Hemoptysis in pulmonary tuberculosis - contrast CT scan diagnosing Rasmussen’s aneurysm

Clinical History

A 45-year-old male patient came to us with a history of massive haemoptysis two weeks before with complaints of low grade fever, weight loss, loss of appetite and shortness of breath for two months.
He had a remote history of pulmonary tuberculosis treated with a full course of therapy in the distant past.

Imaging Findings

Posteroanterior chest radiograph showed airspace consolidation in the right upper lobe (image unavailable).
Contrast-enhanced transverse Computed Tomography (CT) scan obtained at level of the trachea using mediastinal window setting showed a round cavitary lesion in the right upper lobe with intracavitary material and air surrounding it.
CT scan obtained 15 mm inferiorly showed contrast-enhancing round vascular structure in the consolidative lesion. The lesion enhancement was similar to the adjacent pulmonary artery.
CT angiogram demonstrated that this lesion is a saccular Rasmussen aneurysm.
CT scan showed also branching nodular and linear opacities (tree-in-bud signs) and centrilobular small nodule in the right lung and the left upper lobe.
Based on the imaging and clinical features (sputum positive for acid-fast bacilli) a diagnosis of pulmonary tuberculosis with Rasmussen’s aneurysm was made.
Antitubercular treatment was started, and the patient was referred to a university hospital for endovascular management of the aneurysm.

Discussion

Rasmussen’s aneurysm (RA) is an uncommon complication of pulmonary tuberculosis. It may form months to years after formation of the sequellar cavity [1].
Fritz Waldemar Rasmussen, a Danish physician, was the first who described 11 cases of pulmonary aneurysms in patients with tuberculosis in 1868 [2].
He described the RA as a pulmonary vessel traversing the wall of a tuberculous pulmonary sequellar cavity with its aneurysmal dilatation into this cavity [2].
Pulmonary tuberculosis has many complications and sequelae including bronchiectasis, pulmonary fibrosis, aspergilloma (in the cavity of post primary pulmonary tuberculosis), broncholithiasis, empyema, hypertrophy of the bronchial artery and RA. RA has the most devastating course of all these complications, and needs urgent and aggressive management; otherwise it can lead to death due to massive haemoptysis [1].
Progressive weakening of the arterial wall arises when granulation tissue takes the place of both the adventitia and the media. This granulation tissue is then gradually replaced by fibrin, causing thinning of the arterial wall, constitution of pseudoaneurysm, and consecutive rupture [3, 4].
RAs are frequently peripheral and beyond the branches of main pulmonary artery [5].
The prevalence of pulmonary aneurysms detected by multidetector CT in a large retrospective series of 189 patients with massive haemoptysis from tuberculosis was 6.9% [6].
Attentive evaluation of unenhanced and post-contrast CT scan of lungs will show focal contrast enhancement in the aneurysm [7]. CT angiography or Digital Subtraction Angiography (DSA) can confirm the diagnosis. This may be the first clue to the correct cause of the haemoptysis.
Endovascular occlusion of the neck of the pulmonary aneurysm is generally successful in managing the haemoptysis [8]. Steel coils are the best occlusive material; but when vascular access is impossible, thrombin and cyanoacrylate injection percutaneously under fluoroscopic and ultrasound guidance can be used [8, 9].
Even if uncommon, RA are a significant aetiology of massive haemoptysis in patients with tuberculosis. Accurate evaluation of the post-contrast CT examination may be useful in suggesting the correct diagnosis.

Differential Diagnosis List

Final Diagnosis

Rasmussen’s aneurysm

URL:	https://www.eurorad.org/case/13388
DOI:	10.1594/EURORAD/CASE.13388
ISSN:	1563-4086