Bone Infection

Fifth stage

SURGERY
Lec3p3

د.مثنى

18/10/2016

Bone infection

Tuberculosis

causes a granulomatous reaction which is associated with tissue necrosis and caesation.

Mycobacterium tuberculosis (human, less commonly bovine ) enter via the lung or gut or rarely through the skin.

pathology

1.Primary complex:


the initial lesion in lung , pharynx or gut, with lymphatic spread to regional lymph node.

2.Secondary spread:

If the resistance to the original infection is low, wide spread dissemination via the blood stream, giving rise to miliary TB ,or meningitis.

3.Tertiary lesion:

Bone or joint is affected in about 5%.
there is predilection to vertebral bodies and the large synovial joints.

In endemic area skeletal t. b. is seen mainly in children.

In non endemic area is seen in chronic debilitating disease (AIDS).

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Pathology

Once the bacilli have gained afoot hold, so chronic inflammatory reaction.

Then granulomatous lesion started (giant cell surrounded with necrosis and round cell at the periphery).

Spread to soft tissue lead to cold abscess.

Followed with sinus and end with secondary pyogenic infection.

These changes affected either the synovium or the bone is affected and then spread to the near by structure.

Large joint usually involved ( hip , knee , less often shoulder or ankle ).

If the disease is arrested at an early stage, healing may be by resolution to normality.

If the cartilage is destroyed healing by fibrosis and incomplete ankylosis.



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Clinical features

 In monoarticular atrthritis :

History of previous infection.

The patient usually a child or young adult

Pain.


Swelling.

Fever.

Lassitude.

Loss of weight.

Night cries:

(the joint splinted by muscle spasm during the day, relaxes with sleep and damage tissues are stretched).

Muscle wasting.

Movement in all direction limited.

 In T B spine:

Pain may be slight.

Kyphosis (gibbus).

Occasionally the presenting feature is weakness or loss of sensibility in the lower limb.
In neglected cases patient presented with paralysis (potts paraplegia).

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Radiography

Early changes:

o Soft tissue swelling, Periarticular osteoporosis o Bone ends washed out.
o Narrowing the articular ends.

Later on :

Erosions of the subarticular cartilage.

cystic changes appeared.

T B spondylitis may appear as localized bone erosion and collapse across an intervertebral disc space.
There may be soft tissue traces of paravertebral abscess.



Investigation

E S R increased.

Relative lymphocytosis.

Mantoux test positive.

Synovial fluid aspirate (high protein).

Acid fast bacilli ,cultures is positive.

Synovial biopsy is more reliable.

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Differential Diagnosis

Transient synovitis.

Monoarticular rheumatoid arthritis.


Subacute arthritis.

Heamorrhagic arthritis.

Pyogenic arthritis.

Metastatic bone disease.

Multiple myeloma.

Sarcoidosis.

Diagnosis

Long history.

Involvement only one joint.

Marked synovial thickening.

Marked muscle wasting.


Periarticular osteoporosis.

Treatment

 Main stay in RX

o Chemotherapy

(Rifampicin, INH for 6 months) .

in resistance to INH may call for pyrazinamide and streptomycin, or ethambutol.

o Rest.
(splintage for several months , traction).

o Operation for drainage or clearance of Tuberculous abscess .

In severe deformity

Osteotomy.

Arthrodesis.
Joint replacement.


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