Joint tuberculosis in children: causes, symptoms, diagnosis, treatment

Tuberculous lesions of the skeleton in children and adolescents are characterized by extensive destruction of bones and joints, leading to early and steadily progressive disability in the absence of adequate treatment. In most children under 7 years of age, anamnestic data indicate the appearance of the first signs of the disease in the first 3 years of life, but the diagnosis was established at this age in only half of the cases.

The pathogenesis of bone and joint lesions is usually associated with lymphohematogenous spread of mycobacteria to various organs during primary infection. The pathogenesis of bone complications of BCG vaccination is similar, when, as a result of natural dissemination of mycobacteria of the BCG strain from the site of their parenteral administration, either isolated tuberculous foci are formed in the bones (BCG osteomyelitis), or multiple specific lesions develop in different organs and systems (BCG sepsis).

Symptoms and diagnosis of tuberculosis of the joints in children

Diagnosis of osteoarticular tuberculosis in children is carried out in parallel in two directions:

• determination of the activity and prevalence of tuberculosis infection;
• determination of the prevalence of local lesions and their complications.

The activity and prevalence of tuberculosis infection in a child with osteoarticular tuberculosis is assessed in specialized anti-tuberculosis institutions: the fact of infection with MBT, the clinical form of intrathoracic tuberculosis, the degree of sensitivity to tuberculin are established, and other organ lesions are identified.

Diagnosis of local lesions of bones and joints is carried out on the basis of clinical and radiological examination methods.

• The appearance of the affected skeletal region, the presence of abscesses, fistulas, the extent of deformations, contractures, the degree of limitation of organ functions, and pathological neurological symptoms are clinically assessed.
• The basic method of radiation assessment is standard radiography of the affected skeletal section in two projections. To clarify the diagnosis, special methods are used - X-ray tomography, CT, MRI. Each of the specified methods is used according to indications depending on the localization of the process and the diagnostic tasks set.

In the presence of abscesses, fistulas, material from previously performed operations or biopsies, a bacteriological, cytological and/or histological examination is performed.

In the clinical picture of tuberculous osteitis, the leading complaints are moderately expressed transient pain in the limb or joint, moderate edema, lameness (in case of damage to the bones of the lower limbs), later accompanied by limited mobility of the affected limb, reactive arthritis. The general condition of children usually does not suffer, symptoms of intoxication are detected either in multiple bone foci or in the presence of an active intrathoracic tuberculous process. X-ray examination reveals extensive destructive cavities, usually localized in the epimetaphyses of long tubular bones, communicating with each other through a defect in the growth cartilage and often accompanied by a periosteal reaction. In ostitis of small tubular bones, their diaphysis is usually affected, which is radiologically manifested by its swelling and massive destruction (spina ventosa tuberculosa). Radiographic changes detected in tuberculous ostitis often cause erroneous diagnosis of chronic osteomyelitis or tumor and lead to inadequate surgical interventions leading to the formation of fistulas. The correct diagnosis is made either based on a combination of clinical, radiographic, laboratory data and tuberculin tests, or based on the results of histological examination of surgical material.

Differential diagnostics of tuberculosis of joints in children

Differential diagnosis for various lesions of bones and joints has its own characteristic features.

Differential diagnostics of tuberculous ostitis is carried out with focal forms of chronic hematogenous osteomyelitis, bone tumors (osteoid osteomas, chondroblastomas, giant cell tumors), monostotic form of fibrous dysplasia, fibrous cortical defect.

• Focal chronic hematogenous osteomyelitis is usually found in school-age children; the onset of the disease is accompanied by a temperature reaction, laboratory changes (leukocytosis, increased ESR). In young children, chronic osteomyelitis occurs extremely rarely.
• The similarity of the clinical picture of some bone tumors with tuberculous osteitis is due to pain syndrome and reactive synovitis. Tumors are more common in school-age children and are characterized by persistent pain. Chondroblastomas are characterized by epiphyseal localization of the tumor, the focus of destruction has unclear contours and dense inclusions. Osteoid osteoma on radiographs and CT scans looks like a localized focus of rarefaction up to 1-2 cm in diameter against the background of osteosclerosis and hyperostosis. Giant cell tumors are characterized by adolescence, metaphyseal localization of the focus, its polycyclic structure, and bone swelling.
• Dysplastic processes in bone (monostotic form of fibrous dysplasia, fibrocortical defect) are usually accompanied by minimal subjective complaints and are often discovered by chance during X-ray examination.
• Differential diagnostics of rheumatoid arthritis and villous synovitis with primary tuberculous synovitis is carried out on the basis of bacteriological, biochemical and cytological examination of synovial fluid, as well as histological examination of a biopsy of the synovial membrane. In case of damage to the hip joint, differential diagnostics are also carried out with Perthes disease.

Differential diagnostics of spinal tuberculosis in children is carried out with non-specific inflammatory lesions, congenital malformations of the vertebrae, degenerative and tumor processes. They are characterized by a low level of specific allergy according to tuberculin tests, serological and immunological diagnostics.

• Chronic hematogenous osteomyelitis of the spine is typically diagnosed in adolescence, with a history of acute onset of the disease with severe pain syndrome and temperature reaction. Laboratory studies reveal moderate leukocytosis, increased ESR, and dysproteinemia. Radiography reveals less profound contact destruction of the bodies of the II-III vertebrae with osteosclerosis of the affected bodies than in tuberculosis.
• In non-specific inflammatory processes in the spine, MRI predominantly reveals changes in the intervertebral disc (deformation and disappearance of the nucleus pulposus, edema or degeneration of the disc) with an increase in the signal from the bodies of the contact vertebrae.
• Among developmental defects, tuberculous spondylitis is usually differentiated from congenital kyphosis type I, caused by disorders of the formation of vertebral bodies. The anomalies are characterized by the absence of anamnestic, clinical and laboratory signs of inflammation, and radiological examination reveals a violation of the shape of the vertebrae while maintaining their clear contours, structure and the absence of a reaction of soft tissues.
• Among degenerative diseases of the spine in children, tuberculous spondylitis is most often differentiated from juvenile osteochondrosis, usually detected in adolescence. Degenerative processes are characterized by the absence of anamnestic, clinical and laboratory signs of inflammation. On radiographs, as a rule, over a significant length of the spine, loosening of the endplates of the vertebral bodies, changes in their configuration, cartilaginous nodes and Schmorl's nodes are revealed.
• Among tumor and tumor-like diseases, tuberculous spondylitis is most often differentiated from spinal lesions in Langerhans cell histiocytosis, hemangioma, osteoid osteoma, giant cell tumors. Suspicion of a tumor process always requires cytological or histological confirmation.