24th May 2023

Clinical syndromes in sickle cell disease

Sickle cell crisis

This describes several acute conditions seen in sickle cell, although typically refers to painful episodes secondary to vaso-occlusion. These episodes can be precipitated by cold environments, dehydration, infection, and exercise.

Management of these crises focuses on managing pain while minimising the adverse effects of vaso-occlusion. Patients may require opioid analgesia, intravenous fluids, supplemental oxygen, and antibiotics if suspected infection. Blood transfusions are only indicated in patients experiencing anaemia with life-threatening vaso-occlusive events, symptomatic anaemia, organ dysfunction and during high-risk procedures e.g. surgery.

Acute chest syndrome

This can follow a vaso-occlusive crisis and accounts for 25% of deaths in sickle cell disease. Hypoxia secondary to hypoventilation causes sickling of red blood cells and occlusion of the pulmonary microvasculature. This in turn results in localised hypoxia in the lung tissue which contributes to the vicious cycle of more sickling red blood cells.
Patients present with shortness of breath, hypoxia, chest pain, cough, and tachypnoea. Severe cases can present as respiratory distress or even failure. Patients may also have a fever.

The aim of management in acute chest syndrome is to prevent progression to respiratory failure. Patients are treated with blood transfusion, optimal analgesia to improve respiratory effort which prevents atelectasis, and intravenous antibiotics as bacterial pneumonia cannot be ruled out. Incentive spirometry is also used to prevent further atelectasis.

Splenic sequestration crisis

This is a life-threatening crisis that causes a significant haemoglobin drop secondary to trapping and pooling of red blood cells in the spleen. Consequently, patients can present with hypovolemic shock with a rapidly enlarging spleen. Splenic sequestration crises mainly present in childhood where patients have yet to develop fibrotic spleens from repeated splenic infarcts.

Treatment is with blood transfusion and splenectomy.

Aplastic crisis

Aplastic crisis is characterised by an acute drop in haemoglobin with transient cessation of erythropoiesis and hence, reduced reticulocytes in the peripheral bloodstream. This commonly lasts between 7 to 10 days. It is most commonly precipitated by infection e.g. Parvovirus B19, Epstein-Barr virus, and streptococcus pneumoniae.

Management is with blood transfusion in severe cases.

Other complications

The complications of sickle cell disease are extensive due to the multi-organ impact of vaso-occlusion from sickled cells.

Complications of sickle cell disease