HELLP syndrome, the constellation of H emolysis, E levated L iver function tests, and L ow P latelet count, is a complication of preeclampsia and eclampsia that occurs in pregnant women. It is rare but can have devastating consequences. Laboratory monitoring in pregnant women with gestational hypertension or preeclampsia includes platelet counts and liver enzymes. The treatment for HELLP syndrome is delivery after 34 weeks.
Tabs Content Clinical Overview Diagnosis
Indications for Testing
During pregnancy
New-onset high blood pressure or blood pressure increase in patients with established high blood pressure
Proteinuria
Criteria for Diagnosis
Diagnostic Criteria for HELLP Syndrome
Hemolysis
Elevated Liver Enzymes
Low Platelets
Martin Criteria (1991)
LDH >600 U/L
AST >40 U/L
Platelet count <150 x 109 /L
Sibai Criteria (1993)
Abnormal peripheral smear (schistocytes)
LDH >600 U/L
Bilirubin >1.2 mg/dL
AST >70 U/L
Platelet count <100 x 109 /L
AST, aspartate aminotransferase; LDH, lactate dehydrogenase
Source: Rajasekhar, American Society of Hematology (ASH), 2013
Patients with preeclampsia or eclampsia with one to two HELLP criteria (hemolysis , elevated liver enzymes , and low platelets) can be deemed as having partial HELLP
Laboratory Testing
CBC
Hemoglobin and hematocrit – evaluate for hemolysis
Platelets – low platelet counts increase risk in preeclampsia
Counts of <100,000/mm3 meet HELLP criterion
Blood smear – evaluate for evidence of microangiopathic hemolysis
Helmet cells
Burr cells
Schistocytes
Reticulocyte count – consider to evaluate for presence of hemolysis
Liver enzymes
AST – 2 times the upper reference limit meets criteria
LDH – markedly elevated (>600 U/L meets criteria)
Urine protein
Evaluate kidney protein losses
Extent of proteinuria does not correlate with disease severity
24-hour collection is preferred, but spot urine for protein/creatinine ratio can be used for screening
Renal function markers – evaluate for kidney damage
Testing to rule out other conditions, if clinically indicated
Prothrombin time (PT), partial thromboplastin time (PTT), D-dimer, fibrinogen for disseminated intravascular coagulation (DIC) evaluation
Lupus anticoagulant, anticardiolipin, anti-beta-2 glycoprotein 1 for antiphospholipid syndrome (APS) evaluation
Fibrinogen, white blood cells, PT/PTT, uric acid, ammonia, glucose for acute fatty liver of pregnancy (AFLP) evaluation
Differential Diagnosis
Thrombocytopenia
Hemolysis
Elevated liver enzymes
Monitoring
Monitoring for gestational hypertension and preeclampsia – weekly testing for platelet counts, liver enzymes, urine protein
Background
Epidemiology
Incidence – 0.6% of pregnant women (ASH, 2013)
5-10% of pregnancies with preeclampsia
30-50% of pregnancies with eclampsia
Classification
The American College of Obstetricians and Gynecologists (ACOG) classifies various gestational hypertensive disorders as follows
Chronic hypertension – high blood pressure that predates conception or is detected before 20 weeks of gestation
Gestational hypertension – new-onset high blood pressure detected after 20 weeks of gestation without proteinuria
Preeclampsia/eclampsia
Preeclampsia – new-onset high blood pressure detected after week 20 of gestation with proteinuria; can be with or without severe features
Preeclampsia with severe features
Thrombocytopenia, impaired liver function, renal insufficiency, pulmonary edema, cerebral or visual changes
HELLP is a complication of preeclampsia with severe features
Eclampsia – convulsive phase of disorder, often preceded by headaches, vision changes, and altered mental status
Chronic hypertension with superimposed preeclampsia – preeclampsia/eclampsia in patients with previous chronic hypertension
Risk Factors
Caucasian race
Multiparity
Age >34 years
Presence of preeclampsia or eclampsia
Fetus affected with fatty acid oxidation defect (eg, long-chain 3-hydroxyacyl-CoA dehydrogenase [LCHAD] deficiency)
Previous pregnancy with HELLP
Pathophysiology
Placenta in preeclampsia is poorly perfused, which causes release of factors that create endothelial dysfunction
Endothelial dysfunction causes platelet aggregation and altered ratio of thromboxane to prostacyclin
Thrombin-induced activation of the coagulation cascades leads to hemolytic anemia and multiorgan microvascular injury
Clinical Presentation
Usually occurs during pregnancy
Two thirds of patients are diagnosed antepartum
Typically does not present before third trimester
Postpartum presentation usually occurs within first week after delivery
Signs/symptoms
Nonspecific – malaise, fatigue
Gastrointestinal – right upper quadrant pain, nausea, emesis
Central nervous system – headache, confusion
Cardiovascular – hypertension
Complications
Maternal
Subcapsular hematomas and liver rupture
Abruptio placentae
DIC Severe postpartum bleeding
Stroke, cerebral hemorrhage
Renal failure Increased risk of HELLP in subsequent pregnancies
Fetal/perinatal
Prematurity
Placental insufficiency
Intrauterine growth restriction
Neonatal intraventricular hemorrhage
ARUP Lab Tests
Use with hepatic function panel and LDH in the diagnosis of HELLP
Use with LDH and CBC in the diagnosis of HELLP
Use with hepatic function panel and CBC in diagnosis of HELLP
Screening test to evaluate kidney function
Initial test for suspected bleeding disorder
Aid in diagnosing and following DIC
Preferred initial panel for strong suspicion of APS
Determine if fibrinogen deficiency is a potential cause of bleeding
Medical Experts Genzen, Jonathan R., MD, PhD, Chief Operations Officer, Medical Director of Automated Core Laboratory and Farmington Health Center Clinical Laboratory, at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah
Lehman, Christopher M., MD, Co-Medical Director, University Hospitals and Clinics Clinical Laboratory; Professor of Clinical Pathology, University of Utah
Related Topics Last Update: November 2019
