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Constipation

Inability to evacuate stool completely and spontaneously three or more times per week.

May be primary, idiopathic or functional, or associated with a number of disorders or medications.

May occur as a primary motor disorder involving the colon, a defecation disorder, may be associated with a large number of diseases, or may be an adverse effect of many drugs.

Primary motor disorders may slow transit to the colon involving the enteric nervous system and functional disorders of defecation can be related to weak or inadequate propulsion or failure of relaxation of the external anal sphincter and tuborectalis muscles known as dyssynergic defecation.

Functional constipation and constipation predominant irritable bowel syndrome (IBS-C) are defined only by symptoms, bowel symptoms only in functional constipation, or with abdominal pain that is temporary related to bowel disturbance in IBS-C.

Experienced by almost everyone at some time.

Affects between 2-27% of the population.

The median prevalence of constipation is 16% in all adults.

In older people, the prevalence is greater, at 33.5%.

Constipation is greater than people who are not white, in institutionalized people, and women in the median prevalence ratio for women to men is 1.5:1.

Women more frequently use laxatives and seek healthcare for their constipation complaints.

Reported to affect 16% of children, and 15-50% of elderly.

Most constipation is self managed and approximately 22% of patients seek healthcare, mostly from their primary care physician (greater than 50%) and gastroenterologist (14%).

More common in women than men, nonwhites than whites, in children than in adults, and in elderly than in younger adults.

Risk factors include depression, low income, limited education, and physical inactivity.

Accounts for an estimated 2.5 million physician visits annually.

Only 22.3% of patients with costipation seek physician care specifically for the problem.

Affects women 2:1.

Increases with age.

No known cause.

Rome III criteria for diagnosis: At least two of the following

1-Straining during at least 25% of defecations

2-Lumpy or hard stools in at least 25% of defecations

3-Sensation of incomplete evacuation for at least 25% of defecations

4-Sensation of anorectal obstruction for at least 25% of defecations

5-Fewer than 3 defecations per week.

Symptoms associated include infrequent bowel movements, hard stools, lumpy stools, straining at the time of bowel movements, abdominal bloating and feeling of insufficient evacuation of stool.

Normal transmit through the colon is the most prevalent form occurring in 59% of patients, defecatory disorders account for 25% of cases, slow transit form accounts for 13% of cases, and a combination of defecatory disorders and slow transit forms account for 3% of cases.

Normal transit type-stool traverses at a normal rate through the colon and stool frequency is normal but the individuals believe that they are constipated.

Most patients with chronic idiopathic constipation have less abdominal disconfort compared to patients with IBS-constipation.

Most patients with chronic idiopathic constipation respond to conservative therapy, but when they do not respond evaluation for primary motor disorders is required.

Irritable bowel syndrome is a functional gastrointestinal disorder subtyped by predominant stool pattern that includes constipation predominant disease.

There is substantial overlap between chronic idiopathic constipation and IBS-constipation.

Chronic constipation is classified into one of three groups: normal transient constipation, slow-transit constipation, and pelvic floor dysfunction or defecatory disorders.

Abdominal pain is not relieved by improving bowel habits IBS-constipation

Most patients with constipation do not have infrequent stools alone, but complain of defecatory difficulties as well.

Defecatory disorders are defined by bowel symptoms and anolrectal test results indicative of impaired rectal evacuation.

Clinical evaluation includes, the history of the duration of symptoms, frequency and consistency of stools, presence of excessive straining, feeling of incomplete evacuation, or use of manual maneuvers during defecation.

Clinical evaluation focuses on excluding organic causes and medications and to identify alarm symptoms that suggest further work up to rule out colon cancer.

Medication induced constipation is common but constipation due to structural abnormalities, such as strictures or tumors is rare and testing should not be performed unless alarm symptoms are present.

Evaluation for chronic constipation should not include diagnostic colonoscopy unless there are alarm symptoms or patients require cancer screening.

CBC, TSH, calcium are recommended in work up.

Slow-transit constipation occurs most commonly in young females with infrequent bowel movements, i.e. once a week or fewer.

