The HELLP syndrome is a serious variant of preeclampsia. HELLP is an acronym for hemolysis, elevated liver enzymes, and low platelet count. It is the most frequently encountered microangiopathy of pregnancy. Two classification systems exist (Mississippi Classification and Tennessee Classification) (Box E1); degree of maternal thrombocytopenia is a primary indicator of disease severity.

• HELLP
• Hemolysis
• Elevated liver enzymes
• Low platelet syndrome

• HELLP is a rare complication occurring in <1% of total pregnancies, but the rate is estimated to be around 5% to 20% in pregnancies with severe preeclampsia.
• About 20% of patients may not have hypertension, and about 10% of patients may not have proteinuria.
• About 70% of the cases happen antepartum and 30% postpartum.
• Of the patients diagnosed with HELLP syndrome antepartum, 70% are diagnosed in the third trimester peaking between 27 and 37 wk of gestation.
• Younger age, headache, bilirubin >2.0, lactate dehydrogenase (LDH) >1290, and platelets <50,000 are predictive of worse maternal outcomes.

• Although many women with HELLP syndrome are asymptomatic, 40% to 80% report right upper quadrant or epigastric pain, 29% to 84% have nausea and vomiting, and 33% to 61% have headache.

As with other microangiopathies, endothelial dysfunction, with resultant activation of the intravascular coagulation cascade, has been proposed as the central pathogenesis of HELLP syndrome.

• Acute fatty liver of pregnancy
• Thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome
• Appendicitis
• Gallbladder disease
• Peptic ulcer disease
• Enteritis
• Hepatitis
• Pyelonephritis
• Systemic lupus erythematosus
• Box E2 summarizes medical and surgical disorders often confused with HELLP syndrome

Because HELLP syndrome is a disease entity based on laboratory values, initial assessment is detailed below.

• Laboratory Tests (Box E3 and Table E1): Initial assessment of suspected HELLP syndrome should include a CBC, peripheral blood smear, urinalysis, serum creatinine, LDH, uric acid, indirect and total bilirubin levels, and aspartate aminotransferase (AST)/alanine aminotransferase (ALT).
• Most commonly used criteria include hemolysis defined by the presence of an abnormal peripheral smear with schistocytes, LDH >600 U/L, and total bilirubin >1.2 mg/dl; elevated liver enzymes (serum AST >70 U/L); low platelet count <100,000/ml.
• Tests of prothrombin time, partial thromboplastin time, fibrinogen, and fibrin split products are reserved for women with a platelet count well below 100,000/mm³.

Imaging should be considered in the setting of severe abdominal pain and transaminitis to evaluate for hepatic hematoma and rupture.

• Assess gestational age thoroughly. Fetal status should be monitored with nonstress tests, contraction stress tests, and/or biophysical profile.
• Maternal status should be evaluated by history, physical examination, and laboratory testing.
• Magnesium sulfate is administered for seizure prophylaxis regardless of blood pressure.
• Blood pressure control is achieved with agents such as hydralazine or labetalol.
• Indwelling Foley catheter to monitor maternal volume status and urine output.
• Eculizumab has also been proposed as a possible therapy in case reports.

• If the gestational age is greater than 34 wk or if nonviable fetus, consider delivery after maternal stabilization.
• If gestational age is between 27 to 34 wk, and there are no complications such as multiorgan dysfunction, disseminated intravascular coagulation, renal failure, placental abruption, or liver hemorrhage, consider administration of corticosteroid for fetal lung maturation and delivery within 48 h.
• Some reports have shown temporary amelioration of HELLP severity with the administration of high-dose steroids (e.g., dexamethasone 10 mg q12h) measured by increased urine output, improvement in platelet count, and liver function test. A 2015 meta-analysis of multiple studies suggested improvement in lab parameters and decreased length of intensive care unit stay with steroid administration. However, there was not better maternal mortality and morbidity.
• Judicious use of blood products, especially in those requiring surgery.
• The patient requires intensive observation. Laboratory levels may worsen immediately postpartum but should begin to improve within 48 h.
• Hepatic hematoma and its rupture is a potentially fatal complication that warrants promptly consulting a surgical team experienced in liver trauma surgery.

The natural history of this disorder is a rapidly deteriorating condition requiring close monitoring of maternal and fetal well-being.

Preterm patients with HELLP syndrome should be stabilized hemodynamically and transferred to a tertiary care center. Term patients can be treated at a local hospital depending on the availability of obstetric, neonatal, and blood banking services.

• Eclampsia (Related Key Topic)
• Preeclampsia (Related Key Topic)