Coccidioidomycosis

Key Features

Essentials of Diagnosis

• Residence in, or travel to, an endemic area

• Primary pulmonary form: fever, chest pain, cough, anorexia, weight loss, and often a macular rash, erythema nodosum, or erythema multiforme

• Primary cutaneous form: skin trauma followed in 1–3 weeks by an ulcer and regional adenopathy

• Spherules seen in pus, sputum, CSF, joint fluid; positive culture

• Appearance of precipitating (early) and complement-fixing antibodies (late)

General Considerations

• Caused by Coccidioides (immitis or posadasii), which is endemic in the Sonoran Desert areas of western Texas, southern New Mexico and Arizona, southern California, northern Mexico, and South America

• Infection results from inhalation or inoculation of arthrospores (highly contagious and readily airborne in the dry climate)

• Human-to-human transmission does not occur

• More than half of all infections are asymptomatic, and less than 5% are associated with significant pulmonary disease

• Chronic pulmonary disease or dissemination occurs in less than 1% of cases

Clinical Findings

Symptoms and Signs

• Primary disease

  • Incubation period is 10–16 days (range, 7–28 days)

  • Symptoms vary from those of a mild fever and arthralgia to severe influenza-like illness with high fever, nonproductive cough, pleuritic chest pains, arthralgias, headache, and night sweats

  • Upper respiratory tract signs are uncommon

  • Signs vary from none to rash, rales, pleural rubs, and signs of pulmonary consolidation

  • Weight loss may occur

• Skin disease

  • Up to 10% of children develop erythema nodosum or erythema multiforme

  • Less specific maculopapular eruptions occur in a larger number of children

  • Skin lesions can occur following fungemia

  • Primary skin inoculation sites develop indurated ulcers with local adenopathy

  • Contiguous involvement of skin from deep infection in nodes or bone also occurs

• Chronic pulmonary disease

  • Uncommon in children

  • Manifested by chronic cough (occasionally with hemoptysis), weight loss, pulmonary consolidation, effusion, cavitation, or pneumothorax

• Disseminated disease

  • More than one organ may be involved

  • Most common extrapulmonary sites involved are

    • Bone or joint (usually a single bone or joint; subacute or chronic swelling, pain, redness)

    • Nodes

    • Meninges (slowly progressive meningeal signs, ataxia, vomiting, headache, and cranial neuropathies)

    • Kidneys (dysuria and urinary frequency)

Differential Diagnosis

• Primary pulmonary infection resembles acute viral, bacterial, or mycoplasmal infections

• Subacute presentation mimics tuberculosis, histoplasmosis, and blastomycosis

• Chronic pulmonary or disseminated disease must be differentiated from cancer, tuberculosis, or other fungal infections

Diagnosis

Laboratory Findings

• Direct examination of respiratory secretions, pus, CSF, or tissue may reveal large spherules (30–60 μm) containing endospores germinating in tissue

• Periodic acid–Schiff reagent, methenamine silver, and calcofluor stains demonstrate organisms

• CSF cultures are often falsely negative.

• Erythrocyte sedimentation rate is usually elevated

• Eosinophilia may occur, particularly prior to dissemination

• Antibodies consist of precipitins (usually measurable by 2–3 weeks in 90% of cases and gone by 12 weeks) and complement-fixing antibodies ...