Paracoccidioidomycosis of the Central Nervous System: CT and MR Imaging Findings.

BACKGROUND AND PURPOSE: Paracoccidioidomycosis is a fungal infection mainly caused by the thermodimorphic fungus Paracoccidioides. The purpose of our study was to demonstrate the neuroimaging findings from 24 patients with CNS paracoccidioidomycosis. MATERIALS AND METHODS: We performed a retrospective analysis focusing on the radiologic characteristics of CNS paracoccidioidomycosis. The 24 selected patients underwent MR imaging and/or CT, and the diagnosis was made by the presence of typical neuroimaging features, combined with fungus isolation, a serologic test, or the presence of disseminated disease. RESULTS: Headache was the most common neurologic symptom, while the pseudotumoral form was the most common pattern. The number of lesions ranged from 1 to 11, with most localized on the frontal lobe with >2-cm lesions. CT showed mainly hypoattenuating lesions, whereas MR imaging demonstrated mainly hyposignal lesions on T1WI and T2WI. Furthermore, ring enhancement was present in most patients. The "dual rim sign" on SWI occurred in 100% of our patients with lesions of >2 cm. CONCLUSIONS: The diagnosis of CNS paracoccidioidomycosis is difficult. Nevertheless, imaging examinations can play an important role in the diagnosis and evaluation of the disease.

Failure of amphotericin B colloidal dispersion in the treatment of paracoccidioidomycosis.

Although amphotericin B desoxycholate is considered the most effective treatment for disseminated Paracoccidioides brasiliensis infections, little is known about the efficacy of lipid-based formulations of amphotericin B in this infection. In this study, we treated four adults with the juvenile form of paracoccidioidomycosis with 3 mg/kg/day of amphotericin B colloidal dispersion for at least 28 days. Although all of the patients initially responded by clinical observation, all four patients relapsed within six months. The use of amphotericin B colloidal dispersion for the initial induction of paracoccidioidomycosis failed to cure this infection. Possible reasons for failure include dose, duration, or reduced efficacy of this lipid preparation. For many fungal infections, lipid-based preparations have been shown to have a therapeutic-toxic advantage, but our experience with Paracoccidioides infections suggests that more careful studies will need to be performed before they can be recommended for use in this mycosis.

Brazilian spotted fever in Espirito Santo, Brazil: description of a focus of infection in a new endemic region.

Although Brazilian spotted fever is known to occur in several adjacent states, infection with spotted fever group (SFG) rickettsiae has not previously been documented in the Brazilian state of Espirito Santo. We report a cluster of two proven and four suspected cases of Brazilian spotted fever in a small valley near Colatina, Espirito Santo. Four patients died without confirmatory serologic or pathologic studies. The two surviving patients had serologic and/or pathologic evidence of infection with SFG rickettsiae. Results of a survey done in 1991 confirmed the presence of antibodies reactive with SFG rickettsiae in the serum of dogs living in this region. Two of 25 dogs had elevated microimmunofluorescent antibody titers (1:64 and 1:256). Both seropositive dogs were pets of the index cases and lived in the valley where all six human cases were presumed to have acquired their infections. These cases and the results of the canine serosurvey suggest that a focus of virulent disease exists in an area not previously known to be endemic for SFG rickettsiae.