Differentials
Acute fatty liver of pregnancy (AFLP)
SIGNS / SYMPTOMS
Also occurs in the third trimester of pregnancy or postpartum, and may be difficult to distinguish from HELLP.
Patients may have hypertension and/or proteinuria, although not frequently.
INVESTIGATIONS
Total bilirubin is increased much more than in HELLP syndrome, to levels ≥4 mg/dL. The direct fraction of bilirubin is increased (unlike in HELLP syndrome, in which the indirect bilirubin fraction is increased).
Coagulopathy (hypofibrinogenemia, prolonged prothrombin time, low antithrombin) is usually present early in the disease (unlike in HELLP syndrome, in which coagulopathy develops in the late stages). AFLP patients develop a consumptive coagulopathy before they develop thrombocytopenia; HELLP patients develop a microangiopathic hemolytic anemia before they develop evidence of disseminated intravascular coagulation as platelets become scarce.
Liver transaminases are generally <500 IU/L, although in some severe cases may exceed 1000 IU/L.
Hypoglycemia (not typically present in HELLP unless there is liver failure) is a key distinguishing factor, as is leukocytosis (>13,000/mm³ with left shift). There may also be hemoconcentration, metabolic acidosis, increased ammonia, and elevated serum creatinine (mean 2.3 mg/dL) and uric acid (mean 11 mg/dL).[62]
Liver biopsy is the standard for confirming the diagnosis, but it is rarely used in clinical practice. Plasma exchange can be used to facilitate management regarding transfusion of blood products, removal of vascular debris, and maintenance of fluid balance.[52]
Thrombotic thrombocytopenic purpura (TTP)
SIGNS / SYMPTOMS
Can be difficult to distinguish from HELLP.
Classic pentad of TTP consists of thrombocytopenia, hemolytic anemia, neurologic abnormalities, fever, and renal impairment (rare for all 5 to be present).
However, neurologic abnormalities may be nonspecific (such as headaches, visual changes, weakness, and seizures) and therefore difficult to diagnose and to distinguish from HELLP syndrome.
Presenting features may also include abdominal pain, hypertension, nausea, and vomiting, in conjunction with jaundice, petechiae, purpura, or other abnormal bleeding.
INVESTIGATIONS
Thrombocytopenia is more severe than in HELLP syndrome (<25,000/mm³) and often requires transfusion.
Liver transaminases increase less than they do in HELLP syndrome but LDH are much higher, the reason why LDH:aspartate aminotransferase ratio is >22 in TTP patients; usually there is no coagulopathy, and antithrombin levels are unchanged.
Maternal condition does not improve with delivery.[63][64]
ADAMTS13 (a von Willebrand factor-cleaving metalloprotease) is markedly reduced (to >5% of normal) in most patients with congenital TTP, and antibodies that neutralize ADAMTS13 have been found in women with acquired TTP. However, testing for ADAMTS13 is not readily available in most clinical laboratories.[63][64]
Atypical hemolytic uremic syndrome (aHUS)
SIGNS / SYMPTOMS
Rarely associated with pregnancy; almost universally occurring in the postpartum period (up to 10 weeks).[65]
INVESTIGATIONS
Presentation is similar to that in TTP, both being characterized by microangiopathic hemolytic anemia and thrombocytopenia. In HUS, the microvascular injury mainly affects the kidneys, renal function deterioration being more significant than in TTP and HELLP, and hemolysis may also be prominent, frequently requiring blood transfusions.
There are no coagulation abnormalities[65][66] and antithrombin levels are unchanged.
Liver transaminases are less elevated than they are in HELLP syndrome.
Systemic lupus erythematosus (SLE) with/without catastrophic antiphospholipid antibody syndrome (CAPS)
SIGNS / SYMPTOMS
History of SLE and/or CAPS prior to pregnancy/delivery.
INVESTIGATIONS
Standard testing for CAPS must be undertaken; in advanced cases mimicking HELLP syndrome, plasma exchange may be necessary to stabilize patient while definitive diagnosis is pursued.[67]
Use of this content is subject to our disclaimer