Anal fistula is the abbreviation of anorectal fistula, which is a posterior lesion that occurs when an abscess around the anorectum collapses or drains through an incision. Anal fistula is a post-abscess era, which is two stages of one disease. So, what are the causes of anal fistula? The following gives an introduction to the causes of anal fistula.
1, rectal-anal injury
Trauma, swallowing bones, metal, anal thermometer, anoscopy and other injuries to the rectum of the anal canal, bacteria can be caused by invading the wound.
2.Perianal pus
Perianal abscess caused by self-rupture or after incision and drainage.
3.Recurrent infection of anal fissure
Repeated infection of anal fissure can be complicated by subcutaneous fistula.
4.Ulcerative colitis
5.Rectal anal canal cancer
Rectal and anal canal cancer spreads to the deep part and complicates anal fistula.
6.Tuberculosis
There are many cases of tuberculosis complicated by anal fistula. It is as high as 26.9%, but in recent years it has decreased significantly to 4-10%. Mainly caused by swallowing tuberculosis bacteria, a few can also be caused by bloodstream infection.
7, Crohn’s disease with
The number of Crohn’s disease with anal fistula is as high as 14% to 76%.
8.Bloodstream infection
Diabetes mellitus, leukemia, aplastic anemia and other diseases often cause anal fistula by bloodstream infection because of the lowered resistance of the body.
9.Perineal surgery
Infection after injection of internal hemorrhoids into the muscular layer by mistake or after surgery, infection after postpartum perineal suturing, infection after prostate and urethra surgery, etc. can spread to the anorectum and cause abscesses and fistulas.
10.Other
Lymphogranuloma, radiation bacteriosis, caecal osteomyelitis, rectal and sigmoid diverticulitis, etc. can also cause anorectal abscess and fistula.