Our case report describes a unique manifestation of LS, characterized by the rare complication of an internal carotid artery and internal jugular vein fistula, followed by the development of septic thrombosis leading to aneurysm formation and cerebral infarction. This anomaly was observed following a periodontal abscess and tonsillitis, evolving into deep neck space, mediastinal, and chest abscesses, along with left IJV thrombophlebitis. This sequence of events underscores the critical nature of LS and its potential to progress to life-threatening complications, despite the initial administration of broad-spectrum antibiotics. The rarity of this presentation within the context of LS contributes significantly to the medical literature, highlighting the need for vigilance in cases of persistent oropharyngeal infection symptoms, especially when accompanied by vascular complications.
Once labeled the 'forgotten disease' in the 1980s due to effective antibiotic use, LS, a deadly disease in the preantibiotic era, has experienced a documented increase in incidence mainly attributed to the increase in antibiotic resistance (6). Despite its rarity, the syndrome presents diagnostic challenges, necessitating a comprehensive, multidisciplinary approach for effective management (5,7,8). Our case underscores the crucial importance of early diagnosis and prompt initiation of targeted therapy to address potentially life-threatening complications (6).
Demographically, LS primarily affects young individuals, typically aged 15 to 24 years, with a peak incidence in the second and third decades of life and a slightly greater male incidence (male-to-female ratio of 2:1). However, it has been documented in individuals across a wide age range, from as young as 2 months to as old as 78 years (3,9). Fusobacterium necrophorum, identified as the causative agent in 10% of peritonsillar abscesses and 81% of LS cases, is an anaerobic bacterium prevalent in the oropharynx, genitourinary system, and gastrointestinal tract (5,8,10). Heightened suspicion should arise when oropharyngeal pharyngitis or periodontal abscess persists beyond 3 to 5 days and is accompanied by systemic or respiratory symptoms, lateral cervical pain, dysphagia, progression to sepsis or multiple pulmonary abscesses (5,8,9,11)
The common presentation of LS is unilateral neck discomfort and inflammation at the anterior border of the sternocleidomastoid muscle after a recent throat infection (3,12). The detection of this syndrome may be easily overlooked or delayed since patients typically exhibit a palpable, tender cord (or 'cord sign') of the internal jugular vein in only 26% to 45% of cases (1,3,8,13). Furthermore, microbiology laboratories often encounter challenges in cultivating Fusobacterium necrophorum, as observed in our case. The conclusive identification of pathognomonic anaerobes through blood cultures in the laboratory may require several days for growth on specialized media that are not routinely utilized in most laboratory settings (9,10). Moreover, the identification process may be impeded by the widespread use of antibiotics for outpatient treatment of pharyngitis (1,5,14).
The peritonsillar abscesses spread via hematogenesis or through the lymphatic system. Venous drainage of the palatine tonsils occurs through the peritonsillar plexus of veins, which drains into the pharyngeal and lingual veins and ultimately into the internal jugular vein. The palatine tonsils drain to the jugulodigastric node, a node of the deep cervical lymph nodes, where the posterior belly of the digastric muscle crosses the internal jugular vein (15). The most common metastatic abscess sites are the lung (empyema or cavitary nodules), mediastinum, brain, and IJV (2,16). Other organs that may be affected include the bone/joint (septic arthritis), the soft tissue and muscle, intraabdominal abscesses in the liver or spleen, and the central nervous system (in the form of chronic infarcts or abscesses and/or meningitis) (4,10,17,18). In our patient, the infection spread in the cervical, thoracic, or mediastinal spaces up to the dura sinus, and left IJV thrombosis and then left ICA thrombosis resulted in chronic infarction of the left MCA territory (19). The aneurysm at the left common carotid artery CCA-carotid bulb resulted from thrombophlebitis and mechanical pressure from the fistula, leading to damage to the left CCA wall and subsequent aneurysm formation, as typically described in the literature on aneurysm pathophysiology (20–23). However, to the best of our knowledge, this is the first case of LS involving a carotid-jugular vein fistula, a left carotid bulb CCA and left ECA aneurysm, and extensive vascular thrombosis leading to cerebral infarction.
