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→Clinical Signs
Idiopathic megacolon is likely to be a long-term, recurring problem, with clinical sgns presenting over months to years. In acquired megacolon, signs can be acute or chronic in onset. The primary sign of megacolon is constpation or obstipation (severe constipation caused by intestinal obstruction). Animals suffer tenesmus when defaecating and produce little or no faeces. Faeces that is expelled is very hard and dry, and animals defaecate less frequently. After prolonged tenesmus, a small amount of often mucoid diarrhoea may be expelled. Vomiting, anorexia and weight loss are other key features. On clinical examination, an enlarged colon packed with hard faeces is palpated within the abdomen. The animal may be dehydrated, and the hair coat rough. Digital anorectal examination is necessary, and confirms faecal impaction as well as potentially revealing an underlying obstructive cause.
Idiopathic megacolon is likely to be a long-term, recurring problem, with clinical sgns presenting over months to years. In acquired megacolon, signs can be acute or chronic in onset. The primary sign of megacolon is constpation or obstipation (severe constipation caused by intestinal obstruction). Animals suffer tenesmus when defaecating and produce little or no faeces. Faeces that is expelled is very hard and dry, and animals defaecate less frequently. After prolonged tenesmus, a small amount of often mucoid diarrhoea may be expelled. Vomiting, anorexia and weight loss are other key features. On clinical examination, an enlarged colon packed with hard faeces is palpated within the abdomen. The animal may be dehydrated, and the hair coat rough. Digital anorectal examination is necessary, and confirms faecal impaction as well as potentially revealing an underlying obstructive cause.
Megacolon must be differentiated from other causes of palpable colonic masses. These could include adenocarcinoma, lymphoma or intussusception and can be distinugished on the basis of texture, rectal examination and diagnostic imaging. Tenesmus can be caused by colitis as well as megacolon, and palpation, rectal examination and imaging can again be used to exclude this, Dysuria or stranguria may also look similar to the tenesmus caused by megacolon. Palpation of the bladder and colon and urinalyis will help eliminate this differential diagnosis.
===Laboratory Tests===
===Laboratory Tests===