From the Guidelines
Acute chest syndrome is a life-threatening complication of sickle cell disease characterized by a new segmental infiltrate on a chest radiograph, accompanied by lower respiratory tract symptoms, chest pain, and/or hypoxemia, as defined by the most recent guidelines 1. The condition can present acutely or after initial presentation for a pain event and with or without fever, and is a leading cause of hospitalization and death in sickle cell patients. Key features of acute chest syndrome include:
- New pulmonary infiltrates on chest X-ray
- Lower respiratory tract symptoms
- Chest pain
- Hypoxemia
- Potential triggers such as infections, fat embolism from bone marrow, or pulmonary infarction Management of acute chest syndrome typically involves:
- Oxygen therapy
- Pain control
- Antibiotics, such as a macrolide like azithromycin plus a cephalosporin such as ceftriaxone
- Incentive spirometry to prevent atelectasis
- Hydration
- Sometimes blood transfusions or exchange transfusions in severe cases, with the choice between simple and exchange transfusion depending on the severity of the disease and the patient's baseline hemoglobin level 1. Prompt recognition and treatment are essential to prevent progression to respiratory failure and improve outcomes in patients with acute chest syndrome.
From the Research
Definition of Acute Chest Syndrome
- Acute chest syndrome (ACS) is a life-threatening, potentially catastrophic complication of sickle cell disease 2, 3, 4, 5, 6.
- It is characterized by fever and/or respiratory symptoms, accompanied by a new pulmonary infiltrate on a chest X-ray 2, 4, 5.
- The diagnostic criteria for ACS include a new infiltrate on pulmonary imaging combined with any of the following: fever > 38.5°C (101.3°F), cough, wheezing, hypoxemia (PaO2 < 60 mm Hg), tachypnea, or chest pain 2.
Epidemiology and Clinical Presentation
- ACS occurs in approximately 50% of patients with sickle cell disease, with up to 13% all-cause mortality 2.
- It is most common in children aged 2-4, and up to 80% of patients with a prior diagnosis of ACS will have recurrence of this syndrome 2.
- Patients with ACS may present with fever, dyspnea, cough, chills, chest pain, or hemoptysis 2, 3, 4.
Pathophysiology and Etiology
- The pathophysiology of ACS involves vaso-occlusion in pulmonary vessels resulting in hypoxia, release of inflammatory mediators, acidosis, and infarction of lung tissue 2.
- The most common precipitants of ACS are infections (viral or bacterial), rib infarction, and fat emboli 2, 3, 4.
- Other risk factors for ACS include younger age, severe SCD genotypes, lower fetal hemoglobin concentrations, higher steady-state hemoglobin levels, higher steady-state white blood cell counts, history of asthma, and tobacco smoke exposure 4.