Constipation, Diarrhea, and GERD Flashcards
What are the Rome III criteria for functional constipation?
at least two of the following for the last 3 months with onset in the prior 6 months: straining (25% of BMs), lumpy or hard stool (Bristol Stool Scale Form 1 or 2 - 25% of BMs), sensation of incomplete evacuation (25% of BMs), manual maneuvers (25% of BMs), sensation of obstruction (25% of BMs), < 3 BMs/week; loose stools rarely present without laxatives; insufficient criteria for IBS
What is stercoral ulceration?
ulcer of the colon due to pressure and irritation resulting from severe, prolonged constipation due to large bowel obstruction (commonly located in the rectum)
What is the puborectalis muscle?
muscle that contributes towards the maintenance of fecal continence - loops around the rectum like a sling, pulling the rectum forward to create a more acute angle between the rectum and the anal canal => squatting fully relaxes the muscle and allows for easier defecation
What are the three types of primary colorectal dysfunction?
(1) slow transit constipation - delay throughout the colon (dysfunction of colonic smooth muscle or neuronal innervation and obstruction); (2) dyssynergic defecation - difficulty expelling stool from the anorectum; (3) IBS predominant constipation (abdominal pain and altered bowel habits)
What are common causes of secondary constipation?
endocrine/metabolic disorders, neurologic disorders, myogenic disorders, medications (opioids), psychiatric disorders (anorexia nervosa), chronic idiopathic constipation (no physiological abnormality)
What are some neurogenic disorders associated with chronic constipation?
DM, Hirschsprung disease (absence of ganglion cells), Chagas disease (disease of the nervous system that can cause megacolon and chronic constipation), MS, spinal cord injury
What are some non-neurogenic disorders associated with chronic constipation?
hypothyroidism, hypokalemia, anorexia nervosa, pregnancy
Which receptor is associated with opioid-induced chronic constipation?
mu-opioid receptors in the GI tract - opioids bind to these receptors, leading to inhibition of the propulsive activity of the intestine and slowing intestinal transit
Which drugs are commonly associated with constipation?
opiates, antihypertensives, CCBs, iron supplements, aluminum, analgesics, antihistamines, antispasmodics, antidepressants, antipsychotics, serotonin (5-HT3) receptor antagonists (block the vomiting reflex - ondansetron)
What are red flags associated with constipation?
hematochezia (passage of fresh blood through the anus), + fecal occult blood test, obstructive symptoms, acute onset constipation, severe constipation unresponsive to Tx, weight loss > 10 pounds, change in stool caliber, family Hx of colon cancer/IBD
What other factors can contribute to constipation?
immobility, chronic medical problems (pain, DM), psychosocial problems (isolation, poor nutrition)
How should you conduct an exam for constipation?
thorough Hx, rectal exam, and bowel diary => reserve other diagnostic studies for selected individuals
What are the treatments for constipation?
(1) lifestyle and dietary modification, (2) bulk laxatives (psyllium [Metamucil], polycarbophil [FiberCon], wheat dextriumn [Benefiber], methylcellulose [Citrucel]), (3) osmotic laxatives - contain polyethylene glycol (GoLYTELY, GlycoLax, and MiraLax), (4) colon secretagogues (lubiprostone), (5) enemas (only to prevent fecal impaction in PTs with several days of constipation)
What is the mechanism of action of osmotic laxatives (polyethylene glycol - GoLYTELY [electrolyte] and MiraLAX [powdered])?
hold water in the stool to soften the stool and increase the number of bowel movements - improves stool frequency and consistency => start with 17 g powder dissolved in 8 oz of water daily and titrate up/down to effect
What is the mechanism of action of bulk forming laxatives (psyllium seed/Metamucil, methylcellulose/Citrucel, calcium polycarbophil/FiberCon, wheat dextrin/Benefiber)?
natural or synthetic polysaccharides or cellulose derivatives - are not digested but absorb liquid in the intestines and swell to form a soft, bulky stool
What is pelvic floor dyssynergia/functional outlet disorder?
condition in which the external anal sphincter and the puborectalis muscle contract rather than relax during an attempted bowel movement - there is the sensation of incomplete emptying of the rectum; Dx made via manometry and balloon expulsion test => may be treated with biofeedback
What are the recommendations for establishing a regular pattern of bowel movement?
attempt to empty the bowel at the same time every day - within 2 hours of waking and within the first 30 minutes after a meal (to take advantage of postprandial increases in colonic motility); attempt a BM at least twice per day; strain no more than 5 minutes
What dietary changes are recommended to treat constipation?
