Sickle Cell Anaemia
Content of This Page
1- Introduction
2- Pathophysiology
3- Clinical Features (Recognize chronic clinical features)
4- Interpret labs and diagnostics
5-Management of acute complications
6- Preventive strategies
7-Indications for transfusion & transplant
8- Complications
9- Prognosis & mortality trends
Introduction
Sickle cell anaemia is a genetic disorder of haemoglobin caused by a point mutation in the β-globin gene (Glu6Val), leading to the production of abnormal haemoglobin S (HbS).
In homozygous (HbSS) individuals → SCA
In heterozygotes (HbAS) → Sickle cell trait (usually asymptomatic)

Pathophysiology
Under low oxygen, HbS polymerises, distorting red blood cells into a sickle shape.
-Sickled RBCs:
Are less flexible → obstruct small vessels (vaso-occlusion)
Have shortened survival → chronic haemolytic anaemia
This leads to:Tissue ischaemia
Pain crises
End-organ damage over time
Clinical Features
Crisis | Key Features |
---|---|
Vaso-occlusive crisis | Bone pain, dactylitis |
Acute chest syndrome | Chest pain, hypoxia, new infiltrate |
Stroke | Sudden neuro deficits; more common in children |
Sequestration crisis | Splenic/liver pooling → hypovolaemia, shock |
Aplastic crisis | Parvovirus B19, ↓ reticulocytes, sudden anaemia |
Priapism | Painful, sustained erection |
Interpret labs and diagnostics
FBC: Normocytic anaemia, ↑ reticulocytes
Blood film: Sickle cells, Howell–Jolly bodies
Sickling test: Positive
Haemoglobin electrophoresis: Confirms HbS, no HbA in disease
Management of acute complications
Hydration, oxygen, opioid analgesia
Antibiotics if infection suspected
Blood transfusion for severe complications (e.g. stroke, acute chest)
Exchange transfusion in life-threatening crises
Preventive strategies
Folic acid
Vaccinations (pneumococcal, meningococcal, Hib, influenza)
Penicillin prophylaxis in children
Hydroxycarbamide:
↑ HbF → reduces crises, need for transfusion
Indications for transfusion & transplant
Simple or exchange transfusion for:
Stroke, acute chest, surgery
Stem cell transplant:
Potential cure in severe cases with matched donor
Limited availability and risks
Complications
Neurological: Stroke, silent infarcts
Pulmonary: Acute chest syndrome, pulmonary hypertension
Renal: Hyposthenuria, CKD
Ocular: Retinopathy
Bone: Osteonecrosis
Splenic: Functional asplenia → ↑ infection risk
Prognosis & mortality trends
Improved with early diagnosis and modern care
Survival into 40s–60s possible
Leading causes of death:
Stroke, acute chest syndrome, sepsis, multi-organ failure