Clinical Pearls & Morning Reports
Published May 3, 2017
Coccidioidomycosis, which is caused by the fungi Coccidioides immitis and Coccidioides posadasii, is endemic to the southwestern United States. Infections occur after the inhalation of spores. The majority of infections are acquired in southern Arizona, central California, New Mexico, and Texas. Read the latest Clinical Problem-Solving article.
Q. What are some of the clinical features of coccidioidomycosis?
A. Up to two thirds of persons with coccidioidomycosis have an asymptomatic or mild illness and do not present for medical care. Of persons who seek care, the majority present with a self-limited subacute pulmonary process or flulike illness, often referred to as valley fever. Primary coccidioidomycosis is often misclassified as community-acquired pneumonia since it also manifests as fever, cough, and an infiltrate on chest imaging. Most respiratory infections resolve without treatment, and extrapulmonary dissemination from the hematogenous spread of coccidioidomycosis develops in less than 0.5% of immunocompetent patients.
Q. Who is at risk for dissemination of primary coccidioidomycosis?
A. Factors that increase the risk of dissemination include HIV, lymphoma, diabetes, solid-organ transplantation, pregnancy, and treatment with high-dose glucocorticoids or tumor necrosis factor inhibitors. The risk of dissemination also appears to be higher among men than among women and higher among persons of African or Filipino descent than among persons of other ethnic groups. Older age, when adjusted for coexisting conditions, has not been associated with an increased risk of dissemination. The most common sites of dissemination are the skin, meninges, joints, and vertebrae.
A: Coccidioidal vertebral osteomyelitis can involve multiple vertebrae. The intervertebral disk is often spared early in the course of coccidioidal vertebral osteomyelitis, as it is in the course of tuberculous osteomyelitis, and the absence of intervertebral disk involvement can help differentiate this disease from bacterial causes. Unlike tuberculosis, coccidioides does not cause a gibbus deformity (a form of structural kyphosis). As the disease progresses, paraspinal soft-tissue abscesses or epidural abscesses can develop and may lead to neurologic complications. Disseminated spinal coccidioidomycosis is important to recognize since it is associated with a high risk of complications and death if it remains untreated. Most patients present with subacute or chronic back pain and often do not have systemic signs of infection, such as fevers or night sweats. As a result of the indolent nature of this infection, the diagnosis is often delayed by weeks or months.
A: On the basis of limited data from case series, treatment of severe coccidioidal osteomyelitis, defined as extensive vertebral involvement, spine instability, or risk of spinal cord impingement, often consists of initial administration of amphotericin B, followed by administration of itraconazole, fluconazole, posaconazole, or voriconazole. Liposomal amphotericin B can be used as an alternative to amphotericin B in patients who are at risk for drug-induced renal toxic effects. Moderate-to-severe disease is often treated with an oral azole alone. Adjunctive surgical débridement or stabilization is often indicated in these cases and is crucial if there is cord impingement or spine instability. The combination of medical and surgical treatment has been associated with better outcomes, including symptom relief and control of the disease, than medical therapy alone. Most cases of coccidioidal vertebral osteomyelitis require more than 1 year of antifungal treatment, and some require indefinite treatment.