What are the key clinical features that differentiate HELLP syndrome from severe pre-eclampsia?

Key clinical features differentiating HELLP syndrome from severe pre-eclampsia:

• HELLP syndrome is characterised by the triad of haemolysis, elevated liver enzymes, and low platelet count, which are specific haematological and biochemical abnormalities not necessarily present in severe pre-eclampsia.
• While severe pre-eclampsia involves new onset hypertension (≥160 mmHg systolic or ≥110 mmHg diastolic) after 20 weeks of pregnancy with proteinuria or other organ dysfunction, it may also present with elevated liver enzymes and thrombocytopenia, but these are less specific and usually less severe than in HELLP syndrome.
• HELLP syndrome typically shows more pronounced haemolysis and thrombocytopenia (platelet count often <150,000/microlitre) alongside markedly elevated liver transaminases, whereas severe pre-eclampsia may have elevated transaminases but without the full haemolysis and platelet count drop characteristic of HELLP.
• Clinically, HELLP syndrome may present with right upper quadrant or epigastric pain due to liver involvement, which can also occur in severe pre-eclampsia but is more prominent and linked to the liver pathology in HELLP.
• Severe pre-eclampsia is defined by severe hypertension with symptoms such as severe headaches, visual disturbances, nausea, vomiting, oliguria, and progressive laboratory deterioration, but without the full haematological triad of HELLP.

In summary, the presence of haemolysis, significant thrombocytopenia, and markedly elevated liver enzymes distinguishes HELLP syndrome from severe pre-eclampsia, which primarily features severe hypertension and organ dysfunction without the full haematological syndrome ¹.