Sickle cell crises in the lung - otherwise referred to as acute chest syndrome (ACS) - are characterised by pleuritic chest pains, fever, abnormal chest examinations and presence of new infiltrations in the chest X ray (1).
- is the second most common cause of hospital admission in SCD patients (2)
- study evidence showed that 50% of patients with sickle cell crises in the lung, had a pain event in the two weeks preceding the event (3)
- around half of all SCD patients will experience at least one episode of ACS during their lives (4)
- in some areas, the acute chest syndrome is the commonest cause of death in sickle cell anaemia.
They are of mixed pathology; caused by a combination of infection, fat embolism and vaso occlusion of the pulmonary vasculature (2)
- mostly seen during early childhood (usually presents with clinical features that are more typical for pneumonia) (2)
- is a combination of pulmonary infarction, infection, and fat embolism (3)
- caused by sickling and ischaemia in deep tissues of the chest wall (3)
- a review describes typical features as fever, acute respiratory signs and symptoms, such as cough, wheezing, dyspnoea, crepitations or chest pain, and consolidation on chest radiograph (3)
- in later childhood and adulthood, it is more frequent during a painful crises or after anaesthesia (1)
A combination of clinical signs or symptoms of chest consolidation and worsening hypoxia is sufficient for the diagnosis of ACS (since X ray changes often lag behind clinical signs) (4)
Local protocols should be prepared for management of ACS and should include:
- analgesia
- monitoring arterial blood gas measurement
- oxygen and respiratory support - persistent, profound hypoxia is an indication for ventilation.
- incentive spirometry – useful in SCD patients presenting with chest or back pain above the diaphragm to prevent pulmonary complications
- fluid management
- bronchodilator therapy – for patients with evidence of wheeze or reversible airways disease, or a history of asthma
- antibiotic treatment may be indicated
- blood transfusion (4)
Longterm treatment with hydroxycarbamide (former British Approved Name, hydroxyurea) has led to a reduction by 50% in acute chest syndrome in some studies.
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