OVERVIEW
Paracoccidioidomycosis is a systemic granulomatous disease caused by Paracoccidioides brasiliensis that can involve multiple organs, most commonly the lungs, the monocyte-macrophage system, the mucous membranes of the gastrointestinal tract in the upper airways, the skin, and the adrenal glands. The disease is endemic in Central and South America, and is common in males aged 20 to 50 years, especially in coffee workers in Colombia, Venezuela, and Brazil. Unlike other fungal diseases such as candidiasis, cryptococcosis, and disseminated histoplasmosis, paracoccidioidomycosis is usually not associated with immunosuppressive disorders, but cases have been reported in HIV-infected patients, oncology patients, and a very small number of organ transplant recipients. Coccidioides parahaemolyticus is hypothesized to exist as a fungus in soil, and humans become infected by inhaling the spores. The spores transform into invasive yeasts at 37°C in the lungs and can be disseminated to other sites via the bloodstream and lymph. Most patients have a favorable prognosis, with only a few cases developing disseminated infection.
Etiology
Paracoccidioidomycosis is a systemic granulomatous disease caused by Paracoccidioides brasiliensis, which can involve multiple organs, most commonly in the lungs, monocyte-macrophage system, mucous membranes of the digestive tract of the upper airways, skin, adrenal glands, etc. The disease is endemic in Central and South America. The disease is endemic in Central and South America, and is common in males aged 20 to 50 years, especially in coffee workers in Colombia, Venezuela, and Brazil. Unlike other fungal diseases such as candidiasis, cryptococcosis, and disseminated histoplasmosis, paracoccidioidomycosis is usually not associated with immunosuppressive disorders, but cases have been reported in HIV-infected patients, oncology patients, and a very small number of organ transplant recipients. Coccidioides parahaemolyticus is hypothesized to exist as a fungus in soil, and humans become infected by inhaling the spores. The spores transform into invasive yeasts at 37°C in the lungs and can be disseminated to other sites via the bloodstream and lymph. Most patients have a favorable prognosis, with only a few cases developing disseminated infection.
Symptoms
1. Chronic pulmonary paracoccidioidomycosis
The lungs are the most common site of initial infection, but most normal people do not develop any signs and symptoms after lung infection, and some patients develop chronic lung infection or acute disseminated infection. Most patients with chronic pulmonary paracoccidioidomycosis have an insidious onset, with symptoms such as fever, night sweats, malaise, coughing up sputum, lethargy and hemoptysis.
2. Skin and mucous membrane paracoccidioidomycosis
Oral and nasal mucosa is the most common site of involvement, including gingiva, tongue, lips and palate with painful ulcers, which may affect eating. The palate and nasal septum may be perforated by ulcers, and the larynx may be hoarse due to ulceration and scar formation. Skin involvement is most often seen around the mouth and nose. It begins as papules and nodules and after a few weeks or months forms plaques with raised edges that may have a warty or ulcerated surface. Lymph nodes are enlarged, especially in the cervical lymph nodes, which may ulcerate to form fistulas and discharge pus.
3. Disseminated Coccidioidomycosis
Dissemination of the pathogen through the blood circulation and lymph can lead to widespread systemic infection, including nodular ulcerative damage in the large and small intestines. The liver, spleen, adrenal glands are involved or osteomyelitis, arthritis, meningitis and focal damage in the brain may occur.
Laboratory tests
1. Fungal examination
(1) Pus, sputum, skin and mucous membrane damage scrapings, lymph node aspirates, etc., plus 10% KOH, microscopically visible single or multi-budding spores. To daughter cells and mother cell size difference, mother cell is spherical, more than one daughter cell attached to its sailor’s wheel as a typical performance, with diagnostic significance.
(2) Culture, culture is biphasic, see white woolly colonies at 25 ℃; 37 ℃ blood agar for yeast-like colonies. External antigen test can be quickly identified.
2. Serologic tests
Complement binding test is positive in the majority of patients, note that there is cross-reactivity with bacteriosis, sporotrichosis and histoplasmosis. Immunodiffusion test is positive in most patients, and occasionally cross-reacts with histoplasmosis.
3. Histopathology
Histopathology is mainly purulent granuloma with multinucleated leukocyte infiltration, and the sailor’s wheel or “rudder wheel” is the characteristic manifestation of Parasporococcus.
Diagnosis
1. Paracoccidioidomycosis is an endemic fungal disease, and patients often have a history of residence in endemic areas.
2. The possibility of the disease should be considered in the case of pulmonary infections, accompanied by long-lasting skin ulcers and enlarged lymph nodes, or multi-system involvement.
3. The diagnosis of cutaneous paracoccidioidomycosis is relatively easy and is primarily a matter of finding the causative agent.
Although the finding of large (often >15 μm) yeasts forming characteristic multibacillary bodies in specimens can provide a strong basis for diagnosis, fungal culture is required to confirm the diagnosis.
Treatment
Itraconazole and fluconazole are available. Itraconazole is recommended for 6 to 12 months. Amphotericin B may be used if necessary.
Prevention
Paracoccidioidomycosis is caused by skin contact or inhalation of Paracoccidioidomycetes through the respiratory tract, so preventive measures should be taken against the cause of the disease. Anyone who enters an epidemic area should avoid contact with moldy objects and wear a mask to avoid inhaling fungal spores and mycelium. In addition, strengthening physical exercise and improving immunity are also important for the prevention and treatment of this disease.