Septic Infrapatellar Bursitis in an Immunocompromised Female

Bursitis is a relatively common occurrence that may be caused by traumatic, inflammatory, or infectious processes. Septic bursitis most commonly affects the olecranon and prepatellar bursae. Staphylococcus aureus accounts for 80% of all septic bursitis, and most cases affect men and are associated with preceding trauma. We present a case of an 86-year-old female with an atypical septic bursitis involving the infrapatellar bursa. Not only are there very few reported cases of septic infrapatellar bursitis, but also this patient's case is particularly unusual in that she is a female with no preceding trauma who had Pseudomonas aeruginosa on aspirate. The case also highlights the diagnostic workup of septic bursitis through imaging modalities and aspiration. This patient had full resolution of her septic bursitis with appropriate IV antibiotics.