22 April 2012
Unilateral cervical lymphadenitis is a common presentation to hospital. Catastrophic vascular complications associated with these infections are rare, and very few cases have been reported in children.1,2 We report a case of a mycotic pseudoaneurysm secondary to a parapharyngeal infection with reactive lymphadenitis.
A previously healthy 20-month-old girl presented with a 5-day history of fever and lethargy. On examination a large, tender, non-fluctuant right-sided submandibular neck swelling was discovered (Fig. 1). Examination of her oropharynx revealed a medialised right tonsil with no trismus, stridor, airway compromise or dysphagia. The diagnosis of lymphadenitis was made and no imaging was performed. Treatment with 3 days of intravenous ticarcillin-clavulanate led to significant improvement, and she was discharged with 7 days of amoxycillin-clavulanate. One week later the patient presented with an acute recurrence of the right neck swelling and fever. An ultrasound of the neck, suggested the diagnosis of a pseudoaneurysm, but was not definitive. A computed tomography (CT) scan was performed (despite our reluctance to employ that modality in view of high radiation exposure) to provide a diagnosis and detailed anatomy that assisted the vascular surgeon in devising a safe management approach.
CT angiogram of the neck (Fig. 2) confirmed a pseudoaneurysm of the right lingual artery (a branch of the external carotid artery) (13 × 8.5 × 7.4 mm) within a large irregular parapharyngeal collection (58 × 28 × 44 mm in maximal dimensions).
Neck exploration and repair of the pseudoaneurysm were performed on the same day. The right external carotid artery was ligated and the collection drained. The organism identified was Streptococcus anginosus (Streptococcus milleri). Blood cultures taken were negative for bacterial growth. Two weeks of intravenous antibiotics was completed (initially ticarcillin-clavulanate and benzyl penicillin, and later changed to ceftriaxone on the basis of microbiological sensitivities). On review there were no cranial nerve deficits. Repeat ultrasound revealed no fluid collection. She made an excellent recovery.
Mycotic pseudoaneurysm of a branch of the external carotid artery is a rare complication from infection in the head and neck region.3 In children, this can occur from loco-regional spread from adjacent soft tissue abscess or embolisation from an infected thrombus.1 In our case, the patient had adenitis, which initially responded to treatment, but then had recurrence in the second week of treatment. This led to further investigations, revealing the parapharyngeal collection and pseudoaneurysm. The most common species of bacteria that cause mycotic aneurysms are Staphylococcus and Salmonella.1 However, any organism that can cause skin or mucous membrane infections in the head and neck region can cause adenitis in the lymph nodes. The untreated mortality from pseudoaneurysm of the carotid artery is reported to be up to 77%,3 most likely due to catastrophic haemorrhage into the upper aero-digestive tract. However, with treatment this rate is reduced to 35%.3
In conclusion, pseudoaneurysm of the branch of the external carotid artery is a rare complication of parapharyngeal abscess. A notable feature in both our case and those referenced1–3 was the recurrence of disease after the second week of treatment. Successful patient outcome depends on the rapid recognition and treatment of this rare but potentially devastating complication.1–3