Abstract
Snakebite envenomation in pregnancy is rare. We report two cases of vasculotoxic snakebite in pregnancy and discuss the management challenges in pregnancy for successful maternal and perinatal outcomes. The first case was a 19-year-old woman who was eight weeks of gestation in her second pregnancy when she was bitten. She subsequently delivered by caesarean section at 33 weeks and 3 days because she developed eclampsia. The second case was a 24 year old woman in her third pregnancy, who was bitten at 29 weeks of gestation, who delivered vaginally at 36 weeks of gestation. Both were treated with multidisciplinary team approach including antisnake venom and antibiotics, along with fasciotomy for the second case. Both mothers recovered completely, without evidence of attributable fetal or neonatal morbidity. To conclude, antisnake venom, if indicated, and a multidisciplinary team approach plays an important role for successful maternal and perinatal outcomes in snakebite envenomation in pregnancy.
Introduction
Snakebite envenomation in pregnancy is rare, constituting 0.4–1.0% of all snakebite envenomation cases, which is estimated at 600,000–1,600,000 cases annually in India.1–3 We report two cases of vasculotoxic snakebite in pregnancy with successful outcome, and discuss the management challenges in pregnancy.
Case 1
A 19-year-old, with a history of one spontaneous miscarriage, presented with a history of snakebite at eight weeks of gestation. She arrived at the hospital two hours after the bite and also reported abdominal pain and vomiting. She had no significant past medical history or family history. On examination, she was conscious, oriented and afebrile with stable observations. Her abdomen was soft and there was no vaginal bleeding. A bite mark was present on the dorsum of left foot, with a 5 × 5 cm blister above it and there was swelling and tenderness of the left lower limb extending to above the ankle joint (Figure 1(a)). Her haemoglobin was 10.4 g/l, total leucocyte count 13.6 × 109/l, liver and kidney function tests, platelet count and international normalized ratio (INR) were within normal limits. Ultrasonography revealed a single live intrauterine pregnancy, the size of which was consistent with a gestational age of eight weeks. The 20 min whole blood clotting test (WBCT) revealed non-coagulable blood. A diagnosis of vasculotoxic snakebite was made. She received 15 vials of polyvalent antisnake venom (ASV) along with antibiotics and the 20 min WBCT was monitored until the blood became coagulable. She was discharged on day 10 and advised to present for regular follow-up. Her first and second trimester anomaly scans were normal. She was diagnosed with mild preeclampsia at 28 weeks and was not on any antihypertensive medications. At 33 + 5 weeks, she was referred because she developed eclampsia. She delivered a healthy female baby weighing 1760 g by caesarean section. The snakebite wound on the maternal left foot had healed completely (Figure 1(b)). The infant was admitted to the neonatal intensive care unit for 10 days in view of prematurity. The child is now two years old and is developmentally normal.
(a) Dorsum of left foot showing a 5 × 5 cm blister (thick arrow) above the bite mark (thin arrow) and presence of cellulitis in the left lower limb. (b) Healed snakebite wound on the dorsum of left foot at 33 5/7 weeks. (c) Fasciotomy of the snakebite wound in view of large blister with cellulitis.
Case 2
A 24-year-old woman in her third pregnancy presented with a history of snakebite at 29 weeks of gestation. This had occurred four hours previously, and was accompanied by swelling and pain of the left lower limb. She previously had two uncomplicated pregnancies (both vaginal deliveries at term) and her youngest child is now four years old. Her past and family history was unremarkable. On examination, she was conscious, oriented and afebrile with stable observations. Symphysiofundal height corresponded to 28 weeks of gestation, the uterus was relaxed and fetal heart rate was normal. There was no vaginal bleeding. A large 10 × 6 cm blister on the dorsum of left foot was present, along with swelling of her left lower limb. Her haemoglobin was 12.2 g/l, total leucocyte count 11.6 × 109/l, with normal liver function, kidney function, platelet count and INR. Ultrasonography revealed a single live intrauterine fetus with fetal growth restriction, with estimated fetal weight below the fifth centile and no evidence of retroplacental haematoma. A diagnosis of vasculotoxic snakebite was made on the basis of non-coagulable blood on the 20 min WBCT. Fasciotomy was performed prophylactically, given the severity of skin changes (Figure 1(c)). She received 15 vials of ASV, along with antibiotics and was discharged on day 11. She was followed up every two weeks, and went into spontaneous preterm labour at 36 weeks, delivering a healthy female baby weighing 2080 g.