Constipation in children is common and patients can present with fecal impaction was severe lower abdominal colicky pain.

Childhood patients presenting to emergency departments with abdominal pain have constipation as the cause in up to 48% of cases (Loening-Baucke V et al ).

Childhood patients present with fewer than three stools per week, fecal incontinence, largestools which may be palpable, retentive posturing, or painful defecation.

Opioid induced constipation is predominantly related to gastrointestinal m-opioid receptors.

Chronic constipation is defined as presence for more than 3 to 6 months of two or

more of the following: decreased stool frequency, straining, hard schools, sensation of

incomplete emptying or anorectal blockage, requirement for manual maneuvers to pass

stool, and rare loose stools in the absence of laxatives.

Constipation predominant IBS (IBS-C) presents as recurrent abdominal pain or discomfort associated with hard or infrequent stools or relieved by defecation.

Chronic constipation is presumed to be a functional disorder of the colon and anorectal areas.

It is defined by bowel disturbances such as reduced frequency of bowel movements, hard stools, excessive straining to defecate, a sense of anorectal blockage, anal digitation, and a sense of incomplete evacuation after defecation.

There are three categories of chronic constipation: disorders of defecation with dyssynegy, slow transit constipation and normal transit constipation.

Accounts for 8 million annual visits to physicians.

Functional constipation and constipation-predominate irritable bowel syndrome (IBS-C) or defined only by bowel symptoms or abdominal pain that is temporary related to bowel disturbances, respectively.

 

 

Defecatory disorders respond to pelvic floor biofeedback therapy, rather than laxatives.

 

 

Slow transit constipation is an indication for colectomy.

 

 

Some individuals have criteria for functional constipation and IBS-C.

 

 

Compared with constipated patients with no or mild pain, patients with severe abdominal pain have more somatic symptoms, worse overall health, and a great er impact of bowel symptoms on quality-of-life.

 

 

The median prevalence of constipation is 16% in all adults. 

 

 

In older people the prevalence is increased at 33.5% at age 60 and above.

 

 

Constipation incidence is greater in non-white populations, in institutionalized patients, and in women.

 

 

The ratio for women to men for constipation is 1.5:1.

 

 

Women more frequently utilize laxative and seek medical help with their constipation.

 

 

 Risk factors for chronic constipation include increased age, female gender, lower socioeconomic status, lower educational background, less self reported physical activity, certain medications,  stressful life events, physical and sexual abuse, and depression.

 

 

For outpatient clinic visits, constipation ranks among the top five most common diagnoses for a G.I. tract disorders.

 

 

Chronic constipation is uncommon in colon or rectal cancer.

 

 

Among constipated people, general health, mental health, and social functioning are worse than healthy controls.

 

 

Isolated slow transit constipation is regarded as a colonic motor dysfunction process it may result from inadequate caloric intake.

 

 

Slow transit constipation manometric abnormalities reveal fewer high amplitude propagated contractions and retrograde propagated or non-propagated sigmoid or rectal phasic pressure activity: such disturbances may impede colonic flow.

 

 

The contract tile responses to a meal and pharmacologic stimuli are impaired by these manometric abnormalities.

 

 

Defecatory disorders are defined by symptoms of constipation and evidence of impaired rectal  evacuation.

 

 

There is increased resistance to evacuation and or in adequate rectal propulsive forces.

 

 

 The presence of high resting anal pressure, incomplete relaxation, or paradoxical contraction of the puborectalis and external anal sphincters cause increased resistance to evacuating in defecatory disorders.

 

 

Additional abnormalities in defecatory disorders include delayed colonic  transit, rectal hyposensitivity, and structural disturbances.

 

 

Stool form influences the symptoms in constipated patients, as it is more difficult to expel hard than soft stools.

 

 

The etiology of   defecatory disorders is unknown but perhaps related to neglected response to stool urgency or inappropriate sphincter contraction initiated by and avoidance of pain or trauma. 

 

 

Defecatory disorder symptoms often begin in childhood. 

