Tuberculosis (TB) is still a common infection in developing countries. After lung and lymph nodes, bone and joint is the next common site of tubercu- losis in the body. It constitutes about 1-4 per cent of the total number of cases of tuberculosis.
The spine is the commonest site of bone and joint tuberculosis, constituting about 50 per cent of the total number of cases. Next in order of frequency are the hip, the knee and the elbow. Tubercular osteomyelitis more commonly affects the ends of the long bone, unlike pyogenic osteomyelitis which affects the metaphysis. This is also the reason for early involvement of the adjacent joint in tubercular osteomyelitis. Table–23.1 shows the common musculo-skeletal structures affected by tuberculosis.
Table–1: Musculo-skeletal tuberculosis
|• Long bone||TB osteomyelitis||Tibia commonly|
• Short bone
Also called spina ventosa
|• Spine||TB spondylitis||Also called Pott's|
|• Arthritis||TB arthritis||Hip joint commonly|
|• Synovium||Synovial TB||Knee-commonest site|
|• Tendon||TB tenosynovitis||Compound palmar|
|(synovium)||of flexor tendons||ganglion|
|• Bursae||TB bursitis||Trochanteric|
Common causative organism is Mycobacterium tuberculosis. Bone and joint tuberculosis is always secondary to some primary focus in the lungs, lymph nodes etc. Mode of spread from the primary focus may be either haematogenous or by direct extension from a neighbouring focus.
Pathology: Tubercular infection of the bone and synovial tissue produces similar response as it produces in the lungs i.e., chronic granulomatous inflammation with caseation necrosis. The response may be proliferative, exudative or both;
- Proliferative response: This is the commoner of the two It is characterised by chronic granulomatous inflammation with a lot of fibrosis.
- Exudative response: In some cases, particularly in immuno-deficient individuals, elderly people and people suffering from leukaemia , there is extensive caseation necrosis without much cellular reaction. This results in extensive pus formation. These are also termed non-reactive cases.
Natural history: Inflammation results in local trabecular necrosis and caseation. Deminera- lisation of the bone occurs because of intense local hyperaemia. In the absence of adequate body resistance or chemotherapy, the cortices of the bone get eroded, and the infected granulation tissue and pus find their way to the sub-periosteal and soft tissue planes. Here they present as cold abscesses, and may burst out to form sinuses. The affected bone may undergo a pathological fracture.
A tubercular osteomyelitis in the vicinity of a joint may result in the involvement of the joint.
Joint involvement is usually in the form of a low-grade synovitis, with thickening of the synovial membrane. Unlike pyogenic arthritis where proteolytic enzymes cause severe early destruction of the articular cartilage, tubercular infection causes slow destruction. Once the synovium is inflamed, it starts destroying the cartilage from the periphery. This inflammatory synovium at the periphery of the cartilage is called Pannus. Eventually, the articular cartilage is completely destroyed. The joint gets distended with the pus. Joint capsule and ligaments become lax, and the joint may get subluxated. Pus and tubercular debris burst out of the joint capsule to form a cold abscess, and subsequently a chronic discharging sinus.
Healing: It occurs by fibrosis, which results in significant limitation or near complete loss of joint movement (fibrous ankylosis). If considerable destruction of the articular cartilage has occurred, the joint space is completely lost, and is traversed by bony trabeculae between the bones forming the joint (bony ankylosis) as shown in Fig-23.1. Fibrous ankylosis is a common outcome of healed tuberculosis of the joints, except in the spine where bony ankylosis follows more often.
Clinical features depend upon the site affected. Patients of all ages and both sexes are affected frequently. The onset is gradual in most cases.
Usual presenting complaints are pain, swelling, deformity and inability to use that part. Sometimes, the presentation is atypical. The following general principles will help in making a diagnosis:
- High index of suspicion: Tuberculosis should be included in the differential diagnosis of any slow onset disease of the musculo- skeletal system, particularly in countries where tuberculosis is still prevalent. Because of its slow onset and progress, the symptoms and signs are often minimal and non-specific. A high index of suspicion and a close watch over such symptoms in susceptible individuals, is the key to early
- Fallacious history of trauma: Very often the patient assigns all his symptoms to an episode of One should not get carried away by such information, as the injury may be coincidental. A detailed inquiry in such cases will reveal a symptom-free period between the episode of trauma and the beginning of symptoms, thus establishing the non-traumatic nature of the disease.
