Author: Brian Holtry

Severely immunosuppressed patients with invasive aspergillosis may be completely asymptomatic when the disease is first suspected. The initial clue may only be a positive sputum culture or an abnormal chest x-ray.

Cryptococcus neoformans exists as two distinct varieties known as variety neoformans and variety gattii (Table 1). Cryptococcus neoformans variety neoformans exists throughout the world and is found frequently in pigeon droppings that have accumulated over time. The concentrations of these organisms are often quite high in old pigeon droppings found in barns, on window ledges, and around the upper floors of old buildings. Pigeons carrying the organism do not seem to be clinically affected, and wet or fresh droppings rarely contain C neoformans.

Candida organisms are commensal with humans and, in the absence of alterations in host defense mechanisms, usually do not cause disease. Candida exists as normal flora within the oral cavity, throughout the gastrointestinal (GI) tract, in expectorated sputum, in the vagina, and in the bladder of patients with indwelling catheters. There are >150 species within the genus Candida, although the majority are not known to cause disease in humans. C albicans, C krusei, C glabrata, C tropicalis, C pseudotropicalis, C guilliermondii, C parapsilosis, C lusitaniae, and C rugosa are known human pathogens.

Candidemia may present in a variety of fashions, ranging from asymptomatic to fulminant sepsis. The candidemic patient generally has risk factors for infection, such as malignancy, chemotherapy-induced neutropenia, organ transplantation, GI surgery, burns, indwelling catheters, or exposure to broad-spectrum antibiotics. Disseminated candidiasis must be assumed to be present in those with positive blood cultures, although negative cultures do not preclude the possibility of disseminated disease. Dissemination usually manifests with many microabscesses involving multiple organs, especially the liver, spleen, and eye, but almost any organ may be involved (Box 2).

The presence of Candida spp. in the urine is common and does not necessarily represent infection. Candiduria is commonly associated with antibiotic use, indwelling urinary catheters, and diabetes mellitus and frequently resolves if predisposing factors can be corrected. Patients are generally asymptomatic, although some will have symptoms similar to bacterial cystitis, with dysuria, frequency, and urgency (Box 2).

Risk factors for Candida infection of the vagina include pregnancy, oral contraceptive use, diabetes mellitus, HIV infection, and antimicrobial therapy, although the majority of infections occur in the absence of these risks. Typical complaints are vulvar pruritus and vaginal discharge (Box 1), although a wide range of symptoms exists.

Candida infection of the esophagus can present with a range of clinical findings (Box 1). Between 20 and 50% of patients may be asymptomatic. Others will note dysphagia, odynophagia, epigastric pain, nausea and vomiting, or hematemesis. Fever may be present.

Candida infections of the oral cavity are relatively common and may present in several forms. Any of the forms may be asymptomatic or may cause soreness and burning. The most common, acute pseudomembranous candidiasis, or oral thrush, presents with multiple white patches on the tongue, palate, and other areas of oral mucosa.

Skin infections with Candida are common and may manifest in a variety of forms. Intertrigo occurs in warm, moist areas of skin, such as under the breast, in the groin, and in the axilla.

Coccidioidomycosis was first described as a disease a little more than a century ago in Buenos Aires, Argentina. It was in San Francisco that the organism causing the clinical disease was given its name, Coccidioides immitis. Many diseases were later found to be caused by this organism, including San Joaquin Valley Fever.