Diseases of Lower GI Tract Flashcards
1
Q
How adaptive is the small intestine?
A
Very adaptive. >50% needs to be removed to affect functional ability
2
Q
What are the two sphincters of the lower GI tract?
A
- Sphincter of Oddi
* Ileocecal Valve
3
Q
Describe the Sphincter of Oddi
A
Found at the junction of the pancreatic and bile ducts to control flow from gallbladder and pancreas.
Nerve damage causes dysfunction
4
Q
Describe the Ileocecal Valve
A
Controls flow of upper GI contents into lower GI and prevents regurgitation of bacteria from large intestine
5
Q
What three hormones/secretions stimulate release of pancreatic and gallbladder secretion?
A
CCK, gastrin, and secretin
6
Q
Where are most nutrients absorbed?
A
Duodenum and jejunum
7
Q
What nutrient is only absorbed in the ileum?
A
B12
8
Q
What is steatorrhea?
A
Diarrhea that’s high in fat; signals lipid malabsorption
9
Q
What is absorbed in the large intestine?
A
Vitamin K, Biotin (these two endogenously produced in gut)
Na, Cl, K
SCFAs
10
Q
Describe the anatomy of the large intestine
A
Ascending, transverse, descending, sigmoid colon
•No villi or microvilli
11
Q
What is the last sphincter in the GI?
A
Anal sphincter
12
Q
What are the large intestine secretions?
A
- Goblet cells produce mucus
* Potassium and bicorbonate
13
Q
What enzymatic digestion occurs in lg intestine?
A
None. Already done.
14
Q
What is the primary function of the large intestine?
A
Reabsorption of water, electrolytes, and some vitamins (eg: K)
15
Q
What is the secondary function of the large intestine?
A
Formation and storage of feces
•insoluble fiber and bilirubin
•400 species of bacteria
•fermentation of fiber and sugar alcohols
16
Q
Describe fermentation in the large intestine
A
- Produces SCFA and lactate
- Energy produced used by bacteria for tissue growth in colon or used in body
- Excess substrate results in gas
17
Q
What are the three types of diarrhea?
A
- OSMOTIC DIARRHEA - from lg sugar load; goes to stomach and body naturally tries to pull in fluid. Acts as a dumping syndrome. (eg: lactose intolerance)
- SECRETORY DIARRHEA - underlying disease causes secretions - bacteria, viruses, and intestinal hormone secretion, high levels e-lytes
- EXUDATIVE DIARRHEA - associated with mucosal damage, mucus, blood, proteins, e-lytes, water (Chron’s Disese, UC, radiation enteritis)
18
Q
Describe the medical diagnosis of diarrhea
A
- Diagnose underlying etiology
- Age, hydration status, presence of blood in stool, and immunocompetency
- Recurrence of episodes related to time of day and food intake
- Stool cultures
- Endoscopy
- Osmolality and electrolyte content
19
Q
Describe treatment for diarrhea
A
- treat underlying disease
- antibiotics
- restore fluid, e-lyte, and acid/base balance
- IV therapy, rehydration status
- medication to treat symptoms
- suggest prevention strategies
20
Q
Describe the recommended nutrition therapy for diarrhea
A
- Dairy - cut fat; buttermilk and yogurt (high in bacteria)
- Protein - tender, well-cooked meats
- Grains - white or refined flour (low fiber)
- Fruits - avoid all raw fruits except banana and melons (sorbitol - prebiotic)
- Vegetables - (low fiber) well-cooked veggies w/out seeds or skins
21
Q
Name the primary and secondary functions of the large intestine
A
1st: Reabsorption of water, electrolytes, and some vitamins (Vit K)
2. Formation and storage of feces
22
Q
What are the symptoms of irritable bowl syndrome?
A
Abdominal pain, alterations in bowel habits, gas, flatulence
23
Q
What are the three possible types of IBS?
A
- IBS-D (with diarrhea)
- IBS-C (with constipation)
- IBS-M (mixed)
24
Q
What diet intervention is often used for IBS patients?
