Candida albicans is a fungus that can be described as living commensally with humans. It is commonly found on skin and other oral, gastrointestinal and genital sites. The yeast form of the pathogen is consistent with infection in human beings. It is an opportunistic organism that may cause infection in primarily three main groups of individuals: patients who have a drug addiction and use unclean needles; patients who have long-term indwelling catheters for such treatments as renal dialysis; and patients who are immunocompromised as a result of problems such as acquired immune deficiency syndrome (AIDS), treatment for cancer or organ transplantation, and prolonged treatment with systemic antibiotics and corticosteroids. Candida species may lead to both intraocular and extraocular infections in the form of phlyctenular keratoconjunctivitis, keratitis, in a setting of chronic corneal disease in a debilitated patient, anterior and posterior uveitis, retinitis and endophthalmitis.
Patients typically complain of loss of vision, pain, photophobia and floaters, these symptoms being unilateral or bilateral.
The typical signs of anterior uveitis such as ciliary injection, keratic precipitates and cells in the aqueous may be accompanied by hypopyon. Posterior involvement manifests as one or more fluffy, round, yellow-white chorioretinal lesions. In time, and without treatment, they may enlarge and invade the vitreous, becoming groups or strands of floating deposits that have a ‘string of pearls’ appearance. Retinal hemorrhages may ensue, some of which have a pale center (Roth spots), together
with cells in the vitreous and the possibility of a vitreal abscess and retinal detachment. Cultures of blood and urine may be positive for Candida. If the involvement of the vitreous is extensive, a pars plana vitrectomy is indicated and cultures can be taken at that time.
Once rare, fungal infections have become more common in recent decades owing to the widespread use of broad-spectrum antibiotics and increasing numbers of immuno-incompetent individuals as a result of’AIDS and the chemotherapeutic management of cancer. Candida infection is not uncommon in the groups of patients noted above, and is being seen more frequently as an acquired hospital-based complication in immunocompromised patients.
Differential diagnoses include other fungal infections such as aspergillosis and coccidioidomycosis, bacterial endophthalmitis of endogenous origin, syphilitic and toxoplasmic chorioretinitis, retinitis from cytomegalovirus and intraocular lymphoma.
Blood tests Hospitalization and intravenous antifungal medication is indicated if the patient has systemic candidiasis. Consultation with a physician specializing in infectious diseases is indicated. Possible antifungal agents that may be administered include amphotericin B, fluconazole 5-fluorocytosine and ketoconazole.
Incisional surgery As noted above, a pars plana vitrectomy is required in patients with persistent endophthalmitis; the procedure is followed by an injection of amphotericin B into the vitreous cavity.
Two focal lesions inferior to the macula. The superior vessels are obscured by a possible secondary posterior vitreous detachment.