A Pain in the Foot: Delayed Diagnosis of Primary Septic Arthritis of Naviculocuneiform and Second/Third Tarsometatarsal Joints

Patient: Male, 65-year-old Final Diagnosis: Septic arthritis of midfoot Symptoms: Foot pain Medication: — Clinical Procedure: Debridement • drainage Specialty: Family Medicine • General and Internal Medicine • Orthopedics • Emergency Medicine OBJECTIVE: Challenge in differential diagnosis BACKGROUND: Septic arthritis needs to be recognized early because a delay in the treatment leads to significant morbidity and mortality. We present a case of primary septic arthritis of the tarsometatarsal joints in a middle-aged man who presented multiple times to outpatient clinics and the Emergency Department with worsening foot pain. His condition was misdiagnosed several times, and he only received definitive treatment 3 weeks after the onset of his symptoms. CASE REPORT: A middle-aged man developed sudden-onset atraumatic left ankle pain that later localized to his foot. Despite analgesics, his foot pain became severe and persistent, affecting his ambulation and sleep. He had multiple consults with his primary care physician, orthopedic specialists, and emergency physicians. Initial radiological and magnetic resonance imaging (MRI) showed degenerative changes, and osteoarthritis was diagnosed. Despite regular analgesics, he experienced worsening pain, prompting his revisit to the Emergency Department. Upon admission, his inflammatory markers were more elevated and a repeat MRI of the foot showed extensive joint effusion, periarticular marrow edema, and bony erosions. He underwent second to third tarsometatarsal joint debridement, washout, drainage, and biopsy. Intraoperative findings showed purulent fluid and clumps of debris within the joint. He received a 6-week course of intravenous antibiotics and was transferred to a rehabilitation center. CONCLUSIONS: Septic arthritis of the midfoot is rare. Laboratory and radiological investigations have limitations and should be guided by appropriate clinical findings and judgment. It is important to maintain a high index of suspicion for these cases to prevent morbidity in affected patients.