Treatment
In animals, cryptococcosis may be treated with various antifungal drugs including amphotericin B, 5-fluorocytosine (also known as 5-flucytosine), fluconazole, itraconazole, ketoconazole, and terbinafine (Spickler 2013).
The use of amphotericin B represented the first effective therapy for the treatment of cryptococcal infections. Flucytosine in combination with amphotericin B or an azole is recommended for the treatment of cryptococcosis in cats. However, the treatment of dogs with flucytosine is not recommended owing to the risk of potential severe toxic reactions such as toxic epidermal necrolysis (Malik et al. 1995; Panciera and Bevier 1987). Flucytosine should never be used alone because of the rapid development of resistance, and its use may be prohibitively expensive. In numerous areas, fluconazole is widely used in dogs and cats with cryptococcosis (Malik et al. 1992; O'Brien et al. 2006). As the original patent has expired, there are many excellent generic formulations available at quite a reasonable cost in most countries. In dogs, both fluconazole and itraconazole appear to be effective in the treatment of cryptococcosis, although they are less reliable than amphotericin B and best utilized for consolidation therapy (O'Brien et al. 2006). Ketoconazole is licensed for use in dogs only in France. In dogs and cats, ketoconazole has also been used successfully to treat systemic cryptococcosis (O'Brien et al. 2006), and it seems useful in some of the VGII cases encountered in Vancouver Island and surrounding areas.In vitro studies have also shown that voriconazole, posaconazole, and isavuconazole are more active against C. gattii VGII and VGII than fluconazole (Yamazumi et al. 2000; Illnait-Zaragozi et al. 2008; Thompson et al. 2009). Importantly, fluconazole resistance has been reported at a much higher frequency and may have originated from the colonization of patients with AIDS undergoing long-term azole maintenance therapy (Pfaller et al. 2011). It is worth emphasizing that among C. neoformans and C. gattii isolates, the MIC and epidemiological cutoff values for fluconazole against C. gattii VGII and VGIII are substantially higher than in VGI and C. neoformans var. grubii isolates (Espinel-Ingroff et al. 2012). Alterations in ERG11, which encodes a lanosterol 14α-demethylase, have been reported (Sionov et al. 2012).
In addition, surgery can be performed to reduce the size of mass lesions (Spickler 2013). Supportive therapy may be required to treat increased intracranial pressure during meningitis using judicious doses of corticosteroids for the first few days of therapy in patients with CNS disease.
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