Perianal abscess, also known as perianal rectal abscess, is known as anal canker in Chinese medicine. Perianal abscess is an acute purulent infectious disease occurring around the anus, anal canal and rectum, which is a bacterial infection and is the predecessor of anal fistula. It is one of the three major anal diseases with anal fistula, with an incidence rate of about 2%, accounting for 8% to 25% of anal diseases. It is mostly seen in men aged 20 to 40 years old, and the incidence is 3 to 4 times higher in men than in women, and the incidence is also relatively high in children.
Perianal abscesses should be treated seriously when they occur. The most dangerous abscesses occur in the sciatic rectal fossa and pelvic rectal fossa on both sides of the anus and in the anterior side of the male under the perineal fascia.
The disease is a bacterial infection in the intestinal tract, and the “intestinal bacteria” are the source and the causative element. The “anal sinus” is the entrance to the infection and the internal opening for abscesses and fistulas. The “anal glands” are the pathway of infection, which occurs first and then spreads. The “perianal space” is the final site of infection. Intestinal bacteria enter the anal sinus and cause inflammation, blocking the opening of the anal gland and causing obstruction of the outflow of anal fluid, causing infection of the anal gland.
Clinical manifestations
The main symptom of perianal abscess is pain, which can be very intense and gradually worsen, and many patients say they cannot eat or sleep. The pain is only temporarily relieved when the abscess breaks down on its own.
Low-level abscesses all have severe anal pain that persists unabated. A perirectal abscess (high level), on the other hand, is not necessarily painful. Because the perirectal area belongs to the pelvic cavity, the vegetative nerves distributed here are insensitive to common stimuli, and the most important manifestations are localized cramping and a feeling of bowel movements.
Another symptom of perianal abscess is fever, which can exceed 40° at the highest. In general, the larger and deeper the abscess cavity, the greater the probability of fever. Some patients may also suffer from dyspareunia, nausea and insomnia.
Classification
1.Perianal subcutaneous abscess
It is the most superficial abscess, which is distributed subcutaneously at the anal margin, mostly on the posterior side and both sides. The route of infection is the anal sinus and the skin of the anal margin, and the lesion is mostly limited and rarely spreads to the surrounding area. The internal orifice is located at the tooth line corresponding to the lesion. Restricted redness and swelling, pain is obvious, but rarely feverish.
2.Subperineal fascial abscess
Located on the anterior aspect of the anus, mainly in men, it extends up to the root of the scrotum. The abscess in this area is divided into two deep and superficial layers. The route of infection is the anal sinus and the fractured anal canal skin at the anterior lateral dentition, so the internal opening is usually located here as well. If not treated promptly after the onset of the disease, it often spreads to the scrotum. The clinical manifestation is the same as that of subcutaneous abscess.
3.Posterior anal canal gap abscess
It is located at the posterior side of the anus and is divided into two deep and superficial layers, with the superficial layer communicating with the perianal subcutaneous space. The deep layer connects to both sides of the sciatic rectal fossa. The route of infection is the posterior lateral anal sinus at the dentate line and the posterior lateral anal fissure. The internal opening is mostly at the posterior median dentition. It tends to spread to both sides after the onset of the disease. Pain is obvious, fever or no fever, and local redness and swelling are obvious.
4.Sciorectal fossa abscess
This is the largest perianal abscess, one on the left and one on the right, and is connected through the deep posterior space of the anal canal. The route of infection is basically the anal sinus, and there are two possible locations of the internal opening, one in the position opposite to the lesion and the other in the posterior median. An abscess on one side can spread to the opposite side and form a horseshoe or semi-horseshoe abscess. The vast majority of complex anal fistulas originate from abscesses in this area. Redness, swelling, heat, and pain are all evident. The patient is restless, cannot eat or drink, and is in great pain.
5.Inter-sphincter abscess
It is between the internal and external sphincters and is the primary site of many perianal infections. As mentioned earlier, the anal sinus is the most important entrance for bacteria to invade the anus, but it is the anal glands that are really relied on to enter the inside of the anus, and most of the glands of the anal glands are located between the sphincters. Bacteria tend to infect here first and then spread to other interstitial spaces. There is no definite site for the internal orifice, but it is more often located in the posterior median dentition and the direction of spread is variable. Pain is obvious, early redness and swelling are not obvious, and the anus can be flaccid with extensive pressure pain.
6.Proctal submucosal abscess
Submucosal abscess in the lower rectum, both before and after, belongs to high abscess, the bacterial invasion pathway is anal sinus, the lesion is more limited and rarely spreads to the surrounding, the inner mouth and the lesion are in the same position. It is rarely feverish, and the main manifestation is cramping and bowel sensation, and the soft bulge at the lower end of rectum can be palpated by finger diagnosis.
