What Is Coccidioidomycosis?

Coccidioidomycosis, also known as coccidioid granuloma, is a disease caused by Coccidioides. Often manifested as acute benign asymptomatic or self-limiting primary respiratory infections, which occasionally spread, can form focal lesions in the skin, subcutaneous tissues, lymph nodes, bones, liver, kidneys, meninges, brain, or other tissues. The disease, also known as St. Joaquin Fever or Valley Fever, is an endemic disease in the southwestern United States. Susceptible persons acquire the infection by inhaling dust containing fungal spores. Due to the late onset of clinical manifestations, obvious infection symptoms sometimes occur outside the epidemic area.

Basic Information

nickname

Coccidioid granuloma

English name

coccidioidomycosis

Visiting department

dermatology

Common causes

Coccus sphaeroides infection during tissue damage or inflammation

Common symptoms

Diarrhea-like lesions on skin lesions, forming nodules

Causes of coccidioidomycosis

The disease is mainly caused by Coccidioides, which can be isolated from soil in endemic areas and can survive in dry sandy soil. Animals such as cattle, sheep, and dogs can also be infected. This bacterium is a biphasic type, which is a yeast type in a tissue at 37 ° C and a hyphae type on a 28 ° C medium. It can be broken into arthrospores and is highly infectious. Most people pass in from the respiratory tract, but a few can also start with skin infections. Generally more men than women, all age groups can develop the disease. Laboratory infections can occur, but no direct transmission from person to person or from person to animal has been seen. It is easy to be infected when tissue damage or inflammation occurs, and low body resistance is also one of the pathogenic conditions. At this time, it is easy to spread. Coccus is a biphasic fungus that lives in the soil and is highly infectious. Just inhaling a single spore can cause a positive skin test. Humans are infected mainly by sucking joint spores in soil or cultured spores in the laboratory, and a small number can also spread through pollutants.

Clinical manifestations of coccidioidomycosis

1. The incidence is mostly young adults and field workers, more men than women.

2. The primary skin lesions are mostly diarrhea-like lesions that occur 1 to 3 weeks after infection, and then form nodules, which are distributed along the lymphatic vessels, like sporotrichosis, with lymphangitis and lymphadenopathy, most of which can heal themselves .

3. Secondary skin lesions are more common in the nose, cheeks, and scalp. They are manifested as multiple painless nodules, rupture of the central part, and occasionally wart hyperplasia.

4. Mucosa and various organs of the whole body can be affected, but muscles, digestive tracts, and lungs are generally not involved, and severe cases can be fatal.

5. Fungal microscopy showed round thick-walled spores, called spheroids, which could be filled with endospores, and the fungus culture was biphasic.

6. Cocclosporin skin test is positive, serology test is positive.

7. The white blood cell count increased, especially the number of neutrophils increased, the number of eosinophils increased significantly, and the erythrocyte sedimentation rate continued to accelerate.

Coccidioidomycosis

Laboratory inspection

Direct microscopic examination of the fungus revealed sporangia with spores. Mycotic spores can be seen in fungal cultures at room temperature.

2. Serological examination

(1) IgM (immunoglobulin M) The diagnosis index of this disease is that most patients with acute infection can detect specific IgM within 4 weeks before infection, and disappear at 2 months, indicating that the patient has spread. Sexual infection.

(2) IgG (immunoglobulin G) IgG antibody increases from 4 to 12 weeks after infection, and remains positive after disseminated infection, and disappears as soon as the condition recovers.

(3) Histopathological examination The primary skin coccidioidomycosis is chronic granulomatous. There are infiltration of neutrophils, eosinophils, lymphocytes and plasma cells, and sometimes small abscesses can be seen, which contain endospore sporangia. With progressive disseminated coccidioidomycosis, abscesses are formed with caseous necrosis, and endospores are seen in heterotypic giant cells.

Diagnosis of coccidioidomycosis

In addition to the typical clinical symptoms, the diagnosis of this disease is mainly based on:

Skin coccidiosin test

It is usually positive 2 to 6 weeks after infection, especially when there is skin lesion.

2. Fungal inspection

The diagnosis of coccidia in the sputum and skin lesions can be confirmed, but the negative can not rule out the disease.

3. Pathological biopsy

4. Serology

Including precipitation reaction and complement binding test.

Coccidioidomycosis treatment

Diffuse coccidiosis without medication is often fatal, and the prognosis is particularly poor if you have meningitis. In the 1 month after diagnosis, the mortality rate of infected patients exceeds 70%, and it is uncertain whether treatment can change this situation. Low-risk patients do not need to be treated for primary coccidioidomycosis, and high complement-combination titers indicate that dissemination has occurred and requires treatment. Mild to moderate non-meningeal extrapulmonary involvement should be treated with fluconazole or itraconazole. In severe cases, it is best to use amphotericin B intravenously, and continuous medication according to the degree of infection. With histoplasmosis and AIDS with coccidioidomycosis, maintenance therapy should be taken to prevent recurrence. Amphotericin B can be administered intravenously in patients who cannot tolerate azoles.

If amphotericin B is used to treat coccidiomyces meningitis, it needs to be injected from the cerebrospinal sheath or intraventricularly through the subcutaneous channel device. However, fluconazole has replaced amphotericin B in the treatment of most coccidioid meningitis and may be more effective. Coccidioidomyelitis can be surgically removed from affected bones. People with primary infections can recover quickly through rest, enhanced nutrition, etc. Patients with severe allergic disease can consider the application of corticosteroids, but should prevent the spread of pathogens caused by it. Residual benign lung lesions may be considered for surgical resection to avoid repeated hemoptysis. For patients with secondary infection, amphotericin B, lushanmycin, fluconazole or itraconazole should be treated as soon as possible. The course of treatment should be long and the amount must be sufficient.

Coccidioidomycosis prevention

At present, there is no way to prevent coccidioidomycosis. It is recommended to avoid participating in activities that generate a lot of dust in the environment, such as construction work.