Diagnosis and Monitoring Treatment Response of Skeletal Tuberculosis of Foot by Three-phase Bone Scan: A Case Report

Skeletal tuberculosis (TB) is a very rare disease comprising 1-3 % of the total population of TB patients. Skeletal TB most often involves the spine. Involvement of foot is uncommon. We presented a case of skeletal TB of left foot. The initial three-phase bone scan showed a strongly positive result indicating osteomyelitis of left foot. Further evaluation confirmed the diagnosis of skeletal TB. Three-phase bone scan revealed partial resolution during anti-TB therapy. A negative study was shown one year later after clinical resolution of the disease. The successful treatment of skeletal TB requires early diagnosis and early anti-TB therapy. The definitive diagnosis of skeletal TB is isolation of bacteria from a bone biopsy. In clinical practice, noninvasive methods are useful diagnostic tools including clinical information, imaging studies, and laboratory findings. Three-phase bone scan is a sensitive test for diagnosis of skeletal TB. In cases of suspected skeletal TB, it can allow assessment of entire skeleton and provide guidance for biopsy in early stage when radiological imaging is normal. In cases with symptoms of bone infection, tuberculosis should be considered in differential diagnoses if bone scintigraphy is positive. Finally, three-phase bone scan might be helpful in monitoring treatment response of anti-TB therapy.