非結核性抗酸菌症，囊胞内感染に続発したAAアミロイドーシスの１例

A Case Report of AA Amyloidosis associated with Cystic Infection during the Course of Non-tuberculous Mycobacteriosis

　アミロイドーシスは，臓器へのアミロイド沈着による多臓器障害を特徴とする疾患である．今回，アミロイドーシスにて死への転帰をたどり，非結核性抗酸菌症，囊胞内感染が誘因とされた症例を経験した．患者は73歳，男性．発熱，咳嗽が出現し，肺炎の診断で入院治療を受けていた．喀痰検査で抗酸菌塗抹ガフキー5号を呈し，肺結核が疑われて当院に紹介入院となった．当院入院時，画像で右肺に内部の液体貯留を伴う囊胞と周囲の浸潤影を認め，喀痰塗抹検査でガフキー4号であり，非結核性抗酸菌と同定された．治療を開始し，1週目から消化器症状が出現した．消化器内視鏡で十二指腸に多発するびらんを伴う発赤を認めた．組織診で粘膜下筋層のアミロイド沈着がみられたため，続発性のAAアミロイドーシスと診断した．アミロイドーシスに対してジメチルスルホキシドによる治療で一旦は改善したものの，肺炎とアミロイドーシスの悪化により死亡した．

Amyloidosis is a disorder affecting multiple organ systems and is caused by infiltration of tissues by amyloid. We describe the case of a patient in whom amyloidosis developed. The clinical course led to the suspicion of infectious lung cyst and non-tuberculous mycobacteriosis as the cause. The patient was a 73-year-old male who had been sent to this hospital because of his positive sputum for AFB(Acid Fast Bacilli). About two weeks prior to his visit here, the patient felt as if he had caught cold, because of fever and cough. He went to his family doctor and had a chest X-ray which showed an abnormal finding in the right lung field. The physician suspected pulmonary tuberculosis and examined his morning sputum for AFB. The sputum showed Gaffky 5 on smear, so he was referred to this hospital to evaluate his lung disease. On admission, the sputum showed Gaffky 4 on smear, and the AFB was identified as nontuberculous mycobacteria. A week after admission, he experienced a dull continuous pain in the abdomen. Weight loss and fever were also demonstrated and it was found that he had a history of anorexia A gastric fiber revealed diffuse depositions of amyloid in the gastrointestinal tract. This amyloid protein was identified as AA protein, suggestive of secondary amyloidosis. Pulmonary infection due to nontuberculous mycobacteria appears to have been the disease underlying this patient's amyloidosis. Amyloidosis was transitionally recovered, using dimethyl sulfoxide. However, amyloidosis took a turn for the worse and he died of amyloidosis five months after his admission to this hospital.