Rasmussen aneurysm

Last revised by Mostafa Elfeky on 3 May 2023

Rasmussen aneurysm is an uncommon complication of pulmonary tuberculosis and represents a pulmonary artery aneurysm adjacent or within a tuberculous cavity.

It is not to be confused with Rasmussen encephalitis.

It can be present in up to 5% of patients with chronic cavitary tuberculosis on autopsy. 

Hemoptysis is the usual presenting symptom and may be life-threatening when it is massive. 

A weakening of the pulmonary artery wall from adjacent cavitary tuberculosis is the cause of this condition: there is a progressive weakening of the arterial wall as granulation tissue replaces both the adventitia and the media. This is then gradually replaced by fibrin, resulting in thinning of the arterial wall, pseudoaneurysm formation, and subsequent rupture with hemorrhage. 

Usually distributed peripherally and beyond the branches of the main pulmonary arteries 2.

CT pulmonary angiography is the investigation of choice 4. Often seen on contrasted chest images as a focal dilatation of one of the pulmonary segmentary arteries adjacent to tuberculous parenchymal change or a chronic tuberculous cavity.

It is named after Danish physician Fritz Valdemar Rasmussen (1837-1877).

It is almost pathognomonic if present in the right clinical content and in the vicinity of a tuberculous cavity. 

In atypical cases consider:

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