HELLP syndrome: pathogenesis and clinical management

The HELLP syndrome is a serious complication of pregnancy characterized by haemolysis, elevated liver enzymes and low platelet count. In the past it was thought to be related to severe preeclampsia, nowadays it is believed to be a separate disease. Its pathogenesis remains to be elucidated - the importance of genetic and immunological origins is highlighted. This review presents pathogenesis, diagnosis and management in patients with the HELLP syndrome. About 70% of the cases develop before delivery, the majority between the 24(th) and 37(th) gestational weeks; the remainder (rest) within 48 hours after delivery. The HELLP syndrome may be complete or incomplete. In the Tennessee Classification System, diagnostic criteria for HELLP are haemolysis with increased LDH (> 600 U/L), AST (>= 70 U/L), and platelets < 100 000/mm(3). The Mississippi Triple-class HELLP System further classifies the disorder by the nadir platelet counts. The syndrome is a progressive condition and serious complications are frequent. Delivery is indicated if the HELLP syndrome occurs after the 34(th) gestational week or the foetal and/or maternal conditions (status) deteriorate. Conservative treatment (>= 48 hours) is controversial but may be considered in selected cases before 34 weeks' gestation. Most authors prefer a single course of corticosteroid therapy for RDS prophylaxis between 24(th) and 34(th) week of pregnancy. Standard corticosteroid treatment is still of uncertain clinical value in the management of the maternal HELLP syndrome, but justified in some cases, mainly with severe thrombocytopenia. Blood pressure should be kept below 155/105 mm Hg as well as the therapy with MgSO4 should be offered to all patients with the HELLP syndrome.