Perianal and rectal abscess

　　Firstly, Etiology

　　About 99% of perianal abscesses are related to the infection and suppuration of anal glands. Most of the normal anal glands are located between the internal and external anal sphincters, with openings located at the anal crypts. When feces and bacteria pass through the openingsEntering the anal. Inflammation of the glands can cause anal sinusitis and anal gland inflammation, which can spread to the surrounding tissues of the anal canal and rectum to form perianal abscesses. The spaces around the anal canal and rectum are usually filled with fatty tissue and lymphatic tissue, which are loose, and abscesses often occur in these spaces. Other causes include injury, foreign bodies, proctitis, skin diseases, etc.

　　However, it should be pointed out that some lesions are not infected from the anal glands, such as some perianal rectal abscesses that can directly originate from anal fissure,破裂的外痔血栓、脱垂性血栓性内痔、内痔或直肠脱垂药物注射后，can also originate from perianal skin infection, sepsis, blood diseases, or direct trauma. A few cases can also originate from tuberculosis, ulcerative colitis, or Crohn's disease, etc.

　　Secondly, Pathogenesis

　　1. Pathology:Perianal rectal infections can be divided into 3 stages: ①Anal gland infection stage; ②Perianal rectal abscess stage; ③Anal fistula formation stage.

　　After the anal gland infection, abscesses are formed between the internal and external anal sphincters, and then spread to all directions along the conjoint fibers, causing various abscesses. Downward, they reach the subcutaneous tissue around the anus to form perianal subcutaneous abscesses; inward, they form abscesses or ulcerate within the subcutaneous tissue of the anal canal; outward, they penetrate the external anal sphincter to form ischiorectal abscesses, and sometimes continue to spread upward through the levator ani muscle to form pelvic rectal space abscesses. Abscesses can also surround the lower part of the anal canal and rectum, spreading from one side to the other to form horseshoe-shaped abscesses.

　　2. Classification

　　(1) Classification by infectious pathogens: ①Non-specific perianal abscess: caused by mixed infection of Escherichia coli, anaerobic bacteria, etc.; ②Specific infection: clinically less common, mainly tuberculous abscess.

　　（2）按脓肿部位分类：①肛提肌下脓肿（低位脓肿）：包括肛周皮下脓肿、坐骨直肠间隙脓肿、低位马蹄形脓肿等；②肛提肌上脓肿（高位脓肿）：包括骨盆直肠间隙脓肿、直肠后间隙脓肿和高位马蹄形脓肿等。

　　（3）按脓肿的最后结局分类：Eisenhammer（1978）将肛管直肠周围脓肿分成瘘管性脓肿及非瘘管性脓肿2大类。①非瘘管性脓肿：凡与肛窦、肛腺无关，最终不残留肛瘘者，均属非瘘管性脓肿；②瘘管性脓肿：即为经肛窦、肛腺感染而致，最后遗留肛瘘者。

　　由大肠埃希杆菌或厌氧菌等引起的肛管直肠周围脓肿易并发肛瘘，一旦出现有肛门附近有脓性分泌物流出的孔道，就需要警惕已合并本病。对于体质低下，以及长期使用免疫抑制剂患者，由于抗感染治疗效果差，感染容易蔓延，甚至进入血液循环并发菌血症，可以出现高热表现，故临床上应引起重视。

　　本病的一般表现是，患者先感肛门处坠胀痛或刺痛，可扪及一硬块，压痛，继之疼痛加重，痛性肿块增大，并可出现畏寒，发热，在3～5天后局部可形成脓肿，低位脓肿局部症状重而全身症状轻；高位脓肿全身症状重而局部症状轻，脓肿可自行向肛管直肠内破溃自发排出脓液，排脓后疼痛缓解，全身症状好转或消失，形成肛瘘以后脓肿可反复发作。

　　由于脓肿发生部位不同，其症状体征也各有特点：

　　1、肛周皮下脓肿

　　占肛管直肠周围脓肿的40％～45％，位于肛门，肛管下部的皮下组织内，上方由筋膜与坐骨直肠间隙分隔，多发生于肛门后侧方，肛门区肿胀疼痛是本病的主要症状，检查时可见局部红肿，压痛及痛性硬块，化脓后有波动感，自行穿破者可见破口及脓液，本病诊断较易，如疑有脓肿形成，作穿刺即可证实。

　　2、坐骨直肠窝脓肿

　　占肛周脓肿的15％～25％，位于坐骨直肠窝内，坐骨直肠间隙呈楔形，在肛提肌与坐骨之间，底向下是肛门和坐骨结节之间的皮肤，尖向上在闭孔内肌筋膜与肛提肌的膜连接处，炎症初起时常觉肛门部不适或微痛，继之出现全身症状，如头痛，体温升高，脉搏加快，畏寒等，同时局部疼痛加重，坐卧不安，排便时疼痛尤重，有排尿困难，里急后重，查体时可见肛门旁肿胀，皮肤紫红变硬，指诊可扪及坐骨直肠窝饱满隆起，触痛，早期作坐骨直肠窝穿刺是发现脓肿的最简单有效办法。

