What Is Coccidioidomycosis?
Coccidioidomycosis, also known as valley fever, is caused by the fungus Coccidioides. The fungus has been found in the soil of the southwestern United States and parts of Mexico, Central, and South America. The fungus was also discovered recently in south-central Washington. Coccidioidomycosis can be contracted by inhaling microscopic fungal spores in the air, though most people who do so do not become ill. People who get coccidioidomycosis usually recover on their own within weeks to months, but some may require antifungal medication. Certain groups of people are more likely to become seriously ill.
What Are the Symptoms of Coccidioidomycosis?
Primary Coccidioidomycosis:
The majority of patients with primary coccidioidomycosis are asymptomatic, but nonspecific respiratory symptoms resembling influenza, acute bronchitis, or, less frequently, acute pneumonia or pleural effusion (fluid accumulation between the tissues lining the chest and the lungs) can occur. In that order, primary coccidioidomycosis symptoms include fever, chest pain, cough, sputum production, chills, sore throat, and hemoptysis (presence of blood in the sputum).
In addition, some patients experience hypersensitivity to the localized respiratory infection, which manifests as arthritis, conjunctivitis, erythema nodosum, or erythema multiforme.
Progressive Coccidioidomycosis:
Nonspecific symptoms, such as low-grade fever, anorexia, weight loss, and weakness, appear a few weeks, months, or even years after the primary infection. Cutaneous manifestations are caused by immunologically induced reactive eruptions, organism dissemination from the lungs, or direct inoculation (primary cutaneous infection). The most common reactive eruption associated with coccidioidomycosis is erythema nodosum. Erythema nodosum is distinguished by multiple, self-limited, erythematous, painful subcutaneous nodules that appear one to three weeks after the onset of respiratory symptoms. There have also been reports of a generalized toxic exanthem and erythema multiforme. Extensive pulmonary involvement is uncommon in otherwise healthy people and occurs primarily in immunocompromised individuals. It can cause progressive cyanosis, dyspnea, and bloody or mucopurulent sputum.
General symptoms of coccidioidomycosis include:
-
Tiredness (malaise).
-
Fever and cough.
-
Breathing difficulty.
-
Sweating at night.
-
Aches and pains in the muscles or joints.
-
A rash on the upper or lower body is a valley fever rash (erythema nodosum).
-
Fungal spores can enter the skin and cause a skin infection through a cut, wound, or splinter in sporadic cases.
How Is Coccidioidomycosis Diagnosed?
-
Cultures (routine or fungal).
-
Examination of specimens under the microscope for C.immitis spherules.
-
Serologic examination.
Eosinophilia may be an essential indicator of coccidioidomycosis. Coccidioidomycosis is suspected based on history and typical physical findings; chest X-ray findings can help confirm the diagnosis, which can be confirmed by fungal culture or visualization of C.immitis spherules in sputum, pleural fluid, cerebrospinal fluid (CSF), exudate from draining lesions, or biopsy specimens. Spherules in their entirety are typically 20 to 80 micrometers in diameter, thick-walled, and filled with small (two to four micrometers) endospores. Endospores released into tissues by ruptured spherules can be confused with non-budding yeasts. Because culturing Coccidioides can pose a severe biohazard to laboratory personnel, the suspected diagnosis should be reported to the laboratory. Once the fungus has grown in the laboratory, DNA probes can quickly identify it.
Anti Coccidioides antibody serologic testing includes:
-
Enzyme immunoassay is highly sensitive and widely used to diagnose coccidioidomycosis.
-
Kit for immunodiffusion (to detect IgM or IgG antibodies).
-
Fixation on a complement (to detect IgG antibodies).
What Are the Risk Factors for Coccidioidomycosis?
Coccidioidomycosis is rare in otherwise healthy people and is more likely to occur under the following circumstances:
-
Infection with HIV (human immunodeficiency virus).
-
Usage of immunosuppressive medication.
-
Old age.
-
The second half of pregnancy or postpartum.
-
Certain ethnic groups like Filipino, Native American, African American, Hispanic, and Asian.
What Is the Treatment of Coccidioidomycosis?
Fluconazole or Itraconazole are used to treat mild to moderate diseases. Amphotericin B is used to treat severe infections. Patients with primary coccidioidomycosis should be treated if they have severe or progressive disease risk factors. In low-risk patients, treatment for primary coccidioidomycosis is debatable. However, some experts prescribe Fluconazole because of its low toxicity and because, even in low-risk patients, there is a small risk of hematogenous seeding, particularly to bone or brain.
Furthermore, in patients who have undergone treatment, the symptoms resolve faster than in those not treated with an antifungal drug. Fluconazole may suppress the immune response, and the risk of hematogenous seeding in primary infection is too low to warrant its use. High complement fixation titers indicate the spread of the disease and the need for treatment.
Fluconazole 400 mg orally once a day or Itraconazole 200 mg orally twice a day should be used to treat mild to moderate non-meningeal extrapulmonary involvement. Alternatives include Voriconazole 200 mg orally or IV (intravenous) twice a day and Posaconazole 400 mg orally twice a day, but these have not been thoroughly studied. For severe illness, Amphotericin B 0.5 to 1 mg/kg IV over two to six hours once a day is administered for four to 12 weeks until the total dose reaches 1 to 3 g, depending upon the severity of the illness.
Amphotericin B lipid formulations are preferred over conventional Amphotericin B. Once patients have been stabilized, they can usually be switched to an oral azole within a few weeks.
To prevent relapse, patients with HIV -associated coccidioidomycosis require maintenance therapy. Fluconazole 200 mg orally once a day or Itraconazole 200 mg orally twice a day is usually sufficient, given until the CD4 cell count is more significant than 250/mcL.
Fluconazole is used to treat meningeal coccidioidomycosis. The ideal dose is unknown; however, oral doses of 800 to 1200 mg once daily may be more effective than 400 mg daily. Meningeal coccidioidomycosis should be treated for the rest of one's life. In the case of osteomyelitis, the involved bone might be surgically removed as a part of the treatment.
Conclusion:
People with severe lung infections or infections spread to other body parts always require antifungal treatment and may require hospitalization. The course of treatment for these conditions is usually longer than six months. Coccidioidomycosis that progresses to meningitis is fatal if not treated, so lifelong antifungal therapy is required in those cases. The majority of the patients with coccidioidomycosis will recover completely. Long-term lung infections affect a small percentage of the population and can take years to resolve. Coccidioidomycosis can affect the nervous system and cause long-term damage in severe cases. However, this is extremely rare.