- Lack of constitutional symptoms: Symptoms like fever, loss of appetite, weight loss etc. are present in only about 20 per cent cases. An active primary focus is detected only in about 15 per cent of cases at the time of diagnosis; in the rest it has already healed by the time the patient
Specific signs and symptoms in patients with tuberculosis at major sites will be discussed in respective sections.
Radiological examination: X-ray examination of the affected part, antero-posterior and lateral views, is the single most important investigation. Findings in the early stages may be minimal and are likely to be missed. A comparison with an identical X-ray of the opposite limb or with an X-ray repeated after some period, may be helpful. Following are some of the general radiological features of tuberculosis of the bones and joints:
TB osteomyelitis: A tubercular osteomyelitis presents as a well-defined area of bone destruction, typically with minimal reactive new bone formation. This is unlike a pyogenic infection, where reactive periosteal new bone formation is an important feature.
TB arthritis: In tubercular arthritis there is reduction of the joint space, erosion of the articular surfaces and marked peri-articular rarefaction. This is unlike many other causes of joint space reduction such as osteoarthritis, septic arthritis, etc., where there is subchondral sclerosis instead.
X-ray features specific to different sites will be discussed in their respective sections. A chest X-ray should be done routinely to detect any tubercular lesion in the lungs.
Other investigations: Some of the following
investigations may be helpful in diagnosis:
- Blood examination: Lymphocytic leukocytosis,
- Mantoux test: useful in
- Serum ELISA test for detecting anti-myco bacte- rium antibodies.
- Synovial fluid aspiration (see Table–22.3, page 177).
- Aspiration of cold abscess and examination of pus for
- Histopathological examination of the granulation tissue obtained by biopsy or curettage of a lesion.
Principles of treatment: Treatment of tuberculosis of bones and joints consists of control of the infec- tion and care of the diseased part. In most cases, conservative treatment suffices; sometimes opera- tive intervention is required.
Common anti-tubercular drugs and their dosages
Daily dose (max.)
|• Rifampicin (RF)||–Hepatotoxicity, pink coloured|
|10 mg/kg (600 mg)||urine|
|• Isoniazide (INH)||–Hepatotoxicity, Peripheral|
|5-10 mg/kg (300)||neuritis|
|• Streptomycin (SM)||–Vestibular damage, Nephrotoxicity|
|30 mg/kg (1 gm)||Circumoral paraesthesia|
|• Pyrazinamide (PZ)||–Hepatotoxicity|
|25 mg/kg (1.5 gm)|
|• Ethambutol (ETH)||–Optic neuritis, Colour blindness|
|25 mg/kg for 4 wks|
|(1000 mg), thereafter|
|15 mg/kg (800 mg)|
|• Cycloserine||–CNS toxicity -Headache, Tremor,|
|10 mg/kg (500 mg)||Dysarthria|
|• Ethionamide||–Anorexia, Nausea, Vomiting|
|25 mg/kg (750 mg)|
|• Para-amino salicilate||–Anorexia, Nausea, Vomiting|
|200-400 mg/kg (12 g)|
Control of infection: It is brought about by potent anti-tubercular drugs, rest to the affected part and the building up of patient's resistance.
- Anti-tubercular drugs: Table–23.2 shows com- mon anti-tubercular drugs, their dosage, route of administration and common side-effects. It is usual practice to start the treatment with
4 drugs — Rifampicin, INH, Pyrazinamide, Ethambutol for 3 months. In selected cases with multifocal tuberculosis, 5 drugs — RF, INH, PZ, ETH and Streptomycin, may be required for the initial period. The patient is monitored* to detect any failure to respond or for any side- effects of the drugs.
- Rest: The affected part should be rested during the period of In the upper extremities this can be done with a plaster slab; in the lower extremities traction can be applied. In most cases of spinal tuberculosis bed rest for a short period is sufficient; in others, support with a brace may be necessary.
- Building up the patient's resistance: The patient should be given a high protein diet and exposed to fresh air and sunlight to build up his general resistance.
