Fortnightly review: Management of patients with sickle cell disease

Introduction

Sickle cell disease is a family of haemoglobin disorders in which the sickle β globin gene (β^s) is inherited. The most common type is homozygous sickle cell anaemia (haemoglobin SS); while other clinically significant conditions include compound heterozygote states for the sickle β globin gene and haemoglobin C (haemoglobin SC) or β thalassaemia (β⁰ when no normal β chains are produced and β⁺ when reduced amounts of normal β chains are made).1 The sickle β globin gene is spread widely throughout Africa, the Middle East, Mediterranean countries, and India and has been carried, by population movement, to the Caribbean, North America, and Northern Europe. The frequency of sickle cell carriers is up to 1 in 4 in West Africans and 1 in 10 in Afro-Caribbeans2 and has reached high levels in these populations because the carrier state protects against malaria.3 4 5

In this review we have highlighted the important issues in the management of patients with sickle cell disease. These matters are important to healthcare professionals in most parts of the world. The number of patients in the United Kingdom was estimated at 5000 in 1993,2 with the number being estimated as more than 10 000 by 2000.6 Patients usually live in urban areas.

The clinical problems encountered in sickle cell disease relate to vaso-occlusion, caused by polymerisation of deoxygenated haemoglobin S. This results in the pathognomonic change in the shape of erythrocytes to the sickle shape (fig 1), which is stiff, deforms poorly, and can adhere to the vascular endothelium.7 The most common clinical problem is the painful vaso-occlusive crisis resulting from blockage of small vessels. However, large vessel disease also occurs, resulting in thrombotic cerebrovascular accidents, the acute sickle chest syndrome (fig 2), and placental infarction.