Sickle cell disorders

Last updated: Saturday, 29, January, 2011
Key InformationAppropriate 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.

See 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.

See Thalassaemia

Sickle cell/haemoglobin D disease

Double heterozygous state (HbSD).

Sickle-cell haemoglobin C

See Haemoglobinopathy

Sickle cell haemoglobin D

See Haemoglobinopathy

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

Deoxygenation

Dehydration

Acidosis

Low temperature

Infection

Folate deficiency

Pregnancy 

This is an important cause of morbidity and mortality.

Manifestations of sickling

Haemolytic anaemia

See also Haemolysis

Infection

  • Splenic infarction
See Splenic atrophy/absence
  • Splenic atrophy

Pain crises/vaso-occlusive crises

  • Bone pain

Chest syndrome

A potentially life threatening syndrome of progressive pulmonary infiltrates, with increasing hypoxaemia and increased sickling.

Splenic sequestration

Particularly in children, where there can be rapidly progressive anaemia.

  • Aplastic crises
Bone marrow aspiration may be indicated.

Leg ulcers

Renal papillary necrosis

Renal medullary carcinoma

Bony infarction and avascular necrosis

Subarachnoid haemorrhage

Retinopathy

Haemosiderosis

With previous transfusion therapy.