Splenic sequestration is a vital cause of acute anaemia in people living with sickle cell disease. We define it as sudden enlargement of the spleen coupled with a decline in haemoglobin level by 2 g/dL below the baseline value.
Because the spleen acutely sequesters both red blood cells and platelets, these are both reduced on the complete blood count. However, the bone marrow tries to compensate for the developing anaemia. There are increased numbers of both reticulocytes and nucleated red blood cells.
Splenic sequestration is not uncommon between age 1 and 4 years. It can also occur as early as six months of age. People with HbSS are prone to this condition very early in life when compared to those with HbSC, or Hbβ+ -thalassemia, where it tends to occur in older children and adults.
When red blood cells and platelets are trapped in the spleen as it is during splenic sequestration, there are higher chances of the spleen becoming nonfunctional. So, the patient suffers from what is called functional asplenia due to involution and autoinfarction. It is quite common among people with HbSS by age 5. The prevalence of developing acute splenic sequestration if you have HbSS is somewhere between 7 and 30%.
We stress it that splenic sequestration is a sudden event with no known cause in many cases. Parents usually report an increased mass in the left upper quadrant in children with splenic sequestration. The disease, however, takes on an insidious course in adult patients, often accompanied by severe abdominal pain due to infarction of the spleen.
A few patients who don’t develop functional asplenia, go on to develop an enlarged spleen, which can culminate into hypersplenism which is evidenced by a low white cell account in addition to acute anaemia and an enlarged spleen, and these can easily suffer splenic sequestration. At times, infants present with severe anaemia and hypovolemic shock.
It is paramount to note that much as red cell transfusion is part and parcel of management of splenic sequestration, you should take caution not transfuse to haemoglobin levels above 8 g/dL. It is because many of the trapped red cells in the spleen, are eventually returned to the general circulation several days later, which can lead to unwarranted hyperviscosity of blood predisposing the patient to not only iron overload but also increased risk of a stroke.
Related articles: Health Management for People with Sickle Cell Disease.
Because of the high chances of recurrence, it is vital to tell parents of affected children to monitor the size of the spleen and promptly report to the hospital should there rise a concern of an enlarging spleen.
Removing the spleen (splenectomy) is the recommended management of recurrent splenic sequestration. Scheduled transfusions to abate splenectomy haven’t yielded any substantial results to date. Adult patients with hypersplenism will also benefit from a splenectomy.
Having a splenectomy does not increase the risk of death or bacteremia. Most of these patients have functional asplenia already.
Now that we’ve had a thorough look at what splenic sequestration entails: let’s look at its management recommendations from the panel of experts from the evidence-based management of sickle cell disease. You can download a PDF here.
- In people with hypovolemia due to acute splenic sequestration, immediately provide intravenous fluid resuscitation.
- In consultation with a sickle cell expert, transfuse patients with acute splenic sequestration and severe anaemia to raise the haemoglobin to stable levels, while avoiding over-transfusion.
- Consult a sickle cell expert, address when to perform surgery in patients with recurrent splenic sequestration or symptomatic hypersplenism.
As always, don’t forget to share this information with your colleagues. Join us as we discuss acute chest syndrome in the next article.