Characterization of hypofibrinogenemia following rattlesnake envenomation treated with crotalidae immune F(ab')2 (equine) antivenom.

INTRODUCTION: Hemotoxicity is common following rattlesnake envenomation. Published experiences with equine-derived crotalidae immune F(ab')2 antivenom have characterized hemotoxicity as delayed, recurrent, or persistent. This study investigated recovery of hypofibrinogenemia following rattlesnake envenomation treated with equine-derived crotalidae immune F(ab')2 antivenom. METHODS: This is a retrospective analysis of human rattlesnake envenomations reported to the Arizona Poison and Drug Information Center over four years. We included rattlesnake-envenomated patients who developed hypofibrinogenemia (<1,500 mg/L) and were treated with equine-derived crotalidae immune F(ab')2 antivenom. The primary outcomes were recovery period (h) and recovery rate (mg/L/h) of hypofibrinogenemia following equine-derived crotalidae immune F(ab')2 antivenom administration. Collected data included demographics, laboratory values, and antivenom administered. Statistics used were percentages, medians, and Kruskall-Wallis test. RESULTS: There were 527 rattlesnake envenomations treated with antivenom, of which 80 met the inclusion criteria. Patients receiving treatment with F(ab')2 antivenom and had a median fibrinogen concentration recovery rate of 62.3 mg/L/h (IQR: 42.0-74.3 mg/L/h) and median recovery period of 19.2 h (IQR: 13.8-26.2 h). There were statistically significant differences between categories for time to antivenom for the median recovery period (P = 0.0154). DISCUSSION: Hypofibrinogenemia is a common laboratory finding following rattlesnake envenomation in Arizona. This study investigated rattlesnake envenomated patients treated with F(ab')2 antivenom and monitored fibrinogen concentrations as a surrogate marker of venom toxicity. Additionally, time to administration of F(ab')2 antivenom was a statistical significant marker of the recovery period from hypofibrinogenemia. Limitations of this study included the geographic coverage of the poison center and exclusion of patients with insufficient laboratory monitoring or those who received another antivenom. CONCLUSIONS: Following rattlesnake envenomation in Arizona, recovery from hypofibrinogenemia was able characterized in a rate (mg/L/h) and period (h) with the quantity and time to administration of antivenom. More studies are needed to assess this finding with other antivenoms and its clinical significance.

Snake eyes: Characterization of topical ocular exposures from rattlesnakes in Arizona.

Patients occasionally present with reports of ocular exposure to fluids from rattlesnakes, claiming or suspecting the substance to be venom. This study set out to evaluate and characterize reported cases of suspected venom-induced ophthalmia in humans. A retrospective review of rattlesnake exposures reported to the Arizona Poison and Drug Information Center over a 24-year period was conducted for ocular exposures. Recorded information included patient demographics, clinical course, laboratory results, and treatments. Documentation regarding interactions between patients and snakes was reviewed by Arizona Poison and Drug Information Center herpetologists to evaluate what substance was expelled from the snake resulting in ocular exposure. Our review of rattlesnake encounters found a total of 26 ocular exposure cases. Patient demographics were largely intentional interactions and involved the male sex. Symptoms ranged from asymptomatic to minor effects with 46.2% managed from home and treated with fluid irrigation. A review of cases by herpetologists concluded the exposure patients commonly experienced was to snake musk. Kinematics of venom expulsion by rattlesnakes conclude the venom gland must be compressed, fangs erected to ≥60o, and fang sheath compressed against the roof of the mouth for venom expulsion. Evidence suggests the chance of venom "spitting" by rattlesnakes is close to zero. Rattlesnakes are documented to forcefully expel airborne malodorous "musk" defensively. An important distinction to remember is musk has a foul odor and is usually colorless, while venom is comparatively odorless and yellow. Rattlesnake venom-induced ophthalmia is a rare event as venom expulsion requires the kinematics of feeding or defensive bites. If the rattlesnake is not in the process of biting or otherwise contacting some other object with its mouth, it is more biologically plausible patients are being exposed to snake musk as a deterrent. Whether it's venom or musk, topical exposure to the eyes should prompt immediate irrigation.

Pediatric Medical Countermeasures: Antidotes and Cytokines for Radiological and Nuclear Incidents and Terrorism.

The war in Ukraine raises concerns for potential hazards of radiological and nuclear incidents. Children are particularly vulnerable in these incidents and may need pharmaceutical countermeasures, including antidotes and cytokines. Searches found no published study comparing pediatric indications and dosing among standard references detailing pediatric medications for these incidents. This study addresses this gap by collecting, tabulating, and disseminating this information to healthcare professionals caring for children. Expert consensus chose the following references to compare their pediatric indications and dosing of medical countermeasures for radiation exposure and internal contamination with radioactive materials: Advanced Hazmat Life Support (AHLS) for Radiological Incidents and Terrorism, DailyMed, Internal Contamination Clinical Reference, Medical Aspects of Radiation Incidents, and Medical Management of Radiological Casualties, as well as Micromedex, POISINDEX, and Radiation Emergency Medical Management (REMM). This is the first study comparing pediatric indications and dosing for medical countermeasures among commonly used references for radiological and nuclear incidents.