Table 1. Comparison of common clinical characteristics of causes of peripartum TMA [17, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34].

	TTP	“Typical” HUS	Atypical HUS	Pre-eclampsia	HELLP	SRC	APS
Clinical presentation	Fever, HTN, neurologic symptoms, bleeding, purpuric rash	Abdominal pain, bloody diarrhea due to verotoxin-production; neurologic symptoms possible	None or non-specific prodrome with malaise, fatigue, upper respiratory symptoms	HTN, nausea, vomiting, abnormal vision	Abdominal pain, headache, malaise, nausea, vomiting, HTN	Dyspnea, altered mentation, HTN	HTN, arterial and venous thromboses, fetal demise
Typical laboratory findings	MAHA, ↓platelets, AKI, proteinuria, hematuria	MAHA, ↓platelets, AKI, proteinuria, hematuria	MAHA, ↓platelets, AKI, proteinuria, hematuria, ↓complement	Proteinuria, hyperuricemia	MAHA, ↑AST, ↓platelets	MAHA, AKI, proteinuria, hematuria	MAHA, ↓platelets, AKI, proteinuria, hematuria, antiphospholipid antibodies
Other possible laboratory findings	Low level of ADAMTS13	Stool culture positive for verotoxin-producing E. coli	Abnormalities of complement regulatory proteins (Factors B, H, and I, MCP, C3, thrombomodulin)	MAHA, AKI, and ↑AST may occur in severe pre-eclampsia	AKI	Autoantibodies suggestive of scleroderma	Autoantibodies suggestive of SLE
Occurrence and timing related to pregnancy	Rare; generally < 23 – 26 weeks gestation	Rare; post-partum	Rare; post-partum	> 20 weeks gestation; occasionally postpartum	> 20 weeks gestation; occasionally postpartum	Unclear; > 24 weeks gestation when observed	1/3 of cases reported during pregnancy or postpartum period
Treatment	Plasma exchange, steroids, rituximab	Supportive	Plasma exchange, eculizumab	Anti-HTN therapy; when severe, magnesium sulfate and delivery	Delivery	ACE-inhibitor therapy	Anticoagulation, plasma exchange
Renal prognosis	ESRD is rare (0 – 6%)	CKD in 5 – 25%	ESRD in 20 – 60%	Low risk of ESRD (~ 8%)	ESRD is rare (0 – 2%)	ESRD in 20% treated with ACE-inhibitor	ESRD is rare (few case reports)

TMA = thrombotic microangiopathy; TTP = thrombotic thrombocytopenic purpura; HUS = hemolytic uremic syndrome; SRC = scleroderma renal crisis; APS = antiphospholipid antibody syndrome; HELLP = hemolysis, elevated liver enzymes, low platelets; HTN = hypertension; MAHA = microangiopathic hemolytic anemia; AKI = acute kidney injury; AST = aspartate aminotransferase; ADAMTS = a disintegrin-like and metalloprotease with thrombospondin type 1 motif; MCP = membrane cofactor protein; SLE = systemic lupus erythematosus; ACE = angiotensin converting enzyme; ESRD = end-stage renal disease; CKD = chronic kidney disease.