CASE 12500 Published on 15.03.2015

Pulmonary hypertension secondary to sickle cell disease


Paediatric radiology

Case Type

Clinical Cases


Bernardo Silvia1, Haque Saira2

(1) Department of Radiological, Oncological
and Pathological Sciences,
“Sapienza” University of Rome, Italy;
(2) King's College Hospital, London, UK

10 years, male

Area of Interest Arteries / Aorta, Haematologic, Paediatric, Lung, Bones, Cardiovascular system ; Imaging Technique CT, CT-Angiography, Conventional radiography, CT-High Resolution
Clinical History
The patient presented to the emergency department with chest pain and wheezing. Blood tests showed chronic anaemia (haemoglobin 86 g/L and foetal haemoglobin 5.8). Serum biochemistry demonstrated minor haemoylsis (bilirubin of 46 μmol/L, alanine aminotransferase of 24 IU/L and lactate dehydrogenase of 865 IU/L). No associated fever, cough or difficulty in breathing.
Imaging Findings
The patient was known to have longstanding left lower lobe collapse on serial radiographic imaging. The chest radiograph demonstrated progressive enlargement of the aortopulmonary window. A subsequent CT shows volume loss in the left lower lobe. The pulmonary artery (PA) trunk is significantly larger than the adjacent ascending aorta (AA), indicating a PA/AA ratio greater than 1. The PA diameter has been measured at the level of the PA bifurcation, and the AA diameter has been averaged from two perpendicular measurements taken from the same CT image. There is also increase in the segmental artery size relative to adjacent bronchus with loss of peripheral vascularity. The right atrium is dilated. The HRCT images demonstrate mosaic perfusion pattern throughout the lung parenchyma. A reticular pattern of innumerable interlacing line shadows suggesting a mesh-like appearance is seen in the lower lobes.
Sickle cell disease (SCD) is a hereditary autosomal recessive disorder of haemoglobin resulting in chronic anaemia and vaso-occlusion. The main clinical features of SCD in all four genotypes are chronic haemolytic anaemia and microvascular obstruction resulting in acute and chronic ischaemia with painful crises. This can lead to infarction and fibrosis causing irreversible damage to vital organs at an early age [1]. The acute chest syndrome (ACS) in SCD is defined as a new infiltrate on chest radiograph associated with one or more symptoms, such as fever, cough, sputum production, tachypnoea, dyspnoea or new-onset hypoxia. Pulmonary infections can cause ACS and the most common causes included Chlamydia, Mycoplasma and viral infections. Other causes include pulmonary vaso-occlusion, thromboembolism and fat embolism from ischaemic or necrotic bone marrow [2].
Chest radiographic findings of ACS include segmental, lobar or multi-lobar consolidation. Chest radiography can underestimate the degree of pulmonary involvement. CT shows consolidation, ground glass attenuation and paucity of small vessels.
Sickle cell chronic lung disease is presumed to occur secondary to recurrent infection and infarction leading to a significant reduction in pulmonary function and when severe possibly leading to secondary pulmonary hypertension [3]. Studies have shown a correlation between the number of previous episodes of ACS and the degree of interstitial lung abnormalities. Chest CT in sickle cell chronic lung disease shows scars of repeated small pulmonary infarcts, which lead to fibrosis. CT findings include traction bronchiectasis, interlobular septal thickening, parenchymal bands and distortion of pulmonary architecture, which are predominantly seen in a basal distribution.
Secondary pulmonary hypertension is a recognised complication in patients with sickle cell disease. This may be asymptomatic initially but can present with progressive shortness of breath, dyspnoea, chest pain, impaired exercise tolerance and progressive right heart failure. The mechanism of pulmonary hypertension is multifactorial and occurs secondary to progressive obliteration of the pulmonary vasculature. Radiological findings show an increase in the size of the central pulmonary arteries, an increase in the size of the main segmental pulmonary arteries with distal attenuation and pruning of the arteries, related to the adjacent bronchus (loss of artery-bronchus ratio), right ventricular hypertrophy, right atrial dilatation and mosaic perfusion [4].
Pulmonary complications are common and account for a large proportion of deaths among patients with SCD [5]. New drug therapies are being developed that may be beneficial; it is thus important to provide appropriate treatment at an early stage in order to prevent secondary pulmonary hypertension at a young age.
Differential Diagnosis List
Sickle cell crisis with pulmonary hypertension.
Drug-induced pulmonary hypertension
Congenital cardiac disease (e.g. PPVD/septal defect)
Primary pulmonary hypertension
Pulmonary veno-occlusive disease
Final Diagnosis
Sickle cell crisis with pulmonary hypertension.
Case information
DOI: 10.1594/EURORAD/CASE.12500
ISSN: 1563-4086