The purpose of our study was to evaluate clinical and CT findings of paradoxical response during treatment for abdominal tuberculosis.

Authors reviewed the patient records of 138 patients with abdominal tuberculosis during a recent 6-year period and we selected 11 patients with a paradoxical response. The CT findings and pathologic findings of the initial lesions and new lesions were reviewed. The intervals between initiation of therapy and the detection of new lesions, improvement of new lesions and the final follow-up were evaluated.

At the initial presentation, we identified tuberculous peritonitis in 8 patients, tuberculous lymphadenitis in 3 patients and ileocolic tuberculosis in two patients. New lesions were identified at 2-10 months (mean: 3.8 months) after the initiation of therapy and following improvement of the initial lesions. The new lesions were perihepatic caseous abscess (n=4), hepatic tuberculoma (n=3), hepatic caseous abscess (n=1), tuberculous lymphadenitis (n=3), ileocolic tuberculosis (n=3), and splenic tuberculoma (n=1). Improvement of new lesions was noted at 4-14 months (mean: 7.6 months). At the final follow-up of seven patients, the new lesions disappeared and four patients still had small residual lesions.

New lesions that develop in a patient with initial improvement should be considered a paradoxical response that will ultimately improve with continuation of the original medication.