Clinical Features of HELLP Syndrome
HELLP syndrome presents with a characteristic triad of hemolysis, elevated liver enzymes, and low platelet count (<100,000/mm³), occurring in 0.2-0.6% of pregnancies, typically in the third trimester or within 48 hours postpartum, with preeclampsia present in 95% of cases. 1, 2
Cardinal Symptoms and Signs
Abdominal and Gastrointestinal Manifestations
- Abdominal pain occurs in 65% of cases, specifically right upper quadrant or epigastric pain resulting from liver capsule distension due to hepatic edema and subcapsular hemorrhage 2, 3
- Nausea and vomiting are present in 65% of patients 2
- This abdominal pain should immediately trigger suspicion for HELLP syndrome regardless of whether classic preeclampsia signs are present 3
Preeclampsia-Associated Features
- Hypertension (BP ≥140/90 mmHg) and proteinuria are present in 95% of HELLP cases 2
- Severe headache and visual disturbances are common neurological symptoms 2
- Peripheral edema is frequently observed 1
Timing and Demographics
- Onset typically occurs in the third trimester or within 48 hours postpartum 1, 2
- More frequent in older multiparous women aged >35 years 1, 4
- Can rarely develop in the second trimester 5
Laboratory Abnormalities
Hematologic Findings
- Thrombocytopenia with platelet count <100,000/mm³ (often <100×10⁹/L) is a diagnostic requirement 1, 2, 6
- Peripheral blood smear showing schistocytes indicating microangiopathic hemolytic anemia 7
- Elevated lactate dehydrogenase (LDH) reflecting both hemolysis and hepatocellular damage 1, 3
- Decreased haptoglobin levels 6
- Elevated indirect bilirubin (typically <5 mg/dL) 1
Hepatic Dysfunction
- Elevated liver enzymes with ALT typically <500 U/L 1, 2
- AST elevation (can be >135 U/L in severe cases) 7
- The degree of liver enzyme elevation correlates with disease severity 3
Coagulation Abnormalities
- Disseminated intravascular coagulation (DIC) occurs in 29% of cases requiring intensive care 8
- Elevated international normalized ratio (INR) in severe cases 8
- Prolonged prothrombin time (PT) 1
Renal Involvement
- Elevated uric acid levels 1
- Proteinuria (≥0.3 g/24 hours) 1
- Elevated serum creatinine in severe cases 1
Imaging Findings
- Hepatic infarcts, hematoma, or rupture are possible complications 1, 2
- No ascites typically present (distinguishing feature from acute fatty liver of pregnancy) 1, 2
- Abdominal ultrasound is mandatory if symptoms suggest hepatic hematoma, particularly with severe thrombocytopenia and persistent right upper quadrant pain 7, 3
Critical Complications and Severity Markers
Maternal Complications
- Acute renal failure occurs in 25% of ICU admissions 8
- Postpartum hemorrhage in 21% of severe cases 8
- Seizures (progression to eclampsia) 1
- Hepatic rupture (rare but life-threatening) 1, 7
- Maternal mortality rate 1-25% (1% in general population, up to 14% in ICU admissions) 1, 8
Severity Predictors
- Higher mortality risk associated with: elevated INR, higher AST/ALT/LDH levels, higher bilirubin, and lower platelet counts 8
- DIC is a major risk factor for adverse maternal outcome 8
- Severe thrombocytopenia with platelets <50,000/mm³ indicates need for platelet transfusion before cesarean section 7
Fetal/Perinatal Outcomes
- Fetal mortality rate 7-20% (perinatal mortality 11-30% in severe cases) 1, 2, 8
- Increased risk of fetal growth restriction and fetal demise 1
Key Diagnostic Pitfalls
- HELLP syndrome can occur without classic preeclampsia symptoms in 5% of cases, making diagnosis challenging 2
- The syndrome may be confused with acute fatty liver of pregnancy, idiopathic thrombocytopenia, hemolytic uremic syndrome, or appendicitis 5
- Symptoms can develop postpartum (within 48-72 hours after delivery), requiring continued vigilance 5
- Regional anesthesia should not be used with platelets <100,000/mm³ or elevated INR due to epidural hematoma risk 7