A
Fermentable oligo-, di-, and monosaccharides and polyols (FODMAP)
25
Define diverticulosis/diverticulitis. Where is it most commong?
Abnormal presence of outpockets or pouches on surface of SI or colon/ inflammation of
Most common in Western and industrialized countries
26
What are some risk factors for diverticulosis/diverticulitis?
Obesity, sedentary, steroids, alcohol and caffeine intake, cigarette smoking
27
Give the pathophysiology of diverticulosis/diverticulitis
* Fecal matter trapped, excessive pressure against walls of colon
* Development of pouches
* Diverticulitis: pouches become inflamed
* Bleeding abscess, obstruction, fistula, perforation
28
What are the symptoms for diverticulosis? For diverticulitis? How is it diagnosed?
* Diverticulosis: typically asymptomatic
* Diverticulitis: fever, abdominal pain, GI bleeding, elevated WBC
Diagnosed by radiology testing (thickened walls, abscess, inflammation)
29
Give three similarities of Crohn's Disease and Ulcerative Colitis
Both:
• Are classified as Inflammatory Bowel Disease (IBD)
• Have environmental/inflammatory triggers
• Are autoimmune disorders
30
Give the etiology and pathophysiology of IBD
Genetic predisposition + environmental trigger -> inflammatory response -> Damage to cells of small and/or lg intestine with malabsorption, ulceration, or stricture -> symptoms
31
What are some symptoms of IBD?
* Diarrhea
* Weight loss
* Poor growth
* Hyperhomocysteinemia (related to B vitamins)
* Partial GI obstructions
32
Where in the body is affected by Crohn's Disease?
* Distal ileum and colon - 50-60% of cases
* Small intestine - 25% only in SI or colon
* Can affect any part of GI (mouth -> anus)
33
How can you spot Chron's disease on an endoscope?
Inflammatory polyps give a "cobblestone" appearance to the mucosa
34
Give some symptoms of Crohn's disease
* abdominal pain in LRQ
* diarrhea
* rectal bleeding
* weight loss
* fistulas
* fever
* bleeding -> leading to anemia
35
How can Crohn's disease be diagnosed using blood work/body samples?
* Blood tests for anemia
* Check WBC count- if elevated sign of inflammation in body
* Test stool sample for bleeding or infection in the intestines
36
Give two common complications of Crohn's
* Strictures of the intestine - thickened intestinal wall with swelling and scar tissue, narrowing passage
* Fistulas - abnormal connection between two organs or organ and skin. Can become infected and fuse together when healed (forming fistula)
37
What are the three goals of Crohn's treatment?
* Control inflammation
* Correct nutritional deficiencies
* Relieve symptoms
38
What does Crohn's treatment look like?
Includes drugs, nutrition supplements, surgery, or a combo
Can help control, but THERE IS NO CURE
39
What deficiency is common in UC? Why?
| How is it treated?
Iron-deficient anemia due to blood losses
Iron supplements and iron-rich foods + Vitamin C (for absorption)
40
What diet would you recommend to someone during a CD flareup?
* Minimal residue diet with small, frequent, lactose-free meals
* MCTs may be used to add calories
* Avoid foods assoc with gas, reflux, bloating
41
Compare Low Residue vs Low Fiber diets
**All low residue diets are low fiber diets; not all low fiber diets are low residue
• Low residue limits fiber as well as lactose, mannitol and xylitol, fructose, lots of sucrose, caffeine, and alcohol (basically anything that would increase motility)
42
When the colon and rectum are removed, the surgeon performs a _________
ileostomy
43
Describe a COLOSTOMY
When the rectum is surgically removed
Colon is attached to stoma
44
Describe colostomy irrigation
Purpose is to stimulate peristalsis and get BM going; gives freedom to not wear a bag
45
Describe MNT for colostomy patients
* Begin with clear liquids low in simple sugar (lower osmolality) post-op
* Progress to low-fiber nutrition therapy with adequate calories and protein for patient
* Avoid high fiber foods for 2-4 weeks post-op then slowly added back in (water-soluble then insoluble)
* Avoid odor and gas-producing foods
46
When would we use MCT oil?
