10/09/2025
ACUTE CHEST SYNDROME (ACS):
Definition:
A life-threatening complication of sickle cell disease, characterized by a new pulmonary infiltrate on chest X-ray plus one or more symptoms: fever, cough, chest pain, tachypnea, wheezing, or hypoxemia.
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Causes (Multifactorial)
1. Infection (viral, bacterial – Mycoplasma pneumoniae, Chlamydia, Streptococcus pneumoniae)
2. Pulmonary infarction (sickled cells → vaso-occlusion in lung vessels)
3. Fat embolism (from bone marrow infarction)
4. Hypoventilation (due to pain, atelectasis after surgery or narcotics)
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Clinical Features
• Fever
• Chest pain
• Cough, wheezing
• Tachypnea, dyspnea
• Hypoxia
• Pulmonary infiltrate(s) on CXR (new, not chronic)
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Investigations
• Blood tests: CBC (anemia, leukocytosis), Reticulocyte count ↑
• Arterial blood gas: hypoxemia
• CXR: new infiltrates (often multilobar, lower lobes common)
• Blood culture, sputum culture to rule out infection
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Management (Emergency)
“ABCDE” approach
1. A – Antibiotics (empiric, broad spectrum: cephalosporin + macrolide)
2. B – Breathing support (oxygen, incentive spirometry)
3. C – Control pain (avoid excessive opioids → hypoventilation)
4. D – Decrease sickling
• IV fluids (careful – avoid overload)
• Blood transfusion or exchange transfusion (improves O₂-carrying capacity, reduces HbS