From the Guidelines
Acute chest syndrome is primarily caused by infection, pulmonary infarction, and pulmonary fat embolism, as well as other factors such as hypoventilation and reactive airway disease, in individuals with sickle cell disease. The condition develops when these triggers lead to lung tissue damage and respiratory complications. Several specific triggers can precipitate acute chest syndrome, including:
- Respiratory infections (particularly pneumonia caused by atypical organisms like Mycoplasma and Chlamydia) 1
- Pulmonary infarction
- Pulmonary fat embolism
- Severe pain crises
- Hypoventilation due to pain medication or thoracic splinting from rib infarction, which can worsen the condition by causing atelectasis 1
- Reactive airway disease, which can increase the incidence of acute chest syndrome in children with sickle cell disease 1 The pathophysiology involves a cycle of hypoxia causing more sickling, which further worsens hypoxia, creating a dangerous cascade effect that can rapidly progress to respiratory failure if not promptly treated 1. Early recognition and aggressive treatment with oxygen, incentive spirometry, analgesics, antibiotics, and often, simple or exchange transfusions, may be necessary to prevent morbidity and mortality 1.
From the Research
Causes of Acute Chest Syndrome (ACS)
The causes of Acute Chest Syndrome (ACS) are multifactorial and can be attributed to various factors, including:
- Infection, which is the most common identifiable cause of ACS 2, 3, 4, 5, 6
- Fat embolism, which is a common precipitant of ACS, especially in patients with sickle cell disease 2, 3, 5, 6
- Vaso-occlusive crisis (VOC), which can trigger ACS in patients with sickle cell disease 4, 5, 6
- Asthma, which is a risk factor for developing ACS, especially in children with sickle cell disease 4, 5
- Opiate overdose, which can trigger ACS due to resulting hypoventilation 5
- Pulmonary infarction, which can occur due to increased adhesion of sickle red cells to pulmonary microvasculature in the presence of hypoxia 5
- Bronchial hyperresponsiveness, which is a risk factor for developing ACS 6
- Hypoxia, which can contribute to the development of ACS 3, 5, 6
Risk Factors for ACS
Several risk factors have been identified to be associated with an increased incidence of ACS, including:
- Younger age, especially in children with sickle cell disease 5
- Severe SCD genotypes (SS or Sβ0 thalassemia) 5
- Lower fetal hemoglobin concentrations 5
- Higher steady-state hemoglobin levels 5
- Higher steady-state white blood cell counts 5
- History of asthma 5
- Tobacco smoke exposure 5
- SCD genotype 6
- Opioid use 6