A 28-Day-Old Boy with Multifocal Osteomyelitis Mimicking Non-Accidental Injury

Case Report

A 28-day-old male was presented during a night shift to our emergency department with restricted movement of the left arm and excessive crying. A trauma could not be ruled out due to language barriers. Pregnancy, birth and his neonatal medical history had been unremarkable. On examination, the boy was afebrile, in pain and hard to soothe. A swollen and tender non-erythematous left elbow joint was noted, the arm being held in extension and pronation. An ultrasound of the elbow showed an extensive hyperechogenic joint effusion, suggestive of a traumatic incident ([Fig. 1a]). Subsequently, the arm was immobilized with a Desault’s bandage and the boy was admitted to the hospital with suspected child abuse.

Fig. 1 a Ultrasound of the left elbow, showing a hyperechogenic joint effusion; b MRI, T1 weighted, intramuscular abscess in the right thigh (arrow); c MRI, Turbo inversion recovery method, inflammatory lesions of the left elbow, left kidney (arrows); d Plain radiograph at the 14 months follow-up.

The boy was re-evaluated 2 hours later. Now, a painful swelling of the right thigh was noted. Laboratory investigations revealed an elevated C-reactive protein (CRP) of 150 mg/L and a leucocytosis of 32.9 G/L, alongside leucocyturia and a positive nitrite test. Now considering multifocal osteomyelitis and/or urinary tract infection as differential diagnoses, an empiric antibiotic therapy consisting of intravenous cefuroxime and clindamycin was initiated. Lumbar puncture was briefly discussed but not prioritized because of the high suspicion of urinary tract infection, the focal symptoms, and the correlation of pain with the affected body sites.

Due to the multifocality and the yet unclear aetiology of the disease, a whole-body magnetic resonance imaging (MRI) was performed, showing multiple inflammatory lesions in the right femur (with accompanying abscess), the left elbow, the right acromioclavicular joint and in one rib ([Fig. 1b] and [c], [2]). Furthermore, the left kidney was enlarged with a diminished corticomedullary differentiation ([Fig. 1c], [3]). Immediately after diagnosis, the boy underwent surgery for drainage and further diagnostics. Aspirates from both the thigh abscess and the elbow grew Methicillin-susceptible Staphylococcus aureus, which was also present in the clean catch urine (10^6 colony forming units per mL), alongside Enterobacter cloacae complex (10^6 colony forming units per mL). Of note, one blood culture obtained before the initiation of antibiotic therapy remained sterile. An echocardiography revealed no signs of endocarditis. Antibiotic therapy was reviewed by the infectious disease consultant and the antimicrobial stewardship team. In order to optimize intracellular accumulation in light of a possible chronic granulomatous disease (CGD), antibiotic therapy was changed to intravenous ciprofloxacin and teicoplanin and was given for 22 days, followed by cefaclor after CGD was ruled out. Antibiotic prophylaxis was initiated due to 4° vesicoureteral reflux (VUR). At 14 months follow-up, the boy showed a satisfying clinical development, albeit with discrete limping and slight femoral neck shortening ([Fig. 1]d). No further major infections occurred.

Fig. 2 MRI, T1 fat suppression with contrast agent; a right thigh with intramuscular abscess (arrow); b empyema of the left elbow joint (arrow).

Fig. 3 MRI, T1 fat suppression with contrast agent; enlarged left kidney with diminished corticomedullarydifferentiation

Publication History

Article published online:
06 August 2020