肝前面のガスは遊離ガスではなく大腸内ガスである（Chilaiditi's ｓyndrome）．胃壁は全体的に浮腫により肥厚しており，特に体部から前庭部で著明である．図１０〜図1２の白矢印は胃角部から後壁に広がる潰瘍性病変である．胃内腔のガスは前壁側に貯留しニボーを形成しており，他方図４〜図１５の↑はすべて浮腫で肥厚した壁内のガスである．潰瘍や糜爛があり内圧上昇（拡張や嘔吐）があって生じる壁内気腫gastric emphysemaは壁肥厚を伴わないから，この症例は浮腫性に肥厚した壁内にガスが存在するので気腫性胃炎emphysematous gastritisである．従って胃角部の潰瘍性病変と胃角部から胃後壁の気腫性胃炎と診断する．気腫性胃炎は前症例胃蜂窩織炎の一種で，ガス産生菌による胃壁の細菌感染症である．潰瘍からの出血を繰り返し２度の内視鏡的止血にもかかわらず出血が続いたため胃切除となった．図Aが切除標本，△が胃角部潰瘍で，▲が気腫性胃炎の病変．病理：良性潰瘍と，▲の病変の粘膜下にガスが見られ気腫性胃炎compatible．

参考症例（気腫性胃炎）：84歳女性．3日前から嘔吐が続き，当日はコーヒー残渣様につづき血性胃液を認め来院した．腹部エコー検査で肝内門脈内ガスを認めた．図１は臥位腹部単純写真．
図１の腹部単純写真で胃拡張があり，白矢印は胃壁内ガス像を示している．CTでは門脈内ガスは認めないが，図２〜図１１の↑は壁内ガスである．図Aの内視鏡検査で，胃体部小弯側以外はほとんどの粘膜が脱落し，重症の潰瘍性大腸炎を思わせる強い出血性びらん性胃炎を認めた．粘膜が脱落しているので粘膜下浮腫は消失しているが，内視鏡所見も考慮して気腫性胃炎と思われる．敗血症を考慮し抗生物質，抗潰瘍剤投与とNGチューブによる胃減圧で改善・治癒した．

文献考察１）：気腫性胃炎，27例の集計
Rev Infect Dis. 1990 Sep-Oct;12(5):848-55.
Emphysematous gastritis: case report and review.
Moosvi AR, Saravolatz LD, Wong DH, Simms SM.

Emphysematous gastritis is a condition involving gastric wall inflammation, radiologic or intraoperative evidence of intramural gas, and systemic toxicity. A recent case of emphysematous gastritis in a 57-year-old diabetic man is reported, and 27 cases published since 1889 are reviewed. Predisposing factors include ingestion of corrosive substances (37%) and alcohol abuse (22%). Diagnosis of emphysematous gastritis is based on the clinical presentation of an acute abdomen with systemic toxicity and on radiographs demonstrating gas bubbles within the stomach wall. For the case reported herein, computed tomography was useful both in establishing the diagnosis and in following the resolution of emphysematous gastritis. Organisms most commonly involved were Escherichia coli (six cases), Streptococcus species (six cases), Enterobacter species (five cases), and Pseudomonas aeruginosa (three cases). The mortality was 61% (17 of 28 patients), and morbidity with gastric contractures occurred in 21% of cases (6 of 28). Optimal therapy has not been defined; however, antimicrobial chemotherapy and surgery, when appropriate, may improve survival rates.PMID: 2237128

文献考察２）：気腫性胃炎，41例の集計
South Med J. 2003 Jan;96(1):84-8.
Emphysematous gastritis in a hemodialysis patient.
Yalamanchili M, Cady W.

Emphysematous gastritis is a condition characterized by gas within the wall of the stomach and associated systemic toxicity. We report a case of emphysematous gastritis in a 43-year-old diabetic patient receiving hemodialysis and review 41 cases published since 1889. The most common predisposing factors included ingestion of corrosive substances, alcohol abuse, abdominal surgery, diabetes, and immunosuppression. Diagnosis is based on clinical presentation of acute abdomen with associated features of systemic toxicity. The most commonly involved organisms were streptococci (nine cases), Escherichia coli (nine cases), Enterobacter species (six cases), Clostridium welchii (four cases), and Staphylococcus aureus (four cases). Computed tomography (CT) is the diagnostic procedure of choice. The mortality rate was 61% (25 of 41 patients). Gastric contractures after recovery were noted in 10% (4 of 41 patients). Antimicrobial therapy with antibiotics covering gram-negative organisms and anaerobes, and surgery in appropriate cases may enhance survival.PMID: 12602725