Prepatellar bursitis: a rare manifestation of chronic brucellosis

Introduction: Bursitis is a rare complication of brucellosis that has only once been described in a country where disease has been eradicated in domestic animals. Case Presentation: A 63-year-old diabetic man presented with an 11-year history of painless swelling over his right knee. Magnetic resonance imaging (MRI) showed a large, multiloculated cyst overlying the knee joint. The patient underwent bursectomy which revealed caseous necrosis. Operative samples cultured Brucella abortus. The patient was treated with a combination of surgery and antimicrobials (doxycycline, rifampicin and gentamicin). His only risk factor for acquiring Brucella was drinking unpasteurized milk during childhood. Fifty eight cases of Brucella bursitis have been described in the English-language medical literature. Half have involved the prepatellar bursa. Only one case, from Australia, occurred in a country that has eradicated brucellosis in domestic animals. Although symptoms are often prolonged, local features of inflammation are usually absent. Diagnosis is primarily by bursal fluid culture. Treatment involves antimicrobials with or without aspiration or excision of the bursa. As the diagnosis was unexpected, several laboratory workers were exposed to the Brucella isolate before its identification. Follow up according to UK guidelines revealed no cases of occupationally acquired infection. Conclusion: Bursitis is an unusual manifestation of brucellosis. It is extremely rare outside countries where the infection is endemic, but the chronicity of symptoms and increase in global travel mean that patients with the condition may present in non-endemic settings. Clinicians should therefore consider the diagnosis in cases of unexplained chronic bursitis.