gms | German Medical Science

Cryptococcus neoformans is a yeast-like encapsulated fungus and was first isolated from peach juice in the 19^th century. The environmental habitat of C. neoformans includes avian feces (mostly pigeons) and soil. Cryptococcal infection is commonly acquired by inhaling contaminated aerosols [1], [2]. Respiratory symptoms range from transient colonization to severe pneumonia with respiratory insufficiency [3]. Haematogenous spread to the central nervous system leading to cryptococcal meningoencephalitis is the most common manifestation in immunocompromised patients [2]. Cryptococcal infection further may involve the skin, soft tissue, bones and joints, although less frequent [1]. Up-to-date there is no published case of cryptococcal bursitis in an immunocompetent patient.

A 22-year-old patient was seen in an orthopaedic outpatient clinic with recurrent pain in the right knee. His profession as a painter commonly required working in a kneeling position.

Clinical examination revealed swelling and fluctuation of the right knee joint without redness or warmth. There was no history of fever or respiratory symptoms. Diagnostic arthrocentesis was performed revealing bloody serous fluid. Puncture specimen grew Cryptococcus neoformans. Due to the uncommon microbiological result the patient was punctured a second time confirming the diagnosis of Cryptococcal Bursitis infrapatellaris. Therefore, the patient was referred to the Section for Infectious Diseases and Tropical Medicine, University Hospital of Graz.

On admission the patient presented slight swelling of the right knee, negating fever or malaise. There was no recent injury or laceration of the knee. The patient did not report any contact with avian feces, although he described occupational exposure to soil. The patient’s medical history contained a bursectomy of the left knee joint four years ago, lacking further underlying diseases as immune defects in particular. Laboratory findings including HIV serology were inconspicuous. Antifungal therapy with p.o. fluconazole 600mg once daily was initiated under regularly control of laboratory values. Magnetic resonance imaging was performed after one week of therapy showing fluid accumulation (1cm) of the right Bursa infrapatellaris. After two weeks of fluconazole therapy the patient was seen again. He tolerated antifungal therapy well; no adverse events were reported. Physical examination of the knee joint was unremarkable. Fluconazole was prescribed for another four weeks, completing six weeks duration of overall treatment.

Figure 1 [Fig. 1]