I have anal leakage. why?

Anal leakage: "minor incontinence" is partial soiling of occasional loss of loose or watery stool, while "major incontinence" is loss of control of stool of normal consistency. In minor incontinence, consider deficient internal sphicter tone due to trauma, rectal prolapse, prolapsing hemorrhoids, drug effects, fecal impaction (in elderly, neurologic disorders). Anal manometry testing with biofeedback may help.

Possibilities: Sphincter injury, prolapse, colitis.