2015年5月30日
Can we truly rely on urinary antigen test? Legionella Case Report
American College of Physicians Japan Chapter Annual Meeting 2015
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- 開催年月日
- 2015年5月30日 - 2015年5月31日
- 記述言語
- 英語
- 会議種別
- ポスター発表
- 主催者
- Yugo Shibagaki
- 開催地
- Kyoto, Kyoto
- 国・地域
- 日本
Introduction
For the diagnosis of Legionella pneumonia (LP), the urine antigen test (UAT) is often used but the sensitivity is not enough and questionable. We report a case of LP in which history and several clinical findings were useful for diagnosis than this test.
Case presentation
A 69-year-old man was seen in the ED for 3 days history of fever and chill. He did not have cough, dyspnea or loss of appetite. He had a history of diabetes mellitus. He was ex-smoker and gardener, but had not taken a public bath. The body temperature was 36.3 C, the heart rate 91 beats per minute, the blood pressure 99/68 mmHg, the respiratory rate 16 breaths per minute, and the SpO2 98 % in room air. Coarse crackles were found at his right lower lung field. The blood test showed an anemia, thrombocytopenia, liver injury, hyponatremia and rhabdomyolysis. Proteinuria and microhematuria were revealed in urine analysis. The result of Legionella UAT was negative. No specific bacterium was confirmed on sputum smear. On the chest radiography and CAT scan, consolidation on his right lower lobe was found. Despite the negative UAT result, we initiated MINO for LP because of high clinical suspicion based on above clinical history, physical and laboratory findings. We confirmed this diagnosis by sputum Loop-mediated Isothermal Amplification (LAMP) method test. We needed to change MINO to LVFX due to poor clinical response, this patient was recovered to discharge on day 12th.
Discussion
It is critical to diagnose and treat LP without delay because of its high mortality. History is the key to diagnose because the UAT is not helpful due to its limited sensitivity. Some specific types of Legionella are found in the compost, which are not well known. LAMP method test is useful than UAT to confirm the diagnosis when the clinical suspicious is high.
For the diagnosis of Legionella pneumonia (LP), the urine antigen test (UAT) is often used but the sensitivity is not enough and questionable. We report a case of LP in which history and several clinical findings were useful for diagnosis than this test.
Case presentation
A 69-year-old man was seen in the ED for 3 days history of fever and chill. He did not have cough, dyspnea or loss of appetite. He had a history of diabetes mellitus. He was ex-smoker and gardener, but had not taken a public bath. The body temperature was 36.3 C, the heart rate 91 beats per minute, the blood pressure 99/68 mmHg, the respiratory rate 16 breaths per minute, and the SpO2 98 % in room air. Coarse crackles were found at his right lower lung field. The blood test showed an anemia, thrombocytopenia, liver injury, hyponatremia and rhabdomyolysis. Proteinuria and microhematuria were revealed in urine analysis. The result of Legionella UAT was negative. No specific bacterium was confirmed on sputum smear. On the chest radiography and CAT scan, consolidation on his right lower lobe was found. Despite the negative UAT result, we initiated MINO for LP because of high clinical suspicion based on above clinical history, physical and laboratory findings. We confirmed this diagnosis by sputum Loop-mediated Isothermal Amplification (LAMP) method test. We needed to change MINO to LVFX due to poor clinical response, this patient was recovered to discharge on day 12th.
Discussion
It is critical to diagnose and treat LP without delay because of its high mortality. History is the key to diagnose because the UAT is not helpful due to its limited sensitivity. Some specific types of Legionella are found in the compost, which are not well known. LAMP method test is useful than UAT to confirm the diagnosis when the clinical suspicious is high.