increase fluid and fiber intake - fiber intake of 20-25 g/day
What are some types of natural laxatives that may be safe to use with constipation?
flaxseed, psyllium fiber, triphala (composed of 3 fruits common to the Indian subcontinent: Amalaki [Emblica officinalis], Bibhitaki [Terminalia belerica] and Haritaki [Terminalia chebula])
What is anorectal manometry?
a small, flexible sensor is placed in the rectum and connected to a computer with a recording device that measures the pressure and strength of the anal and rectal muscles - the patient is asked to perform certain maneuvers such as squeezing, relaxing, or pushing as if to pass stool - abnormal finding suggests a defecatory disorder
What is the balloon expulsion test?
PT is placed in a left lateral decubitus position with flexion of the knees and hips - a well lubricated empty balloon is gently inserted into the rectum and the balloon is inflated by a fixed volume (typically 50 mL of water or until the patients feel a desire to defecate) => PT is then asked to attempt to evacuate the balloon in the sitting position in privacy - abnormal finding suggests a defactory disorder
Which laboratory tests should be ordered in PTs with constipation?
complete metabolic panel (serum glucose, creatinine, calcium), CBC with differential, thyroid function tests
Which patients should receive laboratory testing with constipation?
PTs with hematochezia, weigh loss > 10 lbs., family Hx of colon cancer or IBD, anemia, positive fecal occult blood test
Which patients should receive diagnostic colonoscopy with constipation?
age < 50 years who have not previously had colon cancer screening, constipation with alarm features, prior to surgery for constipation
Which PTs should receive radiographic studies for constipation?
suspected megacolon and barium radiograph in PTs with suspected Hirschsprung disease
Which PTs should receive assessment with colon transit study for constipation?
those with infrequent defecation - used with radiopaque markers or wireless motility capsule
What is colonic transit time?
time it takes for stool to pass through the colon
What is defecography?
imaging study which provides information about anatomical and functional changes of the anorectum - most useful in examining anatomic causes of constipation - performed by placing 150 mL of barium into the PT’s rectum and having PT squeeze, cough, or bear down
How is dyssynergia diagnosed on defecography?
presence of insufficient descent of the perineum (< 1 cm) and less than a normal change in the anorectal angle (< 15 degrees)
How is defecatory dysfunction managed?
suppositories (glycerin or biscodyl - liquify stool), biofeedback (used to correct inappropriate contraction of the pelvic floor muscles and external anal sphincter), or botulinum toxin injections into the puborectalis muscle (60-100 U into both sides of the muscle)
What is the recommended daily fiber intake?
25 to 30 g/day - there is a dose response between fiber intake, water intake, and fecal output (larger particle size fiber sources enhance fecal bulking) - PTs can add 2-6 Tbs of raw bran followed by a glass of water to achieve optimal fiber intake => side effects: bloating and gas
What is the mechanism of action of surfactants/softeners (docusate sodium/Colace)?
lower the surface tension of stool, allowing water to more easily enter - not as effective as other types of laxatives for chronic constipation
What is the mechanism of action of stimulant laxatives (bisacodyl/Dulcolax, senna/Senokot)?
alter electrolyte transport by the intestinal mucosa and increase intestinal motor activity
How is stool fecal impaction (solid immobile bulk of stool in the rectum) treated?
disimpacted with manual fragmentation or using flexible or rigid sigmoidoscopy with instrumentation - followed by enema with mineral oil to soften the stool and provide lubrication or daily warm water enemas for up to 3 days
What type of drug is linaclotide?
minimally absorbed peptide agonist of guanylate cyclase-C receptor that stimulates intestinal fluid secretion and transit - used to treat chronic idiopathic constipation (145 mcg/day)
What type of drug is lubiprostone?
locally acting chloride channel activator - enhances chloride-rich intestinal fluid secretion (24 mcg/day) - best used in patients who have no responded to other treatments
Which patients are candidates for subtotal colectomy with ileorectal anastomosis?
