4.3. Presentation of chronic bone
and joint infections 
This diagnosis may be relatively
easy when a patient presents with an obvious extruding sequestrum, or a discharging
sinus of long duration. In these circumstances there will often be a history
of a preceding acute infection, but particularly in the Developing World histories
can be widely inaccurate. So ‘beware’ of the usual story of
‘Trauma’.
When available, simple radiography will usually reveal the presence of a sequestrum with a surrounding thick involucrum, and occasionally cloacae.
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'Whole shaft' sequestration
with good involucrum formation. |
But diagnosis can
be difficult when there is bone destruction with little sequestration
or involucrum formation. |
If there is much bone destruction, or much new
bone formation the radiological differential diagnosis between a malignancy
and chronic bone infection can be difficult and biopsy may be necessary (and
the aid of an experienced pathologist).
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 |
| This one turned out to be a Ewing's Sarcoma | This one turned out to be a Ewing's Sarcoma
|
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|
| Another diagnostic problem |
Chronic infections resulting from Tuberculosis
or Fungi can also be relatively easy to diagnose (if the possibility is remembered),
but on occasion they can mimic other conditions.
Classically tuberculous infection of a joint results
in a chronic problem with pain, marked muscle wasting, loss of joint movement,
and occasionally a ‘cold abscess’. These usually arise insidiously
and of course can be associated with tuberculous infection elsewhere in the
patient (or in the family). In the presence of immune suppression the presentation
may be acute.
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|
| A firm anterior thigh swelling in a forty year old
lady. This turned out to be a tuberculous psoas abscess arising in the
lower lumbar spine. |
|
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| The tuberculous spinal lesion | Tuberculous pus removed by aspiration |
Clinical examination will confirm the findings,
and the radiological signs are of local osteoporosis and narrowing of the
joint space. Bone destruction will then follow and there may be sequestration
(especially in vertebral disease), but this can be difficult to see on plain
films.
In the spine there will be pain, gibbus
formation, abscess formation and occasionally one or more sinuses. The different
patterns of disease occurring in different parts of the spine are not considered
here, but a very useful sign of active disease (and hence also of quiescent
or healed tuberculous infection) is local tenderness on moderately firm percussion
of a diseased area, and this disappears when the disease is quiescent or healed.