　　3. Pelvic rectal space abscess

　　It accounts for about 2.5% to 9% of perianal abscesses. The pelvic rectal space is located in the pelvic cavity, below the levator ani muscle, above the peritoneum of the pelvic cavity, behind the rectum and lateral ligament, in front of the male bladder and prostate, and in the female uterus and broad ligament. After the abscess occurs, the main manifestation is systemic toxic symptoms, and the local manifestation around the anus is not obvious. Palpation can feel swelling and tenderness above the levator ani muscle. Due to the deep location of the infection, early diagnosis is difficult. Therefore, for patients with systemic infectious toxic symptoms, even those without a focus of infection, this disease should be considered. Ultrasound or CT examination can help with diagnosis.

　　4. Horseshoe abscess

　　Horseshoe abscess is an abscess that spreads from the anus, posterior and sides of the anal canal, most of which are located at the back, caused by infection of the posterior middle anal gland or spread from one side to the other, which can be divided into high and low horseshoe abscesses. The clinical manifestations include swelling and tenderness at the posterior part of the anal canal, and later stage ulceration and pus discharge. In addition, the abscess can also spread to the anal canal, causing swelling and tenderness at the anal canal, and later stage ulceration and pus discharge.

　　1. Actively prevent and treat constipation and diarrhea. Constipation can easily cause fecal mass to accumulate in the rectum, blocking the anal crypt and causing acute anal cryptitis, which eventually leads to perianal abscess. In addition, dry and hard stools are easy to cause injury to the anal crypt during defecation, leading to perianal infection. Chronic diarrhea can also stimulate the anal crypt to become inflamed, and loose stools are also easy to enter the anal crypt, causing perianal infection. Therefore, preventing and treating constipation and diarrhea is of great significance for preventing the formation of perianal abscess and fistula.

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

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

　　4. Stick to sitting in the bath after each defecation, clean the anus, keep the anal area clean, which is of great significance for preventing perianal infection.

　　5. If there is discomfort or burning sensation around the anus, immediate anal sitz bath and timely medical treatment should be sought.

　　1. Anal canal ultrasound (AUS) examination:For complex perianal abscess diseases that cannot be clearly identified clinically, anal canal ultrasound examination can be used, which helps to determine the anatomical relationship between the abscess and fistula and the anal sphincter, and occasionally can identify the internal orifice.

　　2. Rectal examination:Local tenderness and fluctuation of the abscess.

　　3. Puncture and aspiration.

　　4. Defecation contrast examination:It can show the location, quantity, depth, size, shape and direction of the abscess and fistula.

　　I. Dietetic recipe for perianal rectal abscess

　　1. Peanut, red bean, jujube, garlic soup

　　Recipe: 90 grams of peanuts with skin, 60 grams of red beans and jujube; 30 grams of garlic.

　　Preparation: Boil all the ingredients together in water to make a soup.

　　Effect: Nourish Qi and blood, remove dampness and detoxify.

　　Usage: Take in the morning and evening.

　　2. Chrysanthemum Luffa Clam Soup

　　Formula: Clam meat 30 grams, chrysanthemum 15 grams, luffa 10 grams.

　　Preparation: Boil the above three ingredients in an appropriate amount of water to make a decoction, and add salt to taste.

　　Effect: Nourish Qi and yin, clear heat and unblock the meridians.

　　Usage: Drink the soup and eat the meat, once a day, for 10 consecutive days.

　　3. Herba Houttuyniae and Kelp Soup

　　Formula: Mung beans 30 grams, kelp 20 grams, herba houttuyniae 15 grams.

　　Preparation: Boil the above three ingredients in water to make a decoction, remove herba houttuyniae, and add an appropriate amount of sugar to taste.

　　Effect: Clear heat and detoxify.

　　Usage: Drink the soup and eat the beans and kelp. Once a day, for 7 consecutive days.

　　4. Mung Bean, Lily, and Job's Tears Porridge

　　Formula: Job's tears 50 grams, mung beans 25 grams, fresh lily 100 grams.

　　Preparation: Separate the lily into petals, remove the inner membrane, add water to cook mung beans and Job's tears to half-ripeness, then add lily and cook porridge over low heat, add sugar to taste.

　　Effect: Nourish yin and clear heat, remove dampness and detoxify.

　　Usage: Once or twice a day.

　　5. Amaranthus and Stachys Decoction

　　Formula: Portulaca oleracea, stachys nuda each 30 grams.

　　Preparation: Boil the above two ingredients in water, and then take the juice.

