Tuberculous osteomyelitis

Tuberculous osteomyelitis is one of the rarer musculoskeletal manifestations of tuberculosis.

Epidemiology

Tuberculous osteomyelitis accounts for ~20% of musculoskeletal tuberculosis ⁵.

Clinical presentation

Patients may present with a painful "cold abscess" with a localized mass/swelling +/- draining sinus with erythema or warmth; a low-grade fever may be present ^2,4. 

There is often a delay between presentation and diagnosis, with a median time to diagnosis reported as 26.4 months ⁴. 

Pathology

Most cases are caused by Mycobacterium tuberculosis with non-tuberculosis mycobacterial infections very rare although increased in the settings of AIDS ³. 

Location

Isolated tuberculosis osteomyelitis without associated tuberculous arthropathy most commonly occurs in the metaphyses of the ¹

• femur
• tibia
• small bones of the hand and foot (tuberculous dactylitis)

Radiographic features

Plain radiograph

Plain radiographs can be normal in early infection and when abnormal can show ^2,5:

• eccentric lytic lesion with minimal or no periosteal reaction
• a cortical defect may be present
• local osteopaenia

MRI

Tuberculous osteomyelitis has a variable appearance with signal characteristics similar to pyogenic osteomyelitis (i.e. low T1, high T2) being reported. One study of 11 cases has shown that some cases may have a slightly higher T1 peripheral rim and low-to-intermediate T2 signal and association with soft tissue abscess ⁵.

Differential diagnosis

• chronic pyogenic osteomyelitis: in the skeletally immature pyogenic infections tend not to cross the growth plate, whereas tuberculous infections can ¹
• Brodie abscess ²
• bone tumor ³