Physical examination can rule out anismus (by identifying another cause) but is not sufficient to diagnose anismus.

The rectal cooling test is suggested to differentiate between rectal inertia and impaired relaxation/paradoxical contraction

Other techniques include manometry, balloon expulsion test, evacuation proctography (see defecating proctogram), and MRI defecography. Diagnostic criteria are: fulfillment of criteria for functional constipation, manometric and/or EMG and/or radiological evidence (2 out of 3), evidence of adequate expulsion force, and evidence of incomplete evacuation. Recent dynamic imaging studies have shown that in persons diagnosed with anismus the anorectal angle during attempted defecation is abnormal, and this is due to abnormal (paradoxical) movement of the puborectalis muscle.

For diagnosis, measures of liver biochemistry and pancreatic enzymes are performed. Along with ruling out structural abnormalities, normally by performing an abdominal ultrasound and endoscopic retrograde cholangiopancreatography (ERCP). Measurements of bile transit when performing ERCP are taken to help evaluate different treatment options.

Sphincter of Oddi dysfunction is best diagnosed using manometry-an internal test done to measure the pressures within surrounding ducts to determine whether or not the muscle is functioning normally.

Diagnosis is by rectal examination. A specialized tool called a "Perineocaliper" can be used to measure the descent of the perineum. A retro anal ultrasound scan may demonstrate the condition. "Anti sagging tests", whereby the abnormal descent is corrected temporarily, may help to show whether symptoms are due to descending perineum syndrome or are in fact due to another condition.

Normally, the anal margin lies just below a line drawn between the coccyx (tailbone) and the pubic symphysis. In descending perineum syndrome the anal canal is situated several cm below this imaginary line, or it descends 3–4 cm during straining.

Defecography may also demonstrate abnormal perineal descent.

Identification of the exact causes usually begins with a thorough medical history, including detailed questioning about symptoms, bowel habits, diet, medication and other medical problems. Digital rectal examination is performed to assesses resting pressure and voluntary contraction (maximum squeeze) of the sphincter complex and puborectalis. Anal sphincter defects, rectal prolapse, and abnormal perineal descent may be detected. Anorectal physiology tests assess the functioning of the anorectal anatomy. Anorectal manometry records the pressure exerted by the anal sphincters and puborectalis during rest and during contraction. The procedure is also able to assess sensitivity of the anal canal and rectum. Anal electromyography tests for nerve damage, which is often associated with obstetric injury. Pudendal nerve terminal motor latency tests for damage to the pudendal motor nerves. Proctography, also known as defecography, shows how much stool the rectum can hold, how well the rectum holds it, and how well the rectum can evacuate the stool. It will also highlight defects in the structure of the rectum such as internal rectal intussusception. Dynamic pelvic MRI, also called MRI defecography is an alternative which is better for some problems but not as good for other problems. Proctosigmoidoscopy involves the insertion of an endoscope (a long, thin, flexible tube with a camera) into the anal canal, rectum and sigmoid colon. The procedure allows for visualization of the interior of the gut, and may detect signs of disease or other problems that could be a cause, such as inflammation, tumors, or scar tissue. Endoanal ultrasound, which some consider to be the gold standard for detection of anal canal lesions, evaluates the structure of the anal sphincters, and may detect occult sphincter tears that otherwise would go unseen.

Functional FI is common. The Rome process published diagnostic criteria for functional FI, which they defined as "recurrent uncontrolled passage of fecal material in an individual with a developmental age of at least 4 years". The diagnostic criteria are, one or more of the following factors present for the last 3 months: abnormal functioning of normally innervated and structurally intact muscles, minor abnormalities of sphincter structure/innervation (nerve supply), normal or disordered bowel habits, (i.e., fecal retention or diarrhea), and psychological causes. Furthermore, exclusion criteria are given. These are factors which all must be excluded for a diagnosis of functional FI, and are abnormal innervation caused by lesion(s) within the brain (e.g., dementia), spinal cord (at or below T12), or sacral nerve roots, or mixed lesions (e.g., multiple sclerosis), or as part of a generalized peripheral or autonomic neuropathy (e.g., due to diabetes), anal sphincter abnormalities associated with a multisystem disease (e.g., scleroderma), and structural or neurogenic abnormalities that are the major cause.

Biopsy, the removal of a tissue sample during endoscopy, is not typically necessary in achalasia but if performed shows hypertrophied musculature and absence of certain nerve cells of the myenteric plexus, a network of nerve fibers that controls esophageal peristalsis.

