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Chapter 46: Cystic Fibrosis

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JN is a 2-year-old (8 kg) with repeat visits to her physician for pneumonia. There is a positive family history for CF. What test should be ordered in this patient to diagnose CF?

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a. Chest x-ray

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b. Sputum culture

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c. Sweat test

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d. DNA test

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Answer c is correct. With repeat pneumonias and a positive family history for CF, this patient should receive a sweat test.

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Answers a and b are incorrect. They are tests that would be ordered to diagnose pneumonia.

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Answer d is incorrect. Most patients with CF can be diagnosed with the less expensive sweat test. If the sweat test is inconclusive, then DNA testing can be used for diagnosis.

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JN is diagnosed with CF and treatment for her pneumonia needs to be initiated. Which test should be ordered to guide the antibiotic selection?

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a. Sputum culture and sensitivity

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b. Chest x-ray

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c. Chest MRI

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d. Chest CAT scan

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Answer a is correct. The sputum culture and sensitivity will identify the organism(s) in the lungs and will show the organism’s sensitivity to antibiotics.

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Answer b is incorrect. The chest x-ray and clinical symptoms are used to diagnose pneumonia in children. This test will not help guide antibiotic selection.

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Answers c and d are incorrect. These tests are used to distinguish pathologic tissue, such as a tumor, from normal tissue in the body. These tests will not help guide antibiotic selection.

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Which organism would you empirically treat for in this patient with CF?

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a. Burkholderia cepacia

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b. Pseudomonas aeruginosa

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c. Stenotrophomonas maltophilia

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d. Haemophilus influenzae

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Answer b is correct. Empiric antibiotic therapy is usually aimed at P. aeruginosa in CF patients.

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Answers a and c are incorrect. Burkholderia cepaciaand S. maltophilia are resistant organisms seen in CF patients later in life after exposure to many broad-spectrum antibiotics.

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Answer d is incorrect. This organism may be a copathogen but CF exacerbations are correlated with P. aeruginosa density in the airways. Antibiotic treatment should be aimed at sensitivities of P. aeruginosa.

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Which combination of antibiotics would be appropriate to treat ...

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