Ultrasonography and contrast-enhanced CT findings of tularemia in the neck

Abstract

Purpose: We aimed to evaluate the ultrasonography (US) and contrast-enhanced computed tomography (CECT) findings of tularemia in the neck.

Methods: US and CECT findings of 58 patients with serologically proven tularemia were retrospectively evaluated. Forty-eight patients underwent US and 42 patients underwent CECT. Lymph node characteristics and parotid preauricular region involvement were analyzed using US and CECT. In addition, involvement of larynx, oropharynx, and retropharynx; presence of periorbital edema; and neck abscess formation were evaluated using CECT. Fine needle aspiration cytology (FNAC) results of enlarged lymph nodes were analyzed in 29 patients.

Results: Hypoechoic pattern, round shape, absence of hilum, and cystic necrosis were seen in most of the lymph nodes especially at level 2 and 3 on US and CECT. Matting was more commonly observed than irregular nodal border on US and CECT. Parotid preauricular region involvement was seen in 20.8% of patients on US. Oropharyngeal, retropharyngeal, laryngeal and parotid preauricular region involvement and periorbital edema were seen in 52.4%, 19.1%, 4.8%, 31%, and 9.5% of tularemia patients, respectively. Neck abscess was found in 59.5% of patients on CECT. Suppurative inflammation was the most common finding of FNAC.

Conclusion: Tularemia should be considered in the presence of level 2 and 3 lymph nodes with cystic necrosis, matting, absence of calcification, oropharyngeal and retropharyngeal region involvement, and neck abscess, particularly in endemic areas.

Figure 1

a, b. A 46-year-old woman presented with swelling on the left side of the neck. Gray scale US (a) shows enlarged level 2 lymph node, which is round and hypoechoic without echogenic hilum (arrows). Intranodal cystic necrosis (arrowhead) is seen. Longitudinal US (b) of the same patient shows multiple matted lymph nodes with internal hypoechoic areas consistent with necrosis on the left side of the neck. This patient was diagnosed with the glandular form of tularemia.

Figure 2

A 50-year-old woman with glandular tularemia. Contrast-enhanced CT shows typical tularemic lymph nodes with cystic necrosis (arrows) at left level 1 and 2. Additionally, enlarged lymph node (arrowhead) is seen at right level 2.

Figure 3

a, b. Contrast-enhanced CT (a) shows multiple matted enlarged lymphadenopathy (arrows) with intranodal cystic necrosis. Abscess formation (arrow) is seen near the sternocleidomastoid muscle at the more inferior level of the neck in the same patient (b).

Figure 4

A 45-year-old woman with oropharyngeal tularemia. Coronal reformatted CT image shows oropharyngeal inflammatory soft tissue (arrows) on the right side, which obliterates parapharyngeal fatty tissue. Lymphadenopathies with cystic necrosis (arrowhead) are seen at right level 2.

Figure 5

A 36-year-old woman with oropharyngeal tularemia. Sagittal reformatted CT image demonstrates retropharyngeal abscess (arrow), which was not visible on US.