Because of its sensitivity, manometry (esophageal motility study) is considered the key test for establishing the diagnosis. A catheter (thin tube) is inserted through the nose, and the patient is instructed to swallow several times. The probe measures muscle contractions in different parts of the esophagus during the act of swallowing. Manometry reveals failure of the LES to relax with swallowing and lack of functional peristalsis in the smooth muscle esophagus.

Characteristic manometric findings are:

- Lower esophageal sphincter (LES) fails to relax upon wet swallow (<75% relaxation)

- Pressure of LES 100 is considered achalasia, > 200 is nutcracker achalasia.

- Aperistalsis in esophageal body

- Relative increase in intra-esophageal pressure as compared with intra-gastric pressure

Several severity scales exist. The Cleveland Clinic (Wexner) fecal incontinence score takes into account five parameters that are scored on a scale from zero (absent) to four (daily) frequency of incontinence to gas, liquid, solid, of need to wear pad, and of lifestyle changes. The Park's incontinence score uses four categories:

The fecal incontinence severity index is based on four types of leakage (gas, mucus, liquid stool, solid stool) and five frequencies (once to three times per month, once per week, twice per week, once per day, twice or more per day). Other severity scales include: AMS, Pescatori, Williams score, Kirwan, Miller score, Saint Mark's score and the Vaizey scale.

This investigation is used to diagnose internal intussusception, or demonstrate a suspected external prolapse that could not be produced during the examination. It is usually not necessary with obvious external rectal prolapse. Defecography may demonstrate associated conditions like cystocele, vaginal vault prolapse or enterocele.

Botulinum A toxin is a valuable alternative for patients who do not want surgical methods.

These may reveal congestion and edema (swelling) of the distal rectal mucosa, and in 10-15% of cases there may be a solitary rectal ulcer on the anterior rectal wall. Localized inflammation or ulceration can be biopsied, and may lead to a diagnosis of SRUS or colitis cystica profunda. Rarely, a neoplasm (tumour) may form on the leading edge of the intussusceptum. In addition, patients are frequently elderly and therefore have increased incidence of colorectal cancer. Full length colonoscopy is usually carried out in adults prior to any surgical intervention. These investigations may be used with contrast media (barium enema) which may show the associated mucosal abnormalities.

Medication (to prevent spasms) or Sphincterotomy (surgical procedure to cut the muscle) are the standard treatments for sphincter of Oddi dysfunction. One or the other may be better based on the classification of the condition.

Surgical treatments may be used to treat the condition, and include retro-rectal levatorplasty, post-anal repair, retro-anal levator plate myorrhaphy.

A 2014 meta-analysis of three small trials evaluating probiotics showed a slight improvement in management of chronic idiopathic constipation, but well-designed studies are necessary to know the true efficacy of probiotics in treating this condition.

Children with functional constipation often claim to lack the sensation of the urge to defecate, and may be conditioned to avoid doing so due to a previous painful experience. One retrospective study showed that these children did indeed have the urge to defecate using colonic manometry, and suggested behavioral modification as a treatment for functional constipation.

Obstructed defecation has many causes, so the management in any individual case is specific to the cause of the symptom. For rectal internal intususception treatment is surgical, either STARR or rectopexy. For rectocele STARR or mesh implantation. For anismus/ pelvic floor dessynergia: biofeedback exercise.

Doctors uses a variety of tools and techniques to evaluate the type of anorectal disorder, including digital and anoscopic investigations, palpations, and palpitations. The initial examination can be painful because a gastroenterologist will need to spread the buttocks and probe the painful area, which may require a local anesthetic.

The two key features of obstructed defecation are:

1. An inability to voluntarily evacuate rectal contents

2. Normal colonic transit time

A 5 item questionnaire was validated for diagnosis and grading of obstructed defecation syndrome. The parameters were:

1. Excessive straining

2. Incomplete rectal evacuation

3. Use of enemas and/or laxatives

4. Vaginal-anal-perineal digitations (needing to press in the back wall of the vagina or on the perineum to aid defecation)

5. Abdominal discomfort and/or pain

Anal dilation, or stretching of the anal canal (Lord's operation), has fallen out of favour in recent years, primarily due to the unacceptably high incidence of fecal incontinence. In addition, anal stretching can increase the rate of flatus incontinence.

In the early 1990s, however, a repeatable method of anal dilation proved to be very effective and showed a very low incidence of side effects. Since then, at least one other controlled, randomized study has shown there to be little difference in healing rates and complications between controlled anal dilation and LIS, while another has again shown high success rates with anal dilation coupled with low incidence of side effects.