(1) chronic, severe, disabling symptoms unresponsive to medical therapy, (2) slow colonic transit, (3) no intestinal pseudoobstruction, (4) no pelvic floor dysfunction, (5) no abdominal pain as a prominent symptom - surgery is the treatment of choice of Hirschsprung disease
How is diarrhea defined?
passage of loose or watery stools at least 3X in 24 hours - reflects increased water content of stool due to impaired water absorption and/or active water secretion by the bowel
What is dysentery?
diarrhea with visible blood or mucus
What are the most common causes of acute infectious diarrhea?
viral infections (norovirus, rotavirus, adenovirus)
What are the most common causes of severe diarrhea?
bacteria (Salmonella, Campylobacter, Shigella, E coli, C diff)
When is an office evaluation warranted for acute diarrhea?
patients with persistent fever, bloody diarrhea, severe abdominal pain, symptoms of volume depletion, Hx of IBD
What are the common features of diarrhea of small bowel origin?
watery, large volume, and associated with abdominal cramping, bloating, and gas
What are the common features of diarrhea of large intestinal origin?
frequent, regular, small volume, painful BMs - fever, bloody/mucoid stools are common; RBCs and inflammatory cells routinely seen
What does timing of consumption of suspected contaminated food suggest about likely origins of diarrhea?
within 6 hours and with N/V - suggests ingestion of preformed toxin (Staph aureus or Bacillus cereus); 8 to 16 hours - C perfringens; > 16 hours - viral or bacterial infection
What are aspects of history important to capture when assessing diarrhea?
character of symptoms, duration, frequency, associated symptoms, food history (unpasteurized dairy products, raw/undercooked meat/fish, organic vitamins), exposure to animals, recent travel, occupation in day care centers, recent antibiotic use/medicines, past medical Hx (immunocompromised or nosocomial infection)
What should you look for in the physical exam of a PT with diarrhea?
signs of volume depletion (dry mucous membranes, diminished skin turgor, postural hypotension, altered sensorium), abdominal distension, pain with gentle percussion, abdominal rigidity, rebound tenderness
When should stool samples be taken in patients with acute community-acquired diarrhea?
severe illness (profuse watery diarrhea with hypovolemia, > 6 unformed stools in 24 hours, severe abdominal pain), signs/symptoms of inflammatory diarrhea (bloody diarrhea, small volume stools with blood/mucus, temp > 101.3 degrees), high-risk host features (age > 70, comorbidities, immunocompromised, IBD, pregnancy), symptoms persisting > one week, public health concerns
How should stool samples be taken in patients with suspected parasitic infections?
three specimens on consecutive days - ova and parasitic excretions may be intermittent and may give a false negative reading with only one sample
What are more uncommon causes of diarrhea that occur in immunocompromised PTs?
parasites, microsporidium (fungal infection), cytomegalovirus
What is a common cause of diarrhea in MSM?
proctitis - caused by STIs => perform anoscopy to identify anorectal discharge or rectal mucosal friability
What is the treatment for diarrhea?
1 rehydration (PO - water, salt, and sugar) - diluted fruit juices or flavored soft drinks, (Gatorade not equivalent to rehydration solutions), saltine crackers and broths or soup for PTs with mild symptoms; oral rehydration solutions for PTs with moderate/severe symptoms
What is the recommended composition of oral rehydration solutions for treatment of diarrhea?
3.5 g NaCl, 2.9 g sodium bicarbonate, 1.5 g potassium chloride, 20 g glucose - similar solution can be made with 1/2 t salt, 1/2 t baking soda, and 4 Tbs sugar in 1 L of water
What are dietary recommendations during an episode of acute diarrhea?
boiled starches and cereals (potatoes, noodles, rice, wheat, oat) with salt, crackers, bananas - avoid foods with high fat content; dairy products (except yogurt) may be difficult to digest
When is empiric antibiotic therapy warranted in the treatment of diarrhea?
severe disease (fever, > 6 stools/day, volume depletion requiring hospitalization), bloody/mucoid stools (suggests bacterial infection), host factors (age > 70, immunocompromised, cardiac conditions), prolonged disease (> 1 week) that has not improved, public health concerns
What is the best choice of agent for empiric antibiotic therapy in treatment of diarrhea?
oral fluoroquinolone (ciprofloxacin 500 mg BID, levofloxacin 500 mg daily, or norfloxacin 400 mg BID) for 3-5 days - alternatives: azithromycin (500 mg PO daily for 3 days) or erythromycin (500 mg PO BID for 5 days)
Which causative agent of diarrhea should not be treated with antibiotics?
enterohemorrhagic E coli - can precipitate hemolytic-uremic syndrome
What can PTs with diarrhea take if they want symptomatic relief?
antimotility agent (loperamide/Imodium 4 mg or bismuth salicylate/Pepto-Bismol 30 mL) - use cautiously in patients with no or low-grade fever and lack of blood in stool and use fluids aggressively