Clinical History
A-8-year-old girl had severe left ankle pain during walking for two weeks. The medical history was unremarkable. Physical examination revealed no pathology.
Imaging Findings
A-8-year-old girl had severe left ankle pain during walking for two weeks. The medical history was unremarkable. Physical examination revealed no pathology. Plain radiography of the left ankle showed a poorly defined area of radiolucency that was centered at the postero-inferior aspect of trochlea tali. Cortical surface was irregular. Decreased bone density with prominent trabeculation due to profound osteoprosis was noted at calcaneus and other tarsal bones (Fig 1). Computed tomography (CT) demonstrated an osteolytic lesion that involved posterior aspect of the talus (Fig 2). At magnetic resonance (MR) imaging performed in the sagittal plane, the lesion and the rest of the talus were heterogeneously hypointense on T1-weighted SE images (Fig 3a) and hyperintense on T2-weighted SE images (Fig 3b). There was marked high signal intensity joint effusuion at the tibiotalar and talocalceneal joints (Fig 3c). On contrast-enhanced T1-weighted images, moderate and heterogeneous contrast enhancement was observed at the lesion (Fig 3c).
Discussion
Skeletal tuberculosis represents about 3% percent of all cases of tuberculosis and about 30% of all cases in extrapulmonary location (1). Practically all osseous and articular foci are hematogeneous secondary to a primary focus elsewhere, mostly in the lung.
The most common tuberculosis bone lesion is in the spine, the most frequent tuberculosis arthritis is in the hip or knee (2). The great majority of tuberculosis bone and joint lesion begin in childhood and adolescence. But last years with the increasing rate of acquired immunodeficiency syndrome (AIDS) and the development of resistance to the antituberculosis agents, it is begun to seen more frequently in elderly people (3). Tuberculosis of the ankle involves the tibiotalar joint more commonly than the talocalcaneal joint (1). There is a hematogenous focus in the ossification center of talus in the majority of cases and the infection secondarily extends into the tibiotalar joint. The talus become cavitated and may be completely destroyed. In healing, bony ankylosis between tibia and talus always occurs. Advanced tuberculosis of tibiotalar joint may extend into the talocalcaneal joint. Isolated tuberculosis of the calcaneotalar joint usually follows hematogenous infection of the calcaneal ossification center. This is most likely to occur in patients between the ages of 6 and 16. In patients younger than 6 years, the ossification center of calcaneus is surrounded by a thick layer of cartilage and therefore isolated tuberculosis of the calcaneus is not uncommon (1). Other tarsal bones may participate in advanced tuberculosis of the ankle, but isolated lesions are rare. Healing tuberculosis of the ankle shows some osteosclerosis because of the mechanical burden.
Radiographic findings in tuberculosis include joint effusion, periarticular osteopenia (3,4), joint space narrowing, cortical irregularity (3), lytic lesions, periosteal new bone formation (4) and advanced epiphyseal maturity (3). Monoarticular disease is the rule. Joint effusion may be one of earliest sign of the tuberculosis arthritis. Periarticular osteopenia is the most common finding associated with tuberculosis especially in the weight-bearing joints of the lower extremities than in the upper extremities (3,4). Gradual narrowing of the interosseous space is the characteristic feature of the tuberculosis. Cortical irregularity is common at the bare areas of bone adjacent to the edges of the articular cartilage (3). Round or oval lesions with poorly defined margins in bone adjacent to the affected joint are a common finding in extremity tuberculosis, particularly in children (3). Periosteal new bone formation is relatively uncommon (3).
There is no single pathognomonic finding with which to make the diagnosis of skeletal tuberculosis. Clinical information is crucial but may be without pulmonary manifestation. Periarticular osteopeni, subchondral erosions, slowly progressing joint space narrowing with the formation of oval lytic lesion at the bones adjacent to the joints, especially in the children should suggest the diagnosis of tuberculosis.
Differential Diagnosis List
Histopathologic evaluation of biopsy material showed tuberculosis
Final Diagnosis
Histopathologic evaluation of biopsy material showed tuberculosis
