King Edward Memorial Hospital - Departments: Radiology

Radiology

RASMUSSEN'S ANEURYSM: TREATMENT WITH ENDOVASCULAR EMBOLISATION

Case 27: Contributed by Dr Yogeshwari Deshmukh

Other Cases

Case Report :

A 54-year-old female patient, a known case of hypertension, ischemic heart disease and diabetes mellitus presented with two episodes of massive hemoptysis (300cc at each episode) over a month's duration not responding to conservative management . She had been diagnosed as a case of pulmonary tuberculosis; was an anti tuberculous treatment defaulter; her general condition was poor with severe pallor and tachycardia. Auscultation revealed crepitations in the left upper and mid zones. Her hemoglobin was 7.2 gm%.
A contrast CT scan, in arterial phase, revealed an intensely enhancing 2.5 x 2 cm vascular lesion in the medial wall of a cavity in the left upper lobe (Fig.1).

Fig. 1

Reconstructed images showed the lesion to be arising from the posterior descending branch of the left pulmonary artery


Fig. 2	Fig. 3	Fig. 4

MR Pulmonary angiography revealed an intensely enhancing lesion measuring approximately 3cm in diameter in the posteromedial aspect of cavity in the left upper lobe. (Fig.5)


Fig. 5

Pulmonary angiography confirmed the CT and MR angiographic findings (Fig. 6, Fig.7)


Fig. 6	Fig. 7

Coil embolisation of the aneurysm was performed using a 5F- H1 catheter with two steel coils (35-5-8 "COOK) via the right transfemoral venous route (Fig.8).


Fig. 8

Post embolisation angiography revealed complete isolation of aneurysmal sac from the circulation (Fig.9, Fig.10).


Fig. 9	Fig. 10

The patient had only streaky hemoptysis for two days after the embolisation and was hemoptysis free for next two days. She was discharged on the fourth post procedure day.

DISCUSSION:

Solitary peripheral pulmonary artery aneurysms are a rare entity. Their etiology includes trauma, infection, congenital or acquired pulmonary vascular abnormalities and pulmonary hypertension. The eponym Rasmussen's aneurysm refers specifically to a tuberculous etiology. A pulmonary artery mycotic aneurysm in a tuberculous cavity is known as a Rasmussen's aneurysm.

Rasmussen's aneurysm is a rare phenomenon caused by weakening of the pulmonary artery wall from adjacent cavitary tuberculosis. A review of autopsy findings in patients with a history of chronic cavitary tuberculosis showed a 5% prevalence of Rasmussen's aneurysm. They are usually peripheral and beyond the branches of the main pulmonary artery. Any destructive lung process, irrespective of its pathogenesis, can destroy adjacent lung, weaken the arterial wall or erode any vessel in its vicinity. Progressive weakening of the arterial wall occurs as granulation tissue replaces both the adventitia and the media. The granulation tissue in the vessel wall is then gradually replaced by fibrin, resulting in thinning of the arterial wall, pseudoaneurysm formation and subsequent rupture. Rasmussen's aneurysm involves the small to medium pulmonary artery branches that develops in the vicinity of a tuberculous cavity and are usually distributed peripherally and beyond the branches of the main pulmonary arteries.

Hemoptysis is the usual presenting symptom. It can present as repeated episodes of minor hemoptysis or as a single episode of major hemoptysis which can be life-threatening.

A Rasmussen aneurysm has to be systematically searched for in patients with hemoptysis from a destructive process of the lung. Even in tuberculous patients, the major cause of hemoptysis is of bronchial and not pulmonary arterial origin. Spiral CT angiography including pulmonary and levo phases, helps in diagnosing the lesion. Immediately after a bleeding episode, the aneurysm sac can be collapsed in the cavity. Consequently further CT angiography is advised a few hours after an episode of hemoptysis. Pulmonary angiography is helpful in localizing the lesion as also to plan for endovascular or surgical management.

When hemoptysis is scanty and the radiology does not reveal a significant lesion, medical management is appropriate. If the hemoptysis is large, energetic measures must be taken to identify the lesion. Fibreoptic bronchoscopy will help in localizing the segment of the bleed and bronchial blockade will help prevent asphyxiation when active bleeding is occurring. Transcatheter embolisation is ideal to control the bleeding in an emergency or elective setting. During embolisation active search must be made for multiple sites of bleeding because non-bronchial systemic artery may be the cause of bleeding. Coil embolization is a safe and effective means of treating these pseudoaneurysms.

Surgical excision is recommended where expertise for radiological intervention is not available or when there is considerable destructive process in the lung producing infections like Coccidiodes immitis or aspergilloma.