A 42-year-old woman presents to the clinic with a 4-week history of nonproductive cough, progressive dyspnea on exertion, and joint pain. During this time she has developed night sweats and moderate fatigue. She was born in the United States and denies travel outside the country, homelessness, or incarceration. Review of systems highlights the fact that she recently visited an optometrist secondary to blurred vision, but a change in glasses did not improve the symptom. A 5-lb unintentional weight loss is noted in her chart since her last clinic visit 3 months ago. Current vital signs include BP 110/68, HR 88, RR 22, and oxygen saturation 95% on room air. Her lungs are clear, but she has mild peripheral lymphadenopathy, with bilateral supraclavicular and axillary nodes up to 2 cm in size. The nodes are rubbery and nontender. A chest radiograph performed in your office indicates bilateral hilar lymphadenopathy, with a small area of infiltrate in the right upper lobe.
Of the following, which is the best next step in management of this patient?
A. Place a tuberculin skin test to assess for active TB infectionThis patient presents with a likely diagnosis of sarcoidosis. The differential diagnosis includes tuberculosis (made less likely by her paucity of risk factors) and lymphoma. Sarcoidosis affects the lung in over 90% of patients. Although any organ can be affected by sarcoidosis, skin and eye are often involved. Joint involvement occurs in 10% to 20% of patients, usually affecting knees and ankles. The acute arthritis (often associated with hilar lymphadenopathy) is usually self-limited, but the chronic arthritis can be destructive. The diagnosis of sarcoidosis is made through a combination of clinical and pathologic findings. Although there are several other reasonable “best next” approaches to this patient (including clarification of the x-ray findings with a CT scan, performing additional blood work such as a blood count, hemoglobin, peripheral smear, angiotensin-converting enzyme level), biopsy is necessary to establish the diagnosis. Although ACE levels are elevated in 30% to 80% of patients with sarcoidosis, its relatively low sensitivity and specificity prevent this test from replacing the need for pathologic tissue diagnosis. TB skin testing (TST) is an imperfect approach to diagnosis in the setting of concern for active TB. Some patients exhibit anergy with active TB, leading to a false-negative skin test. Many patients will have a positive skin test that reflects latent TB, atypical mycobacterium exposure, or prior BCG vaccination. If active TB is suspected, sputum smears and cultures with patient isolation would be a more appropriate choice than skin testing, although the TST may be a part of that workup. Additionally, answer a is incorrect because the test itself does not assess “active” infection. Although many patients with asymptomatic sarcoidosis can be managed with conservative therapy and close followup (answer c), the diagnosis must be crystallized first. This patient is not asymptomatic; eye, joint, and lung involvement would likely require active treatment. Beginning empiric anti-tuberculos drugs may be an appropriate step (answer d) in the management of active TB, but the patient’s negative risk factors for TB and the presence of bilateral hilar lymphadenopathy (unusual in TB except for those cases associated with AIDS) militate against empiric therapy. Steroids may very well be used in this patient (answer e) if the diagnosis of sarcoidosis is established, but other etiologies such as lymphoma and TB must be ruled out first.