At the present time, there is one temporary prostatic stent that has received U.S. Food and Drug Administration (FDA) approval. The Spanner

temporary prostatic stent maintains urine flow and allows natural voluntary urination. The prostatic stent is a completely internal device and can be inserted and removed as easily as a Foley catheter. It permits normal bladder and sphincter functioning and can be worn comfortably by patients. The temporary prostatic stent is typically used to help patients maintain urine flow after procedures that cause prostatic swelling, such as brachytherapy, cryotherapy, TUMT, TURP. It has also become an effective differential diagnostic tool for identifying poor bladder function separate from prostatic obstruction.

No useful studies have been done to determine whether acupuncture can help people with stress urinary incontinence.

The pathophysiology of the condition results from neuronal plasticity associated with bladder afferents and motor neurons innervating the external urethral sphincter. People with this condition generally experience daytime and night time wetting, urinary retention, and often have a history of urinary tract and bladder infections. Constipation and encopresis are often associated with this condition.

There is considerable research into the causes, diagnosis and treatments for FGIDs. Diet, microbiome, genetics, neuromuscular function and immunological response all interact. Heightened mast cell activation has been proposed to be a common factor among FGIDs, contributing to visceral hypersensitivity as well as epithelial, neuromuscular, and motility dysfunction.

"Diagnosis" is by examination, either in an outpatient setting or under anaesthesia (referred to as — Examination Under Anaesthesia). The fistula may be explored by using a fistula probe (a narrow instrument). In this way, it may be possible to find both openings. The examination can be an anoscopy. Diagnosis may be aided by performing a fistulogram, proctoscopy and/or sigmoidoscopy.

Possible findings:

- The opening of the fistula onto the skin may be observed

- The area may be painful on examination

- There may be redness

- An area of induration may be felt — thickening due to chronic infection

- A discharge may be seen

CLASSIFICATIONS of ANAL FISTULA

- Park's Classification: This was done in 1976 by Parks et al from UK. This was done in the era when MRI or Endoanal Ultrasound was not there. It classified the fistula in four grades

- St James University Hospital Classification: This was done by Morris et al in the year 2000. This classification was improvement over Parks classification as it was based on MRI studies. It classified the fistula in five grades.

- Garg Classification: This was done by Pankaj Garg in 2017. This classification is improvement over both Parks and St James University Hospital Classification. This was based on MRI studies and operative findings in 440 patients. It classified the fistula in five grades. The grades of this classification correlate quite well with the severity of the disease. Grade I & II are simpler fistulas and can be managed by Fistulotomy whereas grade III-V are complex fistulas in which fistulotomy should be not be done. They should be managed by Fistula experts. Unlike Park's and St James University Hospital Classification, this correlation is quite accurate with Garg's classification. Therefore this new classification is useful to both surgeons and radiologists

Surgical procedures are generally reserved for people with anal fissure who have tried medical therapy for at least one to three months and have not healed. It is not the first option in treatment.

The main concern with surgery is the development of anal incontinence. Anal incontinence can include inability to control gas, mild fecal soiling, or loss of solid stool. Some degree of incontinence can occur in up to 45 percent of patients in the immediate surgical recovery period. However, incontinence is rarely permanent and is usually mild. The risk should be discussed with one's surgeon.

Surgical treatment, under general anaesthesia, was either anal stretch (Lord's operation) or lateral sphincterotomy where the internal anal sphincter muscle is incised. Both operations aim to decrease sphincter spasming and thereby restore normal blood supply to the anal mucosa. Surgical operations involve a general anaesthetic and can be painful postoperatively. Anal stretch is also associated with anal incontinence in a small proportion of cases and thus sphincterotomy is the operation of choice.

Colostomy is recommended by most surgeons, and has a good prognosis, with 90% of patients regaining normal bowel control. Since the rectal opening and anal orifice in a vestibular fistula tend to be short and narrow, a colostomy is usually performed to allow decompression of the bowel unless the orifice is wide enough to allow normal defecation. Colostomy is often followed by posterior sagittal anorectoplasty (PSARP), a surgical procedure to repair the anal orifice, at a later date. Some surgeons prefer to perform an immediate PSARP without a colostomy first, while others perform neither a colostomy nor a PSARP and instead opt for a simple dilatation of the orifice to allow stool to pass and the bowel to decompress. It has been suggested that only experienced surgeons should perform repair without an initial colostomy.