Tuberculous bones and joints

When tuberculosis involves a patient's skeleton, it is the involvement of his joints that matters most[md]his spine, hips, knees, feet, elbows, wrists, and shoulders, in this order of frequency, and occasionally his other joints also. Bacilli reach his joints from some focus elsewhere. So look for lesions in his lungs, and for signs of surgical tuberculosis in other parts of his body. Look particularly for enlargement of his lymph nodes.

He is usually a young adult, or a child over 6 years, although children as young as a year and older people can also be infected. He complains that one or more of his joints has become progressively painful and stiff during the previous few weeks. If his leg is involved, his first complaint is a limp. His infected joint fills with fluid, and the muscles round it waste. He usually has only mild to moderate pain, except on forced movement. Tuberculous arthritis is ''cold', which means that the skin over his infected joint is the same temperature as his normal skin. His joint is not ''hot', as it is in septic arthritis. Sometimes he has systemic symptoms, such as mild fever, night sweats, or loss of weight or appetite. Pain and fever may be quite marked. He may also have signs of tuberculosis in his chest, or a family history of it.

In a synovial joint, the disease starts in the synovium and grows slowly over the cartilage; it then extends through the cartilage into the underlying bone, which decalcifies. In the spine, disease starts in a disc. If you can treat him before his cartilage is destroyed, his joint will recover fully, or nearly so. If you start later, his articular cartilage will be destroyed, so that even if his disease is arrested, his joint will develop a fibrous ankylosis (except in the spine, when ankylosis is always bony). Sometimes, cold abscesses and sinuses form, become secondarily infected, and may track for a considerable distance.

If a tuberculous joint is secondarily infected, the ankylosis that results is always bony.

His diseased limb develops a flexion contracture, and its joints may subluxate or dislocate, especially his hip, knee, shoulder, or elbow.

You can treat tuberculous joints successfully and cheaply[md]if you diagnose them early enough, and can make sure that a patient takes his drugs. ''Early', here means the first few weeks. But even if treatment starts late, when his joint surfaces have already been destroyed, he can expect a fairly good result[md]if you can prevent deformities and contractures.

There are no certain diagnostic signs, so the secret is always to be suspicious. Whenever you see any chronic bone or joint disease, ask yourself: ''Might this be tuberculous?'' If it is, you can treat it. Biopsying a node or the synovium will confirm the diagnosis in about half the cases (see below). If you cannot send tissue for biopsy, you will probably have to rely on the characteristic X-ray changes. Even so, your error rate should be small.

Try to: (1) Give him the drugs he needs in adequate doses for an adequate period[md]much the most important. (2) Rest his joint; if his arm is involved, you can usually treat it in a sling, but if he has tuberculosis of his leg, you will probably have to admit him. (3) If he has disease of his hip or knee, apply traction. This will overcome spasm, prevent his softened bone from collapsing, and keep his inflamed joint surfaces apart. Experts can do major operations to remove or drain a tuberculous lesion, or promote ankylosis. For these, you will have to refer him.

TUBERCULOUS ARTHRITIS X-RAYS. Look for: (1) Generalized rarefaction[md]the patient's whole joint is less dense than it should be. The earliest stage is a lack of definition[md]his joint is not as sharp as it should be. (2) Localized areas of erosion or decreased density, caused by caseous lesions in the bone. (3) The joint space may be abnormally narrow or wide. (4) In late cases it is irregular.

CAUTION ! Joint destruction in tuberculosis is always more severe than the X-ray appearances suggest. (2) Remember to X-ray his lungs.

SPECIAL TESTS. (1) A positive tuberculin test is only of limited value (29.1).

(2) If a joint is swollen, aspirate it by the methods in Section 7.17, and examine the fluid as in Section 79.3. Great patience may occasionally find AAFB in a stained film of the exudate. Most laboratories reckon that this is not worth doing. If possible, send the fluid for culture, and guinea-pig inoculation (even then it is not always positive). You will not know the answer for several weeks.

(3) If he has any enlarged lymph nodes that might be tuberculous, biopsy one. The biopsy of synovial tissue is indicated in special cases only. Taking a biopsy from his spine is difficult, but you may be able to take one from his hip. Use the anterolateral approach, as for septic arthritis (7.18). Biopsy his knee by the methods in Section 7.17. When you take a biopsy, use the opportunity to examine his articular cartilage. A biopsy is useful for distinguishing tuberculosis from late, imperfectly-treated staphylococcal arthritis.

CAUTION ! Biopsies are fallible, so accept a negative biopsy with caution. About 50% of cases of tuberculous synovitis are reported as ''non-specific chronic inflammation'.