Care of the affected part: This consists of protection of the affected part from further damage, correction of any deformities and prevention of joint contractures. Once the disease is brought under control, exercises to regain functions of the joint are carried out. Care consists of the following:
- Proper positioning of the joint: The joints should be kept in proper position so that contractures do not develop.
- Mobilisation: As the disease comes under con- trol and the pain reduces, joint mobilisation is This prevents contractures and helps regain movement. In cases with extreme dam- age to the joint, it is best to expect ankylosis of the joint in the position of most useful func- tion.
- Exercises: As the joint regains movement, muscle strength building exercises are
- Weight bearing: It is started gradually as osteoporosis secondary to the disease is reversed.Operative intervention may be required in some cases. Following are some procedures commonly used:
- Biopsy: For cases where the diagnosis is in doubt, a fine needle aspiration cytology (FNAC) may be performed from an enlarged lymph node or from a soft tissue swelling. An open biopsy may be necessary from a bony lesion, or in case FNAC fails to confirm the diagnosis.
- Treatment of cold abscess: A small stationary abscess may be left alone as it will regress with the healing of the A bigger cold abscess may need aspiration or evacuation (discussed in detail on page 191).
- Curettage of the lesion: If the lesion is in the vicinity of a joint, infection is likely to spread to the joint. An early curettage of the lesion may prevent this
- Joint debridement: In cases with moderate joint destruction, surgical removal of infected and necrotic material from the joint may be This helps in the early healing of the disease, and thus promotes recovery of the joint.
- Synovectomy: In cases of synovial tuberculosis, a synovectomy may be required to promote early
- Salvage operations: These are procedures performed for markedly destroyed joints in order to salvage whatever useful functions are possible g., Girdlestone arthroplasty of the hip (page 198).
- Decompression: In cases with paraplegia secondary to spinal TB, surgical decomp-ression may be
TUBERCULOSIS OF THE SPINE
The spine is the commonest site of bone and joint tuberculosis; the dorso-lumbar region being the one affected most frequently.
Development of a vertebra (Fig-23.2): A vertebra develops from the sclerotomes which lie on either side of the notochord. The lower-half of one vertebra and upper-half of the one below it, along with the intervening disc develop from each pair of sclerotomes and have a common blood supply. Therefore, infections via the arteries involve the ‘embryological’ section, as in the commoner
paradiscal tuberculosis of the spine.
Surface anatomy of the vertebral column: The only part of the vertebra which is accessible to palpation is its spinous process, hence this is used for localising the level of the vertebral segment. Table–23.3 shows the relationship between the vertebral spinous processes to that of some of the easily palpable anatomical landmarks. Once the affected vertebra is known, the corresponding cord-segment can be found as discussed subsequently.
Cord-segment localisation: Because of the disproportionate growth of the vertebral column and spinal cord, the cord ends at the lower border of first lumbar vertebra. Beyond this, up to S2 there is only the dural sac containing a bunch of nerve roots (cauda equina). The segment of the cord which corresponds to a given vertebra is therefore above the level of that vertebra. Relationship
between the spinal segment and cord segment in different regions of the spinal column is as shown in Table–23.4, page 185.
Table.4: Relationship between spinal and cord segments
Spinal segment Cord segment • Cervical vertebrae Add 1 to vertebral level • Upper dorsal vertebrae Add 2 to vertebral level • Lower dorsal vertebrae Add 3 to vertebral level • At D10 All dorsal segments over • At D12 All lumbar segments over • At L1 All sacral segments over • Below L1 Cauda equina
Like tuberculosis of the bones and joints elsewhere in the body, TB of the spine is always secondary. The bacteria reach the spine via the haematogenous route, from the lungs or lymph nodes. It spreads via the para-vertebral plexus of veins i.e., Batson's plexus, which has free communication with the visceral plexus of the abdomen, a common site of tuberculosis.
Types of vertebral tuberculosis: Lesions in the
vertebrae may be of the following types (Fig-23.3):
- Paradiscal: This is the commonest In this, the contiguous areas of two adjacent vertebrae along with the intervening disc are affected.
- Central: In this type, the body of a single vertebra is affected. This leads to early collapse of the weakened vertebra. The nearby disc may be normal. The collapse may be a ‘wedging’ or ‘concertina’ collapse (Fig-23.4); wedging being commoner.
