HELLP - A LIFE THREATENING COMPLICATION OF PREGNANCY

 

Another weekend shift and another emergency case.!!!

This lady recently came into the hospital at 30 weeks pregnant. The clinical details I received were ? Pre-eclampsia.

 The Full Blood Count showed that the platelet count for this lady was low at 64 x 10^⁹/l and had  significantly dropped from 266 x 10^⁹/l, two weeks previously. This situation must always be dealt with immediately. The first question is, is this a genuine result?

After ruling out a clot in the sample, or platelet clumping/ Fibrin strands, the next question is what is going on in the body to make the platelets fall like this? The Scientist must then seek the answer by looking at the white cells and red cells on the blood film, clinical details and other laboratory results.

The potential cause was revealed on the blood film, by the presence of red cell fragments in most fields. This is a serious finding in conjunction with a dropping platelet count and the question is, why are red cells being sheared in half!?

    

                                

My immediate thought was HELLP Syndrome which stands for Haemolysis, Elevated Liver Enzymes and Low Platelets. This is a severe, potentially life -threatening form of pre-eclampsia. Complications include liver haemorrhage or rupture, pulmonary odema, placental abruption, bleeding and clotting issues.

What is the cause for red cells being sheared in half ?

It seems that the main cause is a Microangiopathic Haemolytic anaemia (MAHA). The red cells are sheared off as they pass through capillaries with damaged endothelium and fibrin strands which leads to the red cells being fragmented as they pass through.

Another cause for the red cell damage can also be Disseminated Intravascular Coagulation (DIC).

Why are platelets reduced in HELLP?

The platelets are aggregating and forming clots due to endothelial damage.

Further evidence that this was HELLP Syndrome.

Protein in the urine

 A protein: creatinine ratio or >30mg/mmol suggests significant proteinuria in pregnancy (NICE, 2019). In this case the value was 341.7mg/mmol!

Elevated Liver enzymes

Nice guidelines ( NICE, 2019) suggest a rise in ALT, twice the upper limit of the normal range is of concern. The ALT in this case on presentation was 420 U/L. The normal range is <33 U/L.

What happened next?

The obstetric team and Consultant Haematologist were alerted to the blood film findings and other laboratory results. The Consultant Haematologist should be informed as red cell fragments with low platelets could also be suggestive or other life threatening microangiopathic haemolytic anaemias such as TTP and HUS, where the course of treatment would be entirely different.

The diagnosis of HELLP was indeed made in this case however  and the decision to deliver the baby prematurely, despite the lady only being 30 weeks pregnant. Delivery is the cornerstone of treatment for HELLP syndrome (Baha, 2022).

Post delivery we can see quite a quick improvement with an upward trend in the platelet count and downward trend in ALT. From a haematological point of view, if the platelet count did not improve, an alternate cause for the thrombocytopenia such as a primary Microangiopathic Haemolytic anaemia would be sort.

	Haemoglobin (g/dl)	Platelets (x 109/l)	ALT (U/L)
PRESENTATION	118	64	420
DAY 1 (post delivery)	111	114	300
DAY 2	98	178	212
DAY 3	99	239	117
DAY 4	102	337	85
DAY 8	108	558	32
DAY 15	119	354	14

Hopefuly mother and baby both had positive outcomes in this case.

 References

Baha, S., 2022. UpToDate. [online] Uptodate.com. Available at: <https://www.uptodate.com/contents/hellp-syndrome-hemolysis-elevated-liver-enzymes-and-low-platelets?search=hellp%20SYNDROME&sectionRank=3&usage_type=default&anchor=H24&source=machineLearnin> [Accessed 8 May 2022].

 Petca, A., Miron, B., Pacu, I., Dumitrașcu, M., Mehedințu, C., Șandru, F., Petca, R. and Rotar, I., 2022. HELLP Syndrome—Holistic Insight into Pathophysiology. Medicina, 58(2), p.326.

Nice.org.uk. 2022. Recommendations | Hypertension in pregnancy: diagnosis and management | Guidance | NICE. [online] Available at: <https://www.nice.org.uk/guidance/ng133/chapter/Recommendations#assessment-of-proteinuria-in-hypertensive-disorders-of-pregnancy> [Accessed 8 May 2022].

blood film diagnosis- it's all about texture, colour and shape!

 

Recognising an acute leukaemia heavily depends on your ability to make the distinction between different textures, colours and shapes!

Take a look at this photo of a blast cell (upper left) seen in an Acute Myeloid Leukaemia and a mature neutrophil (cell that looks like a happy face, bottom right). Notice the nucleus. The blast cell has chromatin in the nucleus that is very spread out, almost looks as if dots have been made with a fine pen. Compare this to the neutrophil. The chromatin in the nucleus have condensed, showing lots of texture. To me it almost looks like knots!

Blasts often have spherical inclusion in the nucleus called a nucleolus, which can be seen on the cell above over to the left side. This also tells us we are looking at an immature cell.

Scientists use this along with features such as size of cell and size of nucleus compared to cytoplasm,  in order to recognise an immature cell. 

