Anorectal abscess

Introduction to anorectal abscess Anal canal, acute suppurative infection in or around the soft tissue around the rectum, and the formation of abscess, called anal canal, rectal abscess, which is characterized by easy rupture, or easy to form anal fistula after surgical incision and drainage, It is a common anorectal disease, and it is also an acute stage of anal canal and rectal inflammation. Anal fistula is a chronic phase. Common pathogens include Escherichia coli, Staphylococcus aureus, Streptococcus and Pseudomonas aeruginosa. There are anaerobic bacteria and Mycobacterium tuberculosis, which are often mixed infections of various pathogens. It is worth noting that if the pus is cultured as Escherichia coli or anaerobic bacteria, the infection is mostly from the rectum, and anal fistula is often formed after surgery. Another operation, Eykyn reported 31% (Table 1). If cultured as Staphylococcus aureus, the infection is mostly from the skin, the chance of postoperative anal fistula is reduced, and little surgery is required. Therefore, bacterial culture results can be used as a reference for prognosis when intraoperative drainage is not found. basic knowledge The proportion of illness: 0.013% Susceptible people: no specific population Mode of infection: non-infectious Complications: anal fistula

The cause of abscess around the anorectal rectum

(1) Causes of the disease

Anal gland infection purulent (45%):

About 99% of perianal abscesses are associated with anal gland infection. The normal anal glands are mostly located between the internal and external anal sphincters. The opening is located in the anal crypt. When the feces and bacteria enter the anal gland through the opening, it can cause anal sinusitis. Anal gland inflammation, these inflammations can spread to the perianal rectal tissue to form perianal abscesses. The gaps around the anorectal rectum are usually filled with adipose tissue and lymphoid tissue. The tissue is loose, and abscesses occur during these infections. Causes include injuries, foreign bodies, proctitis, skin diseases, etc.

Other (26%):

However, it should be pointed out that some lesions do not originate from the anal gland. For example, some anorectal abscesses can be directly derived from anal fissures, thrombotic external hemorrhoids, prolapsed thrombotic internal hemorrhoids, internal hemorrhoids or rectal prolapse drug injections. Can be derived from perianal skin infections, sepsis, blood disorders or direct trauma, a small number of cases can also be derived from tuberculosis, ulcerative colitis or Crohn's disease.

(two) pathogenesis

1. Pathology: The infection around the anorectal rectum can be divided into 3 stages: 1 anal gland infection stage; 2 anorectal abscess around the rectum stage; 3 anal fistula formation stage.

After the anal gland infection, an abscess is formed between the internal and external sphincter, and then spreads along the combined fibers to various aspects, and various types of abscesses are formed, subcutaneously forming anal subcutaneous abscess down to the perianal area; an abscess or ulceration is formed in the subcutaneous tissue of the anal canal. Extending through the external sphincter to the ischial rectal fossa to form a sciatic rectal abscess, sometimes continuing upward through the levator ani muscle to form a pelvic rectal abscess, which can spread around the anal canal and the lower part of the rectum from one side to the other to form a horseshoe Abscess.

2. Classification:

(1) Classification by infectious pathogen:

1 non-specific perianal abscess: caused by mixed infection of Escherichia coli, anaerobic bacteria.

2 specific infection: clinically rare, mainly tuberculous abscess.

(2) Classification by abscess:

1 levator ani muscle abscess (low abscess): including perianal subcutaneous abscess, ischial rectal abscess, low horseshoe abscess.

2 levator levator abscess (high abscess): including pelvic rectal abscess, rectal posterior abscess and high horseshoe abscess.

(3) According to the final outcome of abscess classification: Eisenhammer (1978) divided the anorectal abscess into a fistula abscess and a non-tubular abscess 2 categories:

1 non-tubular abscess: Anyone who has nothing to do with the anal sinus and anal gland, and ultimately does not have anal fistula, is a non-tubular abscess.

2 fistula abscess: that is, the transanal sinus, anal gland infection, and finally left anal fistula.

Anorectal abscess prevention

1. Active prevention and treatment of constipation and diarrhea: constipation accumulated in the rectum, the fecal mass is easy to block the anal crypt, resulting in acute anal cryptitis, eventually forming anal abscess, in addition, dry stool and induration, easy to scratch the anus when defecation The fossa causes perianal infection, diarrhea for a long time, can also stimulate inflammation of the anal crypt, loose stools also easy to enter the anal crypt, induce perianal infection, so prevention and treatment of constipation and diarrhea is important to prevent perianal abscess and anal fistula formation.

2. Timely treatment of anal cryptitis and anal papillitis to prevent the formation of perianal abscess and anal fistula.

3. Timely treatment of systemic diseases that can cause perianal abscess, such as Crohn's disease, ulcerative colitis and intestinal tuberculosis.

4. Adhere to bathing after each bowel movement, wash the anus, keep the anus clean, and have important significance in preventing perianal infection.

5. If you feel anal discomfort or burning sensation, you should take an anal bath immediately and seek medical advice promptly.