- Anterior: In this type, infection is localised to the anterior part of the vertebral The infection spreads up and down under the anterior longitudinal ligament.
- Posterior: In this type, the posterior complex of the vertebra i.e., the pedicle, lamina, spinous process and transverse process are affected.
Pathology: Basic pathology is the same as that in other bone and joint tuberculosis. In the commoner paradiscal type, bacteria lodge in the contiguous areas of two adjacent vertebrae. Granulomatous inflammation results in erosion of the margins of these vertebrae. Nutrition of the intervening disc, which comes from the end-plates of the adjacent vertebrae is compromised. This results in disc degeneration, and as the process continues, complete destruction.
Weakening of the trabeculae of the vertebral body results in collapse of the vertebra. Type of collapse is generally a wedging, occurs early, and is severe in lesions of the dorsal spine. This is because, in the dorsal spine the line of weight bearing passes anterior to the vertebra, so that the anterior part of the weakened vertebra is more compressed than the posterior, resulting in wedging. In the cervical and lumbar spines, because of their lordotic curvature (round forwards), wedging is less. Destruction occurs early, and is severe in children.
Cold abscess: This is a collection of pus and tubercular debris from a diseased vertebra. It is called a cold abscess because it is not associated with the usual signs of inflammation – heat, redness etc., found with a pyogenic abscess. The tubercular pus can track in any direction from the affected vertebra (Fig-23.5). If it travels backwards, it may press upon the important neural structures in the spinal canal. Pus may come out anteriorly (pre-vertebral abscess) or on the sides of the vertebral body (para-vertebral abscess). Once outside the vertebra the pus may travel along the musculo-fascial planes or neuro- vascular bundles to appear superficially at places far away from the site of lesion.
Healing: As healing occurs, the lytic areas in the bone are replaced by new bone. The adjacent vertebrae undergo fusion by bony-bridges. Whatever changes have occurred in the shape of the vertebral body are, however, permanent.
Presenting complaints: Clinical presentations of a case of TB of the spine is very variable – from a seemingly non-specific pain in the back to complete paraplegia. Following are some of the common presenting complaints:
- Pain: Back pain is the commonest presenting symptom. It may be diffuse; no more than a dull ache in the early stages, but later becomes localised to the affected diseased It may be a ‘radicular’ pain i.e., a pain radiating along a nerve root. Depending upon the nerve root affected, it may present as pain in the arm (cervical roots), girdle pain (dorsal roots), pain abdomen (dorso-lumbar roots), groin pain (lumbar roots) or ‘sciatic’ pain (lumbo-sacral roots).
- Stiffness: It is a very early symptom in TB of the spine. It is a protective mechanism of the body, wherein the para-vertebral muscles go into spasm to prevent movement at the affected vertebra.
- Cold abscess: The patient may present the first time with a swelling (cold abscess) or problems secondary to its compression effects on the nearby visceral structures, such as dysphagia in TB of the cervical A detailed examination in such cases reveals underlying TB of the spine.
- Paraplegia: If neglected, which is often the case in developing countries, a case of TB of the spine presents with this serious complication. For details see Pott's paraplegia, page
- Deformity: Attention to TB of the spine may be attracted, especially in children, by a gradually increasing prominence of the spine – a
- Constitutional symptoms: Symptoms like fever, weight loss etc., are rarely the only presenting symptoms.
The aim of examination is: (i) to pick up findings suggestive of tuberculosis of the spine; (ii) to localise the site of lesion; (iii) find skip lesions; and (iv) to detect any associated complications like cold abscesses or paraplegia. Following is the systematic way in which one should proceed to examine a case of suspected TB of the spine.
- Gait: A patient with TB of the spine walks with short steps in order to avoid jerking the spine. He may take time and may be very cautious while attempting to lie on the examination In TB of the cervical spine, the patient often supports his head with both hands under the chin and twists his whole body in order to look sideways.
- Attitude and deformity: A patient with TB of the cervical spine has a stiff, straight neck. In dorsal spine TB, part of the spine becomes prominent (gibbus or kyphus*). Significant deformity is generally absent in lumbar spine tuberculosis; there may just be loss of lumbar lordosis.
