A 57-year-old man comes to the office due to 2 months of progressive cough and weight loss. He has a history of diabetes mellitus type 2 and chronic kidney disease. He does not smoke cigarettes. The patient traveled to Denmark 4 months ago for a 2-week vacation. He has 2 cats and a bird. He works in the maintenance department of a large hotel and services the hot tub and swimming pools. Temperature is 38 C (100.4 F) , blood pressure is 140/100 mm Hg, pulse is 88/min, and respirations are 16/min. The patient is 190 cm (6 foot 3 inches) tall. BMI is 22 kg/m². Examination shows cervical lymphadenopathy. Chest imaging is shown in the exhibit.
Hemoglobin A1c is 8.5% and serum creatinine is 3.8 mg/dL. Which of the following risk factors most likely contributed to this patient's current condition?

Question

A 57-year-old man comes to the office due to 2 months of progressive cough and weight loss. He has a history of diabetes mellitus type 2 and chronic kidney disease. He does not smoke cigarettes. The patient traveled to Denmark 4 months ago for a 2-week vacation. He has 2 cats and a bird. He works in the maintenance department of a large hotel and services the hot tub and swimming pools. Temperature is 38 C (100.4 F) , blood pressure is 140/100 mm Hg, pulse is 88/min, and respirations are 16/min. The patient is 190 cm (6 foot 3 inches) tall. BMI is 22 kg/m². Examination shows cervical lymphadenopathy. Chest imaging is shown in the exhibit.

Hemoglobin A1c is 8.5% and serum creatinine is 3.8 mg/dL. Which of the following risk factors most likely contributed to this patient's current condition?

Quizplus · Accepted Answer

11ec160b_3863_8466_9249_adaaaf9679f6_MD0001_00 This patient's chronic cough, weight loss, cervical lymphadenopathy, and cavitary pulmonary lesion suggest active pulmonary tuberculosis (TB). Exposure to Mycobacterium tuberculosis usually results in lifelong latent infection due to the formation of granulomas, which wall off the pathogen and limit spread. However, the formation and maintenance of granulomas rely on coordination between monocytes and T lymphocytes. Host conditions that weaken these aspects of immune function often significantly increase the risk of reactivation TB; these include the following: Increased risk of reactivation TB is also seen in those with immunosuppression (eg, HIV, immunomodulatory/glucocorticoid medications), substance abuse, malnutrition, and advanced age. (Choice A) A tall body habitus is often seen in Marfan syndrome. Although these individuals have an increased risk of spontaneous pneumothorax, manifestations would include acute shortness of breath and imaging evidence of air between the lung and chest wall. (Choice B) Patients who work with hot tubs and swimming pools can develop hypersensitivity pneumonitis due to inhalation of Mycobacterium avium, a nontuberculous mycobacterium. Although most cases are marked by acute dyspnea, chronic symptoms can occur. However, imaging would generally show patchy, ground-glass pulmonary infiltrates, not a cavitary lesion. (Choice C) Living with pets increases the risk of asthma due to increased exposure to allergens. Asthma is typically marked by recurrent bronchoconstriction with acute periods of dyspnea, wheeze, and cough. Chest x-ray may show hyperinflation and bronchial thickening but not cavitary infiltration. (Choice D) Travel to areas endemic for TB can increase risk of exposure and subsequent infection. Endemic regions include India, sub-Saharan Africa, and Southeast Asia. Denmark has a low incidence of TB; it is unlikely that the patient acquired the infection during his visit to this country. Educational objective: Mycobacterium tuberculosis infection is controlled by coordination between macrophages and T lymphocytes. Conditions that impair immune function increase the risk of active tuberculosis; this includes chronic kidney disease, diabetes mellitus, HIV, substance abuse, malnutrition, and advanced age.

A 57-Year-Old Man Comes to the Office Due to 2