From there we need to take this further and distinguish which type of Acute Leukaemia we could be dealing with and again this about recognising subtle features. Look at this picture. The little red ‘comma’ like inclusion in the cytoplasm is called an auer rod. This tells us that this is an Acute Myeloid as opposed to an Acute Lymphoid Leukaemia.

To go further it is possible morphologically to determine more about the type of Acute Myeloid Leukaemia we are dealing with, by looking at shapes and colours and this leads me onto today’s film which my colleague very kindly saved for me . It’s an Acute Promyelocytic Leukaemia (APL). It is vital that the distinctive morphology is not missed as APL is a haematological emergency.

 There are two types of APL, one has abnormal promyelocytes with numerous granules, whilst the other which we have here is the variant form and the blasts have distinctive bilobed nuclei and appear to lack granules. The morphology of the variant is quite distinctive and should always be on the Scientist's mind when assessing a blood film for a new leukaemia.

APL is a haematological emergency as it can be rapidly fatal due to bleeding and thrombotic complications. This patient indeed had a D-Dimer result of 2560 ng/ml. Suggestive of DIC. In DIC clotting factors are abnormally consumed which leads to not only bleeding but also thrombotic issues. Bleeding into the brain or lungs or clots blocking the heart, brain and  lungs can be life threatening.

I’ve been reading an article that explains APL quite nicely at https://rarediseases.org/rare-diseases/acute-promyelocytic-leukemia.

I didn’t know the actual reason behind the coagulation issues in APL but it appears that on the surface of the abnormal promyelocytes is tissue factor which contributes to the activation of the clotting cascade. Also Annexin II, present on the surface of the promyelocytes activates plasmin which breaks down blood clots. The activation of these two leads to excessive clotting, excessive bleeding and excessive breaking down of clots.

The treatment for this type of leukaemia uses a derivative of vitamin A which matures the promyelocytes to mature neutrophils! This treatment is called al-trans-retinoic acid or ATRA.  This is because most patient’s with APL, alterations in the RARA gene occur, which is involved in using vitamin A to mature blood cells. The alteration to the gene occurs where the RARA and PML genes are located leading to the PML/RARA fusion gene. This leads to abnormal vitamin A and stops maturation of the promyelocytes, leaving them in effect ..stuck! Pretty clever treatment based on understanding the role of the RARA gene.

The ability to recognise differences in texture, colour, shape and size of blood cells forms the basis of blood cell morphology . This is vital in the rapid diagnosis and treatment of APL because quick treatment with a vitamin A derivative is required to mature the abnormal promyelocytes and therefore lessen the coagulopathy.

Mother's Immune System Destroys Baby's Red Cells.

Many of us have heard of blood group ABO and whether we are positive or negative for an antigen which is part of the Rh blood group system. I am A positive for example.

These are very clinically significant blood groups but did you know that there are a multitude of other blood group systems and antigens most of which you will never have heard of. They are however very important in blood transfusions and pregnancy.

In pregnancy, an investigation performed by Blood Transfusion laboratories is to identify whether a mother's immune system has been sensitised and created antibodies against one of these blood group antigens on their baby's red blood cells. If this is the case the antibody level needs to be monitored and assessment made regarding how much damage it could cause to the baby and how to manage this.

I haven’t seen a blood film like this on a neonate for a long time, but here is one that presented recently on my weekend shift. Haemolytic Disease of the Fetus or Newborn or HDFN for short.

The only clinical details I received were jaundiced since birth and hence the reason for my decision to make a blood film.

In a normal neonatal film you would expect to see features of the the organs being immature such as occasional echinocytes (spikey red cells  reflecting kidneys), Howell-jolly bodies (a bit of DNA left in the red cell, suggesting an immature spleen), target cells (red cells that look like ..well  a target...reflecting liver immaturity). The red cells are far bigger than an adults and occasional fragments, polychromasia and nucleated red cells are normal. Very occasional spherocytes may also be seen.

Look at this film however, marked spherocytosis (the very dense dark damaged red cells), increased polychromasia ( purple staining young red cells) and increased nucleated red cells (very immature red cells normally seen in the bone marrow). This is not in any way normal for a neonate and my immediate thought was haemolysis. 

So the key word here from a morphological perspective is  'marked' as opposed to  occasional. Neonatal films can be tricky but it is not normal to have 'marked' numbers of anything. 

It worth noting that neonates do not always present in the same way as adults morphologically with haemolysis, and if a blood film shows a dominate poikilocyte or bizarre shaped red cells it is worth considering.

It is also good to remember that premature babies will often have an increase in red cell fragments and morphological signs that their organs are more immature.

Looking at the blood transfusion records the mother had an anti-c antibody. This is likely to have developed during a previous pregnancy. The baby here had the c antigen on it’s red cells and the mother’s immune system was therefore sensitised and primed to destroy the foreign antigen. This in effect means the mothers immune system was destroying the babies red cells! The DAT was strongly positive which supports this.

This rapid destruction of red blood cells can cause an enlargement of the baby’s liver and spleen which quickly try and compensate by making more red blood cells. In severe cases the baby cannot cope with anaemia and heart failure occurs before birth.

