Symptoms include:

- Straining during defecation

- Mucous rectal discharge

- Rectal bleeding

- Sensation of incomplete evacuation (tenesmus)

- constipation, or more rarely diarrhea

- fecal incontinence (rarely)

Solitary rectal ulcer syndrome (SRUS, SRU), is a disorder of the rectum and anal canal, caused by straining and increased pressure during defecation. This increased pressure causes the anterior portion of the rectal lining to be forced into the anal canal (an internal rectal intussusception). The lining of the rectum is repeatedly damaged by this friction, resulting in ulceration. SRUS can therefore considered to be a consequence of internal intussusception (a sub type of rectal prolapse), which can be demonstrated in 94% of cases. It may be asymptomatic, but it can cause rectal pain, rectal bleeding, rectal malodor, incomplete evacuation and obstructed defecation (rectal outlet obstruction).

Inflammation of the diverticulum can mimic symptoms of appendicitis, i.e., periumbilical tenderness and intermittent crampy abdominal pain. Perforation of the inflamed diverticulum can result in peritonitis. Diverticulitis can also cause adhesions, leading to intestinal obstruction.

Diverticulitis may result from:

- Association with the mesodiverticular band attaching to the diverticulum tip where torsion has occurred, causing inflammation and ischaemia.

- Peptic ulceration resulting from ectopic gastric mucosa of the diverticulum

- Following perforation by trauma or ingested foreign material e.g. stalk of vegetable, seeds or fish/chicken bone that become lodged in Meckel's diverticulum.

- Luminal obstruction due to tumors, enterolith, foreign body, causing stasis or bacterial infection.

- Association with acute appendicitis

Diverticula may occur in one of the three areas of the esophagus - the pharyngoesophageal, the midesophageal area or the epiphrenic area of esophagus. Zenker's diverticulum is found three times more frequently in men than in women. It occurs posteriorly through the cricopharyngeal muscle in the midline of the neck. Usually seen in people older than 60 years of age.

- Gastric diverticula - "Although usually asymptomatic, they may cause vague epigastric pain. These lesions may be confused radiologically for gastric ulcers or cancers. Endoscopically, they may be confused for paraesophageal hernias."

- Killian-Jamieson diverticulum

- Meckel's diverticulum: a persistent portion of the omphalomesenteric duct present in 2% of the population

- Rokitansky-Aschoff sinuses: in the gallbladder due to chronic cholecystitis

- Traction esophageal diverticulum: due to scarring from mediastinal or pulmonary tuberculosis

- Urethral diverticulum: congenital in males, post-infectious in females

- Zenker's diverticulum: a diverticulum of the mucosa of the pharynx affecting adults

Most of these pathological types of diverticulum are capable of harboring an enterolith. If the enterolith stays in place, it may cause no problems, but a large enterolith expelled from a diverticulum into the lumen can cause obstruction.

Bleeding of the diverticulum is most common in young children, especially in males who are less than 2 years of age. Symptoms may include bright red blood in stools (hematochezia), weakness, abdominal tenderness or pain, and even anaemia in some cases.

Hemorrhage may be caused by:

- Ectopic gastric or pancreatic mucosa:

1. Where diverticulum contains embryonic remnants of mucosa of other tissue types.

2. Secretion of gastric acid or alkaline pancreatic juice from the ectopic mucosa leads to ulceration in the adjacent ileal mucosa i.e. peptic or pancreatic ulcer.

3. Pain, bleeding or perforation of the bowel at the diverticulum may result.

4. Mechanical stimulation may also cause erosion and ulceration.

- Gastrointestinal bleeding may be self-limiting but chronic bleeding may lead to iron deficiency anaemia.

The appearance of stools may indicate the nature of the haemorrhage:

- "Tarry stools": Alteration of blood produced by slow bowel transit due to minor bleeding in upper gastrointestinal tract

- "Bright red blood stools": Brisk haemorrhage

- "Stools with blood streak": Anal fissure

- ""Currant jelly" stools": Ischaemia of the intestine leads to copious mucus production and may indicate that one part of the bowel invaginates into another intussusception.

