November 8, 2024

Presentation with long-term low-grade fever, chills, and cough

By Med-Challenger · 2 minute read

A 40-year-old high school teacher presents to you with 3 weeks of low-grade fever, chills, and cough. She had been visiting relatives in Bakersfield, CA, over spring break.

She saw her primary care physician 1 week ago and received 5 days of azithromycin for what she called "bronchitis." The treatment was ineffective.

Her vital signs are: temperature 99.8 °F, blood pressure 122/82 mm Hg, heart rate 120 beats/minute, and oxygen saturation 94% on room air. She is mildly tachypneic.

Findings on lung examination reveal crackles on auscultation in the left axillary area. Abdominal and extremity examination findings are unremarkable.

You order radiography of her chest (Figure 1).

40yo

You also obtain a sputum culture, and the KOH stain of the sputum is shown (Figure 2).

40yosputum

What organism is causing her symptoms?

Entamoeba histolytica
Coccidioides immitis
Histoplasma capsulatum
Blastomyces dermatitidis

The correct answer is:

Coccidioides immitis

Educational Objective:

Diagnose coccidioidomycosis

Key Point:

Suspect coccidioidomycosis in a patient with a history of travel to an endemic area who is presenting with pneumonia unresponsive to antibiotics. Confirm diagnosis by culture or serology.

Explanation:

The patient's travel to the southwestern United States and the subacute pneumonia unresponsive to antibiotics strongly suggest a diagnosis of coccidioidomycosis. The fungus is endemic to the Southwest and the area around Bakersfield, CA. The organism can cause acute pulmonary infection, chronic lung disease, skin disease, or disseminated disease; it often involves the central nervous system.

Most people will recover from primary acute pulmonary coccidiodomycosis without treatment. For persistent symptoms and signs, fluconazole is usually effective. In rare instances, when diffuse pneumonia is noted or the disease becomes rapidly progressive, amphotericin B may be used.

Clinically, it may be difficult to distinguish blastomycosis from coccidiodoycosis. Both are endemic infections occurring in the southwestern part of the country. Blastomycosis may result in fever, cough, and chest ache---all of which are no different from the symptoms seen in cases of coccidiodomycosis. More often, it is asymptomatic until or unless the infection becomes systemic, most often in immunocompromised patients. An enzyme immunoassay is available for the diagnosis of this fungal disease.

Histoplasmosis is the result of inhaling the spores of the fungus H capsulatum. It is an endemic infection in the Midwest, particularly the Ohio Valley. The spores come from the droppings of birds and bats. Respiratory symptoms may be similar to those of coccidiodomycosis. It can be a life-threatening illness for infants and people who are immunocompromised. Diagnosis may be difficult. Biopsy of an infected organ (eg, lung) and obtaining a culture (eg, blood, urine) is the most common approaches to diagnosis.

E histolytica is a parasite that causes amebiasis. Its symptoms are different from the other 3 fungal infections listed. Diarrhea is the universal complaint.

Reference:

Kauffman CA, GaglianiJ JN, Thompson, GR. Endemic Mycoses. In: Goldman-Cecil Medicine, 2020; 317: 2046-2048. E2

This question appears in Med-Challenger Internal Medicine Review with CME

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