Historically, LS diagnosis has relied on criteria such as primary head or neck infection, thrombosis of head/neck veins, and isolation of Fusobacterium necrophorum from blood cultures (2,5). However, evolving diagnostic criteria currently acknowledge challenges in isolating Fusobacterium necrophorum, making it nonmandatory, as a result of potential negative cultures resulting from empirical antibiotic therapy (10,17). Radiological investigations, particularly duplex ultrasonography, CT scans, and magnetic resonance imaging, play a crucial role in diagnosis. Contrast-enhanced CT is considered optimal because it offers accessibility, cost-effectiveness, and visualization of adjacent structures (6,24). The radiological findings reported in other studies align with our case, where similar modalities were employed and yielded comparable results, confirming the diagnosis of LS.
Our patient received ceftriaxone and metronidazole in combination with anti-TB therapy following the standard treatment protocol because of the high TB prevalence in this region. This combination was effective in treating extensive abscesses. Although neither Ceftriaxone nor anti-TB drugs are known for treating LS, evidence indicates that similar cephalosporins have been effective against LS due to their action on anaerobic bacteria (10)(25). Given the occurrence of beta-lactamase-producing Fusobacterium. For necrophorum strains resistant to macrolides and penicillin (6,26), the literature recommends the use of a beta-lactamase-resistant beta-lactam antibiotic in conjunction with metronidazole, which is initially advised for two weeks, transitioning to metronidazole alone for six weeks (13,14). This approach ensures deep penetration into fibrin clots and addresses potential resistance issues. The use of antituberculosis therapy underscores the diagnostic challenges of LS, a condition easily mistaken for others due to its severity and rarity, as well as the complexities involved in identifying the responsible bacteria.
The use of prophylactic anticoagulant agents for managing LS remains a subject of considerable debate within the medical community. This controversy stems from the disparate findings reported in the literature, compounded by the disease's rarity, which inherently limits the feasibility of conducting statistically robust trials to assess the effectiveness of anticoagulation therapy comprehensively (27). Despite these challenges, a consensus among several authors advocates for the utilization of anticoagulation therapy in LS patients as a strategy to mitigate neurological complications. This underscores the importance of a tailored approach that weighs the estimated risk of venous thromboembolism against potential contraindications (5,6,13,14). Specifically, the deployment of anticoagulant therapy is recommended for patients identified as high risk, emphasizing a judicious evaluation of benefits and risks (28,29). In the case presented, the incorporation of an anticoagulant regimen is strongly corroborated by evidence from the literature, which posits that anticoagulation, particularly in scenarios of carotid thrombosis, is associated with a diminished recurrence of ischemic events (30,31).
In the context of LS, surgical procedures have predominantly focused on the drainage of pus, as indicated by the literature (10). To our knowledge, the present case is unprecedented in necessitating vascular surgery as a part of LS management. Surgery was required to mitigate the effect of the mass on cranial nerves IX and XII. The standard of care for treating infected carotid artery pseudoaneurysms predominantly involves traditional open repair. This approach includes aneurysmectomy, debridement of surrounding infected tissues, and carotid artery ligation (32–35). Revascularization of the ICA is generally considered only in cases where it is deemed essential, such as in patients with bilateral ICA disease (36,37). This cautious approach is due to the potential risk of embolic events in the brain (38,39). In line with recommendations from several studies, our patient underwent ligation of both the left ICA and the ECA without attempting revascularization of the left IJV and ICA, owing to thrombosis. During the repair process, we observed evidence of spontaneous closure of the internal jugular vein-carotid artery (IJV-ICA) fistula, which was secondary to thrombosis in both the IJV and ICA. These observations are consistent with findings reported in the literature, specifically the spontaneous resolution of direct carotid-cavernous fistulas documented in 2019 (40,41)