A 31-year-old man comes to the office due to a week of low-grade fever, dry cough, and right-sided chest pain. The pain is intermittent, sharp, and worse with deep inhalation or cough. The patient also notes mild "achiness" in his knees and ankles that started around the same time. He does not use tobacco, alcohol, or illicit drugs. The patient is an Army officer, and he returned to Connecticut 2 weeks ago after completing desert training exercises in Arizona. He does not know if other participants developed similar symptoms. Temperature is 37.8 C (100 F), blood pressure is 120/80 mm Hg, pulse is 78/min, and respirations are 16/min. Lung auscultation shows right-sided crackles. No joint swelling or tenderness is present, but there are erythematous, tender nodules on the bilateral shins. Chest x-ray reveals a right lower lobe infiltrate with a prominent right hilum. Which of the following is most likely causing this patient's condition?

Question

A 31-year-old man comes to the office due to a week of low-grade fever, dry cough, and right-sided chest pain.  The pain is intermittent, sharp, and worse with deep inhalation or cough.  The patient also notes mild "achiness" in his knees and ankles that started around the same time.  He does not use tobacco, alcohol, or illicit drugs.  The patient is an Army officer, and he returned to Connecticut 2 weeks ago after completing desert training exercises in Arizona.  He does not know if other participants developed similar symptoms.  Temperature is 37.8 C (100 F), blood pressure is 120/80 mm Hg, pulse is 78/min, and respirations are 16/min.  Lung auscultation shows right-sided crackles.  No joint swelling or tenderness is present, but there are erythematous, tender nodules on the bilateral shins.  Chest x-ray reveals a right lower lobe infiltrate with a prominent right hilum.  Which of the following is most likely causing this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d442_d821_bc81_0100aba84d90_MD0003_00 Coccidioides is an endemic mold of the desert southwest whose spores are easily aerosolized in the dry months after a rainy season. Inhalation of a single arthroconidium is sufficient to cause infection (usually 7-14 days after inoculation). Symptoms may be subclinical, but many patients (>50%) develop community-acquired pneumonia (CAP) (fever, chest pain, productive cough, lobar infiltrate) often accompanied by arthralgias, erythema nodosum, or erythema multiforme. This clinical syndrome is also called Valley Fever, and symptoms frequently last weeks or months. Diagnosis should be suspected in any patient living in or traveling to an endemic region (particularly Arizona or California) who has a lower respiratory illness lasting >1 week. Confirmation primarily relies on serologic testing, but cultures are often sent. Most patients who are otherwise healthy and have mild or moderate disease do not need antifungal treatment and can have regular follow-up to ensure resolution. However, patients with severe disease or certain risk factors (eg, HIV, immunosuppressive medications, diabetes mellitus) are much more likely to develop dissemination (bones, central nervous system, skin); these patients require antifungal treatment. (Choices A and D) Blastomyces dermatitidis and Histoplasma capsulatum are common endemic mycoses in the United States, but both occur primarily in the central and midwestern states (not the desert southwest or Connecticut). Blastomyces may cause acute or chronic pneumonia (often with skin lesions), but it has a longer incubation time (3-6 weeks). (Choice B) Chlamydia psittaci is usually acquired through close contact with birds and causes the abrupt onset of fever, dry cough, and headache. Subacute pulmonary findings after recent travel to Arizona make coccidioidomycosis far more likely. (Choice E) Legionella pneumophila usually causes high fever (>39 C [102.2 F]), pulmonary symptoms (dyspnea, cough), and gastrointestinal symptoms (nausea, vomiting, diarrhea). This patient has low-grade fever and no gastrointestinal symptoms. (Choice F) Nocardia asteroides may cause pulmonary or cutaneous infection; however, patients are almost always immunocompromised (eg, HIV, glucocorticoid therapy, diabetes mellitus), and infection frequently involves the central nervous system. This patient had recent exposure to the Arizona desert and developed symptoms a week later, making coccidioidomycosis likely. (Choice G) Sporothrix schenckii is a fungus that primarily causes ulcerative, nodular lesions of the skin. Educational objective: Coccidioides is an endemic mycosis of the desert southwest that causes community-acquired pneumonia (fever, chest pain, cough, lobar infiltrate) often accompanied by arthralgias, erythema nodosum, and erythema multiforme. Symptoms may last weeks to months. Most otherwise healthy patients do not require antifungal therapy. Patients who are at high risk (eg, immunocompromised) for dissemination are often given ketoconazole or fluconazole.

A 31-Year-Old Man Comes to the Office Due to a Week