食道失弛緩症合併巨結腸症及甲狀腺功能亢進

Achalasia Coexistent with Megacolon and Hyperthyroidism

食道失弛緩症的發生率在東方人原本就很低，併發巨結腸症更是少見，本病例不但前述兩病齊發，而且還罹患甲狀腺功能亢進，更是罕見。在食道失弛緩症的病人，腸肌神經叢（myenteric plexus）神經細胞大幅減少而致下括約肌無法鬆弛以及食道無法蠕動。神經細胞減少可能是慢性神經節發炎所致（chronic ganglionitis），據推測腸肌神經細胞自體抗體，是此病的可能致病機轉。本病例以其發病年齡及結腸組織病理的結果來看，應考慮神經節細胞減少症（hypoganglionosis），換言之，食道失弛緩症及巨結腸症兩者擁有相似的致病機轉，亦即神經節細胞減少，而前述的神經細胞自體抗體，正可以同時詮釋這兩個病。再者，本病人亦併發甲狀腺機能亢進，過去有有論文提及食道失弛緩症的病人有23％同時有甲狀腺疾病，另有論文發現食道失弛緩症病例併發自體免疫疾病（包括糖尿病，乾燥症，紅斑性狼瘡，虹膜炎，甲狀腺機能異常）的機會是常人很多倍。本病例三症集于一身，如果以自體免疫來詮釋其病因似乎是一個可以接受的說法。

The incidence of achalasia and megacolon are low in Asian. So, the coexisting of achalasia and megacolon was rarely reported in the past. Here, we reported a case of achalasia coexisting with megacolon and hyperthyroidism. Achalasia is characterized by loss of enteric neuron in the myenteric plexus leading to aperistalsis and impaired relaxation of lower esophageal sphincter. Autoantibody to myenteric neurons might induced chronic ganglionitis and led to neuron loss. In the other hand, the adult-onset megacolon shared the similar pathogenesis with achalasia. Hypoganglionosis was found in parts of adult onset megacolon, as is this case. Autoantibody to ganglion neuron might explain the coexistence of achalasia and megacolon. Furthermore, hyperthyroidism also noted in this patient. There were scarce reports about the association of achalasia with several autoimmune disorders, such as diabetes mellitus (DM), sicca syndrome, systemic lupus erythematosus (SLE), uveitis, and thyroid dysfunction. Triple disease in this adult male might not just a coincidence. It can be explained by an autoimmune induced disorder.