HELLP Syndrome

HELLP stands for haemolysis, elevated liver enzymes and low platelets. In Canadian practice it is understood as a severe end-organ manifestation of the preeclampsia disease process, not as a completely separate disease, although its presentation and laboratory abnormalities can differ from typical preeclampsia. The three letters on the laboratory report are three views of one injury: a damaged lining of small blood vessels. Hold that picture, because it explains the whole syndrome. Abnormal placental vascular development and inflammatory signalling release injury into the maternal circulation. The endothelium is the target. Once it is damaged, the rest follows in a chain: 1. Placental and maternal vascular dysfunction develops. 2. Endothelial injury activates platelets and coagulation pathways. 3. Platelet-rich thrombi form in small vessels. 4. Red cells fragment as they pass through narrowed, damaged vessels. This is microangiopathic haemolysis. 5. Injury around the hepatic sinusoids reduces hepatic perfusion, causes hepatocellular necrosis and leaks AST and ALT into the blood. 6. Platelets are consumed, and the count may fall rapidly. 7. Severe cases progress to haemorrhage, organ dysfunction or disseminated intravascular coagulation (DIC)....