DIFFERENTIAL DIAGNOSIS. Septic arthritis is the main one.

Suggesting septic arthritis [md]a history of onset over hours or days, rather than weeks; a ''hot' joint, which is acutely painful to move in any direction. He is ''ill', with a high fever and a leucocytosis. Aspiration produces frank pus, rather than slightly cloudy fluid. Bacteria (usually staphylococci) are visible in a Gram stained film. If septic arthritis has been partly treated, diagnosing it may be difficult.

If his hip is involved, flex his knee to 90[de] and then flex his hip. If his leg goes into external rotation, as you do this, as in Fig. 7-17, it is a sign that his upper femoral epiphysis is slipping. This is much more likely to happen in septic arthritis (or spontaneous slipping of the epiphysis, 77.10) than it is in tuberculosis.

Both tuberculosis and septic arthritis eventually involve the bone of the pelvis. If it is already involved when you first see him, this suggests tuberculosis.

Suggesting trauma [md]a history of injury, or a haemarthrosis: the X-ray may be normal, or show widening of the joint.

Suggesting other forms of arthritis [md]a history of dysentery, brucellosis, or gonorrhoea.

If a joint looks like tuberculosis, but tests are negative, he may have rheumatoid arthritis presenting in a single joint. Other joints may flare up later. If possible, take a biospy, do a Rose[nd]Waaler test, and/or a latex test. Remember that tuberculosis is commoner than monarticular rheumatism in most of the developing world.

If he is a child and his hip is involved, consider Perthes' disease (27.14), or a slipped epiphysis (77.10).

If he is old, or had an injury previously, consider the possibility of osteoarthritis and look for lipping, areas of increased density (eburnation), and sometimes associated cysts (especially in his hip).

TREATMENT [s7]FOR SURGICAL TUBERCULOSIS Start by admitting him in order to: (1) Confirm the diagnosis. (2) Give him the confidence that he can be cured. (3) Convince him that he needs long-term treatment. (4) Apply traction to his lower limb, if this is needed. (5) Give him his initial course of streptomycin, if he lives far from a clinic.

CHEMOTHERAPY. Treat him as in Section 29.1. Do all you can to persuade him to continue treatment to the end. Review him regularly. When his course of treatment is completed, warn him that his joint may flare up again at any time. If so, he must return for further treatment.

POSITION OF FUNCTION. The range of movement of his joint may be limited or absent, so make sure that it is kept in the position of function in Fig. 7-16.

ANKYLOSIS. A fibrous ankylosis may be acceptable, even in his leg, especially if he is a child. It is also acceptable in his arm, provided it is near the optimum position of function[md]see Fig. 7-16.

Fig. 29-2 TUBERCULOUS OSTEITIS in this patient improved rapidly on chemotherapy, and his sinuses healed. Kindly contributed by Gerald Hankins.

PARTICULAR JOINTS [s7]INFECTED BY TUBERCULOSIS SHOULDER. Aim for a loose fibrous ankylosis. Rest his arm in a sling, and then gradually encourage him to do without it. If it is painful at the end of treatment, refer him for an arthrodesis. This will not be a significant disability, because of his scapulo-humeral movement.

ELBOW. An elbow fixed in the position of function as in Fig. 7-16, is likely to be better than a stiff painful one. If non-operative treatment fails to give him a pain-free elbow, refer him for an excision/arthroplasty. This will give him a considerable range of movement, but little stability. Fusion is rarely necessary.

HIP. He is usually a child who presents with a painful hip or a limp. For the differential diagnosis, see Section 27.13. Symptoms may start slowly, but he ultimately becomes ill, and fretful, with painful restriction of the movements of his hip. To begin with it is flexed and abducted; later it is flexed and adducted, his leg is shortened, his thigh is wasted, and he may have abscesses in his buttock or groin, as in Fig. 29-1. There is loss of joint space, and a characteristically severe rarefaction of the bone round his hip. If possible, aspirate or explore it, so as to confirm the diagnosis bacteriologically.

Give him chemotherapy and rest his hip, at first in bed only, and then, when pain is a little less, apply skin traction (70.10). If there is abscess formation, and the whole of the head of his femur is necrotic (uncommon in tuberculosis), refer him for the removal of necrotic tissue.

If his hip is in spasm (as diagnosed by rolling it), or his hip or knee show any flexion deformity, apply extension traction (78.3) for several weeks. This will control pain and prevent a flexion contracture.

If there is only narrowing of the joint space, and no bony destruction, allow him up, usually after about 2 months, and let him use his leg cautiously, starting with partial weight bearing, using crutches and a patten (raised shoe) on his normal leg to keep his diseased one off the ground. Skin traction should have corrected any flexion contracture (if present) by this time.

