partial thromboplastin time, coagulation factor activity levels, lupus anticoagulant [LA] testing) of 2 patients seen at our institution following brown recluse spider envenomation. We also comprehensively reviewed the literature for all reported cases of brown recluse spider envenomation and assessed patient demographics, clinical presentations, coagulation laboratory parameters, and outcomes.

RESULTS

We identified 2 patients with loxoscelism (1 cutaneous only, 1 systemic with hemolysis) with prolonged partial thromboplastin times but with normal clotting factor levels following envenomation. Literature review identified 263 patients: 12 patients had at least 1 prolonged clotting time, 31 reported a platelet count below 150 × 109/L, and there was clinical concern for DIC in 12 cases. The odds of death were statistically significantly higher in patients with clinical concern for DIC than in cases without concern for DIC or coagulopathy (odds ratio, 82.9 [95% CI, 12.6-433.8]; P < .001).

CONCLUSIONS

Following brown recluse spider envenomation, hemostatic perturbations are infrequent and clinical coagulopathy is uncommon, but the odds of death following a brown recluse spider bite are statistically significantly greater if DIC develops, even when compared to individuals with hemolysis without DIC.