TUBERCULOUS INFECTION OF BONE AND JOINT

The incidence of TB. Infection is decrease in the developed countries during 1960 s and 1970 s of the last century due to improvement in the general health programs, and the improvement in the chemotherapy . There is increase in incidence of extrapulmonary TB.infection in the last 2 decades due to i.v. drug abuse , AIDS . The predisposing factors: all the conditions that decrease the defense mechanism of the body like ch. Debilitating diseases , drug abuse , prolong corticosteroid medication , AIDS .

pathology TB. M.O. either human type or bovine type , Enter the human body through : 1- droplet inhalation to the lung . 2- to the G.I.T. by infected milk . 3- through a wound in the skin . This type of M.O. not cause pyogenic infection like other bacteria , but it cause Granulmatous reaction which associated with tissue necrosis and caseation .

Pathology cont. Primary complex :initial small lesion in the lung , pharynx or gut with lymphatic spread to regional lymph node (primary complex) . Secondary spread :in case of decrease resistance to original infection ; wide spread via the blood lead to miliary TB.or meningitis or pulmonary TB. . Tertiary TB. : bone and joint are affected in 5% of patient with TB. ; skeletal TB. Affect mainly synovium of the larg joint and the vertebral body

The infection either started in the bone and spread to the joint or vice versa . Bone lesion spread quit rapidly ; epiphyseal plate is not act as a barrier . At the beginning the synonvium will be involved by the infection , this lead to effusion ; then panus of granulation tissue extend across the joint and destroy the articular cartilage slowly . The increase vascularity cause local osteoporosis . If the condition not treated , the infection may extend into the surrounding tissue to produce cold abscess and it is cold only in comparison to a pyogenic abscess and this may burst through the skin cause chronic discharging sinus .

If this condition treated early , there will be no residual injury to the joint . If the articular cartilage is damaged then the healing will be by fibrosis .

clinically The patient is usually a child or young adult , complain from pain and in the superficial joint there is marked swelling . In the advanced cases there may be fever , lassitude and loss of weight . The pain is mainly at night ; and this due to muscle relaxation at sleep ; also in advanced cases there will be muscle wasting and joint stiffness .

In the back the patient develop low grade back ache ; and some time the patient presented with visible swelling (abscess) in the groin or lumber spine( to one side of the mid line) . Or the patient presented with localized kyphosis due to collapse of the body of the vertebrae . Lastly the patient may presented with weakness and loss of sensibility of the lower limb

X-ray of TB.infection : Soft tissue swelling and periarticular osteoporosis are characteristic ; the bone ends take on a washed out appearance and narrow joint space . In spine there is bone erosion and collapse ; Soft tissue shadow may define a paravertebral abscess .

TB.arhritis(dec.joint space, periarticular osteoporosis)

Investigation ESR increased . Lymphocytosis . Mantoux test +ve (sensitive not specific) . Synovial fluid aspiration: cloudy, increase protein , acid fast bacilli identified in the synovial fluid in 10 – 20% of the cases ; and culture is +ve in 50%of the cases . Synovial biopsy show characteristic histological feature ; culture of the biopsy is +ve in 80% of the cases

Differential diagnosis 1- transient synovitis 2- pyogenic arthritis 3- monoarticular rheumatoid arthritis 4- hemorrhagic arthritis

treatment Rest : splintage of the joint or traction , the patient kept in bed . The symptoms are subside especially if the disease diagnosed and treated early . The changes take 6 months to subside completely , so returning to full activity not before that time . In neglected cases need prolong period of rest and immobilization to prevent ankylosis in bad position

Treatment cont. Chemotherapy : combination of anti TB. drugs usually contain refampicine , INH ,and ethambutol for eight weeks ; then refampicine and INH for further 8-12 months . Streptomycin and ethambutol are more toxic and they should not be used for long time .

surgical treatment Operative drainage of TB. Arthritis is seldom necessary now a day . A cold abscess need drainage . If the joint is severely destroyed and still there is sever pain during the movement of the joint after healing of TB. Infection , then arthroplasty (joint replacement) is indicated , and if it is impossible for any cause , then arthrodesis (joint fusion) is indicated to relief the pain .