Anal burning pain when defecating

Introduction Anal fissure can cause periodic pain due to defecation, which is the main symptom of anal fissure. When defecation, the fecal block stimulates the nerve endings of the ulcer surface, and immediately feels the burning pain of the anus, but the pain is relieved a few minutes later. This period is called the intermittent period of pain. Anal fissure is often a breach, the vast majority occurring in the midline of the anal canal. Of the 355 cases of anal fissures reported abroad, 89% were located in the posterior median, 7% in the anterior median, and 2% in both sides and anterior and posterior. The front center is more common in women. It is helpful for the diagnosis to see the sputum and then see the spur at the time of the examination.

Cause

1. Anatomical factors: The anal canal sphincter forms an anal ligament at the back of the anus, which is harder and less stretchable; most of the levator musculature adheres to both sides of the anal canal, so the front and back of the anal canal are not as strong as the two sides. Easy to damage, the anal canal and rectum form anal canal rectal angle, so that the back of the anal canal is subjected to large fecal pressure and other factors that cause anal fissure.

2. Trauma: Chronic constipation patients, due to dry stools, excessive force during defecation, easy to damage the anal canal skin, repeated damage to the deep laceration and full-thickness skin, the formation of chronic infectious ulcers. It has been reported that constipation caused by anal fissure accounted for 14% to 24%, but constipation may also be the result of anal fissure, which is caused by the patient's fear of defecation. In addition, birth injury can also cause anal fissure, accounting for about 3% to 9%. Frequent defecation during diarrhea, sensitive and tight anal canal injury, repeated damage to form chronic infectious ulcers.

3. Infection: Chronic inflammation near the dentate line, such as anal sinusitis in the posterior midline, causing subcutaneous abscess to spread down, causing chronic ulcers; the cause of difficult healing after anal canal injury is still unknown. Mainly due to injury combined with infection, inflammatory cells can release collagenase during infection, preventing epithelial tissue regeneration and extension.

4. Ischemia: Recently, it has been suggested that the median line of ischemia after anal canal is the reason why anal fissure occurs in this place, because the distal end of the anal canal is supplied by the inferior rectal artery, which passes through the ischial rectal fossa and divides the small branch. The anal canal sphincter to the mucosa, but most of the posterior joints lack the branch of the lower rectal artery (85%). Capillary morphology studies also suggest that the capillaries inside the medial sphincter are sparse. Some people used a laser Doppler flowmeter to measure blood flow in the posterior joint of the anal canal compared to other quadrants. All of the above indicate that ischemia is the main cause of chronic anal fissure.

5. Anal canal stenosis: An anal canal stenosis caused by congenital malformation, trauma or surgery, which is more vulnerable to anal fissure when dry feces pass.

6. Internal sphincter tension: An anal fissure has abnormal internal contraction of the internal sphincter. The reflective internal sphincter spasm is currently considered to be an important cause of the inability of the anal fissure to heal. The anal canal pressure in patients with anal fissure was significantly higher than that of normal people, reaching 127.5±42.2 kPa (956±316 mmHg), while the normal person was only 86.3±33.3 kPa (647±250 mmHg). This high pressure can return to near normal after anal expansion treatment.

an examination

In addition to the anus examination, there is usually no special examination, but if the cause is unknown or combined with other diseases, the appropriate inspection plan should be selected according to the specific situation.

1. Digital rectal examination and endoscopy: For the diagnosis of an anal fissure that is difficult to diagnose, rectal examination and anal microscopy may be performed as appropriate, and the operation should be gentle, so as not to cause severe pain to the patient.

2. Histopathological examination: For chronic ulcers located in the lateral position, it is necessary to consider whether there are rare lesions such as tuberculosis, cancer, Crohn's disease and ulcerative colitis, and biopsy can be used for differential diagnosis.

Differential diagnosis

Anal fissure ulcer: A small ulcer formed after an anal canal skin laceration below the dentate line is called an anal fissure ulcer, also called an anal fissure.

Acute pain in the anus: As the name suggests, it is severe pain in the anus. This usually happens during defecation, but it can also occur during non-defecation. Mainly related to the following diseases: perianal abscess, internal hemorrhoids incarceration, anal fissure, advanced anorectal cancer and anal foreign body.

Anal short-term paroxysmal dull pain: the anus often has short-term paroxysmal dull pain, or pain lasts for several hours, which is a common manifestation of clinical symptoms of anal sinusitis. Anal sinusitis, also known as anal cryptitis, is often the origin of infectious diseases of the anorectal and rectal parts. Because the symptoms are not heavy, it is easy to be ignored.

In addition to the anus examination, there is usually no special examination, but if the cause is unknown or combined with other diseases, the appropriate inspection plan should be selected according to the specific situation.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.