HELLP syndrome

INTRODUCTION

HELLP syndrome refers to a syndrome characterized by hemolysis with a microangiopathic blood smear, elevated liver enzymes, and a low platelet count [1]. The syndrome probably represents a severe form of preeclampsia (table 1 and table 2), but this relationship remains controversial. As many as 15 to 20 percent of affected patients do not have antecedent hypertension or proteinuria, leading some experts to believe that HELLP is a separate disorder from preeclampsia [2-4]. Both severe preeclampsia and HELLP syndrome may be associated with other hepatic manifestations, including infarction, hemorrhage, and rupture. (See "Clinical features, diagnosis, and long-term prognosis of preeclampsia".)

INCIDENCE AND ONSET OF DISEASE

HELLP develops in approximately 1 to 2 per 1000 pregnancies overall and in 10 to 20 percent of women with severe preeclampsia/eclampsia. The majority of cases are diagnosed between 28 and 36 weeks of gestation.

An illustrative series included 437 women who had 442 pregnancies complicated by the HELLP syndrome; 70 percent occurred prior to delivery [5]. Of these patients, approximately 80 percent were diagnosed prior to 37 weeks of gestation and fewer than 3 percent developed the disease between 17 and 20 weeks of gestation. The disease presented postpartum in 30 percent, usually within 48 hours of delivery, but occasionally as long as seven days after birth. Only 20 percent of postpartum patients with HELLP had evidence of preeclampsia antepartum.

CLINICAL MANIFESTATIONS

The clinical presentation of HELLP is varied (table 3). Symptoms typically develop in the third trimester, but, as discussed above, second trimester or postpartum disease is also possible. The most common clinical presentation is abdominal pain and tenderness in the midepigastrium, right upper quadrant, or below the sternum [5]. Many patients also have nausea, vomiting, and malaise, which may be mistaken for a nonspecific viral illness or viral hepatitis, particularly if the serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) are markedly elevated [6]. Hypertension (blood pressure ≥140/90) and proteinuria are present in approximately 85 percent of cases, but it is important to remember that either or both may be absent in women with otherwise severe HELLP syndrome [7].

Serious maternal morbidity may be present at initial presentation or develop shortly thereafter. This includes disseminated intravascular coagulation (DIC), abruptio placentae, acute renal failure, pulmonary edema, subcapsular liver hematoma, and retinal detachment [5]. Jaundice and ascites may also be present. Bleeding related to thrombocytopenia is an uncommon presentation. Some patients are asymptomatic.