Anorectal abscess complication Complications

Anorectal abscess caused by Escherichia coli or anaerobic bacteria is easy to develop anal fistula.

Anal canal rectal abscess symptoms Common symptoms Anal internal slight painful fall ... Anal abscess anal gland secretion reduced rectal anal pain, discomfort, perianal skin, flushing, rectal pain, anal external sphincter rupture

The general manifestation of the disease is that the patient first feels pain or tingling in the anus, can lick a hard block, tenderness, followed by increased pain, increased painful mass, and chills and fever, in 3 to 5 After the day, local abscess can form, the local symptoms of the lower abscess are heavy and the systemic symptoms are light; the high abscess has severe systemic symptoms and local symptoms are mild. The abscess can spontaneously discharge the pus into the anorectal rectum, relieve the pain after drainage, and the systemic symptoms improve. Or disappear, after the formation of anal fistula, the abscess can recur.

Because of the different parts of the abscess, its symptoms and signs also have their own characteristics:

Perianal subcutaneous abscess

It accounts for 40% to 45% of the anorectal abscess. It is located in the subcutaneous tissue of the anus and the lower part of the anal canal. The upper part is separated by the fascia and the ischial rectal space. It occurs mostly in the posterior side of the anus. The anal area is swollen and painful. The main symptoms, local redness, tenderness and painful lumps can be seen during the examination. There is a sense of fluctuation after suppuration. If you wear it yourself, you can see the broken mouth and pus. The diagnosis of this disease is easy. If the abscess is suspected, it can be confirmed by puncture.

2. Ischial rectal abscess

It accounts for 15% to 25% of perianal abscess. It is located in the rectal fossa of the ischial bone. The space of the ischial rectum is wedge-shaped. It is between the levator ani muscle and the ischial bone. The bottom is the skin between the anus and the ischial tuberosity. In the pore junction between the myofascial fascia and the levator ani muscle, the anal discomfort or slight pain often occurs at the beginning of inflammation, followed by systemic symptoms such as headache, elevated body temperature, rapid pulse, chills, etc., while local pain is aggravated. Sitting uncomfortable, the pain is particularly heavy during defecation, there is difficulty in urinating, and it is heavy after urgency. When the body is examined, it can be seen that the anus is swollen, the skin is purple and hard, the doctor can squat and the ischial rectum is full of bulge, tenderness, early sciatic rectal puncture It is the easiest and most effective way to find an abscess.

3. Pelvic rectal abscess

About 2.5% to 9% of perianal abscess, pelvic rectal space is located in the pelvic cavity, under the levator ani muscle, upper pelvic peritoneum, posterior rectal and lateral ligament, male bladder and prostate in front, female uterus and broad ligament After the occurrence of abscess, the main manifestations are symptoms of systemic poisoning. The local manifestations of the anus are not obvious. The diagnosis can be swollen and tender on the levator ani muscle. Because the infection is deep, early diagnosis is not easy, so the symptoms of systemic infection are poisonous. Even if you can't find a lesion with septic shock, you should consider the disease. B-ultrasound or CT examination can help diagnose.

4. Horseshoe abscess

Horseshoe abscess is an abscess that spreads in the anus, behind the anal canal and on both sides. Most of them are in the posterior, caused by infection of the posterior anal gland or one side of the abscess spread to the opposite side. It can be divided into a high horseshoe abscess and a low horseshoe abscess. In addition to the symptoms of systemic infection, the local manifestations are swelling and tenderness in the posterior anal canal, and the pus in the later stage.

Examination of anorectal abscess

1. Anal canal ultrasound (AUS) examination: for complex perianal purulent diseases, clinically unclear abscesses, can be used for anal canal ultrasound examination, help to determine the anatomic relationship between abscess and hernia and sphincter, and occasionally identify the internal mouth .

2. Digital rectal examination: local tenderness and fluctuation of abscess.

3. Puncture suction.

4. Defecation angiography: can show the abscess, the location, number, depth, size, shape and direction of the fistula.

Diagnosis and diagnosis of anorectal abscess

Diagnostic criteria

1. Clinical symptoms: persistent perianal severe pain, increased when stressed or coughed; may have generalized fatigue, fever and other infections.

2. Signs: The skin around the anus has obvious erythema, with induration and tenderness, can be fluctuating, is an perianal abscess; rectal examination, the tender side of the affected side is the ischial rectal abscess; the upper side of the upper rectum is Tenderness, bulge is pelvic rectal abscess; rectal examination in the rectum posterior wall has tenderness, uplift and wave sensation, rectal posterior wall abscess, high intermuscular abscess, no abnormal appearance of the anus, rectal examination in the upper or lower end of the anal canal And the surface is smooth, oval, with neat edges, hard, tender mass, or undulating high intermuscular abscess.

3. Anal microscopy: Sometimes the opening can be seen. If it is pressurized around, pus can also be seen flowing out of the opening.

Differential diagnosis

When the perianal abscess expands to the ischial rectal fossa, it is easy to be confused with thrombotic external hemorrhoids.

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