For Doctors in a Hurry
- Clinicians often struggle to identify rare vascular complications following untreated upper respiratory infections in elderly patients.
- The researchers documented a 78-year-old patient who developed a mycotic pseudoaneurysm of the internal carotid artery.
- Microbiological analysis identified Pseudomonas oryzihabitans as the causative pathogen in this specific vascular infection case.
- The authors conclude that direct bacterial invasion via periarterial lymphatics likely caused this rare arterial wall damage.
- Physicians should consider mycotic pseudoaneurysm when patients present with a pulsatile neck mass after recent respiratory illness.
Extracranial carotid artery aneurysms are rare clinical entities, with those of infectious or mycotic origin representing a particularly challenging subset for vascular surgeons [1]. While Staphylococcus species and Mycobacterium tuberculosis remain the most frequently identified pathogens, these lesions often arise from direct local spread or hematogenous seeding, which is the spread of bacteria through the bloodstream [1, 2]. Clinical presentation typically involves a pulsatile neck mass and fever, though compression of adjacent structures can lead to respiratory distress or neurological deficits [1, 3]. Current management strategies are shifting toward endovascular interventions due to lower complication rates compared to open surgical reconstruction, yet the high risk of fatal hemorrhage necessitates prompt diagnosis [1, 4, 3]. A recent case report now provides new insights into the role of rare opportunistic pathogens and the potential for common infections to trigger these life-threatening vascular complications.
Clinical Presentation and Diagnostic Imaging
The clinical course began when a 78-year-old gentleman presented to the vascular surgery department with the abrupt formation of a pulsatile neck mass and concurrent hoarseness. His medical history revealed that three weeks prior to admission, he had experienced symptoms of an upper respiratory tract infection, which he described as a common cold. Despite the persistence of these symptoms, the patient did not seek medical attention for the initial respiratory illness, a delay that likely allowed for the progression of the underlying infection. This case represents a rare instance of a mycotic pseudoaneurysm, an infected arterial wall lesion where the vessel wall is breached and the hematoma is contained only by the surrounding soft tissues, developing in an elderly patient following a previously untreated upper respiratory tract infection.
To evaluate the rapidly expanding mass, clinicians performed a contrast computed tomography (CT) scan. The imaging studies identified a pseudoaneurysm of the left internal carotid artery (ICA), confirming a localized disruption of the arterial wall. The diagnostic imaging further showed that the pseudoaneurysm was compressing the laryngeal wall, providing a clear anatomical explanation for the patient's hoarseness. This finding necessitated immediate surgical intervention to prevent rupture and restore vascular integrity, as the lesion posed a significant threat to the patient's airway and neurological stability. For the practicing clinician, this highlights the importance of considering vascular complications when a patient presents with sudden onset hoarseness or neck swelling following a recent infection.
Surgical Intervention and Pathogen Identification
To address the immediate risk of rupture and alleviate the compression on the laryngeal wall, the surgical team performed an excision of the pseudoaneurysm. This procedure required the complete removal of the infected and compromised segment of the left internal carotid artery to ensure no residual nidus of infection remained. Following the debridement of the infected site, the surgeons prioritized the maintenance of cerebral perfusion. Blood flow was restored using a saphenous vein graft interposition, a technique where a segment of the patient's own vein is used to bridge the gap in the artery. This autologous reconstruction is frequently selected in the context of mycotic lesions because biological tissue typically demonstrates higher resistance to recurrent infection than synthetic prosthetic materials, which are prone to biofilm formation and persistent sepsis.
The subsequent microbiological report provided definitive identification of the underlying pathogen, confirming a bacterial infection caused by Pseudomonas oryzihabitans. This organism is characterized as an opportunistic bacterium, meaning it typically lacks the virulence to infect healthy hosts but can cause severe disease in individuals with weakened immune defenses or through direct entry into the bloodstream. The researchers emphasized that this is the first reported case describing Pseudomonas oryzihabitans as a causative agent for a mycotic pseudoaneurysm of the internal carotid artery. The clinical significance of this finding lies in the recognition that even common respiratory symptoms can precede the translocation of rare environmental pathogens into the vascular system, leading to life-threatening arterial wall destruction. Clinicians should remain vigilant for unusual pathogens in patients with atypical infectious presentations.
Pathophysiology of Direct Bacterial Invasion
The clinical management of mycotic pseudoaneurysms of the extracranial internal carotid artery is notoriously difficult because these lesions are rare and challenging to manage due to their proximity to critical cranial nerves and the high risk of cerebrovascular accidents. In this specific case, the timeline suggests a direct link between the patient's untreated upper respiratory tract infection and the subsequent arterial wall failure. The researchers proposed that the presumed mechanism of pseudoaneurysm formation was direct microorganism invasion of the arterial wall, a process that bypassed the intimal surface, or the innermost lining, of the vessel.
This pathological progression likely occurred via the periarterial lymphatics and the vasa vasorum, which is the specialized network of small blood vessels that supply oxygen and nutrients to the walls of large arteries. By infiltrating these microvascular and lymphatic channels, the Pseudomonas oryzihabitans bacteria were able to establish a nidus of infection within the tunica media and adventitia, the middle and outer layers of the artery. This localized infection led to the progressive weakening and eventual rupture of the arterial layers, resulting in the abrupt formation of the pulsatile neck mass and laryngeal compression observed three weeks after the initial respiratory symptoms. This mechanism underscores the potential for localized infections to migrate into the vascular wall even in the absence of systemic bacteremia, necessitating a high index of suspicion in patients with persistent localized symptoms.
References
1. Hanger M, Hamilton G, Baker D. Mycotic Extracranial Carotid Artery Aneurysms: A Systematic Review. Journal of Vascular Surgery. 2022. doi:10.1016/j.jvs.2022.03.144
2. Matić P, Ljatifi E, Atanasijević I, Pešić S. Mycotic Pseudoaneurysm of the Internal Carotid Artery After a 'Common Cold': A Rare Case Report.. Vascular and endovascular surgery. 2026. doi:10.1177/15385744261447463
3. Rajagopal R, Sharma S, Bagarhatta M, Tiwari S, Bagarhatta R. Endovascular Management of Internal Carotid Artery Pseudoaneurysm Secondary to Pediatric Deep Neck Space Infection: A Case Report and Review of Literature. The Arab Journal of Interventional Radiology. 2022. doi:10.1055/s-0041-1740341
4. Hot A, Mazighi M, Lecuit M, et al. Fungal Internal Carotid Artery Aneurysms: Successful Embolization of an Aspergillus-Associated Case and Review. Clinical Infectious Diseases. 2007. doi:10.1086/523005
