title: Rebound coagulopathy in patients with snakebite presenting with marked initial coagulopathy.
abstract: OBJECTIVE
  An estimated 70% of patients with pit viper snakebites require antivenom to treat serious complications such as coagulopathy. Evidence-based guidance is limited for the appropriate administration of Crotalinae Polyvalent Immune Fab (FabAV) and the duration of laboratory follow-up. The objective of our study was to assess the incidence of marked and recurrent envenomation coagulopathy at our trauma center and identify practice patterns that may prevent serious complications.
  
  
  METHODS
  A retrospective case review was conducted over a 3-year period on patients treated for symptomatic snakebite injury. Case records were reviewed for the inclusion criteria of international normalized ratio (INR) greater than 2.0. The exclusion criterion was limited to patients receiving anticoagulant therapy.
  
  
  RESULTS
  In all, 61 patients were identified on retrospective chart review and 3 patients (4.9%) met inclusion criteria. Two of the 3 patients had marked rebound coagulopathy requiring readmission and additional treatment. In our small series, 2 patients presenting after crotaline envenomation with increased INR (>6.0), decreased fibrinogen (<60 mg/dL), and decreased platelet count (<100,000/mL) had recurrent coagulopathy and were asymptomatic, and recurrence was noted only with follow-up laboratory testing. All patients responded positively within a matter of hours to repeat FabAV administration, with resolution of rebound coagulopathy.
  
  
  CONCLUSIONS
  We recommend periodic monitoring of patients with increased INR, decreased fibrinogen, and decreased platelet count. Patients should be monitored for 10 to 14 days after envenomation to identify asymptomatic rebound coagulopathy. Prompt readministration of FabAV appears to correct the coagulopathy.
authors.affiliation: Trauma Department, Texas Health Harris Methodist Hospital Fort Worth (Dr Witham and Ms McNeill), Fort Worth, TX. Electronic address: withamwr@sbcglobal.net.
authors.forename: Willam R
authors.initials: WR
authors.lastname: Witham
authors.affiliation: Trauma Department, Texas Health Harris Methodist Hospital Fort Worth (Dr Witham and Ms McNeill), Fort Worth, TX.
authors.forename: Cathy
authors.initials: C
authors.lastname: McNeill
authors.affiliation: Clinical Research Master's Program, University of North Texas Health Science Center (Mr Patel), Fort Worth, TX.
authors.forename: Sunny
authors.initials: S
authors.lastname: Patel
mesh_terms: D000368:Aged; D000818:Animals; D000997:Antivenins / Q000627:therapeutic use*; D001778:Blood Coagulation Disorders / Q000209:etiology* / Q000473:pathology; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000627:therapeutic use*; D019934:International Normalized Ratio; D008875:Middle Aged; D010976:Platelet Count; D012189:Retrospective Studies; D012909:Snake Bites / Q000150:complications* / Q000188:drug therapy*
chemical_list: D000997:Antivenins; C431183:Crotalidae Polyvalent immune Fab; D007140:Immunoglobulin Fab Fragments; D005340:Fibrinogen
keywords: Crotalinae; FabAV; coagulopathy; envenomation; hypersensitivity