Disseminated Invasive Candidiasis in an Immunocompetent Host

Outcome and Follow-up

An autopsy disclosed the cause of death to be bilateral candida pneumonia, part of a disseminated (invasive) candidiasis, in a patient rendered vulnerable to such infection by peripheral vascular disease and renal insufficiency. Purulent inflammation was noted at the site of disarticulation of the left foot and confluent consolidation of the lower lobes of both lungs as well as focal consolidation of the middle lobe of the right lung. Examination of histologic sections, with staining both by routine method (hematoxylin and eosin) and the Grocott-Gömöri methenamine silver method for fungus, disclosed fungal forms (yeast and filamentous) in most tissues, including the lungs (Figure 1 A and B) and kidneys (Figure 1 C and D). The pulmonary sections in addition to massive inflammation showed macrophages with engulfed yeast (Figure 2 A) and a lymphatic channel, stuffed with yeast in an alveolar septum (Figure 2 B). These findings confirmed the antemortem presence of the fungus and the body’s response to it. Inflammation was noted around glomeruli overgrown by candida (Figure 1 C and D); fungi also were seen in capsular regions (not depicted). C albicans was present in the myocardium (Figure 1 E and F), brain, thyroid, and adrenal glands (Figure 3); the only organ without C albicans was the liver, either because invasion was truly absent here or because sampling had not managed to retrieve it.

Paraffin-embedded blocks of lung tissue, sent to the University of Washington Molecular Diagnosis Microbiology Laboratory for broad-range polymerase chain reaction (PCR) identification, were positive for C albicans after extraction of gDNA and conduction of PCR using internal transcribed spacer 1 and 2 specific primers.

Discussion

IC is rare among immunocompetent individuals, but C albicans can evolve into a fatal disseminated infection. We report an atypical case of IC, with profound pulmonary infection in a patient who died 1 month after hospitalization for lower extremity pain.

Cell-mediated immunity involving neutrophils and macrophages plays a major role in protection against candidiasis, while cytokines and chemokines involve regulating balanced immunity.^1,2 A series of recent studies show that alcohol impairs neutrophil-mediated killing and phagocytic-mediated uptake of a pathogen in this process.^8,9 As the patient chronically misused alcohol, his immune system may have experienced a subclinical immunosuppression, which would have become clinically relevant once C albicans was introduced systemically. Recent studies of bacterial pathogenesis and alcoholism strongly support this hypothesis.^10,11

Most patients with the unusual diagnosis of candida pneumonia have had a background of malignancy or immunosuppressive factors (eg, administration of corticosteroids).¹² In a series of 20 cases, 14 had sputum cultures positive for the organism, 6 had positive urine cultures, and 6 had positive blood cultures. Chest radiographs usually showed confluent bronchopneumonia. Five patients were diagnosed antemortem and treated with amphotericin B, but none survived.¹³ In the literature a positive blood culture or demonstration of yeast within pulmonary histiocytes has been considered proof of the pathogenicity of the fungus, as opposed to noninvasive colonization of the airways, a common occurrence in patients receiving mechanical ventilation.²