TUBERCULOSIS OF BONES AND JOINTS

Historical aspects Oldest recognized disease of mankind Percival Pott presented the classic description of spinal tuberculosis in 1779 Robert Koch discovered Mycobacterium tuberculosis in 1882

Predisposing factors Malnutrition's Poor sanitation Living in crowded areas Close contact with TB patients Immunodeficiency states

Lesions of individual bones Spine Greater trochanter Phalanx Skull Joint lesions

infection by mycobacterium tuberculosis of one or more extradural components of spine namely the vertebra, intervertebral discs, paraspinal soft tissues and epidural space Tuberculosis of spine

Pathophysiology Usually by hematogenous route Midthoracic spine and the region below it is more frequently involved Usually two continuous vertebrae are involved but several vertebrae may be effected Skip lesions or solitary vertebral involvement may occur

Clinical features Constitutional symptoms Malaise Loss of appetite/weight loss Night sweats Specific features Stiffness Enlarged lymph nodes Neurodeficit

Imaging modalities Conventional radiographs CT MRI Ultrasonography

1.Conventional Radiographs Reduced disc space Blurred paradiscal margins Destructions of bodies Loss of trabecular pattern Increased prevertebral soft tissue shadow Subluxation/dislocation Decreased lordosis/kyphosis

Central type of lesion: Spread through batson’s venous plexus/ branches of posterior vertebral artery Minimal disc space reduction At the end concentric collapse

Anterior type lesion Starts beneath the anterior longitudnal ligament & periosteum Collapse & disc reduction usually minimal & occurs late Erosion is primarily mechanical Appendicular type Rare Isolated infection of pedicles/lamina/transver se process/spinous process Erosions Paravertebral shadows Intact disc space

Lateral shift & scoliosis: More destruction of vertebral body on one side Posterior articulation involvement in addition to usual paradiscal lesions

Skipped lesions: More than one TB lesion present in vertebral column with one or more healthy vertebrae in b/w the 2 lesions 7% on routine x-rays More frequently detected on CT/MRI

Healing is indicated by decreased soft tissue shadow Disappearance of erosions Return of normal density(mineralization) Bony ankylosis

CT & MRI the extent of involvement presenceof epidural component cord compression Irregularity of both end plate and anterior aspect of vertebral bodies Bone marrow edema Enhancement on MRI

T2 Weighted sagital image of lumbar spine shows altered Marrow signals involving anterosuperior margin.

Ultrasonography To diagnose the presence of tubercular abscesses in dorsolumber vertebral disease

Ultrasound Joint effusion may bethe only finding but is nonspecific.

Difference TB spondylitis a pattern of mainly bone destruction relative disc preservation(destruction is late sign) focal and heterogeneous contrast enhancement of the vertebral body well-defined paraspinal area of abnormal signal intensity Pyogenic spodylitis a pattern of mainly discitis mild to moderate peridiscal bone destruction relative diffuse and homogeneous contrast enhancement of the vertebral body

Difference TB spondylitis vertebral intraosseous rim enhancement on sagittal views. Calcification when present indictes TB. Pyogenic spodylitis ill-defined paraspinal area of abnormal signal intensity peridiscal rim enhancement

Tuberculous dactylitis

spina = short bone ventosa = expanded with air Plain Radiography is the modality of choice Tends to affect the bones distal to tarsus and wrist upper limb being more commonly involved involved bone shows a diaphyseal expansile lesion a periosteal reaction is uncommon healing is by sclerosis and is usually gradual

Poorly defined lytic change with medullary expansion, cortical erosion and mild periosteal reaction in the mid and distal aspect of the right middle finger in a patient with TB dactylitis.

Calvarial tuberculosis

Rare entity May be localized and well defined Or may be more diffuse Associated with cold abscess

1) Lateral radiograph shows large circumscribed lytic lesion in frontal bone. 2) AP radiograph demonstrates a large frontoparietal lytic lesion suggestive of diffuse spreading type. 3) Frontal radiograph shows a lytic lesion with a sclerotic margin.

Joint Lesions One of the common cause of infectious arthritis in developing countries Never a primary lesion it is always a sequelae of pulmonary or lymph node tuberculosis It can occur at any age.

Radiographic features Plain film  early stages (stage of synovitis and arthritis) periarticular demineralisation joint space widening (due to joint effusion) mild subchondral erosion

 late stages (stage of erosion and destruction) gradual narrowing of joint space (there is involvement of articular cartilage) severe subchondral erosion and destruction pathological subluxation and dislocation fibrous ankylosis atrophic changes in bones may occur and lead to atrophic arthropathy (seen in shoulder joint as carries sicca)

CT degree of bone destruction or rarely sequestrum Extension of infection in surroundings or any sinus tract formation can also be demonstrated on post contrast scan.

Caries sicca : there is erosion and destruction of humoral head and glenoid cavity with soft tissue swelling, along with fibrotic opacites in the right upper and middle lobe.

Osteolytic lesion in distal shaft of radius with osteopenia

There is a lucent lesion in the medial tibial metaphysis with thinning of the cortex, subtle periosteal reaction and faint calcification in the adjacent soft tissue.

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