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Flashcards in Nichols + ??? 3 Deck (75)
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1

Constipation

-Infrequent BM <3/week for 12 months with straining/feeling of incomplete evacuation/hard stool at least 25% of time

2

Normal Colonic Motility

-motor function depends on contraction of circular layer of smooth muscle
-has 3 patterns of contractions

3

Short Duration Colonic Contractions

Stationary Motor Contractions
-Present over short areas of colon
-Causes mixing of fecal material and extraction of water
-Persists for <15 seconds

4

Long Duration Colonic Contraction

-may be stationary or propagate for short distances
-may travel in orad or aboral direction
-assists in mixing and local propulsion of feces
-migrates toward rectum in distal colon

5

Giant Migrating Complexes of Colon

-propagates aborally aver extended distances
-causes mass movement of feces
-normally occurs 1-2 times/day
-may be precipitated by colonic distention

6

Food Intake & Colonic Motility

-food causes increased segmental activity
-gastrocolic reflux-may be mediated by CCK
-response is proportional to caloric content of meal

7

Hormones & Colonic Motility

CCk causes increased frequency & amplitude of segmental contractions
PgF
PgE
Serotonin

8

PgF

stimulates longitudinal muscle contraction

9

PgE

inhibits circular muscle contraction

10

Serotonin

mediates intestinal peristalsis and secretion in GI tract as well as modulation of pain perception

11

Role of Serotonin

-serotonin (5-HT) is an important neurotransmitter in the brain-gut interaction (released by enterochromaffin cells)
-80% of total body 5-HT located in GI tract
-5-HT3 receptor antagonists have offered some help in alleviating pain in IBS and functional dyspepsia
-5-HT4 receptor agonists have a prokinetic effect in humans

12

Epidemiology of Constipation

-12-19% of people
-more common in individuals with little daily physical activity, low income, and poor education
-in patients 65 years of age, especially more in women

13

Constipation: Pediatric Etiology

95% functional
5% organic
-anatomic
-metabolic
-neuropathic
-drugs
-endocrine connective tissue D/O
-lead intoxication or botulism

14

Functional Constipation

-infants and pre-school
-2 weeks duration Pebble-like, hard stools

15

Functional Fecal Retention

-common cause of chronic constipation
-with fear and toilet refusal from infancy to 16 years old

16

Constipation: Elderly

-endocrine and metabolic disease
-neurologic disease
-psychological conditions
-structural abnormalities
-lifestyle
-iatrogenic (meds)

17

Constipation Diagnosis

-H&P/other medical conditions
-evaluate current meds
-rule out thyroid disorders or electrolytes problem
-colonoscopy or Barium Enema
-colon transit of markers
-anorectum manometry

18

Lab Data of Constipation

performed in patients with rectal bleeding, weight loss of >10lbs, a family history of colon cancer, IBD, anemia, positive fecal occult blood, short-term constipation
-CBC
-serum glucose, creatinine, calcium
-TSH

19

Malabsorption

-problem in GI lumen, Defects in epithelial absorptive surface, post-epithelum defect
-steatorrhea, carbs, proteins

20

Steatorrhea

greater than 5% of dietary fat intake

21

Patients with steatorrhea?

-weight loss
-stool characteristics
-osteomalacia
-easy bruising
-Fe deficiency anemia not due to blood loss
-adult dev. of lactase insufficiency
-gastric surgery, specially Billroth II

22

Steatorrhea Stool Characteristics?

-floats
-greasy
-stinks
-hard to flush
-oil droplets with minimal stools

23

Mechanisms causing diarrhea in steatorrhea?

-increase of osmotically active particles of mal-absorbed dietary constituents
-hydroxylation of 10-hydroxy-oleate which acts as cathartic
-fatty acids themselves impair fluid & electrolyte absorption

24

Diagnostic Studies with Steatorrhea?

-chemical fat balance, D-xylose absorption, secretin test, X-ray (flat plate of abdomen, CT scan, barium)
-hydrogen breath test, aspiration of duodenal content for giardia & quant

25

Stages of Malabsorption

1. Intraluminal Stage
2. Intestinal Stage
3. Lymphatic Transport Stage

26

What Causes the most Steatorrhea?

pancreatic insufficiency

27

Intraluminal Stage

-chronic pancreatitis
-Zollinger-Ellison Syndrome
-Post-gastrectomy
-cystic fibrosis
Solubilization: bile acid insufficiency
-cholestatic liver disease, terminal lleum resection, bacterial overgrowth in small intestine, reduced CCK released

28

Effects of Impaired Circulation of Bile Salts

-diarrhea and if severe steatorrhea
-increased proportion of the bile acids pols conjugated with glycine vs. taurine
-increased proportion of deoxycholate in bile
-a reduced bile salt pool size

29

Intestinal Stage

Epithelial cell surface digestion
-Disaccharidase Insufficiency
-Stasis Syndrome

30

Intestinal Stage: Intestinal Cell Dysfunction

-gluten sensitivity enteropathy
-stasis syndrome
-whipple's disease
-intestinal ischemia
-radiation enteritis
-tropical sprue
-genetic disorders such as cystinuria
-anderson's disease
-abetalipoproteinemia