7.Posterior rectal space abscess
It is located on the posterior side of the rectum and is the most highly located of all abscesses. The route of bacterial infection is the anal sinus, and the internal opening is at the posterior median dentition. After the onset of the disease, it may spread to both sides of the pelvic rectal space and form a high horseshoe abscess and anal fistula, which is difficult to treat clinically. The pain is significant or not significant, cramping, bowel sensation, fever, hard bulge is palpated on the posterior side of the rectum, and scar-like changes of the anorectal ring.
8.Pelvic rectal fossa abscess
Located on both sides of the lower end of the rectum, one on each side, above the pelvic floor, below the peritoneum, and below the corresponding scirorectal space, it is a high abscess. The route of infection is the anal sinus, and the internal opening is mostly located in the posterior median dentition line. After the onset of the disease, it may spread to the opposite side by means of the posterior rectal space, and may also spread downward to the sciatic rectal space. The presentation is the same as that of a retrorectal abscess, with a hard bulge palpable on both sides of the lower rectum.
Examination
1.Conventional anorectal examination
Look: see the scope of redness and swelling, see whether there is mucus flowing out at the tooth line, and judge the location of the internal opening by this.
Feel: finger diagnosis is very important, whether it is low or high, finger diagnosis is sometimes more accurate than ultrasound.
2.Blood test
The severity of the abscess can be judged by routine blood tests.
3.B ultrasound examination
Ultrasound is now widely used in the diagnosis of anal fistula and perianal abscess. An experienced examiner can accurately describe the direction of the pus cavity and fistula, the relationship with the sphincter, and the location of the internal opening.
4.CT and magnetic resonance examination
They are mainly used for high abscesses that cannot be seen or felt.
Differential diagnosis
Subfascial perineal abscess should be distinguished from necrotizing fasciitis.
Necrotizing fasciitis is a kind of necrotizing soft tissue infection caused by a variety of bacterial infections, which is rare in clinical practice but has a very high mortality rate. If not diagnosed and treated properly, it can cause toxemia, sepsis and infectious toxic shock.
Patients have a rapid onset, fever, significantly higher white blood cell count, perianal and perineal black lesions, subcutaneous twisted pronunciation, and in severe cases, progressive necrosis of large areas of skin and fascia, spreading to the scrotum, labia majora, and in some cases to the lower rectum, lower abdomen, and posterior lumbar region, with a wide area and rapid spread. Some cases are also combined with diabetes mellitus, hypoproteinemia, toxemia, sepsis, infectious toxic shock, and uremia.
Treatment
There are not many options for the treatment of this disease; the only cure is surgery, and the earlier the better. In the absence of conditions or physical conditions that do not allow surgery can choose drug treatment.
1.Medication
(1) Anti-inflammatory superficial abscesses can choose oral antibiotics, generally with broad-spectrum antibiotics. For abscesses of relatively large scope, a combination of drugs is needed, metronidazole, etimesine sulfate, kanamycin, streptomycin, etc.
(2) Topical application of golden ointment, blood circulation and pain relief, four yellow ointment, yulu ointment, etc.
(3) Chinese herbal medicine is used internally. The treatment concept of dissipation at the initial stage and toxicity at the pus-forming stage is proposed in “The Essence of Surgery” by Ming Xue. It can be treated by adding and subtracting Xianfang Livestrong Drink and Huang Lian Detoxification Tang.
2.Surgical treatment
(1) local sterilization of pus extraction and decompression, stabbing the pus cavity with a 20ml syringe from the weakest part of the abscess and extracting pus, moving the needle up and down while extracting until there is no pus to be extracted.
This method can temporarily reduce the tension of the abscess cavity and relieve pain, and is suitable for temporary emergency treatment, but cannot replace surgery. It cannot be used if the disease develops rapidly, such as necrotizing fasciitis, so as not to delay the disease.
(2) Incision and drainage of pus under local anesthesia, from the middle part of the pus cavity, small incision is made to drain the pus, and the pus cavity is flushed with metronidazole after surgery, and oil gauze is placed for drainage.
It is a temporary emergency treatment or the first operation of secondary surgical treatment. It can drain the pus and rapidly reduce the symptoms, but it cannot replace radical surgery, and it usually takes about 3 months for the fistula to form and the internal opening to be clear before radical surgery is performed.
(3)Radical surgery
①Low abscess-direct incision.
(ii) Horseshoe abscess-incision with open placement.
(③) High abscess – thread hanging
④High abscess-isobaric drainage. Since cutting and hanging still cuts off the anorectal ring, the pain is great and the incision is deep. In order to further reduce surgical trauma, two-way isobaric drainage surgery can be performed, in which a half-cut hanging wire is adopted and a drainage tube is placed, so that the abscess cavity can be healed without cutting off the rectal ring.
Prognosis
Most perianorectal abscesses can be cured by aggressive surgical treatment at an early stage. High-grade abscesses are complex and have the potential for recurrent attacks. In a very small number of patients, overwhelming infection can result in death.
Prevention
There are various reasons for the development of perianal abscess, but intestinal flora dysbiosis and decreased immunity are two fundamental causes, so preventing intestinal flora dysbiosis and improving immunity are the fundamental strategies to prevent perianal abscess.