Candidiasis or thrush cs an acute cr chronic fungal disease involving superficial tissues of skin or mucous membrane cr less frequently disseminating hematogenously to produce systemic disease, especially in kidneys, heart, and brain.
History of Candidiasis
Oral candidosis or thrush was first described by the English physician Unde:beck, a German surgeon, discovered C smoztw, and two years later Berg, a Swedish physician, demonstrated this fungus to be the cause of thrush. It was first recognized in 1869 by Parrot, and proved by positive antemortem blood culture srss reported by Joachim and Polages.
Etiology of Candidosis
Man may be infected by a variety of species of Candida which :n tissues or on direct examination of fresh material appear as 2 to 4 /x, budding, thin-walled, oval yeast like forms, or occasionally as pseudo- or true hyphal forms. On Sabouraud glucose medium, moist, cream-colored colonies appear. Some Candida species can infect laboratory animals, especially those treated with corticoids or made diabetic with alloxan. In some patients especially prone to repeated or severe Candida infections, there has been absence of a leukocyte enzyme, myeloperoxidase, or of a serum candidacidal alpha (or beta, but not gamma) globulin. Delayed cutaneous hypersensitivity and agglutinogen antigens are produced.
Epidemiology of Candidiasis
Candida organisms are commonly present in the mouth, vagina, sputum,and stools of otherwise normal persons. Candidosis in the form of oral thrush, skin lesions, or disseminated disease seems to arise in patients with other diseases or under special circumstances: infancy, diabetes, debilitated or dehydrated states, antibacterial or corticoid treatment, drug addiction, leukemia, and tuberculosis. Candidosis i.s also more frequent in occupational groups (housewives, fruit packers, bartenders) whose skin is frequently in water and macerated. Thrush may occur in epidemics. Birds more frequently, but other animals as well, may be naturally infected, but animal-to-man contagion is not important.
Pathology of Candidosis
The histopathologic lesion in candidosis may be variously acute and suppurative with multiple abscess formation, or chronic and inflammatory with giant cells and occasionally caseation. Either yeastlike or hyphal forms may be seen after hematoxylin and eosin or periodic acid-Schiff staining.Candidosis of the skin and mucous membranes is superficial and epithelial. When dissemination occurs, kidneys, heart, brain, pancreas, lungs, adrenals, thyroid, liver or joints may be involved.
Clinical Forms of Candidiasis
Mucous Membrane Form (Thrush. In infants or in older patients with debilitating, dehydrating disease, the classic lesion of thrush of the oral cavity appears as multiple, sometimes confluent, white to creamy patches of exudate on a fiery red and painful mucosa. The disease may spread to the pharynx and esophagus to produce dysphagia. Similar lesions and local irritation may occur also in the mucosa of the rectum or of the vagina and cervix.
Skin lesions may be those of intertrigo with reddening, maceration, and weeping of contiguous folds of skin; onychia with hardening, thickening, grooving, and loss of the nail; or paronychia with reddening, swelling, and pain of the skin about the nails. Candididiasis with multiple, grouped vesicles is another form of the skin disease.
From superficial and endogenous sites, Candida species may occasionally invade local tissue directly or distant tissues hematogenously under conditions listed earlier. Pulmonary disease may result as a spread from the oral cavity or bronchi with completely nonspecific lobar or patchy bronchopneumonia.
When Candida invades the bloodstream, symptoms may be absent or transient and self-limited. Although such invasion may begin in the lung, no characteristic clinical disease has ever been defined in that organ.Three distinctive forms are well accepted. Candida septicemia bears the earmarks of other bacterial disease: fever, chills, shock, oliguria, coma, and bleeding. Candida meningitis is usually less acute than bacterial disease, but is accompanied by headache, stiff neck, and delirium.
The third and striking form is an endocarditis with characteristically large vegetations and large artery embolism (see accompanying figure). Disease occurs after vascular trauma, notably in heroin addicts and in patients who have had cardiac surgery. Antimicrobial therapy in man probably predisposes toward Candida superinfection at this site, and in animals is essential to the production of lesions.
Diagnosis of Candidiasis
A typical clinical picture of thrush, vulvovaginitis, onychia, or skin lesions and the finding of organisms on direct examination or culture constitute the diagnosis in superficial infection. A biopsy demonstrating tissue invasion of typical fungal forms or a positive culture from blood, cerebrospinal fluid, or deep tissue is conclusive evidence of disseminated disease.
Candidosis of the skin must be distinguished from other dermatophytosis. Thrush may resemble exudative disease of bacterial (streptococcal or diphtherial) origin, infectious mononucleosis, or Koplik spots. Endocarditis meningitis, or septicemia caused by Candida resembles its bacterial equivalent.
Treatment of Candidiasis
Local lesions of thrush respond to a variety of procedures, including hydration, better oral hygiene, and, as necessary, mouth washes four times a day with nystatin solution (2 ml. of 200,000 units per milliliter). Gastrointestinal or vulvovaginal thrush should be treated with oral tablets of nystatin, 1 million units four times daily by mouth. A suppository (100,000 units) may also be inserted intravaginally nightly. This drug in the form of cream should be applied locally to skin or nail lesions.
Candida fungemia may clear spontaneously. The factors, other than antibacterial therapy, are not well known or clinically recognizable that lead to implantation on heart valves or to multiple abscesses. For the latter complications amphotericin B is advisable (see Histoplasmosis). Nystatin is not absorbed from the gastrointestinal tract and is not available for parenteral use.
Prognosis of Candidosis
Untreated disease of the skin and mucous membranes may be chronic and respond poorly to therapy, but dissemination and fatal outcome are rare. Candida septicemia is a severe and usually fatal disease; survival time is often insufficient to achieve an effective concentration of drug in the blood and tissues. By contrast, Candida meningitis, curiously, can be less severe and spontaneous; recovery, (without appropriate antifungal therapy), ensues frequently. Candida endocarditis is a chronic and inexorably fatal disease in at least 90 per cent of patients, even when treated with amphotericin B.