For fat malabsorption patients.
| **but provide no essential fatty acids
47
Describe Ulcerative Colitis
* An IBD that causes inflammation and ulcers in lining of lg intestine
* Usually occurs in rectum and lower part of colon
* Inflammation causes rectal bleeding or bloody diarrhea
48
Name 4 ways UC is different from Chron's?
* UC affects only large intestine (colon) and rectum; Crohn's can affect anywhere in GI
* UC only in continuous stretches; Crohn's occurs in patches
* UC only the innermost lining; Crohn's deep layers of tissues
* UC can be cured through surgical removal of colon; Chron's is incurable and surgery doesn't always work
49
What are the most common symptoms of UC?
Abdominal pain and bloody diarrhea
50
When does short bowel syndrome occur (SBS)?
After resection of small intestine
••severity of problems dependent on what section is removed and health of remaining bowel (eg: ileum causes more deficiencies)
51
What parts of small bowel are best to keep to avoid SBS?
Proximal duodenum, prox jejunum, distal ileum and ileocecal valve and ascending colon
52
Why is the ileocecal valve important?
* Prolongs intestinal transit time and prevents ileal contamination with colonic bacteria
* If removed it results in severe diarrhea
53
What happens if duodenum is removed?
Compromised absorption of Ca++, Mg++, and feSo4 (severe hypocalcemia and anemia)
54
Why is removal of the ileum problematic?
• Bile salts and B12 are absorbed at terminal end (if cannot reabsorb bile salts
- liver can't compensate --> steatorrhea)
- B12 defic. can cause megaloblastic anemia ~4-5 years
• Reduced absorption of fat soluble vits
- night blindness (Vit A)
- hypoprothrombinemia (Vit K)
- osteomalacia, osteopenia (Vit D)
55
SBS patients are prone to kidney stones. Explain.
* Decreased colonic absorption of oxalate
* Oxalates normally bind calcium and can't be absorbed; with low bile salts the FFA and calcium bind instead; unbound oxalates are absorbed and excreted by kidney where they're bound to Ca++ and form calcium oxalate stones
56
Describe the main goal of nutrition therapy in SBS
Aim to prevent malnutrition and dehydration (may include oral eating, enteral nutrition, and parental nutrition - just depends on how bad it is)
57
What are the general dietary guidelines with SBS patients with colon?
* Low fat, high carbohydrate diet --> fat divided equally between meals
* Chopped, ground, or well-chewed nutrient rich foods
* Small, frequent meals (~6-8/day)
* Fluids between meals
* No concentrated sweets
* Low oxalate foods to avoid kidney stones (spinach, bran flakes, beets, potato chips)
* Multivitamin/mineral supplement
* Lactose restricted
58
Describe gastric hypersecretion in SBS. What does it cause and what is the treatment?
Loss of small bowel segments results in change in levels of CCK, secretin, and gastrin), resulting in continued acid secretion
• Increased acid load causes: erosion of gut lining, diarrhea, altered pancreatic enzymes
• Treatment: H2 blockers, PPIs
59
What are the two functions of bile secretions?
* Emulsifying agent
| * Absorption - formation of micelles
60
What is the pH of food entering the duodenum?
Should be pH 4-5
61
Describe CHOLESTASIS
A condition where little/no bile is secreted or bile flow into GI is obstructed
62
What stimulates bile secretion and pancreatic juices?
Food entering duodenum and CCK
63
Name and describe some risk factors for gallstones
* High dietary fat, low fiber intake - constant bile synthesis for fat digestion
* Rapid weight loss (gastric, fasting, etc)
* Central obesity, insulin resistance, diabetes
64
What are four causes of gallstones?
1. too much water absorption from bile
2. too much absorption of bile acid from bile
3. too much cholesterol in bile
4. inflammation of epithelium
65
What is CHOLELITHIASIS?
Presence or formation of gallstones in the gallbladder or bile ducts
66
Describe the nutrition intervention for cholelithiasis
* Low fat, modest protein
* Small, frequent meals
* Inactive during acute attacks - NPO
* Post surgery - high fiber
