Low anal fistula refers to an anal fistula in which the fistula duct or wound cavity is located deep below the external anal sphincter. It is called anal leakage in Chinese medicine. The disease can occur in all age groups and different genders, and it is more common in young adults. There are more men than women. In recent years, the incidence of children has increased year by year. Due to the special anatomical and physiological environment of the perianal area, if anal fistula is not treated in time after occurrence, it often leads to repeated perianal infection, swelling and pain, and scarring.
1. Perianal abscess
Perianal abscess is caused by spontaneous ulceration or incision and drainage.
2. Rectal and Anal Injury
Trauma, swallowing bones, metal, anal thermometer, anoscopy and other damage to the anal canal and rectum, bacteria can invade the wound.
3. Recurrent anal fissure infection
Recurrent infection of anal fissure can be complicated by low fistula.
4. Perineal surgery
Internal hemorrhoid injection into the muscle layer by mistake or infection after surgery, infection after postpartum perineum suture, infection after prostate and urethral surgery, etc., can spread to the anus and rectum, causing abscesses and fistulas.
Tuberculosis can be complicated by tuberculous anal fistula.
6. Ulcerative colitis
7. Crohn's disease
As many as 14% to 76% of Crohn's disease with anal fistula.
8. Blood infection
Diabetes, leukemia, aplastic anemia and other diseases are often caused by low anal fistulas due to reduced body resistance.
Intermittent or persistent anus discharge
2. Swelling and pain
-Generally, there is no obvious pain. When pus accumulates, anal swelling and pain can be felt. When the pus is drained, the swelling and pain will be relieved immediately.
Due to the continuous outflow of pus or secretions, it stimulates the perianal skin and causes moisture, itching, and sometimes perianal eczema.
4. Systemic symptoms
Low anal fistula generally has no obvious systemic symptoms. If it recurs and discharges pus for a long time, symptoms such as weight loss and listlessness may appear. Tuberculous anal fistula may be accompanied by symptoms such as flushing of cheeks and low fever.
Visible rupture of the outer mouth, induration can be palpable if the outer mouth is closed.
It is the simplest and most direct method to diagnose low anal fistula. You can understand the depth, direction and position of the internal opening of the fistula tube by touching it. Low-position anal fistulas can generally touch hard cords. Pressing the fistula can cause secretions to overflow from the outer mouth, and most of the inner mouth attached to the tooth line can feel induration or depression.
The main observation is whether there is hyperemia, depression, and pus in the anal crypt. During the treatment, the probe can be used to check the position of the inner mouth.
4. Dyeing inspection
Place a piece of dry gauze inside the anus and inject the methylene blue solution from the outer mouth. If the inner mouth is not closed, the gauze will be colored, which can help find the position of the inner mouth.
5. Imaging examination
Intra-anal B-ultrasound and magnetic resonance imaging are generally seldom used for low anal fistulas, but they have certain diagnostic value for complex low anal fistulas.
Palpation is the simplest and most direct method to diagnose low anal fistulas. You can understand the depth, direction and position of the internal opening of the fistula tube by touching it.
Drug therapy is suitable for those who are accompanied by pus, redness, pain and other symptoms during the onset, or those who are not suitable for surgery temporarily, they can first take drug therapy to temporarily relieve the symptoms.
(1) External treatment Use huoxue swelling and pain relief lotion to sit in the bath, and apply golden ointment.
(2) Use of antibiotics Antibiotics can be used during acute attacks, but generally do not exceed one week.
(3) Oral use of traditional Chinese medicine: Use 萆薢 Shenshi Decoction plus Huadu Dehumidification Decoction, and those with fever can use Xianfang to drink for life.
2. Surgical treatment
The purpose of surgical treatment is to open the fistula so that it can flow smoothly and the wound will heal gradually. The key to a successful operation is to find the inner opening correctly, and then cut or remove the inner opening. Common surgical methods are:
(1) Incision Use a probe to find out the direction of the fistula and the position of the internal opening, cut the fistula all at once, remove the fistula wall and necrotic tissue, trim the wound edge, and drain the flow smoothly. Incision is a common operation method for low anal fistulas, with simple operation and high cure rate.
(2) Resection is suitable for low anal fistulas that have been fibrotic. Use scissors to completely free the outer wall from the bottom of the fistula, remove the fistula and the internal and external openings together, and also remove the scar tissue around the fistula until the healthy tissue is exposed.
1. The postoperative complications of low anal fistulas are less, and the surgical cure rate is high. If the internal opening is accurately located during the operation, the recurrence rate is small.
2. Patients with diabetes, leukemia, Crohn's disease, ulcerative colitis and other diseases need to actively treat the primary disease at the same time.
1. Develop good bowel habits, take a bath after defecation every day, keep the anus clean, avoid prolonged squatting and standing, overeating, spicy stimulation, diarrhea, constipation, etc. It is of great significance to prevent the formation of low anal fistula.
2. Treat anal cryptitis and anal papillitis in time to avoid the development of perianal abscess and anal fistula.
Department of Anorectal, Tongchuan District Hospital of Traditional Chinese Medicine, Dazhou City