Depending on the level of obstruction, bowel obstruction can present with abdominal pain, swollen abdomen, abdominal distension, vomiting, fecal vomiting, and constipation.

Bowel obstruction may be complicated by dehydration and electrolyte abnormalities due to vomiting; respiratory compromise from pressure on the diaphragm by a distended abdomen, or aspiration of vomitus; bowel ischemia or perforation from prolonged distension or pressure from a foreign body.

In small bowel obstruction, the pain tends to be colicky (cramping and intermittent) in nature, with spasms lasting a few minutes. The pain tends to be central and mid-abdominal. Vomiting may occur before constipation.

In large bowel obstruction, the pain is felt lower in the abdomen and the spasms last longer. Constipation occurs earlier and vomiting may be less prominent. Proximal obstruction of the large bowel may present as small bowel obstruction.

Early symptoms can include periodic abdominal pain, nausea, vomiting (sometimes green in color from bile), pulling legs to the chest area, and intermittent moderate to severe cramping abdominal pain. Pain is intermittent—not because the intussusception temporarily resolves, but because the intussuscepted bowel segment transiently stops contracting. Later signs include rectal bleeding, often with "red currant jelly" stool (stool mixed with blood and mucus), and lethargy. Physical examination may reveal a "sausage-shaped" mass, felt upon palpating the abdomen. Children, or those unable to communicate symptoms verbally, may cry, draw their knees up to their chest, or experience dyspnea (difficult or painful breathing) with paroxysms of pain.

Fever is not a symptom of intussusception. However, intussusception can cause a loop of bowel to become necrotic, secondary to ischemia due to compression to arterial blood supply. This leads to perforation and sepsis, which causes fever.

In rare cases, intussusception may be a complication of Henoch-Schönlein purpura (HSP), an immune-mediated vasculitis disease in children. Such patients who develop intussusception often present with severe abdominal pain in addition to the classic signs and symptoms of HSP.

Diverticula are described as being true or false depending upon the layers involved:

- True diverticula involve all layers of the structure, including muscularis propria and adventitia, such as Meckel's diverticulum.

- False diverticula (also known as "pseudodiverticula") do not involve muscular layers or adventitia. False diverticula, in the GI tract for instance, involve only the submucosa and mucosa.

Diverticular disease can present with painless rectal bleeding as bright red blood per rectum. Diverticular bleeding is the most common cause of acute lower gastrointestinal bleeding. However, it is estimated that 80% of these cases are self-limiting and require no specific therapy.

Obstructed defecation is one of the causes of chronic constipation. Obstructed defecation could be considered to be a type of bowel obstruction, where it may be classified under large bowel obstruction. Obstructed defecation frequently gives rise to a symptom called tenesmus. Constipation, bowel obstruction and tenesmus are therefore all closely related topics.

Outlet obstruction can be classified into 4 groups.

- Functional outlet obstruction

- Mechanical outlet obstruction

- Dissipation of force vector

- Impaired rectal sensitivity

Some people with diverticulosis complain of symptoms such as cramping, bloating, flatulence, and irregular defecation. However, it is unclear if these symptoms are attributable to the underlying diverticulosis or to coexistent irritable bowel syndrome.

Diverticular disease was found associated with a higher risk of left sided colon cancer.

Causes of small bowel obstruction include:

- Adhesions from previous abdominal surgery (most common cause)

- Barbed sutures.

- Pseudoobstruction

- Hernias containing bowel

- Crohn's disease causing adhesions or inflammatory strictures

- Neoplasms, benign or malignant

- Intussusception

- Volvulus

- Superior mesenteric artery syndrome, a compression of the duodenum by the superior mesenteric artery and the abdominal aorta

- Ischemic strictures

- Foreign bodies (e.g. gallstones in gallstone ileus, swallowed objects)

- Intestinal atresia

After abdominal surgery, the incidence of small bowel obstruction from any cause is 9%. In those where the cause of the obstruction was clear, adhesions are the single most common cause (more than half).

