Table 1.
Clinical and laboratory features of pregnancy-associated microangiopathies
| Preeclampsia/HELLP | TTP | HUS | AFLP | |
|---|---|---|---|---|
| Elevated blood pressure | +++ | + | + | ++ (50% of cases) |
| Neurological symptoms | +/++ (headache) | +++ (numbness, weakness, aphasia, mental status) | + | + |
| Abdominal symptoms | + (RUQ pain) | ++ (unspecific/diffuse) | + | +++ (unspecific/diffuse) |
| Fever | − | −/+ | −/+ | − |
| Easy bruising | − | −/+ | − | − |
| Thrombocytopenia | +/++ (>50 × 109/L) | +++ (<20 × 109/L) | + (<100 × 109/L) | + |
| Renal impairment (elevated creatinine; > ∼2 mg/dL) | +/++ | +/++ | +++ | ++/+++ |
| Hepatic dysfunction and inflammation (AST/ALT) | + | −/+ | −/+ | +++ (and bilirubin) |
| Coagulopathy | −/+ | − | − | +++ |
| LDH | + | +/+++ | +/++ | +++ |
| Microangiopathic hemolytic anemia | + | +/+++ | +/++ | + |
| Hypoglycemia | − | − | − | + |
| ADAMTS13 activity | Normal | <10%* | >20%-30%† | >30% |
Estimated prevalence of clinical signs and symptoms and laboratory features in women with TMAs during pregnancy. Reference ranges in healthy pregnancy must be taken into consideration.
+, prevalence; −, not usually present; ALT, alanine aminotransferase; AST, aspartate transaminase; LDH, lactate dehydrogenase; RUQ, right upper quadrant.
Some investigators require that the ADAMTS13 activity level in plasma be below 10% of normal to make the diagnosis of TTP, whereas others use this solely as providing confirmation of a clinical diagnosis.
ADAMTS13 activity is generally above 30% of normal in patients with a clinical diagnosis of aHUS, but there are no guidelines that exclude this diagnosis based on activity levels per se.