Guideline on the management of acute chest syndrome in sickle cell disease – PubMed (nih.gov)
Most common in HbSS and HbS-betao-thalassemia than HbSC or HbS-beta+-thalassemia.
Mortality rate of 4.3% in adults
Pathophysiology:
Vaso-occlusion of the pulmonary microvasculature caused by:
- Increased RBC sickling
- Emboli (fat/bone marrow) released due to bone
marrow ischemia
- Bone marrow necrosis leads to increased inflammatory cytokine production and hypoxemia, leading to worsening vaso-occlusion. The most common triggers for vaso-occlusion in adults are asthma, hypoventilation and infection (most frequently by atypical bacteria).
Triggers:
- Asthma exacerbation
- Hypoventilation
- Infection
- Smoking
Diagnosis:
Acute Chest is characterized by evidence of a new consolidation on imaging and at least one of the following:
- Fever (>38.5˚C)
- Increased oxygen requirement
- Tachypnea
- Increased work of breathing or wheezing
- Chest pain
- Cough
- Rales
- A rapid drop in platelet count may indicate a more rapidly progressive form of ACS.
Management:
- Fluid management- it is essential to keep the patient well hydrated and avoid pulmonary edema. Can start at 1.5x maintenance D5 1/2NS and decrease the rate as PO intake improves.
- Pain control
- Empiric antibiotic therapy- ACS is indistinguishable from pneumonia so patients should receive empiric CAP treatment (note ceftriaxone can cause drug-induced immune hemolysis)
- Transfusion- increases oxygenation and decreases
the number of sickle RBCs in circulation
- Exchange transfusion is recommended over simple transfusion in cases of rapidly progressing or severe acute chest syndrome (requires HD catheter and coordination with blood bank)