Constipation Week 5 Flashcards
Constipation
is a common complaint in older adults & the most common digestive complaint in the general population
Rome III criteria: functional constipation is defined as any two of the following features:
- straining - lumpy hard stools - sensation of incomplete evacuation - use of digital maneuvers - sensation of anorectal obstruction or blockage with 25 percent of bowel movements - decrease in stool frequency (less than three bowel movements per week)
Rome III criteria requirements
need 2 of the features for the last 3 months with symptom onset 6 months prior to diagnosis
in older adults constipation may be associated with what?
fecal impaction and fecal incontinence
fecal impaction can cause
stercoral ulceration, bleeding, anemia
Stercoral ulceration is ?
the loss of bowel integrity from the pressure effects of inspissated feces
prevalence of constipation
prevalence of constipation in the older adult has not been well defined, but may be as high as 24- 50% of older adults, of whom 10- 18% use daily laxatives (especially community dwellings/ nursing homes)
Constipation in the older adult- why?
Primary colorectal dysfunction or secondary to several etiologic factors (often multi- factorial in older adults)
Primary colorectal dysfunction categorized into 3 broad sub- types:
slow transit constipation dyssynergic defecation irritable bowel syndrome
slow transit constipation
- prolonged delay in stool transit throughout the colon - Possibly primary dysfunction of colonic smooth muscle: myopathy, neuronal innervation (neuropathy), secondary to dyssynergic defecation
Dyssynergic defecation
- difficulty with or inability expelling stool from the anorectum - prolonged colonic transit time
irritable bowel syndrome
- predominant constipation (IBS-C) is characterized by abdominal pain with altered bowel habits. - may or may not have slow colonic transit or dyssynergia - many have visceral hypersensitivity
Constipation may be conceptually regarded as
disordered movement of stool through the colon or anorectum since, with few exceptions, transit through the proximal gastrointestinal tract is often normal. Slowing of colonic transit may be idiopathic or may be due to secondary causes.
what kinds of drugs are associated with constipation?
- analgesics - anticholinergics (antihistamines, antispasmodics, antidepressants, antipsychotics) - cation- containing agents (iron supplements, aluminum ie. antacids, sucralfate, barium - neurally active agents (opiates, antihypertensives, ganglionic blockers, vinka alkaloids, calcium channel blockers, 5HT3 agonists)
what receptor is at the root of this problem? (drugs causing constipation)
?? no idea
alarm features of constipation
hematochezia, weight loss of ≥10 pounds, a family history of colon cancer or inflammatory bowel disease, anemia, positive fecal occult blood tests, or acute onset of constipation in elderly persons
what can be considered when alarm features are absent?
empiric treatment (patient education, trial of dietary changes, and a trial of fiber) without diagnostic testing
An important part of the history includes defining ? regarding constipation
the nature and duration of constipation. Can do 2 week bowel diary to make sure they are actually constipated and not just thinking they are- Reassurances regarding the broad range of normal bowel frequency may be all that is necessary in some cases.
history should also focus upon
identifying secondary causes of constipation. (Most patients with idiopathic constipation are otherwise asymptomatic.)
A recent and persistent change in bowel habits, if not associated with a readily definable cause of constipation (eg, medications) should
prompt an evaluation to exclude structural bowel changes or organic diseases, especially in older adults. A diagnosis of functional constipation should be considered only after these other diseases have been excluded.
general physical examination is not helpful in most patients presenting with chronic constipation- instead what is useful? and why?
a rectal exam: - can identify fissures or hemorrhoids which may be caused by constipation, or which can be painful and thereby lead to voluntary stool retention and secondary constipation - A gaping or asymmetric anal opening may suggest that a neurologic disorder is impairing sphincter function - Responses of the puborectalis and external anal sphincter muscles may be evaluated by asking the patient to strain during the rectal examination; this is particularly useful in identifying patients with possible dyssynergic defecation
Normal defection involves the:
coordinated relaxation of the puborectalis and external anal sphincter muscles, together with increased intraabdominal pressure and inhibition of colonic segmenting activity
But in patients with dyssynergic defecation:
ineffective defecation is associated with a failure to relax, or inappropriate contraction of, the puborectalis and external anal sphincter muscles. This narrows the anorectal angle and increases the pressures of the anal canal so that evacuation is less effective. Relaxation of these muscles involves cortical inhibition of the spinal reflex during defecation; so, this pattern may represent a conscious or unconscious act.
The pathogenesis of dyssynergic defecation
is not completely understood but is probably multifactorial. It is thought to be an acquired, learned dysfunction rather than an organic or neurogenic disease.
