Large Bowel Disorders

Question 1

Types of Diverticular Disease

Answer 1

1. Diverticulosis
   Diverticula present
   Asymptomatic
2. Diverticulitis
   Inflamed diverticula
   May cause potentially fatal obstruction, infection or hemorrhage

Question 2

Most common sites: Diverticula

Answer 2

Sigmoid colon

Descending colon

Question 3

Contributing factors: Diverticular Disease

Answer 3

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

Question 4

Pathophysiology: Diverticular Disease

Answer 4

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

Question 5

Signs & Sx’s Diverticulosis

Answer 5

Most asymptomatic

Some pts may have nonspecific complaints:

• Chronic constipation
• Abd pain
• Fluctuating bowel habits

Exam usually unremarkable

Question 6

Diagnostic Studies: Diverticulosis

Answer 6

No imaging needed for uncomplicated disease

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

Colonoscopy less sensitive in detecting diverticula

Question 7

Treatment: Diverticulosis

Answer 7

High fiber diet or fiber supplements reduce likelihood of complications

Question 8

General Characteristics: Diverticulitis

Answer 8

Defined as inflammation of diverticula caused by obstructing matter

Patients with diverticulosis are at risk of developing diverticulitis

Question 9

Pathophysiology: Diverticulitis

Answer 9

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

Question 10

Signs & Sx’s Diverticulitis

Answer 10

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

Question 11

Differential Dx: Diverticulitis

Answer 11

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

Question 12

Diagnostic Studies: Diverticulitis

Answer 12

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. ColonoscopyorBE done ≈ 6 weeks later
   - R/O IBD orcolonCA
   - Evaluate extent of tics/obstruction risk

Question 13

Treatment: Diverticulitis

Answer 13

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

Question 14

Surgery: Diverticulitis

Answer 14

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

Question 15

General Characteristics: Irritable Bowel Syndrome

Answer 15

Functional disorder without known pathology

Most common cause of chronic or recurrent abd pain in US

Intermittent, lifelong problem

F > M

Question 16

Pathophysiology: IBS

Answer 16

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

Question 17

Sx’s: IBS

Answer 17

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

Question 18

Differential Diagnosis: IBS

Answer 18

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

Question 19

Diagnostic Studies: IBS

Answer 19

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

Question 20

Treatment: IBS

Answer 20

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)

Question 21

Constipation: General Characteristics

Answer 21

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

Question 22

Etiology: Constipation

Answer 22

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

Question 23

Work - Up: Constipation

Answer 23

1. Complete Hx & PE is essential, including:
   - DRE
   - Stool guaiac
2. Diagnostic Studies
   - CBC
   - Electrolytes
   - Ca, glucose
   - TSH
   - Colonoscopy

Question 24

Treatment: Constipation

Answer 24

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

Question 25

Colon Polyps: General Characteristics

Answer 25

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

Question 26

Types of Polyps

Answer 26

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

Question 27

Prevention: Colon Polyps

Answer 27

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

Question 28

Risk Factors: Colon Polyps

Answer 28

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

Question 29

Signs & Sx’s: Colon Polyps

Answer 29

Polyps generally asymptomatic May be asst with rectal bleeding & iron deficiency anemia

Question 30

Diagnostic Studies: Colon Polyps

Answer 30

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

Question 31

Treatment: Colon Polyps

Answer 31

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

Question 32

Familial Adenomatous Polyposis

Answer 32

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

Question 33

Colorectal Cancer: General Characteristics

Answer 33

1. Almost all colorectal cancers are adenocarcinomas a. Form bulky masses 2. Majority of colorectal cancers arise from malignant transformation of adenomatous polyps

Question 34

Colorectal Cancer: Risk Factors

Answer 34

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

Question 35

Colorectal Cancer: FH Risk Factors

Answer 35

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

Question 36

Colorectal Cancer: Sx’s & Tumor Location

Answer 36

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

Question 37

Colorectal Cancer: Sxs

Answer 37

Physical exam may be normal (+) guaiac common Palpable mass -Suggests advanced disease Hepatomegaly -Suggests metastatic spread

Question 38

Colorectal Cancer: Differential Dx

Answer 38

``` IBS Diverticular disease Ischemic colitis IBD Hemorrhoids ```

Question 39

Colorectal Cancer: Diagnostic Studies

Answer 39

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

Question 40

Colorectal Cancer: Imaging

Answer 40

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

Question 41

Colorectal Cancer: Staging

Answer 41

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)

Question 42

Colorectal Cancer: Treatment

Answer 42

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

Question 43

Screening Recommendations for Colorectal CA

Answer 43

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

Question 44

Colorectal Cancer: Screening Methods

Answer 44

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

Question 45

Toxic Megacolon: General Characteristics

Answer 45

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

Question 46

Toxic Megacolon: Signs & Sx’s

Answer 46

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

Question 47

Toxic Megacolon: Diagnostic Studies

Answer 47

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

Question 48

Toxic Megacolon: Treatment Goals

Answer 48

Reduce colonic distention to prevent perforation Correct fluid and electrolyte disturbances Treat toxemia & precipitating factors

Question 49

Toxic Megacolon: Treatment

Answer 49

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