What is Perirectal Abscess?
An anorectal abscess, which is a painful condition where a pus-filled cavity forms near the anus or rectum, can differ greatly in how complicated it is. This depends on where the abscess is located and how much the surrounding tissue is involved. It’s vital to understand the layout of the body’s structures in this area to accurately diagnose the condition and provide the right treatment. This can help to prevent complications from multiple procedures and higher costs associated with a delayed diagnosis.
What Causes Perirectal Abscess?
Anorectal abscesses generally occur as a result of inflammation, often from a blocked gland near the anus referred to as a crypt gland. Our bodies naturally have these glands, and usually, they perform as they should. However, sometimes debris can cover and block these glands. This blockage can then give harmful bacteria a path into the deeper tissues, causing an infection.
These dangerous bacteria can include things like Escherichia Coli, Staphylococcus aureus, and Streptococcus, among others. There are also certain risk factors that can make people more prone to abscesses. These include injuries, using tobacco, having liquid stool enter the duct, and having expanded ducts that don’t empty well.
It’s important to note that certain conditions and factors may be linked with around 10% of anorectal abscess cases. These include HIV, Crohn’s disease, trauma, tuberculosis, sexually transmitted diseases, radiation exposure, foreign bodies, and cancer.
The anorectal abscess can happen in different locations, which include:
* Around the anus – the most common location (60%)
* The ischiorectal region (20%)
* The upper anal muscle area and between the anal sphincters (5%)
* Underneath the mucosal lining of the rectum (less than 1%).
Risk Factors and Frequency for Perirectal Abscess
This condition affects about 68,000 to 96,000 people in the United States each year, with it being most prevalent in males (at a ratio of 3 to 1) during their thirties and forties. The condition is more common during the summer and spring months. Even though people may worry about it, there is no evidence that poor hygiene, anal-receptive intercourse, diabetes, obesity, race, or changes in bowel habits increase the risk. This disorder is more common in men than women.
Signs and Symptoms of Perirectal Abscess
People often come to the hospital emergency room due to sudden, severe pain in the area around their anus or rectum. Sometimes that pain gets worse when they move, sit, cough, or use the restroom. Other symptoms might include fever, feeling unwell, discharge from the rectum, urine retention, skin redness near the area, and lower back pain or pelvic discomfort in extreme cases.
Doctors usually check these symptoms by having patients lie on their stomach or their left side. During a physical exam, the doctor might see swelling, redness, tenderness, or pus in the affected area. They might also feel a tender lump during the rectal exam, and patients could have pain or discharge. However, the accuracy of detecting this lump varies among doctors. Some patients might also have pain during bowel movements, which could lead to constipation.
In many cases, a thorough rectal exam can’t be completed without anesthesia. To properly see the fistula opening—a hole caused by an infection or an abscess—doctors usually need to do an exam while the patient is under anesthesia.
Testing for Perirectal Abscess
If your doctor suspects you have a specific medical condition, they might carry out several laboratory tests. One such test looks at your count of white blood cells. If that count is high, this could raise suspicion. Another test checks for neutrophils, a type of white blood cell that increases when your body is fighting infection. They might also check for ‘bands’, which are immature white blood cells, and raised levels of lactate, a chemical your body produces when there is not enough oxygen in your cells.
On top of these lab tests, your doctor may conduct some imaging scans to get a visual look at what’s going on inside your body. These scans could involve an endoanal ultrasound, in which a small, wand-like device is inserted into your bottom to take pictures. Transperineal sonography is a kind of ultrasound which can take an image through the perineum, the area between the anus and the genitals. Computed tomography (CT) is basically a fancy type of X-ray, and Magnetic Resonance Imaging (MRI) uses strong magnets and radio waves to create detailed images of inside your body.
If your condition happens to be complex, or you have other serious health issues, a CT scan could be the most useful option. This might also be the case if surgical advice isn’t immediately available. For some conditions, the optimal imaging might require using something called ‘triple contrast’ and taking smaller slices (2.5mm) for clearer images. When an endoanal ultrasound is carried out, it might be done using a two- or three-dimensional probe with a frequency of 5 to 16 MHz to get the best possible images.
