Sickle Cell
- Sickle cell disease (SCD) and its variants - genetic disorders resulting from the presence of a mutated form of Hb, HbS.
- most common form of SCD = homozygous HbS disease (HbSS), an autosomal recessive disorder
Pre-empting factors which may promote erythrocyte sickling (and vaso-occlusive crises) include:
- Hypoxemia is the strongest stimulus for sickling (deoxygenated hemoglobin S is less soluble).
- Acidosis
- Dehydration
- Infection and inflammation
- Fever
- Stasis of blood (e.g., reduced cardiac output)
Types of sickle cell crisis presentations:
1. fever
- consider veno-occlusive disease, acute chest syndrome, osteomyelitis, local or systemic infection
- vaso-occlusive crisis
- assume this is the cause of any painful presentations
2. acute chest syndrome
- life-threatening lung infarction
- assume if hypoxia + chest pain
3. acute splenic sequestration
- typically occurs in infants
- associated with increased spleen size
- fall in Hb by >20 g/L, thrombocytopenia but normal or increased reticulocytes
4. aplastic crisis
- fall in Hb as well as reticulocytes <1%
- triggered by parvovirus infection
5. stroke
6. priapism
- stuttering (2-4h duration and may be recurrent)
- severe (>4 hours and may lead to permanent impotence)
Management
Priorities:
- Analgesia - requires aggressive pain Mx
- oxygenation
- rehydration - ECF (N saline)
- may need transfusion
- may need antibiotics
- avoid thrombolytics in stroke
- priapism may require surgical intervention