Heel Pain - Atraumatic

HISTORY: An 8 y/o female presents to the emergency department with 1 week of right heel pain aggravated by ambulation. She is also newly febrile with a Tmax of 101.5 F. Bedside ultrasound demonstrates a small pocket of fluid in her posterior heel. Orthopedics and plastic surgery are consulted, and no further intervention is recommended. Blood cultures are drawn. Infectious workup in the emergency department is unremarkable, at which time family voices preference for discharge with close follow up. 48 hours later, blood cultures previously drawn grew gram-positive cocci in clusters. The patient re-presents with ongoing fevers, worsening right ankle pain and inability to bear weight. PHYSICAL EXAM: On initial presentation, there is mild swelling and erythema over the posterior aspect of the heel with point tenderness over the posterior calcaneus. Heel pain is exacerbated with passive ankle dorsiflexion. No overlying skin changes or fluctuance noted. On reexamination 2 days later, patient is increasingly in the posterior heel. She is unable to actively dorsiflex or plantarflex her ankle. DIFFERENTIAL DIAGNOSIS: 1. Calcaneal apophysitis (Sever’s disease)2. Calcaneal abscess, osteomyelitis3. Achilles tendonitis. TEST AND RESULTS: Initial labs demonstrate a WBC of 10.12 k/uL, CRP 69 mg/L, and ESR 93 mm/hr. Plain films are unremarkable. At admission, an MRI confirms the diagnosis of osteomyelitis with an abscess involving the Achilles paratenon. The patient goes to the OR for abscess drainage and subtalar joint arthrotomy with irrigation/debridement. FINAL DIAGNOSIS: Right calcaneal abscess, osteomyelitis. TREATMENT AND OUTCOMES: 1. Post-operatively patient is non-weight bearing (NWB) in short leg splint, physical therapy for ROM and ambulation with crutches.2. At 3 weeks, patient progresses to NWB with boot for 2 weeks followed by weight-bearing as tolerated.3. At 6 weeks, patient is out of the boot with activity as tolerated.4. After working with physical therapy and regaining strength, patient was able to fully return to unrestricted activities 3 month post-operatively. A metanalysis by N Thakolkaran N et al. (2019) estimates rates of osteomyelitis at 8 in 100,000 children, with an insidious course that most commonly presents as pain, localizing symptoms, and fever, as in our case.