Severe local and systemic haematotoxic envenoming caused by a Malayan pit viper (Calloselasma rhodostoma) in a pregnant woman in Lao People's Democratic Republic.

Abstract

Snakebite envenoming in pregnant women is rare, accounting for approximately 0.5-1.8% of all snakebite cases. A thirty-year-old six months pregnant woman was admitted to Setthatirath Hospital in Vientiane Capital, Lao People's Democratic Republic two hours after a Malayan pit viper bite at her right lower leg. She developed extensive local swelling affecting the entire right leg and a severe coagulation disorder with clinical signs of bleeding, requiring ten blood transfusions. Due to antivenom shortage only one vial of Hemato Polyvalent snake antivenom produced at Queen Saovabha Memorial Institute (QSMI) in Bangkok, Thailand was given shortly after admission although the recommended initial dose in case of Malayan pit viper envenoming is at least three vials. The patient received ten units of fresh frozen plasma and six platelet transfusion without effect on the unmeasurable prothrombin time or the platelet count of less than 20,000/μl. On day nine, two additional vials of monovalent Malayan pit viper antivenom produced at QSMI were given which eventually normalized the coagulation disorder. There was no vaginal bleeding and repeated ultrasound examinations showed a single live intrauterine pregnancy with a foetal size consistent to a gestational age of 26 weeks. A healthy baby was born three months after the snakebite but the mother retained a permanent nervus peroneus paresis on her right lower leg.