Chest ImagingCoccidioidomycosis
fungus infection caused by the fungus
Coccidioides immitis. This disease is generally found in the south-western United States as well as Mexico and some Central and South American countries. The fungus is acquired through inhalation after being stirred up in its natural soil environment. While many patients who come into contact with the fungus will acquire the infection, only a small percentage will exhibit long-lasting illness or dissemination.
Primary coccidioidomycosis develops as a pneumonia with radiographic findings of homogeneous opacification, at times simulating ordinary bacterial infection. Cavitation, ipsilateral adenopathy (Fig.1) and pleural effusion may be seen in approximately 20% of patients. Clinically patients present with fever and cough occasionally accompanied by an erythematous rash. In most patients the disease spontaneously resolves without chest film residual abnormalities although occasionally a calcified lymph node or calcified lung nodule is identified. Another form of primary coccidioidomycosis may be seen in asymptomatic individuals who present with chest films demonstrating multiple nodules measuring approximately 0.5 to several cm in diameter typically located in the upper lobes. They may be well defined or poorly defined and cavitation may ultimately result in thin walls.
Chronic coccidioidomycosis may resemble tuberculosis with linear changes in the upper lobes, fibrosis and retraction, and cavitation. Patients may present with cough and weight loss, fever and haemoptysis.
Disseminated coccidioidomycosis may rarely be seen in both normal and immunocompromised hosts. The disease may be an extension of earlier infection or possibly represent newly acquired disease. Radiographically diffuse small nodules are identified. Patients present with fever and dyspnoea. Rapid progression leading to death may occur. The diagnosis may be inferred by skin testing with spherulin, and identification of organisms in sputum or tissue. Treatment is with conventional or antifungal agents such as amphotericin B or ketoconazole.
PGO
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A PA chest film demonstrates an area of homogeneous opacification in the left upper lobe. Associated with this are cavitation and ipsilateral hilar lymphadenopathy. Coccidioidomycosis may also occur as a well defined nodule or nodules in the lung. Adenopathy and cavitation are seen approximately 20% of the time.
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Coccidioidomycosis, Fig.1 | |