Acute
osteomyelitis
Pathogenesis
Acute osteomyelitis now
commonly occurs in three different groups.
1. It can occur in the premature
baby, possibly as a result of blood-borne spread of infection from intravenous
cannulae or other portals.
2. Secondary to open fractures where
there has been inadequate cleaning of a wound or it has been closed before it is
clean.
3. Following joint replacement or
open reduction in internal fixation of fractures where contamination of the hone
has occurred.
Osteomyelitis
of the neonate
An infant with acute osteomyelitis will be fretful and pyrexial and will
not feed. The only clue to the underlying diagnosis may be the child failing to
move one limb. Premature babies on intensive care are particularly susceptible,
especially as they will have drips and arterial lines, all of which can act as a
source for septicaemia. The infection may be remote from the source as the
infection spreads through the bloodstream. Unlike osteomyelitis in older
patients, the pathogen need not be Staphylococcus aureus. It may be Streptococcus,
Pneumococcus, Haemophilus influenzae or even Escherichia coli. The
key to successful treatment is a high index of suspicion leading to early
diagnosis by blood culture. High-dose intravenous antibiotics should be
started as soon as possible but not before blood cultures have been taken. If
the diagnosis and treatment are delayed, pus may collect either under the
periosteum or within the medulla of the bone. The epiphyseal plate may be
damaged and it will not be possible to bring the infection under control until
the abscess has been drained.
Osteomyelitis
in the neonate
• Premature are babies susceptible
• The baby may not move the limb
• Organism may not be Staphylococcus
• Antibiotics should be started as soon as cultures have been taken
Antibiotics
must be starred blind after blood cultures have been taken because if the
disease can be sterilised within the first 48 hours of onset, complete
resolution can be guaranteed. If, however, the diagnosis is reached more than
48 hours after the onset of symptoms, it should be assumed that there is a
collection of pus and therefore surgery to drain this pus should be considered.
Flucloxacillin should be given at a daily dose of 250 mg/kg in the very
young child. Ampicillin 150 mg/kg should also be considered because it has a
better spectrum against H. influenzae. If the child fails to settle
rapidly, it must be assumed either that the organism is not sensitive to the
antibiotic being used or that there is a collection of pus present which
requires drainage.
Operation
Drainage
of pus
Under general anaesthetic, the skin is opened over the most tender red
area. The incision is carried down to the periosteum and when this is opened
it is usual to find pus expressed at high pressure. This pus should be sent for
culture. If no pus is found it is probably worth drilling through the cortex to
make sure that there is no pus in the medullary cavity (Fig.
24.1).