Clinical feature | Preeclampsia/HELLP | TTP | PHUS | CAPS |
Incidence | 100 in 10,000 pregnancies | 1 in 10,000 pregnancies | Unknown. May be similar to TTP. | Unknown. |
Time of occurrence | By definition, occurs after 20 weeks of gestation; more common near term and within three days postpartum | May occur throughout pregnancy, but most common near term and several weeks postpartum | May occur throughout pregnancy, but most common postpartum | May occur throughout pregnancy, but most common near term and several days postpartum |
Vital signs | Hypertension, by definition, BP ≥ 160/110mmHg | Normal BP, fever may be present but is rare | Hypertension due to AKI | Multi-organ thrombosis |
Neurologic abnormalities | Headache, vision changes. Less commonly eclamptic seizures, stroke. | Severe in 41% (transient focal defects, seizure, stroke); minor in 30% | None | Headache, vision changes, transient focal defects, seizure or stroke |
Microangiopathic hemolysis/schistocytes | Moderate | Severe | Moderate | Severe |
Kidney injury | Usually mild, but severe AKI is possible. Dialysis is rarely required. | Usually mild or absent; severe AKI requiring dialysis in <5% | Severe, typically dialysis is required | Usually mild, but severe AKI is possible. Dialysis is rarely required. |
Liver function tests: ALT, AST | From normal to markedly increased | Normal or slightly increased | Normal | From normal to markedly increased |
Typical course following delivery | Stabilization or improvement within 48 hours | No stabilization or improvement within 48 hours | Increasing serum creatinine | Most unchanged, but may improve after delivery |
Specific management | Delivery of infant is curative | Plasma exchange, immunosuppression if acquired autoimmune TTP suspected. If hereditary TTP is strongly suspected, plasma infusion is sufficient | Anti-complement agent | Plasma exchange, glucocorticoids, IVIG, anticoagulant |
PE/HELLP: preeclampsia/hemolysis, elevated liver enzymes, low platelets; TTP: thrombotic thrombocytopenic purpura; PHUS: postpartum hemolytic-uremic syndrome; CAPS: catastrophic antiphospholipid syndrome; AKI: acute kidney injury; IVIG: intravenous immune globulin; ALT: alanine aminotransferase; AST: aspartate aminotransferase.