Para-vertebral swelling: A superficial cold abscess may present as fullness or swelling on the back, along the chest wall or anteriorly. It is easy to diagnose because of its fluctuant nature. Sometimes, an abscess may be tense and it may not be possible to elicit fluctuation. A needle aspiration may be performed in such cases, to confirm the diagnosis. It is important to look for cold abscesses in not so obvious locations, depending upon the region of the spine affected.
Table–5: Presentation of cold abscesses from different regions of the spine
|of spine Anteriorly
|On||the sides||Along musculo-facial plane Along|
|Cervical||Retro-pharyngeal||Para-vertebral||At the posterior border of sterno-cleidomastoid muscle, in the posterior triangle of neck Trickles downward and enters either of the two lumbo costal arches:
• Lateral lumbo-costal arch
–to present as lumbar abscess
• Medial lumbo-costal arch
–to present as psoas abscess Lumbar abscess or psoas abscess
|To axilla, to arm along neuro-|
|spine||abscess||abscess||vascular bundle of the arm|
|Thoracic||Mediastinal||Para-vertebral||Along thoracic spinal nerves to|
|• Anterior chest wall|
|• Mid-axillary line|
|• Posterior chest wall|
Along neurovascular bundle of
|spine||abscess||abscess||the leg to present in groin or|
|down in the leg|
- Tenderness: It can be elicited by pressing upon the side of the spinous process in an attempt to rotate the
- Movement: There is no necessity to examine for spinal movement in a patient with obviously painful spine. Spinal movement are limited in a case of TB of the spine, and can be tested, wherever considered
- Neurological examination: A thorough neuro- logical examination of the limbs, upper or lower, depending on the site of tuberculosis should be performed. In addition to motor, sensory and reflexes examination, an assessment should be made of urinary or bowel functions. Aim of neurological examination is to find: (i) whether or not there is any neurological compression;(ii) level of neurological compression; and (iii) severity of neurological compression.
- General examination: A general physical examination should be performed to detect any active or healed primary The patient may have some other systemic illness like diabetes, hypertension, jaundice etc., which may have a bearing on further treatment.
X-ray examination: One must specify the level of the suspected damage, when requisitioning an X-ray of the spine. Minimum of two views, AP and lateral, are necessary. A chest X-ray for primary focus or an X-ray of the abdomen – KUB, if a psoas abscess is suspected, may also be taken. Following are some of the important radiological features.
- Reduction of disc space: This is the earliest sign in the commoner, paradiscal type of tuberculosis (Fig-23.6a). In early stages, reduction in disc space may be minimal, and may be detectable only on comparing the height of the suspected disc with those In advanced stages, disc space may be completely lost (Fig-23.6b). A lateral X-ray is better for evaluation of disc space. Reduction of disc space is an important sign because in other diseases of the spine e.g. secondaries in the spine, the disc space is well preserved.
- Destruction of the vertebral body: In early stages, the contiguous margins of the affected vertebrae may be The diseased, weakened vertebra may undergo wedging. In late stages, a significant part or whole of the vertebral body may be destroyed (Fig-23.6c), leading to angular kyphotic deformity. Severity of the deformity depends upon the extent of wedging and number of affected vertebrae (Table–23.6).
- Evidence of cold abscess: Radiological evidence of a cold abscess is a very useful finding in diagnosing a case of suspected spinal Following abscesses may be seen on X-rays:
- Para-vertebral abscess: A para-vertebral soft tissue shadow corresponding to the site of the affected vertebra in AP view indicates a para-vertebral abscess. It may be of the following types: (i) a fusiform para-vertebral abscess (bird nest abscess – an abscess whose length is greater than its width (Fig-23.7a); and (ii) globular or tense abscess – an abscess whose width is greater than the length (Fig-23.7b). The latter indicates pus under pressure and is commonly associated with paraplegia.
- Widened mediastinum: An abscess from the dorsal spine may present as widened mediastinum on AP X-ray.
- Retro-pharyngeal abscess: In cervical spine TB, a retro-pharyngeal abscess may be seen on a lateral X-ray. Normally, soft tissue shadow in front of the C3 vertebral body is 4 mm thick; an increase in its thickness indicates a retro- pharyngeal abscess (Fig-23.7c).