Solitary rectal ulcer syndrome

Colitis cystical profunda

Internal intussusception

Mucosal prolapse

Rectal prolapse

Fecal incontinence to gas, liquid, solid stool, or mucus in the presence of obstructed defecation symptoms may indicate occult rectal prolapse (i.e. rectal intussusception), internal/external anal sphincter dysfunction, or descending perineum syndrome.

In children, insussusception at the ileocecal junction and accounts for 90 percent of all cases.

There are many different types of rectal discharge, but the most common presentation of a discharge is passage of mucus or pus wrapped around an otherwise normal bowel movement.

Rectal discharge has many causes, and may present with other symptoms:

- Staining of undergarments

- Constant feeling of dampness around anus

- Frequent urge to open bowels, but passage of only small amounts of mucus or pus-like liquid rather than normal feces

- Rectal pain

- Rectal malodor, when the discharge is foul-smelling, e.g. associated with certain infections

- Pruritus ani

- Rectal bleeding

- Perianal erythema, swelling and tenderness

A common symptom is a continual urge to have a bowel movement—the rectum could feel full or have constipation. Another is tenderness and mild irritation in the rectum and anal region. A serious symptom is pus and blood in the discharge, accompanied by cramps and pain during the bowel movement. If there is severe bleeding, anemia can result, showing symptoms such as pale skin, irritability, weakness, dizziness, brittle nails, and shortness of breath.

Symptoms are ineffectual straining to empty the bowels, diarrhea, rectal bleeding and possible discharge, a feeling of not having adequately emptied the bowels, involuntary spasms and cramping during bowel movements, left-sided abdominal pain, passage of mucus through the rectum, and anorectal pain.

Rectal tenesmus (Latin, from Greek teinesmos, from teinein to stretch, strain) is a feeling of incomplete defecation. It is the sensation of inability or difficulty to empty the bowel at defecation, even if the bowel contents have already been evacuated. Tenesmus indicates the feeling of a residue, and is not always correlated with the actual presence of residual fecal matter in the rectum. It is frequently painful and may be accompanied by involuntary straining and other gastrointestinal symptoms.

Tenesmus has both a nociceptive and a neuropathic component.

Vesical tenesmus is a similar condition, experienced as a feeling of incomplete voiding despite the bladder being empty.

Often, rectal tenesmus is simply called tenesmus. The term rectal tenesmus is a retronym to distinguish defecation-related tenesmus from vesical tenesmus.

Tenesmus is a closely related topic to obstructed defecation.

In simple words, when there is excessive pressure within the lower pharynx, the weakest portion of the pharyngeal wall balloons out, forming a diverticulum which may reach several centimetres in diameter.

More precisely, while traction and pulsion mechanisms have long been deemed the main factors promoting development of a Zenker's diverticulum, current consensus considers occlusive mechanisms to be most important: uncoordinated swallowing, impaired relaxation and spasm of the cricopharyngeus muscle lead to an increase in pressure within the distal pharynx, so that its wall herniates through the point of least resistance (known as Killian's triangle, located superior to the cricopharyngeus muscle and inferior to the Thyropharyngeus muscle. Thyropharyngeus and Laryngopharyngeus are the superior and inferior parts of inferior constrictor muscle of pharynx respectively). The result is an outpouching of the posterior pharyngeal wall, just above the esophagus.

While it may be asymptomatic, Zenker diverticulum can present with the following symptoms:

- Dysphagia (difficulty swallowing), and sense of a lump in the throat

- Food might get trapped in the outpouching, leading to:

- Regurgitation, reappearance of ingested food in the mouth

- Cough, due to food regurgitated into the airway

- Halitosis, smelly breath, as stagnant food is digested by microorganisms

- Infection

It rarely, if ever, causes any pain.