After birth build up of bilirubin can lead to liver enlargement and brain damage. The billribun here was very raised at 289 umol/L which required phototherapy to try and clear it.

I’ve been reading the following guidelines:

Article title:	Blood Grouping and Antibody Testing in Pregnancy | British Society for Haematology
Website title:	B-s-h.org.uk
URL:	https://b-s-h.org.uk/guidelines/guidelines/blood-grouping-and-antibody-testing-in-pregnancy/

 

Anti-D, anti-c and anti-K are the antibodies most often implicated in destroying the babies red cells severely enough to need antenatal intervention.

Clinically significant red cell antibodies should have their concentration measured throughout pregnancy, in order to guide the management and invervention in pregnancy before the antibody causes harm to the baby.

The guidelines suggest that Anti-D and anti-c are the only antibodies currently quantified, whereas the other clinically significant antibodies are titrated.

The mother in this instance initially had the anti-c antibody at a very low level of 0.2 IU/ml. Three weeks later this had only slightly increased to 0.5 IU/ml.  Just under a month later however the antibody level had risen to 10.6 IU/ml.

The table below taken from the BCSH guidelines indicates that this level would give a moderate risk of haemolytic Disease of the Fetus or Newborn.

The guidelines indicate that before 28 weeks anti-D and anti-c should be serologically tested every 4 weeks, then every 2 weeks after 28 weeks until delivery.

An interesting case and as I said, one I haven't seen morphologically for some time. A number of laboratory disciplines were involved in this, demonstrating the importance of Pathology in every diagnosis.

A Medical Emergency

A case here that I wasn’t expecting to see on a recent weekend late shift, but a condition that is a medical emergency and fatal without the appropriate treatment, Thrombotic Thrombocytopenic Pupura or TTP for short.

This is a rare condition, and therefore even more important to keep in the forefront of the scientist’s mind when reviewing blood results. 

This patient attended Accident and Emergency, very unwell with a rash. The platelet count was 4 x10^9/l. The blood film was classic, severe thrombocytopenia with numerous fragments of red cells. This picture is consistent with  microangiopathic haemolysis.

Other significant markers are a raised bilirubin, LDH, Reticulocyte count , all markers of haemolysis and a raised creatinine, indicative of renal damage.

 

In this condition, clots are forming in blood vessels throughout the body, blocking oxygen flow to the body’s organs including  the brain, kidneys and heart, leading to complications such as stroke, myocardial infarction and renal failure.

The platelet count was so low because the platelets are being used up as the clots are forming, which will result in bleeding internally and under the skin. The red cell fragments are caused by red cells squeezing past blood clots, which leads to anaemia and a progressively falling haemoglobin. 

 For Scientists the action should involve

1. looking under the microcscope immediately on any new low platelet count. 

2. Note whether the haemoglobin is dropping aswell. 

3. The presence of red cell fragments, polychromasia and thrombocytopenia on a blood film is highly suggestive of a microangiopathic haemolytic anaemia which includes TTP and HUS. DIC also gives a similar picture. 

NOTE: even the very occasional red cell fragment is enough to consider this condition.

4. Add haemolysis markers on. We added a reticulocyte count, bilirubin and LDH. 

5.Phone the Consultant Haematologist and clinician immediately with all the relevant             information.

6. Further tedts of use are ADAMST13, Haptoglobin, clotting screen and D-Dimer.

The condition is caused by a lack of an enzyme called ADAMST13 that breaks down a clotting protein, Von Willebrand factor. This patient was indeed very deficient in ADAMST13. The cause of this to happen in this patient is unknown, but something had triggered the body to make antibodies against ADAMST13. A virus perhaps. In a separate case I was involved in a few years ago, a drinking binge in a young adult, triggered TTP!

The treatment for TTP is to exchange the plasma, giving back the ADAMST13 enzyme, which is a life saving treatment. Very sadly this patient didn't survive long enough to receive this treatment.

 This is a medical emergency with often only hours before life threatening and fatal complications occur, which unfortunately was the outcome in this case.

Digital Morphology 2004DM 04/10/20

Digital Morphology 2004DM CPD date 04/10/20 

 I got this right! Myeloproliferative disorder transformed to Acute Megakaryoblastic Leukaemia. 

 I love the training links on the UK NEQAS digital morphology website. Take a look https://www.instagram.com/haematography/, really useful for anyone involved in blood cell morphology.

 I particularly found useful, the guidance on when to use the term 'Megakaryocyte fragment' and when to use the term 'Giant platelet'. Megakaryocyte fragments are basophilic, often atypical in shape, may be vacuolated and lack granules. A giant platelet however is enlarged but has very typical platelet features.

Another learning point from the case narrative was that the heavy granulation (what I would call toxic granulation) in this case, may not neccessarily be due to infection or inflammation, but yet another bizarre abnormaility. A point that I had not previously considered. 

 The narrative also mentions that the fragments seen are not associated with with an acute microangiopathic haemolytic anaemia (MAHA), as they are note sharp in appearance. The bizarre shaped fragments seen here are found in Dyserythropoiesis. I have personally however, seen blunt red cell fragments in TTP but I accept the bizarre shapes are not a feature of MAHA.

Lots of learning points on this film.