- Psoas abscess: In dorso-lumbar and lumbar tuberculosis, psoas shadow on an X-ray of the abdomen may show a bulge.
- Rarefaction: There is diffuse rarefaction of the vertebrae above and below the
- Unusual signs: In tuberculosis involving the posterior complex, there may be erosion of the posterior elements of pedicle, lamina These are better visible on oblique X-rays of the spine. Anterior type of vertebral tuberculosis may show erosion of the anterior part of the body, much the same as that possibly seen sometimes in cases with aneurysm of aorta, thus termed aneurysmal sign. There may be lytic lesions in the ribs in the vicinity of the affected vertebra.
- Signs of healing: Once the disease starts healing, the density of the affected bones gradually Areas surrounding the lytic lesion show sclerosis, and over a period of time these lesions are replaced by sclerotic bone. The adjacent vertebrae undergo bony fusion.
- CT scan: It may detect a small para-vertebral abscess, not otherwise seen on plain X-ray; may indicate precisely the extent of destruction of the vertebral body and posterior elements; and may show a sequestrum or a bony ridge pressing on the cord (Fig-23.8). This is a very useful investigation in cases presenting as ‘spinal tumour syndrome’, where there may be no signs on plain X-rays.
MRI is the investigation of choice to evaluate the type and extent of compression of the cord (Fig- 23.9). It also shows condition of the underlying neural tissues, and thus helps in predicting the prognosis in a particular case.
Myelography: This may be indicated in cases presenting with ‘spinal tumour syndrome’, or when the clinical level of neurological deficit does not correspond to the radiological level of the lesion.
Biopsy: CT guided needle biopsy, or an open biopsy may be required in a case with doubtful diagnosis.
Other general investigations: Investigations like ESR, Mantoux test, ELISA test for detecting anti- tubercular antibodies, chest X-ray, etc., to support the diagnosis of tuberculosis, may be carried out whenever required.
Cases with TB of the spine report fairly late in developing countries, so they present mostly with classic signs, symptoms and radiological features. In the early stages, and sometimes in some atypical presentations, diagnosis may be difficult. Some of the common differential diagnosis and their differentiating features are given in Table–23.7.
Principles of treatment: Aim of treatment is:
- to achieve healing of the disease; and (ii) to prevent, detect early, and treat promptly any complication like paraplegia Treatment consists of anti-tubercular chemotherapy (page 184), general care (page 184), care of the spine, and treatment of the cold abscess. Only the latter two will be discussed here.
Care of the spine: This consists of providing rest to the spine during the acute phase, followed by guarded mobilisation.
- Rest: Ashort period of bed rest for pain relief may be sufficient during early stages of treatment. In cases with significant vertebral destruction, a longer period of bed rest is desirable to prevent further collapse and pathological dislocation of the diseased In children, a body cast is sometimes given, basically to force them to rest. Minerva jacket or a collar may be given for immobilising the cervical spine.
- Mobilisation: As the patient improves, he is allowed to sit and walk while the spine is supported in a collar for the cervical spine, or an ASH brace for the dorso-lumbar spine. The patient is weaned off the brace once bony fusion occurs. He is advised to avoid sports for 2 Years.
Treatment of cold abscess: A small cold abscess may subside with anti-tubercular treatment. Abscesses presenting superficially need treatment as discussed below;
- Aspiration: A thick needle is required because often there is thick caseous material. It should be an anti-gravity insertion with the needle entering through a zig-zag
- Evacuation: In this procedure, the cold abscess is drained, its walls curetted, and the wound closed without a drain. This is unlike drainageof a pyogenic abscess, where a post-operative drain is always left. A psoas abscess can be drained extra-peritoneally using a kidney incision.
Medical Research Council of Great Britain conducted controlled trials to study various aspects of TB spine and published findings in four reports (1973-74). Their conclusions were that (i) bed rest is not necessary; (ii) Streptomycin is not necessary; (iii) PoP jacket offers no benefit; and (iv) debridement is not a good operation.
- Cold abscess: This is the commonest complication of TB of the Treatment is as discussed above.
- Neurological compression: At times the patient presents as a case of spinal tumour syndrome; the first clinical symptom being a neurological deficit (discussed subsequently).