An 18-year-old girl comes to the office with 3 days of fever, nonproductive cough, dyspnea, and fatigue. The symptoms started after she returned home from a summer school trip to Europe with friends. Her roommate had similar symptoms. The patient has no prior medical issues, and her vaccinations are up to date. She is not sexually active. She does not use tobacco, alcohol, or illicit drugs. Temperature is 38.3 C (101 F), blood pressure is 120/80 mm Hg, pulse is 88/min, and respirations are 16/min. The patient does not appear ill. Faint bilateral crackles are present. Chest x-ray reveals bilateral diffuse infiltrates. Which of the following is the most appropriate next step in management?

Question

An 18-year-old girl comes to the office with 3 days of fever, nonproductive cough, dyspnea, and fatigue.  The symptoms started after she returned home from a summer school trip to Europe with friends.  Her roommate had similar symptoms.  The patient has no prior medical issues, and her vaccinations are up to date.  She is not sexually active.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 38.3 C (101 F), blood pressure is 120/80 mm Hg, pulse is 88/min, and respirations are 16/min.  The patient does not appear ill.  Faint bilateral crackles are present.  Chest x-ray reveals bilateral diffuse infiltrates.  Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

11ec25c8_d600_b48b_bc81_0f9eb097c2f5_MD0003_00 This young woman with no significant medical history has fever, cough, dyspnea, and bilateral pulmonary infiltrates on chest x-ray indicating atypical pneumonia, likely due to Mycoplasma pneumoniae. M pneumoniae is a small, highly contagious organism transmitted by aerosolized droplets in close-quarter environments (eg, school trip). It is a common cause of upper respiratory illness (eg, bronchitis, sore throat) and community-acquired pneumonia (CAP). Most cases of Mycoplasma CAP are quite mild; patients typically present with slow-onset headache, malaise, low-grade fever, cough, and shortness of breath, which minimally limit activity (hence the term "walking pneumonia"). Because cold agglutinins often occur in Mycoplasma CAP, ~60% of patients have evidence of hemolysis. Unlike typical causes of CAP (eg, Streptococcus pneumoniae), which cause lobar infiltrate on chest x-ray, patients with M pneumoniae usually have bilateral reticulonodular or patchy pulmonary infiltrates. Treatment with a macrolide (eg, azithromycin) or fluroquinolone is typically curative; azithromycin is generally preferred due to a narrow spectrum of activity and less risk for development of resistance. Because M pneumoniae lacks a cell wall, beta-lactam antibiotics such as amoxicillin have no efficacy against the pathogen (Choice A). (Choice C) Although the illness tends to be mild, antibiotics are given to speed resolution and prevent complications. Given this patient's significant pulmonary infiltrate, antibiotics are warranted. (Choice D) Given the summer season, this patient's full vaccination status, and her lack of preceding upper respiratory symptoms, influenza infection (treated with oseltamivir) is less likely than M pneumoniae infection. In addition, primary influenza pneumonia (ie, influenza directly affecting lungs) is rare in young adults and is typically a severe form of viral pneumonia (eg, toxic appearance, pronounced dyspnea, cyanosis). (Choice E) Pneumocystis pneumonia is treated with trimethoprim-sulfamethoxazole. Although this infection often causes bilateral reticulonodular or patchy infiltrates on chest x-ray, it is very rare in an otherwise healthy young person with no risk factors for immunocompromise. Furthermore, Pneumocystis in patients with HIV usually has a subacute (not acute) onset. Educational objective: Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP). Patients typically present with slow-onset malaise, cough, dyspnea, and fever. In contrast to other many forms of bacterial CAP, patients with Mycoplasma pneumonia typically have patchy or reticulonodular bilateral pulmonary infiltrates (rather than lobar infiltrate). Treatment with azithromycin is first-line; beta-lactams are ineffective because the organism lacks a cell wall.

An 18-Year-Old Girl Comes to the Office with 3 Days