Most common cause of per rectal bleeding in infant is -

Ans. is 'a' i.e., Anal fissure Anal fissure :-o Anal fissure is a laceration of the anal mucocutaneous junction. It is an acquired lesion of unknown etiology thought to be secondary to the forceful passage of a hard stool, mainly seen in infants < 1 yr of age. Fissures may be the consequence and not the cause of constipation.o A histoiy of constipation is often noted. A patient may have a painful bowel movement, which may correspond to the fissure formation after passing of hard stool. The patient then voluntarily retains stool to avoid another painful bowel movement. This exacerbates the constipation, and, eventually, the passing of harder stools. Pain on defecation and bright red blood on the surface of the stool may be observed. The diagnosis is established by inspection of the perineal area. The infant's hips are held in acute flexion, the buttocks are separated to expand the folds of the perianal skin, and the fissure becomes evident as a minor laceration. Sometimes, peripheral to the laceration, the patient has a little skin appendage that actually represents epithelialized granulomatous tissue, secondary to the chronic inflammation; this is usually known as a ''tag." On rectal examination, there may be hard stool in the ampulla and rectal spasm.