If there is considerable bony destruction, especially of the head of his femur, he still has some hope of a reasonably functioning joint. Don't worry about whether his ankylosis is fibrous or bony. Apply skin traction for 3 months and then get him up on crutches.

Alternatively, and less satisfactorily, put him into a hip spica, in the position of function (7-16). Start him on full weight-bearing. After 3 months, remove his spica and fit him with a removable splint of plaster, leather, or metal, which he can take off for bath or bed. He may need some kind of splint permanently, or until his hip has fixed.

If, after 4 to 6 months, he still has a painful joint with very limited movement or no movement, except under anaesthesia (unusual), consider referring him for operative arthrodesis of his knee, or of his hip. Both these operations should be done during the first two years, while he is still on chemotherapy.

KNEE. He presents with a limp, mild pain, a swollen knee, marked wasting of his quadriceps, limitation of movement (especially extension), and a flexion deformity.

Put him into a Thomas splint, or extension skin traction (78.3), for at least 3 months, and then get him up on crutches. Gradually increase the weight his leg bears, until he is walking as well as he can. If his disease is advanced, or if his pain continues, you may have to fit him with a long leg plaster cylinder; otherwise avoid one.

If a child requires an arthrodesis of his knee, try to delay this until growth has stopped.

ANKLE. Give him chemotherapy, and apply a short leg walking cast (81.5).

TENDON SHEATHS. If he develops a chronic swelling of the tendon sheaths of his hand, or the bursae round his shoulder, don't forget that tuberculosis can involve any of the synovial membranes.

DIFFICULTIES [s7]WITH A TUBERCULOUS JOINT If his symptoms are mild so that DIAGNOSIS is DIFFICULT, you can: (1) Wait 4 to 6 weeks, before committing him to long-term treatment[md]provided you are sure you are not missing acute untreated septic arthritis. During this time some diseases (transient synovitis and rheumatic fever) will settle, and others may reveal themselves (partly-treated septic arthritis). Tuberculosis will not advance much during this time. (2) Explore the joint, biopsy the synovial membrane, and remove a lymph node for biopsy. An ESR may also be useful.

Alternatively, and less satisfactorily, you can start a trial of treatment with streptomycin and isoniazid for a month. If your diagnosis was correct, the spasm in the muscles round his tuberculous joint will become less, and his general symptoms will improve.

If you are not sure if he has septic arthritis, or tuberculosis, even after opening the joint, treat him for both, and review him later when the histological report is available.

If DEFORMITY PREVENTS SATISFACTORY WALKING, corrective surgery is essential. If an arthrodesis is needed (more likely in the knee than the hip), it is usually best done 6 to 8 weeks after chemotherapy starts.

If an OLD TUBERCULOUS JOINT IS INJURED, observe him closely. A fibrous ankylosis is always unsafe, and can flare up at any time. If pain, etc. continue, and he has no bony injury and no ligament rupture, give him another full course of chemotherapy.

If a COLD ABSCESS develops, leave it, unless it is very big and is causing pain and discomfort. All but the big ones settle on chemotherapy in 12 months. If you have to aspirate a cold abscess (unusual), do so repeatedly with a wide-bore needle. If you can introduce the needle through a long oblique track, a sinus is less likely to form. If it is very large, explore it, clear out its contents, and close it to prevent the entry of secondary infection.

CAUTION ! Don't leave a drain in a cold abscess, or it will become secondarily infected.

If a SINUS develops, it is the result of an abscess opening on to his skin, and is a sign of low resistance. Sinuses are rare once chemotherapy has started, although an old one may open up temporarily. Chemotherapy will usually close it. A sinus may become secondarily infected, but does not require specific treatment. A biopsy from the track is unlikely to confirm tuberculosis, because non-specific granulation tissue lines it.

If A JOINT BECOMES WARM AND TENDER, with deteriorating X-ray signs, and he has general symptoms, he is experiencing a flare-up. This is unlikely to happen if he has completed his course of treatment, and is a sign that chemotherapy has failed. Consider some other disease, such as septic arthritis, gonococcal arthritis, monarticular rheumatism, or gout. Give him a further course of treatment.

If his LEG ends up SHORT, raise his shoe.

ANY PERPLEXING JOINT IS TUBERCULOUS UNTIL PROVED OTHERWISE Fig. 29-3 TUBERCULOSIS OF THE SPINE. A, a boy from Nepal. B, another patient with a gibbus. Note that in both these patients the lower thoracic region is involved (the common site). C, the X-ray signs (see text). A, kindly contributed by David Nabarro.