Discussion
Snakebite envenomation in pregnancy is rare, accounting for 0.4–1.0% of all snakebite envenomations, which is estimated at 600,000–1,600,000 cases annually in India.1–3 This may be under-reported too. Due to the rarity of this condition, the treating obstetricians may not be familiar with the diagnostic and management protocols in pregnancy. In fact, none of the major obstetric and gynaecological societies of the world offer treatment guidelines of snakebite envenomation in pregnancy. The management guidelines from the World Health Organization and the Indian guidelines are commonly used for treatment. 4 , 5 The venom exerts its effects through enzymatic action, which results in endothelial cell damage, increased vascular permeability and consumptive coagulopathy. 5 ASV neutralizes unbound, free flowing venom in the bloodstream or tissue fluid. The common complications encountered are systemic haemorrhage, disseminated intravascular coagulation, hypotension, shock, acute kidney injury, myotoxicity, neurotoxicity and local envenomation. 4 , 5 The snake venom has been known to cross the placenta. 2
The four most common snakes responsible for majority of snakebite envenomations in India are the Cobra (Naja naja), common Krait (Bungarus caeruleus), Russell’s Viper (Dabiola russelii) and saw-scaled Viper (Echis carinatus). 6 In our case, the vasculotoxic effects were most likely due to Russell’s viper envenomation, given the verbal description by the women, corroborated by the signs and symptoms and the findings of the 20 min WBCT. 5 The management of snakebite envenomation in pregnancy is essentially the same as that in non-pregnant individuals. 5 ASV plays a crucial role, and should be given to any snakebite victim with progressive signs and symptoms, including pregnant women. 5 The average amount of venom injected during a viper bite is 63 mg. 4 Each 10 ml vial of polyvalent ASV neutralizes 6 mg of the venom. 4 Hence, an initial dose of 10 vials or 100 ml of ASV is usually administered, with further doses added based on the clinical response. Haemostatic disturbances respond dramatically to ASV therapy. Spontaneous systemic bleeding usually stops within 15–30 min and blood coagulation profile is restored within six hours. 6 However, the use of ASV carries with it the risk of anaphylaxis, serum sickness and hypersensitivity reactions. 4 Hence, all women administered ASV should be monitored for 24 h after the administration of the last dose. Supportive management with antibiotics is indicated when there is significant local reaction due to the high risk of secondary infection from the micro-organisms present in the oral cavity of the snake. In pregnancy, care should be taken to administer only those antibiotics which are known to be appropriate to use in pregnancy. Amoxicillin and clindamycin were used in both the cases described here. Viper envenomation is marked by local tissue necrosis which takes months to heal, like in case 1. Dead tissue should be surgically debrided. Fasciotomy is reserved for compartment syndrome, which is common with Russell’s viper (D. russelii) envenomation. Blood and blood products are used only in cases of severe bleeding.
A maternal mortality rate of 10% and a fetal mortality rate of 43% has been reported with snakebite envenomation in pregnancy. 1 , 7 Maternal complications have been reported as antepartum haemorrhage, placental abruption, preterm labour, postpartum haemorrhage, disseminated intravascular coagulation, hypotension, hypovolemic shock, anaemia, acute kidney injury and posterior reversible encephalopathy syndrome.7–10 Reported fetal complications include miscarriage, fetal distress, intrauterine death, prematurity, hydrocephalus and polydactyly.7–11 Given the dearth of literature and lack of specific obstetric guidelines, the follow-up plan of antenatal care should be individualized. Our first case is unique as the time period from snakebite envenomation (eight weeks) to delivery (33 weeks and 5 days) is probably the longest reported in literature.
Future studies should focus on the long-term neuro-developmental issues in the surviving babies. Pregnancy-specific guidelines will help in improving the management of these cases. Establishment of an international registry of pregnant women with snakebite will also help provide more data.
To conclude, Russell’s viper (D. russelii) envenomation in pregnancy is rare. ASV plays an important role in management, along with surgical debridement and fasciotomy of the local site, if indicated. A multidisciplinary team approach, including an obstetrician, physician, general surgeon, toxicologist and neonatologist, is important for optimizing maternal and perinatal outcomes.
Footnotes
Contributorship
Sweta Singh and Rashmi R Mohanty managed the cases, researched literature and conceived the study. Sweta Singh wrote the first draft of the manuscript. Both authors reviewed and edited the manuscript and approved the final version of the manuscript.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Guarantor
Sweta Singh
Informed consent
Written consent was obtained from the patient(s) for their anonymized information to be published in this article.
