Value of bowel ultrasonography in the diagnosis of typhoid fever

Abstract

Objective: Mural thickening of ileum (MT) and enlargement of mesenteric lymph nodes (LN) has been previously reported by abdominal ultrasound (US) in three patients with typhoid fever (TF). This study was performed to define the features of MT and LN and to assess their sensitivity and specificity as diagnostic signs for TF. Materials and methods: This study consists of two steps: (1) evaluation of 95 patients affected from TF to analyze features of MT and LN signs. (2) Evaluation of 62 consecutive patients admitted for fever to compare abdominal US findings in 19 62 patients with fever due to TF against those observed in 43 62 patients with fever due to diseases other than TF. Bowel wall thickness of terminal ileum, caecum and ascending colon was measured by US in all cases within 1–5 days after admission (n.v. ≤ 3 mm). Number and size of mesenteric enlarged LN were also searched in all abdominal quadrants (normal size ≤ 5 mm). Results: Enlarged LN were detectable at US in 53 95 patients with TF (55.8%). They were always multiple (range = 5–14) and their diameter ranged 5–32 mm (mean: 14 mm). MT sign was evident at US in 35 out of the 95 patients (36.8%). MT was always associated with enlarged LN. Eighteen patients showed only LN. Bowel wall thickness ranged 4–9 mm. In the group of 62 patients admitted for fever, 13 19 patients with TF (68%) showed MT (thickness range = 4–8 mm) and/or enlarged LN (diameter range = 6–21 mm) at US. In the 43 patients affected from diseases other than TF, US showed MT and/or enlarged LN in 8 cases (18.6%). Sensitivity and specificity of MT and enlarged LN for diagnosis of TF in patients admitted for fever were 68 and 81% respectively with 77% accuracy. Conclusion: In areas with high incidence of Salmonella typhi infections, MT and enlarged LN at US can suggest the diagnosis of TF when serologic tests are negative and blood cultures are not yet available.