[Osteomyelitis from Cryptococcus neoformans]

Cryptococcus neoformans osteomyelitis of the tibia: a case report and review of the literature

INTRODUCTION

Osteomyelitis is a bone inflammation that can be related to various infectious agents. As with any other type of inflammation, the prevailing symptoms and signs may include redness, swelling, pain, and heat. Fungal osteomyelitis is rare and usually found in immune-compromised patients.

CASE PRESENTATION

A non-human immunodeficiency virus immunocompromised Greek female patient, 82 years old, visited the emergency department due to a 3 day pain located mainly over the left tibia's anterior surface, accompanied by swelling and redness. There was also a subcutaneous lesion of her left breast. Medical history revealed that the patient had an unmasked close contact with pigeons, a main host of the disease. Initial x-ray imaging showed an osteolytic area in the upper third of the tibial diaphysis. The patient was admitted and underwent a computed tomography-guided biopsy. The specimen revealed a Cryptococcus neoformans infection of the bone and the breast. She was treated with 400 mg fluconazole twice a day for 3 weeks while in hospital and 200 mg twice a day upon discharge for 9 months. After that, she underwent surgical debridement because of lasting local irritation. She was closely monitored in our outpatient office, and in her last visit, 1 year after the initial admission, inflammatory signs had regressed vastly.

CONCLUSIONS

To our knowledge, this is the ninth cryptococcal osteomyelitis of the tibia to be recorded since 1974, and the most unusual finding was the bifocal nature of the infection, affecting both the tibia and the breast.

Skeletal cryptococcosis from 1977 to 2013

Skeletal cryptococcosis, an aspect of disseminated cryptococcal disease or isolated skeletal cryptococcal infection, is a rare but treatable disease. However, limited information is available regarding its clinical features, treatment, and prognosis. This systematic review examined all cases published between April 1977 and May 2013 with regard to the factors associated with this disease, including patient sex, age, and epidemiological history; affected sites; clinical symptoms; underlying diseases; laboratory tests; radiological manifestations; and delays in diagnosis, treatment, follow-up assessments, and outcomes. We found that immune abnormality is a risk factor but does not predict mortality; these observations are due to recent Cryptococcus neoformans var gattii (CNVG) outbreaks (Chaturvedi and Chaturvedi, 2011). Dissemination was irrespective of immune status and required combination therapy, and dissemination carried a worse prognosis. Therefore, a database of skeletal cryptococcosis cases should be created.

Phenotypic and genotypic differentiation of several human and avian isolates of Cryptococcus neoformans

The Cryptococcus neoformans strains isolated from two human cases could be diagnosed as Cr. neoformans var. neoformans by differentiation on the basis of their characteristics determined by proline, canavanine and EDTA urease tests. The results of the serovar assignment were: for the isolate from the meningoencephalitis patient with lethal outcome, serovar A; for the strain isolated from the osteomyelitis patient with benign course, serovar D. Also, the PCR fingerprinting using primers (GACA)4, (CAC)5 and FM 1 resulted in a clear and reproducible assignment of the Cr. neoformans strains to the varieties neoformans and gattii, respectively, and, in addition, it confirmed the serovar assignment. No statistically confirmed differences in virulence between the osteomyelitis and the meningoencephalitis strain could be established by i.v. testing in mice, nor did the PCR with several primers provide any clues to a genetically determined higher virulence of the meningoencephalitis strain. The different classification as serovars A and D does not allow any conclusions concerning different virulence. It was not possible to retrospectively establish the sources of infection of the two Cr. neoformans infections, but pigeon faeces may well have played a role as a reservoir for one of the illnesses.

Cryptococcal rib osteomyelitis in a pediatric patient

A case of cryptococcal rib osteomyelitis in a pediatric patient is described. Isolated cryptococcal osteomyelitis in pediatric patients is a rare entity, and only 10 cases have been reported in the literature. The radiological findings are reviewed to include chest films, nuclear bone scan, and computed tomographic imaging scan. Because of its rarity, the management of isolated cryptococcal osteomyelitis is controversial. Although antifungal antibiotics and surgery are the two therapeutic options, the treatment of cryptococcal osteomyelitis has not been standardized yet. This patient was treated successfully with limited resection of the involved rib and antifungal chemotherapy. This article describes the second case in the literature of cryptococcal rib osteomyelitis in a pediatric patient, reviews the literature of similar cases, and evaluates the current role of surgery in its treatment.