Hepatosplenic candidiasis: successful treatment with fluconazole

Nonculture methods for diagnosis of disseminated candidiasis

Two of the nonculture approaches to the diagnosis of DC, enzymatic-fluorometric determination of serum D-arabinitol and detection of marker antigens in antigenemia (enolase and CWMP), have been commercialized and have shown promise in limited clinical trials. These approaches are not new but are the culmination of efforts made over 10 or more years. Clearly, further fine-tuning of both metabolite and antigen detection is needed to simplify the methods and to improve their sensitivity and specificity so that they will be valuable in guiding clinical treatment decisions. An alternative approach, detection of DC by DNA amplification methods such as PCR, is a special case of a compelling technology and one that is capable of standardization across microbial genera. The availability of simplified PCR diagnostic methods for DC remains a tantalizing prospect. Nevertheless, the development of methods to release DNA from very small numbers of Candida organisms in the blood in a form that is sufficiently free of inhibitors of PCR will require further intensive effort. The maturation of these converging laboratory approaches to nonculture diagnosis of DC leads to more optimism about the eventual use of these methods in clinical laboratories.

Febrile neutropenia

Fever is associated with malignancy and is a common problem in cancer patients. Fever in the cancer patients is closely linked with infection, especially when the patient is granulocytopenic. When fever appears, a series of diagnostic and therapeutic measures must be taken even if precise knowledge of the cause of the infection is lacking. Fever can be caused by infection or by the cancer itself through tumor-related necrosis, hemorrhage or pyrogens. Infection is the more common cause, however. Bacterial and fungal sepsis can coexist and the bacteremia can overshadow the more difficult to determine fungal infection. For this reason it has become accepted practice to administer amphotericin B to granulocytopenic patients who remain febrile after a few days of broad-spectrum antimicrobial therapy and in whom no bacteria can be documented. Viral infection is rarely diagnosed in neutropenic patients without concomitant immunosuppression.

Pharmacokinetics of 18F-labeled fluconazole in healthy human subjects by positron emission tomography

The distribution of fluconazole in tissue of human volunteers was determined by positron emission tomographic scanning over a 2-h period following the infusion of a tracer dose of 18F-fluconazole (5 to 7 mCi) plus 400 mg of unlabeled drug (the standard daily dose of fluconazole). Previous studies have validated this approach for animals. From serial positron emission tomographic imaging and blood sampling, pharmacokinetics of fluconazole in tissue were determined. There was significant distribution of the radiolabeled drug in all organs studied, with nearly constant levels achieved by 1 h. Plateau concentrations of fluconazole in key organs (micrograms per gram) included the following: whole brain, 4.92 +/- 0.17; heart, 6.98 +/- 0.20; lung, 7.81 +/- 0.46; liver, 12.94 +/- 0.24; spleen, 22.96 +/- 2.5; kidney, 11.23 +/- 0.61; prostate, 8.24 +/- 0.58; and blood, 3.76 +/- 0.30. Since levels of fluconazole of > 6 micrograms/g are needed to treat infection with most strains of Candida and levels of > 10 micrograms/g are needed for Cryptococcus neoformans, Coccidioides immitis, and Histoplasma capsulatum, the following predictions can be made. The current standard dose of 400 mg/day should be more than adequate in the treatment of urinary tract and hepatosplenic candidiasis but problematic in the treatment of candidal osteomyelitis, even with the higher levels that develop after multiple doses. Similarly, higher doses should be considered, particularly in immunocompromised patients, with infection with C. neoformans, H. capsulatum, and C. immitis that involves the central nervous and musculoskeletal systems.

Empiric treatment of localized infections in the febrile neutropenic patient with monotherapy

Empiric therapy is necessary for febrile, neutropenic patients in order to minimise morbidity and mortality. Certain agents are now available for monotherapy which offer comparable success to combinations of either an aminoglycoside with a beta-lactam or two beta-lactams. However, no regimen offers complete treatment under all circumstances in all patients. It is also apparent that febrile, neutropenic patients comprise a more heterogeneous group than just those with bacteraemia, clinically apparent infection and unexplained fever. Localized infections occur in just under a third of cases at the onset of fever and a similar number will develop during the course of fever. Mortality is higher in infections that are accompanied by bacteraemia and also those that develop subsequently, especially when related to the lung. The aetiological agent also differs with each type of infection as does the duration of fever and symptoms. Consequently modifications are required more often. The length of treatment may also differ. Therefore, during the first 3-4 days of empiric therapy, every effort should be made to identify incipient localized infections in addition to detecting bacteraemia. Changes in therapy can then be based on objective grounds rather than continued fever offering more patients individual treatment than is possible when relying only on the temperature chart.