　　Effect: Clear heat and dampness, cool blood and detoxify.

　　Usage: Drink, once a day.

　　6. Smilax Glabra and Dried Date Decoction

　　Formula: Dried dates, rhizoma et radix smilacis glabrae each 30 grams.

　　Preparation: Boil the above two ingredients in water to make a decoction.

　　Effect: Clear heat, detoxify, and cool blood.

　　Usage: Drink the soup, twice a day.

　　7. Lotus Leaf Porridge

　　Formula: Fresh lotus leaves 20 grams, glutinous rice 200 grams.

　　Preparation: Boil lotus leaves for 20 minutes first, then remove the residue and add glutinous rice to cook porridge.

　　Effect: Clear heat and purify turbidity.

　　Usage: Take twice a day, as needed.

　　Two, what foods are good for anal and rectal abscess around the anal canal and rectum

　　1. Patients should eat light and fibrous foods as appropriate in their diet, such as spinach, celery, winter melon, luffa, pumpkin, mung beans, soybeans, rapeseed, chrysanthemum, mushrooms, kelp, radishes, and lotus roots. Regularly eating these dishes such as cold mixed bean sprouts with dried bean curd, stir-fried bean curd with celery, stir-fried pork slices with mushrooms, and stir-fried luffa, all have the effect of clearing heat and detoxifying, which can alleviate local swelling and pain, and relieve symptoms such as pus and discharge.

　　2. Choose foods such as mung bean porridge, celery porridge, egg noodles, vegetarian porridge, etc., which have the effect of moistening intestines and defecating.

　　3. Fruits such as watermelons, apples, pineapples, pears, etc.; green tea, chrysanthemum tea, honeysuckle tea, mung bean soup, and other beverages can also prevent the formation of anal and rectal abscess and alleviate the symptoms of anal and rectal abscess.

　　Three, what foods should be avoided for anal and rectal abscess around the anal canal and rectum

　　1. Abstain from alcohol, chili, ginger, garlic, cinnamon, and other spicy foods, which can stimulate local inflammation and worsen the condition of anal and rectal abscess.

　　2. When taking medication for anal and rectal abscess, some drugs should avoid certain foods. When taking cooling and detoxifying agents, avoid fish, shrimp, lamb, coriander, chives, etc., including bamboo shoots, seafood, dog meat, and other stimulating foods; when taking agents that tonify both Qi and blood, avoid radishes, peaches, plums, etc., otherwise it may affect the efficacy.

　　Firstly, Non-Surgical Treatment

　　1. Antibiotic treatment: 2-3 types of antibiotics effective against Gram-negative bacilli can be selected together;

　　2. Take a warm bath or Chinese herbal medicine bath;

　　3. Local physiotherapy can be applied;

　　4. Take oral laxatives or paraffin oil to alleviate pain during defecation

　　Secondly, Surgical Treatment

　　1. Incision and Drainage of Abscess: The main method for treating rectal perianal abscess, once diagnosed, incision and drainage should be performed early, without concerning about the presence or absence of fluctuation. The surgical method varies depending on the location of the abscess. Perianal abscess can be performed under local anesthesia, taking a folding knife position or lateral position, making a radiating incision at the most fluctuating site, cutting off the surrounding skin to make the incision elliptical, without packing to ensure unobstructed drainage. For ischiorectal abscess, spinal or sacral anesthesia is required, and a large-bore needle is used to puncture the site of tenderness first, withdraw the pus after puncture, and make an arched incision parallel to the anal margin at that site. The incision should be long enough, and the distance from the anal margin should be 3-5cm to avoid damaging the sphincter. Fingers can be used to explore the abscess cavity and separate the fibrous septa inside. A rubber tube or gauze strip can be left in place for drainage, and the dressing should not be too tight.

　　The abscess in the pelvic rectal space should be performed under spinal or general anesthesia, and the incision site varies due to different sources of infection:

　　(1) Infections originating from the sphincter should be drained by incising the corresponding rectal wall under the anal scope, as draining through the ischiorectal (anal canal) space is likely to result in an external anal canal sphincter fistula in the future;

　　(2) Infections originating from anal fistulas through the sphincter should be drained through the perineum, as incising and draining through the rectal wall is likely to lead to intractable anal canal sphincter fistulas;

　　(3) For abscesses in other parts, if the position is low, directly incise and drain the abscess on the perianal skin; if the position is high, it should be incised and drained through the rectal wall under the anal scope or through the posterior fornix of the vagina.

　　2. Incision and Suturing of Abscess: After incising the abscess at the fluctuating site, probe the abscess cavity, find the internal orifice, and hang a suture on the sphincter muscle between the internal orifice and the incised abscess, which can achieve the purpose of drainage and prevent the occurrence of iatrogenic anal fistula.[2-3]