4.1. Acute bone and joint
infection in an otherwise healthy infant or child 
The Baby or Child will
be ill or very ill, with a high fever and severe malaise. In the very young
the affected limb may not be moving (pseudo-paralysis) and may thus mimic
acute poliomyelitis; while the older child will complain of severe pain. Apart
from the signs of the general septicaemia the crucial physical finding is
local tenderness often accurately localised, and this must be carefully sought
by gentle palpation. When a joint is infected the limb is likely to lie in
a typical position (flexion of the knee, flexion and external rotation of
the abducted hip) and even very gentle movement will cause a violent reaction
from the child. In the Tropics some children present with acute bone or joint
infection but very little pain and minimal or no fever. This is likely to
be due to immuno-suppression either because of HIV infection or more commonly
from malnutrition.
Swelling of a limb, or of a joint then occurs
and fluctuation (when this can be tested) suggests that pus has burst out
of the periosteum. The huge thigh of a late presenting hip infection may be
associated with dislocation of the joint.
 |
 |
| THe hugely swollen thingh of a child suggesting
that pus may have burst out of the hip joint, or through the periosteum
of the femur |
An X-ray revealing osteomyelitis of the femur, with septic arthritis of the hip complicated by dislocation. |
However, the most important point in making
the diagnosis is to think of the possibility of acute osteomyelitis or septic
arthritis in a sick baby or child with septicaemia. It is important to remember
that in some cases there may be multiple sites of infection. Thus even though
a single site of infection is found, the whole patient should be carefully
examined clinically, looking for other sites.