Cervical webs are seen associated in 50% of patients with this condition.

Rarer forms of cervical esophageal diverticula are the Killian's diverticulum and the Laimer's diverticulum. Killian's diverticulum is formed in the Killian-Jamiseon triangle (located inferior to the cricopharyngeus on both sides of this muscle's insertion into the cricoid cartilage). Laimer's diverticulum is formed in Laimer's triangle (located inferior to the cricopharyngeus in the posterior midline above the confluence of the longitudinal layer of esophageal muscle). Laimer's triangle is covered only by the circular layer of esophageal muscle.

Urethral diverticula are often asymptomatic and symptoms that are present tend to be nonspecific. They can co-occur with cancer, in approximately 6-9% of cases, most commonly adenocarcinoma, but also including squamous cell carcinoma and transitional cell carcinoma. Approximately 10% of cases co-occur with kidney stones.

There are 2 types of urethral diverticulums. Congenital and acquired. In infancy usually the urethral diverticulum is congenital but in rare instances acquired urethral diverticulum can be seen in infancy specially following traumatic catheterization.

Common symptoms of urethral diverticulum include incontinence, urinary frequency and urgency, pain during sex, and pain during urination. Other symptoms include pain localized to the urethra or pelvis and frequent urinary tract infection.

When urethral diverticulum becomes severe, a painful mass can sometimes be felt inside the introitus of the vagina, which can discharge pus. If the mass is hard or bleeds, complications like cancer or kidney stones may be present.

A rectovaginal fistula is a medical condition where there is a fistula or abnormal connection between the rectum and the vagina.

Rectovaginal fistula may be extremely debilitating. If the opening between the rectum and vagina is wide it will allow both flatulence and feces to escape through the vagina, leading to fecal incontinence. There is an association with recurrent urinary and vaginal infections. The fistula may also connect the rectum and urethra, which is called recto-urethral fistula. Either conditions can lead to labial fusion. This type of fistula can cause pediatricians to misdiagnose imperforate anus. The severity of the symptoms will depend on the size of fistula. Most often, it appears after about one week or so after delivery.

A Zenker's diverticulum, also pharyngoesophageal diverticulum, also pharyngeal pouch, also hypopharyngeal diverticulum, is a diverticulum of the mucosa of the pharynx, just above the cricopharyngeal muscle (i.e. above the upper sphincter of the esophagus). It is a pseudo diverticulum (not involving all layers of the esophageal wall).

It was named in 1877 by German pathologist Friedrich Albert von Zenker.

Megarectum is a large rectum as a result of underlying nerve supply abnormalities or muscle dysfunction, which remains after disimpaction of the rectum. The Principles of Surgery textbook describes any rectum that can hold more than 1500cc of fluid as a megarectum. The term megarectum is also used for a large rectal mass on rectal examination, a wide rectum on an abdominal x-ray, the presence of impaired rectal sensation or the finding of large maximal rectal volumes on anorectal manometry. In addition, can be the bloating of the colon due to infection, also called megacolon. On defecography, megarectum is suggested by a rectal width of >9 cm at the level of the distal sacrum.

A urethral diverticulum is a condition where the urethra or the periurethral glands push into the connective tissue layers (fascia) that surround it.

Diversion colitis is an inflammation of the colon which can occur as a complication of ileostomy or colostomy, often occurring within the year following the surgery. It also occurs frequently in a neovagina created by colovaginoplasty, with varying delay after the original procedure. Despite the presence of a variable degree of inflammation the most suggestive histological feature remains the prominent lymphoid aggregates. A foul smelling, mucous rectal discharge may develop from the inflamed mucosa of the distal, unused colon.

The diagnosis cannot be safely reached without knowing the clinical story. In many milder cases after ileostomy or colostomy, diversion colitis is left untreated and disappears naturally. If treatment is required, possible treatments include short-chain fatty acid irrigation, steroid enemas and mesalazine.