 

 

One in  three children with childhood constipation have persistent symptoms beyond puberty.

 

 

Patients with constipation have an altered clonic mucosal microbiome with increased Bacteroides.

 

 

The range of normal bowel movements in the United States is 3-21 bowel movements per week.

 

 

Among constipated patients colonoscopy to identify colon cancer is required only when there are clinical features compatible with that diagnosis and/or constipation refractory to medical management, and for patients who have not had an age-appropriate colon cancer screening procedure.

 

 

In patients who don’t respond to a high fiber diet and laxatives, a rectal balloon expulsion test and anorectal manometry is  recommended.

 

 

The rectal balloon expulsion test measures the time required for a patient to evacuate a water filled balloon in the seated position, and is generally less than one minute.

 

 

The rectal balloon expulsion test is used to identify defecatory disorders.

 

 

Some secondary causes of constipation include: colorectal cancer, colorectal strictures, rectocele,megacolon, stroke, spinal cord lesion, Parkinson’s disease, multiple sclerosis, hypercalcemia, severe hypokalemia, hypomagnesemia, severe hypothyroidism, opiates, anti-cholinergics, calcium channel blockers, anticonvulsants, antidepressants, anti-spasmodics, antihistamines, anti-emetics, amyloidosis, scleroderma, and heavy-metal poisoning.

Prucalopride approved for chronic idiopathic constipation.

Stimulant osmotic laxatives, intestinal secretagogues and peripherally restricted mu-opiate antagonists or effective and safe.

Secretagogues such as libiprostone, linaclotide, and plecanatide can be used for treating current chronic constipation and IBS-C.

Secretagogues increase intestinal chloride secretion   by activating channels on the enterocyte surface: to maintain electric neutrality, sodium is also secreted into the intestinal lumen and to preserve osmolality, water secretion follows.

 

By increasing intestinal secretion, secretagogues accelerate transit and facilitate ease of defecation.

Plecanide is a guanylyl cylase C Agonist for the treatment of both chronic constipation and IBS-C.

Plecanide has about a 7% improvement in patients with chronic constipation over placebo.

Prucalopride is a serotonin five-hydroxytryptamine receptor agonist approved for chronic idiopathic constipation:it is safe and does not have adverse cardiovascular events.

Osmotic agents including polyethylene glycol, magnesium citrate based products, sodium phosphate based products, and nonabsorbable carbohydrates such as lactulose draw fluid into the intestinal lumen to maintain gut isomolality increasing stool water and  loon propulsion.
Fiber supplementation, osmotic laxatives and/or stimulant laxatives are effective and generally less expensive and should be implemented before newer more expensive agents.
Polyethylene glycol is better than lactulose in improving stool frequency, stool consistency and abdominal pain in randomized trials.
In a randomized crossover study lactulose and  sorbitol were equally affected, but lactulose had more nausea.

Stimulant laxatives such as senna, bisacodyl, and sodium picosulfate induce propagated colonic contractions.

Bisacodyl and sodium picosulfate have anti-absorptive and secretary effects.
Stimulant suppositories such as bisacodyl and glycerin should be given about 30 minutes after breakfast to synchronize their effects with the gastrocolonic response.
Stimulant laxatives do not damage the enteric nervous system.

Constipation refractory to common laxatives should be evaluated for disorders of defecation and slow transit constipation, including studies of anorectal function and colonic transit.

Magnesium hydroxide and other salts improves the frequency and consistency.

Defecatory disorders may respond to biofeedback therapies.

Slow-transient constipation may require surgical intervention in some patients.

Except for dehydration, increase fluid intake does not treat constipation.
There is an inverse relationship between physical activity and the severity of constipation.
Moderate to vigorous intensive physical activity improve symptoms and quality of life in IBS.

Soluble dietary fiber such as psyllium supplements reduce bowel symptoms in chronic constipation and IBS.
Insoluble dietary fiber such as wheat bran does not reduce spell symptoms.
Fiber supplementation, either through diet or as a supplement should be considered as the first step in constipated patients.

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