Acute chest syndrome in sickle cell disease is a leading thoracic complication - as well as leading cause of mortality - in those affected by sickle cell disease. The diagnosis is made on the combination of new pulmonary opacities on chest radiograph with at least one new clinical symptom or sign.
For a general discussion of sickle cell disease, please refer to sickle cell disease.
On this page:
Clinical presentation
Patients may present with acute fever, cough, wheezing, tachypnea and/or chest pain on a background of established sickle cell disease.
Pathology
There is no single underlying etiology in acute chest syndrome but rather a variety of infectious and non-infectious causes including 5:
rib or sternal infarct causing atelectasis (from splinting)
Radiographic features
Plain radiograph
Chest radiograph typically shows segmental or subsegmental atelectasis/consolidation with a lower lobe predilection, and/or pleural effusion.
A chest radiograph may also show other sequelae from sickle cell disease such as bone infarcts, rib enlargement, and cardiomegaly (from anemia).
Ultrasound
Point-of-care lung ultrasonography in acute chest syndrome may reveal one of the following patterns;
-
alveolar consolidation
the most common abnormality found, with a posterobasal regional predilection
air bronchograms may be visualized
-
anterior subpleural consolidations
presence of small (≤1 cm) crescentic hypoechoic collections disrupting the pleural line (C-lines thought to represent lung infarction 10)
often associated with adjacent pleural thickening and loss of lung sliding
-
lung rockets
three or more B-lines per sonographic field, typically 3 cm apart (B3 lines): defines the sonographic interstitial syndrome
bilateral diffuse anterolateral interstitial syndrome may be observed 7
CT
CT may show a mosaic perfusion pattern that may be associated with a pleural effusion. The radiographic signs above may also be seen on CT.
Treatment and prognosis
Broad-spectrum antibiotics, bronchodilators, and oxygen form the basis of treatment 12. Although severity is variable, 13% of patients with acute chest syndrome require ventilation and 3% do not survive 12.
History and etymology
The term was first proposed in patients with sickle cell disease by Charache et al. in 1979 to describe the combination of chest pain, fever, leukocytosis, and the appearance of a new opacity on a chest radiograph.
Differential diagnosis
General imaging differential considerations include: