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Flashcards in Large Bowel Disorders Deck (49):
1

Types of Diverticular Disease

1. Diverticulosis
Diverticula present
Asymptomatic

2. Diverticulitis
Inflamed diverticula
May cause potentially fatal obstruction, infection or hemorrhage

2

Most common sites: Diverticula

Sigmoid colon
Descending colon

3

Contributing factors: Diverticular Disease

1. Diminished colon motility & increased intraluminal pressure
2. Low fiber diet
3. Connective tissue disorders
-Scleroderma
-Marfan Syndrome

4

Pathophysiology: Diverticular Disease

Diverticula result from high intraluminal pressure on area of weakness in GI wall where blood vessels enter

Diet may be contributing factor

Insufficient fiber reduces fecal residue --> narrows bowel lumen --> leads to high intra-luminal pressure during defecation

5

Signs & Sx’s Diverticulosis

Most asymptomatic

Some pts may have nonspecific complaints:
-Chronic constipation
-Abd pain
-Fluctuating bowel habits

Exam usually unremarkable

6

Diagnostic Studies: Diverticulosis

No imaging needed for uncomplicated disease

Diverticula best seen on barium enema or CT abd & pelvis w/contrast

Colonoscopy less sensitive in detecting diverticula

7

Treatment: Diverticulosis

High fiber diet or fiber supplements reduce likelihood of complications

8

General Characteristics: Diverticulitis

Defined as inflammation of diverticula caused by obstructing matter

Patients with diverticulosis are at risk of developing diverticulitis

9

Pathophysiology: Diverticulitis

Undigested food & bacteria accumulate in diverticular sac

Hard mass cuts off blood supply to thin walls of sac --> increased risk of infection

Untreated --> increased risk of perforation

10

Signs & Sx’s Diverticulitis

1. Abd pain
-Sudden onset
-Usually LLQ (site of tics)
2. +/- fever
3. Diarrhea OR constipation
4. N / V
5. +/- distention
6. Palpable tenderness
- +/- mass in affected area
- Guarding
- +/- rebound tenderness
7. DRE may be tender

11

Differential Dx: Diverticulitis

1. Perforated colon CA
2. Crohn’s Disease
3. Appendicitis
4. Ischemic colitis
5. C. Difficile colitis
6. GYN disorders
-Ectopic pregnancy
-Ovarian cyst
-Ovarian torsion

12

Diagnostic Studies: Diverticulitis

1. Guaiac (+) stool common
2. Mild-mod leukocytosis
3. CT Abd/pelvis
-Recommended in pts who do not respond to empiric therapy after 2-4 days
-Evaluates extent of disease and R/O underlying colon CA
4. Barium enema & colonoscopy should be avoided during acute phase due to risk of perforation & peritonitis
5. CT Abd/pelvis
-Colonic diverticuli & wall thickening
-Peri-colic fat infiltration
-Abscess formation
-Extraluminal air
6. Colonoscopy or BE done ≈ 6 weeks later
-R/O IBD or colon CA
-Evaluate extent of tics/obstruction risk

13

Treatment: Diverticulitis

1. Mild diverticulitis
a. Clear liquid / BRAT / Low residue diet
b. Add antibx if persistent
-Broad spectrum antibiotics x 7-10 days
(Fluoroquinolones/Ciprofloxin (Cipro) 500 mg po bid
+
Metronidazole (Flagyl) 500 mg po tid)

2. Moderate diverticulitis
a. Hospitalization & NPO
b. IV antibiotics x 5-7 days [gram (+), gram (-) & anaerobic coverage]
(Cefotaxime (Claforan) or piperacillin (Zosyn)
OR
Metronidazole (Flagyl) + ceftriaxone (Rocephin))
3. Bowel rest (NPO)
4. Analgesia
5. NG tube if ileus develops

14

Surgery: Diverticulitis

1. Severe diverticulitis or unresponsive to Tx
a. Done if:
-Peritonitis
-Large abscess
-Fistulas
-Obstruction
2. Two stage procedure:
a. Diseased colon resected, proximal colon brought out to form temp colostomy; distal stump closed
b. 3-6 months later, after inflammation subsides, colon can be reconnected electively

15

General Characteristics: Irritable Bowel Syndrome

Functional disorder without known pathology

Most common cause of chronic or recurrent abd pain in US

Intermittent, lifelong problem

F > M

16

Pathophysiology: IBS

1. Current evidence suggests combination of:
-Altered motility
-Hypersensitivity to intestinal distention
-Psychological distress

17

Sx’s: IBS

1. Abd pain
a. Hypogastrium
b. LLQ
2. Pain worsened w/ food & relieved w/ defecation
3. Postprandial urgency
4. Bowel distention
a. Accumulation of gas
5. Constipation, diarrhea or both
6. PE Normal

18

Differential Diagnosis: IBS

Lactose intolerance
Cholecystitis
Chronic pancreatitis
Intestinal obstruction
Pancreatic CA
Stomach cancer
Celiac disease

19

Diagnostic Studies: IBS

1. Dx of exclusion
2. Stool for O&P, fecal WBC’s, blood, culture
a. R/O infection
3. CT w/contrast/Ba enema
a. R/O obstructing mass, pancreatic cancer
4. Endoscopy
a. R/O celiac disease, stomach cancer

20

Treatment: IBS

1. Reassurance
2. Strong provider-patient relationship
3. Avoidance of known triggers
4. High fiber diet
5. Bulking agents
-Psyllium / Metamucil
-Methylcellulose / Citrucel
-Calcium Polycarbophil /FiberCon

6. Anti-diarrheal meds
a. Opioid Agonists
b. Activate opioid receptors in GI smooth muscle  inhibits AcH release --> inhibits peristalsis
c. Includes:
-Loperamide (Immodium) – opioid analogue
-Diphenoxylate (Lomotil)

7. Anti-constipation meds
a. Increase intestinal fluid secretion & motility
-Lubiprostone (Amitiza)
-Linaclotide (Linzess)

8. Prokinetic meds
a. Stimulates motility of upper GI tract w/out stimulating gastric, biliary or pancreatic secretions
-Metochlopramide (Reglan) 10 mg po 30 min ac & hs

9. Antidepressants/antidiarrheal (females only)
a. Used in severe cases only, restricted use
b. Serotonin (5HT3) receptor agonist
c. Slows down GI motility
-Alosetron (Lotronex)

21

Constipation: General Characteristics

Normal bowel function ranges from 3 stools/day to 3 stools/week

Decrease in stool volume & increase in stool firmness accompanied by straining

Patients > 50 yr with new onset constipation should be evaluated for colon cancer

22

Etiology: Constipation

1. Primary constipation
a. Anal stricture
b. Rectocele
c. Rectal prolapse
2. Secondary constipation
a. Systemic disease
-Hypothyroidism, DM, hypercalcemia
b. Medications
-Opioids, diuretics, anticholinergics, Ca & Fe supplements
c. Obstructing colonic lesions

23

Work - Up: Constipation

1. Complete Hx & PE is essential, including:
-DRE
-Stool guaiac

2. Diagnostic Studies
-CBC
-Electrolytes
-Ca, glucose
-TSH
-Colonoscopy

24

Treatment: Constipation

1. Increase fiber
-10-20 gm daily
2. Increase fluid intake
-1.5 – 2 L / day
3. Increase activity
4. If constipation lasts > 2 weeks or if constipation refractory to above measures, further investigation to detect etiology

25

Colon Polyps: General Characteristics

1. Colon polyps are discrete mass lesions that protrude into intestinal lumen
a. Can be benign or malignant

2. Removal of colon polyps can reduce occurrence of colon cancer

3. Familial polyposis syndrome is a genetic predisposition to multiple colon polyps
a. High risk colon cancer

26

Types of Polyps

1. Mucosal neoplastic (adenomatous)
a. Most common type
b. 95% adenocarcinoma of colon arise from these polyps

2. Mucosal non-neoplastic (hyperplastic)
a. Non malignant

3. Submucosa
a. Lipomas
b. Lymphoid aggregates

27

Prevention: Colon Polyps

1. Diet high in fruits, vegetables & fiber
2. Low fat diet
3. Limit ETOH intake
4. Avoid tobacco
5. Anti-oxidant vitamins
a. A, C, E, beta carotene
6. NSAID Tx
a. Due to risks asst w/long term use, ASA not recommended in pts w/polyps unless there are other medical indications
b. Reduces number of recurrent adenomas at 1-3 yr
-Low dose ASA 81 mg PO qd
-Celecoxib (Celebrex) 400 mg PO bid

28

Risk Factors: Colon Polyps

Diet rich in fats and red meats
(+) FH
IBD
Age

29

Signs & Sx’s: Colon Polyps

Polyps generally asymptomatic

May be asst with rectal bleeding & iron deficiency anemia

30

Diagnostic Studies: Colon Polyps

1. Guaiac (+) stool common
2. Imaging studies:
a. Barium enema
-Not used much today
b. Colonoscopy
- Diagnostic study of choice for localizing & identifying (Bx) polyps
(Histologic evaluation of polyps
Virtual colonoscopy/ pill camera)

3. Family members of pts w/ familial polyposis should be evaluated q 1-2 yr beginning at 10-12 yr of age

31

Treatment: Colon Polyps

1. Colonoscopic polypectomy

2. Post-polypectomy Surveillance
a. Colonoscopy w/in 3-5 yr after initial exam
-Adenomas found in 30-40% of pt after initial (+) exam
-Colonoscopy in 5-10 yr after first normal post-polypectomy exam
3. Patients with 3-10 adenomatous polyps or polyp > 1 cm
a. Colonoscopy in 3 yr

32

Familial Adenomatous Polyposis

1. Inherited condition characterized by early development of hundreds to thousands of colonic adenomatous polyps & adenocarcinoma

2. Genetic testing confirms mutation of:
-APC gene (90%)
-MYH gene (8%)

3. Prophylactic colectomy recommended to prevent otherwise inevitable colon cancer
-Usually before age 20 yr

33

Colorectal Cancer: General Characteristics

1. Almost all colorectal cancers are adenocarcinomas
a. Form bulky masses

2. Majority of colorectal cancers arise from malignant transformation of adenomatous polyps

34

Colorectal Cancer: Risk Factors

1. Aging
a. 90% cases > 50 yr
2. (+) FH
3. IBD
a. Cumulative risk 5-10% after 20 yr & 20% after 30 years
4. High fat diet
5. ETOH
a. > 1 drink/day
6. M > F
7. B > W
8. Tobacco use
9. Obesity
10. Lack of physical activity

35

Colorectal Cancer: FH Risk Factors

Pts w/one 1st degree relative w/colorectal CA have increased risk 2x that of general population

Risk is 4x greater if relative was diagnosed < 45 yr

20-30% lifetime risk if two 1st degree relatives have colon CA

36

Colorectal Cancer: Sx’s & Tumor Location

1. Right sided colon CA
a. Fatigue/weakness

2. Left sided colon CA
a. Fatigue/weakness
b. Colicky abd pain
c. Change in bowel habits
d. Obstructing lesion

3. Rectal CA
a. Fatigue/weakness
b. Tenesmus
c. Urgency
d. Recurrent hematochezia

37

Colorectal Cancer: Sxs

Physical exam may be normal

(+) guaiac common

Palpable mass
-Suggests advanced disease

Hepatomegaly
-Suggests metastatic spread

38

Colorectal Cancer: Differential Dx

IBS
Diverticular disease
Ischemic colitis
IBD
Hemorrhoids

39

Colorectal Cancer: Diagnostic Studies

1. CBC
-Iron Def Anemia
2. Elevated LFT’s
-Metastatic Dz
3. Carcinoembryonic Ag (CEA)
-Tumor marker
-Pre-op level > 5 ng/ml poor prognosis
4. Colonoscopy
-Diagnostic procedure of choice
-Provides histologic Dx

40

Colorectal Cancer: Imaging

1. CT Chest/Abd/Pelvis
a. Demonstrates distant mets

2. Ultrasound liver
a. More accurate than CT for liver mets

3. Pelvic MRI
a. Rectal cancer
-Determines depth of penetration of CA through rectal wall

41

Colorectal Cancer: Staging

Stage 0
-Polyp or lesion at innermost lining of the colon
Stage 1
-Beyond innermost lining of colon to second & third layers 
Stage II
-Extends thru muscular wall of colon, but not in nodes
Stage III
-Extends outside colon to ≥ lymph node
Stage IV
-Extends outside the colon to distant organs (liver or the lungs)

42

Colorectal Cancer: Treatment

Resection of tumor

Regional lymph node dissection
-Minimum 12 nodes
-Determines staging & adjunctive chemoTx

Rectal CA
-Pre-op chemo-radiation followed by surgery

Patients should be evaluated q 3-6 months for 3-5 yrs:
-Hx
-Physical
-CEA
-Repeat colonoscopy 1 yr post-op; then q 3-5 yr

43

Screening Recommendations for Colorectal CA

1. Screening colonoscopy
a. USPTF & ACS recommends start screening at age 50 yr
b. If 1st degree relative with colon CA, begin screening at 40 yr OR at age 10 yr younger than age at which relative was Dx’d
-Single 1st degree relative w/ CA > 60 yrs, begin screening at age 40 & screen q 10 yr
-Single 1st degree relative w/CA < 60 yrs, OR 2 1st degree relatives, begin screening at 40 yr or younger; screen q 5 yr

44

Colorectal Cancer: Screening Methods

1. Stool Guaiac (FOBT)
2. Flexible sigmoidoscopy
a. Detects approx 65% advanced neoplasms
b. Does not examine proximal colon
3. Colonoscopy
a. Permits exam of entire colon
b. Preferred
-Allows detection and removal polyps
c. Although most sensitive test, not infallible
4. Barium Enema
a. Rarely used today

45

Toxic Megacolon: General Characteristics

1. Extreme dilatation & immobility of colon
2. True emergency!!
3. Hirschsprung’s Dz
a. Congenital aganglionosis of colon
b. Leads to functional obstruction in newborn
4. In adults, toxic megacolon occurs as a complication of:
a. UC
b. Crohn’s Disease
c. Pseudomembranous colitis
d. Infections
-Shigella, Campylobacter, C. Difficile

46

Toxic Megacolon: Signs & Sx’s

1. Fever
a. Hypothermia if sepsis
2. Prostration
3. Severe cramps
4. Abd distention
5. Rigid abdomen
6. Localized or diffuse rebound tenderness
7. Tachycardia
8. Dehydration

47

Toxic Megacolon: Diagnostic Studies

1. CBC
a. Leukocytosis most common
b. If sepsis→ leukopenia
2. BMP
3. KUB
a. Colonic dilatation

48

Toxic Megacolon: Treatment Goals

Reduce colonic distention to prevent perforation

Correct fluid and electrolyte disturbances

Treat toxemia & precipitating factors

49

Toxic Megacolon: Treatment

1. Decompression of colon within 24 hr
a. NG tube, long intestinal tubes
b. If unable, then:
-Subtotal colectomy w/ ileostomy
2. attention to fluid & electrolyte balance
a. High risk for septic shock
3. Corticosteroids if resulted from active IBD
4. Antibiotics given to prevent sepsis
a. Ampicillin, gentamicin, & metronidazole (or equivalent)
5. D/C possible triggers: narcotics, antidiarrheals, & anticholinergics
6. Risk of death is high 2* perforation, sepsis, shock