Treatment Options for Perirectal Abscess
If you have an abscess, a pocket of pus that can appear anywhere on your body, a common treatment is to cut it open and let the pus drain out. This is especially important because the abscess can potentially spread to the surrounding tissues if not treated promptly. Simple abscesses located near your anus or some deeper abscesses can be drained during a doctor’s visit. However, a large abscess that is deep and spreads across to both sides, known as a horseshoe abscess, needs to be treated in a hospital operating room by a specialist.
For superficial abscesses near the anus, local anesthetics can numb the area so a healthcare professional can make a small cut and drain the abscess. The cut is usually in a cross or circular shape and is made as close as possible to the anus to minimize the chances of forming a long abnormal connection or “fistula”. If a fistula is associated with the abscess, some specific procedures may be carried out to treat it, one of which has a significantly lower chance of recurrence than simple drainage procedure. Deciding whether or not to pack the wound after the drainage procedure is a matter of debate, with some studies not finding significant advantages to it.
If you have recurring or bilateral abscesses, your doctor may perform an exam under anesthesia to evaluate the need for draining it in an operating room. More significant abscesses might require a temporary drain to be placed in the wound for up to three weeks. If you have serious health conditions, such as diabetes or severe obesity, your doctor may opt to place special catheters. These can be secured in place after a small incision is made in the skin. Follow-up visits usually occur 2-3 weeks after the procedure for most patients and 7-10 days for those with catheters. These visits continue until the area is fully healed. During recovery, a high fiber diet is often recommended.
In severe cases, a surgery to reroute bowel movements (colostomy) may be considered, but it is essential to ensure that the abscess is adequately drained to control the infection. Dealing with a fistula is not straightforward, and it might be managed with several different techniques, including setting in a thread, cutting open, cutting out, glue therapy, creating a pouch, or creating an anal flap. Antibiotics are typically used when there is a skin infection near the abscess, in patients whose condition doesn’t improve after drainage, and in patients with a weakened immune system. Research hasn’t shown that antibiotics will reduce fistula formation. In case antibiotics are used, they must cover the common types of bacteria causing the infection, and wound cultures may be necessary, especially in patients who have had previous antibiotic treatment.
In some cases, hospital admission may be recommended, especially if the patient is weak, has a fever, has low blood pressure, or has a weakened immune system. It’s important for patients to understand that healing from this condition is not immediate, and there can be moderate to severe pain after the surgery.
What else can Perirectal Abscess be?
When a doctor is trying to figure out the cause of a patient’s symptoms, they might consider the following conditions, among others:
- Anal fissure
- Anal fistula
- Thrombosed hemorrhoid
- Pilonidal cyst
- Abscess on the buttocks
- Cellulitis of the skin
- Crohn’s disease
- Ulcerative colitis
- Cancer (malignancy)
- Proctitis
- HIV/ AIDS
- Other sexually transmitted diseases
- Bartholin’s abscess
- Hidradenitis suppurativa
What to expect with Perirectal Abscess
Perirectal abscess is a condition that can cause a lot of discomfort. Over 30% of patients may deal with recurring symptoms and chronic pain. If only treated with a simple cut and drain procedure, it’s quite likely a persistent type of wound, known as a chronic fistula, will develop.
Other complications that can arise from a perirectal abscess include irritation of the tube that carries urine out of the body (urethra), difficulty in urinating, and constipation.
Even with more targeted treatments like fistulotomy (a surgical procedure to treat the fistula) or the use of a special thread to help drain and heal the fistula (a Seton), there is still a 1 to 3% chance that the condition may come back.
Being young and not having diabetes contribute to an increased risk of developing a fistula following a perirectal abscess.
It’s also important to note that the quality of life for those with recurrent anorectal abscesses (abscesses in the anus or rectum) can be significantly impacted.
Possible Complications When Diagnosed with Perirectal Abscess
- Bloodstream infection or sepsis
- Development of abnormal passageways between organs (fistula)
- Difficulty controlling bowel movements (fecal incontinence)
- Difficulty urinating (urinary retention)
- Difficulty with bowel movements (constipation)
Recovery from Perirectal Abscess
After their procedure, patients will require medications to manage their pain and prevent constipation. They’ll also be given instructions on how to do sitz baths, which are warm, shallow baths that clean and soothe the area around your bottom.
The doctor may prescribe antibiotics for patients to take at home, but this depends on the type and sensitivity of the bacteria found during the procedure.
Due to the likelihood of the condition recurring, it’s important for patients to have regular check-ups until they’re fully healed. This healing process can take anywhere from 3 to 8 weeks.
