Hepatic infarction, hematoma, and rupture in HELLP syndrome: support for a vasospastic hypothesis

Purpose: HELLP syndrome is a relatively uncommon pregnancy-related condition characterized by hemolysis, elevated liver function tests, and low platelets. It can be accompanied by life-threatening hepatic complications including hepatic infarction, hematoma formation, and hepatic rupture. HELLP syndrome occurs in approximately 0.2% of pregnancies. Major hepatic complications occur in less than 1% of HELLP patients suggesting an incidence of 1/50,000. The pathogenesis is incompletely understood and in particular, it is difficult to understand a disorder with both major thrombotic and bleeding manifestations. Methods: Literature review. Results: On the basis of reports in the published literature, and our own clinical experience, we suggest that vasospasm is one of the principal drivers with hepatic ischemia, infarction, and hemorrhage as secondary events. It is known that vasoactive substances are released by the failing placenta. We suggest these cause severe vasospasm, most likely affecting the small post-sinusoidal hepatic venules. This leads to patchy or confluent hepatic ischemia and/or necrosis with a resultant increase in circulating liver enzymes. Reperfusion is associated with a fall in platelet count and microvascular hemorrhage if the microvasculature is infarcted. Blood tracks to the subcapsular space causing hematoma formation. If the hematoma ruptures the patient presents with severe abdominal pain, intra-abdominal hemorrhage, and shock. Conclusions: We suggest that hepatic and other complications associated with HELLP syndrome including placental abruption, acute renal failure, and posterior reversible encephalopathy syndrome (PRES) may also be due to regional vasospasm.