Purpose: To describe the anesthetic and peripartum management of a parturient with paroxysmal nocturnal hemoglobinuria complicated by severe preeclampsia, review the pathophysiology of this condition, rationale for thromboembolic prophylaxis, and its implications on the choice of labour analgesia and anesthesia.
Clinical features: A 35-yr-old primigravida was diagnosed with paroxysmal nocturnal hemoglobinuria at 18 weeks gestation following new onset pancytopenia. Venous thromboembolic prophylaxis with low molecular weight heparin (LMWH) was started, and continued despite a persistent thrombocytopenia. At 34 weeks, labour was induced after she developed signs of severe preeclampsia, and intravenous magnesium sulfate therapy was commenced. The use of a twice daily dosing regime of LMWH, along with severe thrombocytopenia contraindicated neuraxial anesthesia. As a result, labour analgesia was provided with an intravenous patient-controlled analgesia system with fentanyl. The patient subsequently had an uneventful Cesarean delivery under general anesthesia. Anticoagulation with LMWH was restarted postoperatively, and continued for six weeks postpartum. She was discharged home on day 20 postpartum, on oral prednisolone under the care of the hematologists.
Conclusion: Paroxysmal nocturnal hemoglobinuria is associated with an increased risk of venous thromboembolism, and so anticoagulation therapy assumes primary importance. The use of LMWH for prophylaxis in combination with thrombocytopenia may contraindicate neuraxial anesthesia. General anesthesia should be aimed at preventing or exacerbating complement mediated intravascular hemolysis.