This is a particularly high-risk form of pre-eclampsia. "Haemolysis, LFT derangement, low platelets" is what HELLP stands for. Basically, it is pre-eclampsia, with all its various hemodynamic and neurological features, but with a vastly more deranged biochemical profile, and with hemolysis. About 20% of pre-eclampsia patients go on to develop this syndrome, and about a third tend to develop it post-partum, when you thought they were safe. The college loves HELLP and the pregnant patient with deranged LFTs keeps coming up in the exam; in fact roughly half of the pregnancy-related SAQs include HELLP as a differential.
Previous SAQs on this topic:
- Question 30.2 from the second paper of 2016
- Question 21.1 from the second paper of 2012
- Question 9.1 from the first paper of 2008
What else would it be? The clever CICM fellowship candidate will be able to regurgitate a stream of differentials:
Differential causes of hemolysis, hepatitis and thrombocytopenia in pregnancy
- benign thrombocytopenia of pregnancy
- Acute fatty liver of pregnancy
Differential causes of hemolysis, hepatitis and thrombocytopenia in general
- Viral hepatitis
- Idiopathic thrombocytopenic pupura (ITP)
- Thrombotic thrombocytopenic purpura (TTP)
- Hemolytic-uremic syndrome (HUS)
- Systemic lupus erythematosus (SLE), antiphospholipid syndrome
Diagnosis of HELLP
There are several sets of strict criteria: Sibai's "Tennessee" criteria have been expanded upon and reconfigured as "the Mississippi classification":
Mississippi class 1:
Mississippi class 2:
Mississippi class 3:
These really differe only according to the platelet count (and you should use the platelet nadir). Other feature to be expected is haemolysis due to microangiopathic haemolytic anaemia (MAHA):
- Blood film shows fragmented RBCS - schistocytes
- There is a raised reticulocyte count
- The unconjugated bilirubin fraction increases
- The haptoglobin decreases (as haptoglobin/hemoglobin complexes are removed)
Distinguishing HELLP from the differentials
Benign thrombocytopenia of pregnancy has ...only thrombocytopenia, and none of the other features of HELLP, and perhaps not even pre-eclampsia. Its a completely benign thrombocytopenia, seen in normal pregnant woemn.
Acute fatty liver of pregnancy is very similar to HELLP, but may not have much of a thrombocytopenia, and does not present with proteinuria.
Viral hepatitis should not present with proteinuria either.
In fact, proteinuria (and thus preeclampsia) are pretty specific, and will exclude a lot of these differentials.
TTP can be confirmed with the ADAMTS13 test, and HUS is more likely if renal failure is the dominant presenting feature of the patient.
In order to discriminate among the differentials, you should launch investigations in addition to the routine FBC/EUC/LFT/Coags that you would normally already have in your pre-eclampsia patient:
- Blood film
- Reticulocyte count
- Unconjugated fraction of bilirubin
- Haptoglobin level
Additionally, it would be good to perform a liver ultrasound. It may reveal a subcapsular haematoma, or confirm rupture (which is a surgical emergency).
Management of HELLP
Again, the specific management revolves around getting the baby out. Not much else is of any use. One can press on with the standard suportive care for pre-eclampsia, and replace whatever blood products are being depleted, but none of this is definitive.
Because HELLP is a lifethreatening condition, serious thought must be given to the delivery of a premature foetus. Corticosteroids may not be helpful in preventing maternal mortality and morbidity, but they do play a role in accelerating foetal lung maturation.