Successful treatment of chronic disseminated candidiasis with high-dose fluconazole in a child with acute myelo-monocytic leukemia

A 6-year-old boy with acute myelo-monocytic leukemia [French-American-British classification, M4 (Bennett et al., Br J Haematol 1976; 33: 451-458)] developed chronic disseminated candidiasis (CDC) in a phase of remission induction chemotherapy. The diagnosis was made based on the histological examination of the biopsy specimen of the liver that showed invasion of Candida. High-dose fluconazole (FCZ) therapy (up to 23.5 mg/kg/day) was given effectively and without significant side effect over a period of 15 months. Pharmacokinetic analysis revealed that FCZ showed one or two compartment model. Administration of 12 mg/kg/day of the drug showed that t (1 2 ) were 11.5 and 16.1 h, respectively. We would suggest that if lesser doses are ineffective in eradicating invasive fungal infection, dose escalation of FCZ was possible up to a single administration of 20 mg/kg daily in children.

What's new in fungal infection in leukemic patients

Fungal infections have become an important cause of mortality in patients with hematological malignancies. In recent years, fungi such as Candida tropicalis, Aspergillus spp, Fusarium spp and Trichosporon spp have emerged as important pathogens. Amphotericin B remains the antifungal agent with the broadest spectrum of activity, although some of the newer pathogens may be resistant. The administration of this drug in lipid vehicles reduces the toxicities, permitting the administration of higher doses that may be more effective. The new agents, fluconazole and itraconazole, have activity against some fungal pathogens, although their role in therapy has not been fully determined. Fluconazole has been shown to be effective for prophylaxis of Candida infections.

The use of fluconazole prophylaxis in patients with chemotherapy-induced neutropenia

Systemic Candida infections are a major cause of infectious morbidity and mortality during chemotherapy-induced neutropenia. Because of the unreliability of conventional diagnostic tests to detect systemic infection early in its course, treatment of established disseminated Candida infection has been generally disappointing with mortality rates of 60-80% in leukemia and bone marrow transplant patients and 30-40% in solid tumor patients. The use of empiric amphotericin B in patients with fever not responding to empiric antibacterial agents has been shown to be successful in reducing morbidity and mortality from fungal infections. However, its toxicity has mitigated the success of this approach. Fluconazole given prophylactically at the institution of chemotherapy has been shown to be a safe and effective alternative. It, however, is not active against all fungal species, especially Aspergillus and some of the less virulent Candida species. Some centers have reported break-through infections by these less susceptible organisms. Whether or not these limitations in its spectrum of activity will limit its usefulness in the future remains unanswered at this time and could pose a cloud to an otherwise bright promise.

Chronic systemic candidiasis in acute leukemia

In the past few years a new syndrome of invasive Candida infection, the so-called hepatosplenic or chronic systemic candidiasis (CSC), has been recognized with increasing frequency in neutropenic patients. From January 1985 to December 1990, ten of 305 acute leukemia (AL) patients treated at our institution were diagnosed as having CSC. In contrast, during the same period this type of Candida infection was not observed in any patient with hematological diseases other than AL treated in our center, including 277 patients who underwent bone marrow transplantation. All patients with CSC had fever and hepatomegaly, and five complained of abdominal pain. Seven patients had neutrophilic leukocytosis and six an increased serum alkaline phosphatase activity. Abdominal computed tomography and ultrasound study showed typical lesions in eight and seven patients, respectively. In four patients a laparoscopy-guided needle liver biopsy displayed yellowish nodules on the liver surface, and the histologic study revealed large granulomas with yeasts and pseudohyphae. All patients were given amphotericin B (mean: 4.6 g, range: 1-12.5 g) and 5-fluorocytosine, and five received fluconazole. No patient died as a direct consequence of CSC and in six the infection resolved. Finally, once controlled, the infectious complication did not preclude subsequent intensive antileukemic therapy, including bone marrow transplantation.