Anal Abscess And Fistula, A Simple Guide To The Condition, Diagnosis, Treatment And Related Conditions

An anal abscess is an infected cavity filled with pus found near the anus or rectum.
Ninety percent of abscesses are the result of an acute infection in the internal glands of the anus.
Occasionally, bacteria, fecal material or foreign matter can clog an anal gland and tunnel into the tissue around the anus or rectum, where it may then collect in a cavity called an abscess.
An anal fistula (fistula-in-ano) is often the effect of a previous or present anal abscess.
This occurs in up to 50% of patients with abscesses.
The fistula is the tunnel that forms under the skin and connects the clogged infected glands to an abscess.
The anal fistula can be present with or without an abscess and may join just to the skin of the buttocks near the anal opening.
Classification of Anal Abscess
1. Superficial abscesses (subcutaneous, sub-mucosal, ischiorectal abscesses) show typical symptoms such as pain, swelling, tenderness and fever.
Due to their anatomic location, they often cause discomfort on walking and sitting.
Normally the surrounding area to the anal canal induces painful defecation
2. Deep abscesses (inter-muscular, pelvi-rectal) often lack typical symptoms
Types of Anal Fistula
Fistulas are classified by their relationship to parts of the anal sphincter complex (the muscles that allow people to control the stools).
They are classified as:
Inter-sphincteric,
Trans-sphincteric,
Supra-sphincteric and
Extra-sphincteric
Causes of Anal Abscess:
Both aerobic and anaerobic bacteria have been found to be responsible for abscess formation.
The aerobes most often implicated are Staphylococcus aureus, Streptococcus, and Escherichia coli.
The anaerobes most often implicated are Bacteroides fragilis, Peptostreptococcus, Prevotella, Fusobacterium, Porphyromonas, and Clostridium.
Causes of Anal fistula
Most anal fistulas begin in anal glands that become infected with resulting abscess formation.
When the abscess is opened or when it bursts, a fistula is formed.
Fistulas are also found in patients with inflammatory bowel disease especially Crohn disease.
The most frequent symptoms of an abscess are:
1. Anorectal pain,
2. Anal swelling,
3. Peri-anal cellulitis (redness of the skin) and
4. Fever
A patient with an anal fistula may complain of:
1. Recurrent malodorous drainage from the peri-anal skin,
2. Pruritus and irritation of the peri-anal skin,
3. Recurrent abscesses,
4. Fever
5. Rectal bleeding
Diagnosis:
Many anal abscesses and fistulas are diagnosed and treated on the source of medical findings.
Both traditional 2-dimensional and 3-dimensional endo-anal ultrasound are a very effective way of:
1. Diagnosing a deep peri-rectal abscess,
2. Identifying a horseshoe extension of the abscess
Occasionally endosonography of fistula, if required with contrast medium, and recently MRI have been useful to find the best treatment method.
Treatment:
Abscesses
The treatment of an abscess is surgical incision and drainage under most situations.
An incision is made in the skin near the anus to drain the infection.
This can be done in a doctor’s clinic with local anesthetic or in a surgical theater under general anesthesia.
Anal Fistula
Presently, there is no medical treatment available for this disorder and surgery is almost always necessary to cure an anal fistula.
If the fistula is straightforward (affecting minimal sphincter muscle), a fistulotomy may be done.
This surgery involves un-roofing the tract, thereby connecting the internal opening within the anal canal to the external opening and producing a groove that will heal from the inside out.
Fistulotomy
Fibrin glue
Bioprosthetic plug
Advancement flap procedure
LIFT Surgery

TABLE OF CONTENT
Introduction
Chapter 1 Anal Abscess and Fistula
Chapter 2 Causes
Chapter 3 Symptoms
Chapter 4 Diagnosis
Chapter 5 Treatment
Chapter 6 Prognosis
Chapter 7 Anal Fissure
Chapter 8 Hemorrhoids
Epilogue