Subclavian artery aneurysm: a rare cause of massive haemoptysis

Abstract

A 35-year-old man was admitted to the intensive care unit with massive haemoptysis. CT of the chest revealed a necrotic right upper lobe mass. Angiography of his thoracic vasculature revealed a pseudoaneurysm in the right subclavian artery with active contrast extravasation. This anatomic deformity was stented and coiled with the assistance of interventional radiology. Bronchoscopy with lavage and brushings of the right upper lobe mass revealed fungal hyphae and positive galactomannan, supporting that the patient developed invasive pulmonary aspergillosis leading to a mycotic pseudoaneurysm of the right subclavian artery followed by massive haemoptysis.

Background

This case documents and illustrates one of the more uncommon causes of massive haemoptysis that we witnessed while training as critical care physicians. Massive haemoptysis is a life-threatening condition given the risk of asphyxiation. A mycotic pseudoaneurysm of the subclavian artery should be part of the differential diagnosis, especially in patients who are immunocompromised or have a history of illicit drug abuse.

Case presentation

A 35-year-old Caucasian man presented with a 1-day history of haemoptysis after 4 weeks of non-productive cough. He reported a 6-month history of weight loss but denied fever, chills, night sweats, any foreign travel or prior episodes of haemoptysis. He does have a prior history of using marijuana and cocaine. He has been living in a homeless shelter and notes that many of the residents have been coughing, although none with haemoptysis. Physical examination revealed a dishevelled male in no respiratory distress. He had a temperature of 101.3°F with a pulse of 140 beats/min. A CT angiography of the chest revealed a large bilobular necrotic-appearing mass in the right lung apex with mediastinal lymphadenopathy (figure 1). Initial laboratory work revealed a haemoglobin of 102 g/L and a white cell count of 15.9×10⁹ cells/L. On the following day, the patient had an episode of massive haemoptysis leading to cardiopulmonary arrest. After resuscitation, emergent bronchoscopy was performed and revealed haemorrhage from the apical segment of the right upper lobe. A bronchial blocker was placed to tamponade the bleeding. Haemoglobin level dropped to 57 g/L. He was transfused with 2 units of packed red cell count. Right bronchial arteriogram and empiric embolisation of the right bronchial artery was performed, although no pathology was found on arteriogram. Other thoracic vasculature was not examined at this time. Six days later, a second episode of massive haemoptysis with subsequent cardiopulmonary arrest led to emergent arteriography revealing a large right subclavian artery pseudoaneurysm (figure 2). The subclavian artery was stented with a 7 mm×5 cm Viabahn stent across the mouth of the pseudoaneurysm. Post-stenting angiography demonstrated a patent vertebral artery and stent but persistent filling of the pseudoaneurysm (figure 3). Because of this persistent filling defect, coil embolisation of the pseudoaneurysm was performed with two 4 mm Nester coils and one 7/3 tornado coil. Post-embolisation arteriography revealed no further flow within the pseudoaneurysm and a patent right subclavian artery (figure 4). Next, the patient underwent bronchoscopy. Transbronchial brushings of the right upper lobe were obtained. No malignant cells were identified; however, a few structures suggestive of fungal hyphae were visualised. Regarding the cell count of the bronchial wash, 3% lymphocyte, 9% macrophages, 1% monocytes and 87% segmented neutrophils. Given these findings, amphotericin B was added to his regimen along with vancomycin and piperacillin-tazobactam.

Figure 1.

Mass-like consolidation in the right apex.

Figure 2.

Contrast extravasation within the right subclavian artery pseudoaneurysm.

Figure 3.

A 7 mm×5 mm Viabahn stent deployed across the mouth of the pseudoaneurysm with persistent contrast filling the pseudoaneurysm.

Figure 4.

Post-coil embolisation revealing no further flow within the pseudoaneurysm and a patent right subclavian artery.

Outcome and follow-up

Following the above interventions, the patient has had no more episodes of massive haemoptysis. Unfortunately, due to his cardiac arrest, the patient suffered from significant neurological deficits and anoxic brain injury. Thoracic surgery had been consulted for possible right upper lobectomy; however, given his neurological status, this option was not perused. Goals of care were discussed with the family. A palliative and comfort-centred approach was perused.

Discussion

Massive haemoptysis is a fatal condition resulting in asphyxia from airway obstruction and exsanguination. Mortality rates from massive haemoptysis are generally between 30% and 70%.¹ Although challenging at times, due to the high mortality rate, it is imperative to find the aetiology of haemoptysis in a timely fashion.

Subclavian artery aneurysm (SAA) leading to haemoptysis is uncommon. Between 1960 and 1980, the Mayo Clinic reviewed 32 cases of subclavian axillary artery aneurysms and 14 were located in the subclavian artery.¹ The current prevalence is unknown. The incidence of mycotic subclavian artery pseudoaneurysms is even less well defined. The subclavian artery rises from the brachiocephalic trunk. As it ascends above the clavicle, the pleura is in close proximity, which separates it from the apex of the lung. There are various causes for an aneurysm to occur in the subclavian artery including atherosclerosis, thoracic outlet syndrome, collagen disorder, trauma and infection. If symptoms do manifest, it typically presents as shoulder pain, thrombosis and even Horner’s syndrome from local compression of the sympathetic nerve supply.² Haemoptysis is an uncommon presenting symptom. It can be difficult to detect an SAA even in the presence of frank haemoptysis. Once the patient’s airway and haemodynamics are stabilised, diagnosis is acquired through CT of the chest with angiography. Angiography through interventional radiology is another alternative method for diagnosis and can provide an immediate therapeutic option as well. Given the rarity of this condition, there are no guidelines published to direct treatment. Of the reported cases reviewed, treatment options included ligation and excision of the aneurysm, aneurysmorrhaphy, cardiopulmonary bypass and coil embolisation.³ It is unclear in the patient’s chart why the first arteriography only visualised the bronchial vessels and not the rest of the thoracic vasculature. Perhaps a more thorough evaluation at that time would have demonstrated the right subclavian artery pseudoaneurysm earlier in his course.

Infected pseudoaneurysms occur in individuals who are immunosuppressed, whether that be from medications or chronic medical conditions like end-stage renal disease, diabetes mellitus, liver cirrhosis, alcoholism, recent chemotherapy, transplant history, illicit drug use or HIV. Our patient did have a bronchoscopy with bronchial wash and brushings earlier in his hospital course which did reveal positive Aspergillus galactomannan as well as a few structures suggestive of fungal hyphae. The patient certainly could have developed a mycotic pseudoaneurysm in the subclavian artery by erosion of the vessel from an adjacent process of the lung by direct extension or lymphatics leading to rupture due to invasive aspergillosis. Although we do not have surgical pathology demonstrating septated hyphae with dichotomous acute angle branching, a positive galactomannan antigen, evidence of fungal hyphae on the bronchial fluid, and clinical presentation certainly raises invasive aspergillosis to be part of the differential diagnosis.

Learning points.

• Aneurysm originating from the subclavian artery leading to massive haemoptysis is infrequently reported and should be on the differential diagnosis when performing an assessment for massive haemoptysis.

• Once the patient’s airway is stabilised, diagnosis of this condition is made through CT of the chest with angiography or an angiography through interventional radiology which provides a therapeutic avenue as well.

• Invasive pulmonary aspergillosis is seen most commonly in immunodeficient patients including stem cell transplants, solid organ transplants, HIV and neutropenia.

• Transbronchial biopsies of the lung with histopathological evaluation showing hyphae support the diagnosis of invasive pulmonary aspergillosis but the culture is required to confirm the identity.