Discussion:
Sternal osteomyelitis is rare and usually occurs after
sternotomy following cardiac surgery. Primary sternal osteomyelitis has
rarely been described in individuals with intravenous drug use,
immunodeficiency, acne fulminans, palmoplantar pustulosis, SAPHO
syndrome (synovitis, acne, pustulosis, hyperostosis, and osteomyelitis),
and vascular access infections.⁴ It is classified as *primary* when no
other focus of infection is present and *secondary* when associated with
procedures such as sternotomy, trauma, or mediastinitis. Few cases of
primary sternal osteomyelitis have been reported in international
literature.²
Patients often present with fever, localized pain,
tenderness, and swelling over the affected sternal area. While complete
blood counts may be normal in two-thirds of cases, CRP and ESR are
typically elevated. Blood cultures are frequently negative, but bone or
abscess samples yield positive results in 65% of cases.⁵
Our patient presented with fever, chest pain, and
tender swelling, suggesting osteomyelitis as the provisional diagnosis.
A lack of proper clinical observation can delay diagnosis and lead to
complications such as mediastinitis, chronic osteomyelitis, and chest
wall deformities.⁶ Immediate antibiotic therapy is recommended when
osteomyelitis is suspected, even before confirmatory investigations.
Ultrasound is a valuable tool in identifying soft
tissue collections and periosteal involvement. In our resource-limited
setting, ultrasonography revealed a hypoechoic collection adjacent to
the sternum, which guided the diagnosis. Taneja et al. (1992)
demonstrated the utility of ultrasound in detecting early osteomyelitis,
distinguishing it from soft tissue abscesses and cellulitis.⁸
Radiographs are often normal in early stages, with changes like
periosteal reactions becoming visible after two weeks,⁹ as seen in this
case.
Treatment involves empirical antibiotics targeting
*Staphylococcus aureus*, followed by targeted therapy based on culture
and sensitivity results. Early short-course intravenous therapy,
followed by oral antibiotics, is effective.¹⁰ In our case, intravenous
flucloxacillin was initiated empirically and later combined with
clindamycin after culture results. The patient received a total of six
weeks of antibiotics, including one week intravenously and five weeks
orally, with full recovery. Transitioning to oral antibiotics requires
clinical stability, absence of severe complications, and a significant
reduction in CRP levels.¹¹
Surgical intervention is reserved for cases with
abscesses or when conservative treatment fails. It involves drainage and
debridement, performed under aseptic conditions.¹² In this case, no
surgical intervention was needed, and the patient responded well to
medical management.
In conclusion, sternal osteomyelitis is rare. Strong
clinical suspicion, along with basic imaging modalities like
ultrasonography, can facilitate early diagnosis even in resource-limited
settings. Prompt antibiotic therapy often ensures a favorable outcome
without complications.