Introduction

For purposes of description osteoarticular tuberculosis can be discussed under the following heads:

·                 Tuberculosis of joints

·                 Bone tuberculosis

·                 Spine tuberculosis

Infection of a joint or bone with Mycobacterium tuberculosis is almost always secondary to a primary focus, in the lymphatic glands or lungs or mesentery, from where it disseminates by hematogenous route. Malnutrition or any debilitating disease, poor environment increase the incidence of the disease. Patients with immunodeficiency disease or HIV infection are more prone to develop tuberculosis. Primary bone tuberculosis is not uncommon.

Involvement of any bone or joint in the body can be affected by tuberculosis.

Case definition the lesion in the joint can be:

·                 Extra-articular

·                 lntra-articular: It can originate in the bone (osseous lesion) or in the synovium (synovial disease).

Vertebral body involvement with tuberculosis is the most common and is nearly equal to tuberculosis of all other regions put together.

There may be a history of trauma, under the effect of which a small hematoma may form resulting in vascular stasis in that area. The hematoma may become a nidus for the tubercle bacilli to settle down and form a tuberculosis follicle with caseation, epitheloid cells, giant cells and fibrosis at the periphery.

The response to a tuberculous lesion is exudative and may form a cold abscess, which is nothing but a collection of necrotic material, caseous tissue and the exudative reaction. These cold abscesses than track through the fascial planes or the neurovascular bundles and may present at a distant site. Since the abscess is away from the area of inflammatory activity, it has no signs of inflammation in the skin overlying the abscess. A superficial abscess may burst and result into a sinus or an ulcer.

Granulation tissue is almost always present in the tuberculous lesion. lschemic necrosis of bone due to endarteritis and thromboembolic phenomenon in bone lead to formation of sequestra, which in osseous tuberculosis happen to be small. Isolated large sequestrate in osteroarticular tuberculosis are rare.

Differential Diagnosis

It can mimic almost any condition seen in bone like chronic osteomyelitis, osteoid osteoma, fibrous dysphasia, malignant/benign tremors.

Prevention and Counseling

In case of pain, swelling, night cries fever an orthopedics surgeon may be consulted.

Clinical Diagnosis

The tuberculosis of the joints mainly involves big joints. The common differential diagnosis includes pauciarticular juvenile chronic arthritis and septic arthritis. The involvement of joints may be osseous or synovial but if not treated, one would infect the other. Tuberculous synovitis leads to effusion in the joint and synovial membrane becomes edematous. At this stage the joint would look swollen and movements may be present or limited due to muscle spasm. The radiological picture may show an increased joint space.

Clinical features

It is characteristically insidious in onset, and starts as monoarticular or mono-osseous involvement. The child complains of pain in the joint, aggravated by movement, and often wakes 'up at night because muscle spasm gets reduced and causes pain. It is classically called as "night cries". Low- grade fever, loss of weight and appetite are some of the symptoms of generalized toxemia usually seen. Joint movements are painful and elicit muscle spasm on attempted movement. In later stages when the cartilage gets eroded, all movements get restricted. Muscle atrophy around the joint is a predominant feature and occurs early. Sometimes an abscess forms, which bursts to form a sinus. It may get secondarily infected and may alter the radiological picture.

Investigations

·                 Blood- A low hemoglobin, relative lymphocyfosis and raised erythrocyte sedimentation rate (ESR) are often found in the active stage of the disease. The ESR is often used as aguide in monitoring the progress of the disease during treatment, though some people do not consider it a reliable investigation.

·                 Mantoux Test- A positive Mantoux test is seen in patients with active tuberculous lesion. A negative test may rarely be seen in severe or disseminated disease or in an immunocompromised patient.

·                 Radiographic Examination- It can be diagnostic in view of the typical radiological appearance of the tuberculous lesions. In early stage of the joint disease, capsular markings may become prominent. The earliest sign is widespread osteoporosis around a joint. Lytic lesions and periosteal reaction are seen, although latter is much more prominent in pyogenic infection.

In case of joints, small bone erosions occur near the capsular reflection. Joint space decreases due to cartilage erosion and lytic lesions are seen in the epiphyseal area. The radiological signs of a healing lesion are absence of rarefaction and bony ankylosis.

·                 Smear and Culture- Tuberculous pus, joint aspirate, granulation tissue, sputum etc. may be examined by smear and culture for tubercu bus bacilli.

·                 FNAC (Fine Needle Aspiration Cytology)- Occasionally, even the most

modern methods of imaging may not help the clinician to reach to a final diagnosis, and therefore FNAC or biopsy may be undertaken to obtain tissue diagnosis. FNAC is now available for the cytological diagnosis of vertebral tuberculosis. 'Biopsy is a safe and a quick diagnostic procedure with high accuracy in the hands of trained cyfopathologists. It is recommended that it should be practiced in all diagnostic centres of our country, even for suspected vertebral tuberculosis.

Biopsy

Biopsy may have to be done in cases where there is doubt about the diagnosis, particularly in the early stages of the disease. Biopsy from the bone or synovium can provide on early diagnosis for starting the treatment in time and preventing damage to the joint. Biopsy from a cystic lesion in the bone or from synovium is more likely to be positive.

Treatment

The patient's response to treatment is as variable as anywhere else in the body and is dependent upon the host resistance, severity of infection, and the stage of the disease when the diagnosis is first made and treatment started. Eradication of the disease and preservation of function are important both in osseous and joint diseases.

General measures:

Good nutrition consisting of a high-calorie and high-protein diet is essential to be the resistance. General rest and local rest to the specific bone and joint are essential path treatment Local rest can be provided by means of splints or plaster casts However, in where the articular surface is not involved a judicious blend of rest and mobilization has to be resorted to for restoration of function.

Chemotherapy:

Most of osteoarticular lesions would respond to antituberculous drugs if the therapy is started early.

A standard drug regimen is given which includes rifampicin, pyrazinamide, ethanbutol, isoniazid, and in some cases even streptomycin. The latter is useful because it kills the rapidly multiplying extracellular tubercle bacilli in the lungs for the initial six months. After two clinically and radiologically clear intervals, pyrazinamide is stopped and isoniazed, rifampicin and ethambutol are continued for one year. In some cases therapy may be required for 18 months for complete healing of the lesion. In case the infection is suspected to be with multidrug resistant ofloxacin, capreomycin, kanamycin, etc. may have to be given.

Surgical Treatment

Surgical treatment is an adjunct to the anti-tuberculosis drug therapy. The surgical procedures generally perfomed in children are:

•           Drainage of an abscess

•           Excision of a focus

•           Curettage of the lesion

•           Synovectomy

•           Costotransversectomy

•           Anterolateral decompression

The general principle of surgery in tuberculosis demands that the abscess should be completely evacuated. In case of an osseous lesion, all sequestra, granulation tissue and caseous material should be removed till new bleeding bone is encountered, so that the antibiotics may reach the site of lesion better. The cavities so produced should be packed with autogenous bone grafts. Avoid dead spaces to prevent hematoma formation and close the wound primarily with or without suction.  -

Tuberculosis can involve any bone or joint of the body but in children it has a special predilection for the hip and knee joints commonly, and for ankle and elbow joints rarely. Tuberculosis of spine with or without paraplegia is extremely common. Long bones are rarely involved but the short long bone involvement is somewhat common.