Sickle cell disorders
Last updated: Saturday, 29, January, 2011
|Key Information||Appropriate Tests|
Disorders in which the red cells contain sickle haemoglobin (HbS) and undergo sickling when deoxygenated. The sickle cell disorders occur with high frequency in West African derived populations and the Middle East.
FBC, blood film; haemoglobin electrophoresis; haemoglobin S (qualitative test and quantitation); haemoglobin A2, haemoglobin F estimation.
Prenatal diagnosis - molecular genetics - individual genetic disorders.
Sickle cell disease (HbSS)
Clinically severe (usually). Pregnancy is a high risk time for patients with sickle cells disease and all patients should be referred to specialist units, even if they have had mild disease up until this point.
Sickle cell/ß0 thalassaemia
Double heterozygous state; clinical severity variable, depending on the type of ß thalassaemia.
Sickle cell/ß± thalassaemia
Double heterozygous state; clinical severity variable, depending on the type of ß thalassaemia. The disese may become severe with precipitants such as pregnancy.
Sickle cell/haemoglobin D disease
Double heterozygous state (HbSD).
Sickle-cell haemoglobin C
Sickle cell haemoglobin D
Sickle cell trait
Heterozygous state (HbAS) - these patients do not sickle and are phenotypically normal. These patients rarely encounter anaesthetic problems.
The red cell indices may be normal.
Couples from high risk populations should be screened using Haemoglobin electrophoresis and thalassaemia screen, since at risk couples will be missed by reliance on full blood count alone.
Precipitants of sickling
This is an important cause of morbidity and mortality.
Manifestations of sickling
|See also Haemolysis|
|See Splenic atrophy/absence|
Pain crises/vaso-occlusive crises
A potentially life threatening syndrome of progressive pulmonary infiltrates, with increasing hypoxaemia and increased sickling.
Particularly in children, where there can be rapidly progressive anaemia.
|Bone marrow aspiration may be indicated.|
Renal medullary carcinoma
Bony infarction and avascular necrosis
With previous transfusion therapy.