MEDizzy - A 72-year-old woman with a history of tuberculosis presents

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Infections Due to Mycobacteria

A 72-year-old woman with a history of tuberculosis presents to your clinic with fever, headache, weight loss, cough, dyspnea, and dysuria of 2 months' duration. Her examination is remarkable for coarse breath sounds. The neurologic examination is normal. Chest x-ray shows a miliary reticulonodular pattern. Laboratory results are remarkable for an elevated alkaline phosphatase level. Which of the following statements is true regarding this patient's presentation?

ExplanationAlthough the lungs are the portal of entry of tuberculosis, it is truly a disseminated disease. After a few weeks multiplying in the lungs, bacilli invade lymphatics, spread to regional lymph nodes, and then reach the bloodstream. It is not uncommon for patients with miliary tuberculosis to have a history of tuberculosis, but it is not the norm. Virtually all of those patients who have a history of tuberculosis and who develop an extrapulmonary manifestation were inadequately treated initially. Tuberculous meningitis is the most rapidly progressive form of tuberculosis. Without therapy, the illness progresses from headache, fever, and meningismus to cranial nerve palsies or other focal deficits, alterations of sensorium, seizures, coma, and eventually death. Renal tuberculosis generally presents with symptoms and signs of UTI, such as hematuria, dysuria, and pyuria. However, asymptomatic sterile pyuria occurs in up to 20% of patients with tuberculosis. Acid-fast staining of the urine should not be performed because of the significant likelihood that nonpathogenic mycobacteria exist in the urine. Instead, three first-morning urine specimens should be submitted for analysis; positive cultures will be obtained in at least 90% of patients with renal tuberculosis. Acid-fast sputum staining is positive in only 30% of patients with miliary tuberculosis, despite the presence of pulmonary infiltrates. Bronchoscopy with biopsy can establish the diagnosis in 70% of patients with an abnormal chest x-ray. Liver biopsy is especially helpful, revealing granulomas in 60% of patients. However, these granulomas are often noncaseating and nonspecific. Clinical improvement is often very slow, with fever persisting for 1 to 3 weeks. Despite therapy, mortality is 5% to 35%.