Constipation Flashcards
What are some of the functions of the small intestine?
- Reabsorbs water and compact material into feces
- Absorbs vitamins produced by bacteria
- Store fecal matter prior to defecation
List the areas of the colon and what each are involved in?
- Ascending , Tranverse, descending - ivolved in the reabsorption of water and vitamins
- Sigmoid, rectum, anal canal - Involved in packaging of the remaining material into feaces
The ransit of small labeled markers through the large intestine occurs in 36-48hrs. TRUE OR FALSE?
TRUE
What does haustrations and mass movement do and what do they aid in?
- Haustrations (mixing movement) : aids in reabsorption and packaging
- Mass movement (Propulsive movements) : Keeps material moving though the colon
List some of the Rome criteria for the diagnosis of constipation?
- Two stools or less per week
- A feeling of incomplete evacuation at least 25% of the time
- A feeling of anal blockage
- Straining at stool at least 25% of the time
What are the pathophysiological components of chronic constipation?
- abnormal intrinsic motility
- Lack of luminal factors
- Medications (can cause abnormal motility)
- Impaired defecation
- Lack of extrinisic innervation in paraplegia
- Hormones
What is latrogenic constipation?
-When symptoms are caused by medication
What type of medications cause constipation?
-Pain medications, iron, calcium, blood pressure medications
Opiods induced constipation in palliative care is common. TRUE OR FALSE?
TRUE
How do opiods cause constipation?
- They increase smooth muscle tone which supresses forward peristalsis, increases tone in anal sphincters, Increases transit time and water absorption
- They reduce sensitivity to anal distention which reduces urge to defecate
What is the most common cause of constipation?
-Through the misuse of laxatives
How do the misuse of laxatives cause constipation?
- Longer interval needed to refill colon is misinterpreted as constipation which leads to further laxative use
- Causes eneteral loss of water and salts leads to release of aldosterone which stimulates reabsorption in intestine, but increaseenal excretion of potassium ions
What does the dobule loss of potassiu ions from renal excretion lead to and what does this do the rate of peristalsis?
Hypokalemia which reduces peristalsis
What is the role of aldosterone?
Stimulates the kidneys to absorb and retain water
What is impaired defecation?
-The loss of feedback between components of the fecal reflex
Constipation is a disease. TRUE OR FALSE?
FALSE
List the therapy classes for constipation?
- Bulk forming laxatives
- Osmotic laxatives
- Stimulant laxatives
- Stool softeners
- Other agents
what is the mechanim of action for each of the therapy classes for constipation?
- Bulk forming laxatives : Fiber increases bulk of the stool which activates stretch receptors in the wall of the colon which acts to increase colonic activity
- Osmotic laxatives : Increases fluid content of stools which activates stretch receptors which increases fecal activity.
- Stimulant laxatives : They increase peristalsis by increasing the activity of muscles in the colon
- Stool softeners : These lubricates the stool and helps them pass through the colon easily
What are some of the general contraindication for use of laxatives?
- Laxatives should not be used in the presence of undiagnosed abdominal pain
- The drug may cause cause an inflamed organ to rupture and spill in GI
- Oral drugs are also contranindicated when a diagnosed GI disturbance is likely to be worsened by increased motility
Bulk laxatives are insoluble, non digestible and non absorbable. TRUE OR FALSE?
TRUE
How long do bulk laxatives take to act?
-Takes several days (2 weeks)
List three bulk laxatives?
- Isphagula
- Methylcellulose
- Sterculia
What are some fo the ADRs of bulk laxatives?
-Bloating and flatulence, GI obstruction and impaction
What are the cautions for taking bulk laxatives?
-Adequate fluid intake should be maintained to avoid obstruction
