Colorectal Disorders

Question 1

Colon CA is the ____ most common cause of CA death in the US. what is the 5 yr survival rate. MC site of metastasis?

Answer 1

3rd; 64%

metastasis: LIVER (usually goes to regional lymph nodes prior to liver)

Question 2

what’s the biggest risk factor for colon cancer? other risk factors?

Answer 2

AGE: risk doubles each decade after 50 yr old
**other risk factors: family history, genetics (FAP, Lynch syndrome), hx of IBD, Hx of prior polyps, behavioral things (obesity/DM, ETOH, smoking, high fat diet)

Question 3

what % of colon rectal cancer occurs after age 50?

Answer 3

90%

Question 4

having a first degree relative with colon CA _________ the risk of you having it

Answer 4

doubles

Question 5

what are two genetic conditions that put people at risk for colon CA?

Answer 5

1) . familial adenomatous polyposis (FAP) = adenomas begin in childhood, almost all will get CA, tx by proph colectomy
2) . hereditary non polyposis coli (HNPCC)- LYNCH SYNDROME = AD inheritance

Question 6

what does most CRC come from?

Answer 6

adenomatous polyps that progress into adenocarcinoma (larger polyps more likely to contain neoplastic cells)

Question 7

what type of polyps have a higher risk for invasive carcinoma?

Answer 7

villous polyps

Question 8

what are screening recommendations for CRC for average risk patients? what tool and how often?

Answer 8

1) . Colonoscopy every 10 years starting at age 50 through 75 yo (individualized after age 75) BEST
2) . Flex sig every 5 years with fecal occult blood testing every 3 years
3) . high sensitivity fecal occult testing annually: if results are positive, NEED to do colonoscopy

Question 9

for people with a prior adenoma or a previous resection of cancer, what screening test should be done?

Answer 9

colonoscopy

Question 10

what are the screening guidelines for a person with a 1st degree relative with colon CA?

Answer 10

start screening that person at 40 years old OR 10 yrs before their family member was diagnosed with CA
*usually colonoscopy every 5 years, or annual FOBT if pt declines colonoscopy

Question 11

how do you dx CRC? common lab finding?

Answer 11

TEST OF CHOICE: colonoscopy w biopsy
*see “apple core lesion” on barium enema = needs colonoscopy after
Labs: usually iron deficiency anemia

Question 12

what is carcinoembryonic antigen monitoring (CEA)? what two things can it be used for? is increased or decreased levels better?

Answer 12

its a marker for CRC (not only specific for this type of CA) that can be used to monitor success of tx or recurrence; don’t want an inc in this

Question 13

what is usual tx for CRC?

Answer 13

surgical based on staging and metastasis (radiation maybe for rectal CA)

• localized = surgical resection followed by postop chemo
• metastatic = palliative chemotherapy

Question 14

what is the recurrence rate at 5 yrs for people with localized colon CA?

Answer 14

1.5% (considered “curative”)

Question 15

what is a potential problem with using only a flex sig for CRC screening?

Answer 15

unable to assess for proximal lesions for which women are more susceptible to

Question 16

what are five risk factors for rectal cancer? what is the best way to prevent this cancer?

Answer 16

HPV infection, MSM, Age > 50 yo, anal fistula hx, smoking

**prevention is best with HPV vaccine

Question 17

CP, Dx, and Tx for rectal cancer

Answer 17

CP: rectal bleeding, change in bowel habits, abdominal pain, maybe urinary or low back sxs (rectal - tenesmus, keep pooping) and small caliber stool)
Dx: DRE/protoscopy, biopsy used for staging
Labs = CBC, CEA/19-9 for monitoring
Tx: surgical resection +/- chemo/radiation

Question 18

what are the four types of colon polyps?

Answer 18

1) . pseudopolyps “inflammatory”: due to inflammatory bowel disease NON-CANCEROUS
2) . Hyperplastic: low risk of malignancy
3) . Hamartomatous “hereditary”: Juvenile (AD inheritance, inc risk of malignancy), FAP, Peutz-Jegher’s (can turn malignant so usually resected, starts with freckles and turns into numerous polyps)
4) . Adenomatous polyps: MC NEOPLASTIC polyp

Question 19

3 types of adenomatous polyps

Answer 19

1) . Tubular: MC type, non-pedunculated, least risk of malignancy
2) . Tubulovillous: mixture of types, intermediate risk
3) . Villous: HIGHEST risk of becoming cancer, tends to be immobile

Question 20

what are anal fissures and what are the most commonly caused by?

Answer 20

painful linear cracks in the distal anal canal

etiologies: constipation, hard stools, low fiber diets

Question 21

CP, PE finding, and tx for anal fissures

Answer 21

CP: SEVERE rectal pain and painful BMs causing the patient to refrain from defecating
PE: longitudinal tear in anoderm that usually doesn’t cross dentate line
Tx: supportive measures bc most heal spontaneously (warm water sitz baths, analegics, high fiber diet), 2nd line is topical vasodilators, surgery if refractory

Question 22

how does an anal abscess form? most common bug and site?

Answer 22

often results from bacterial infection of anal ducts or glands (anal ducts at dentate line)
S. Aureus MC, E. coli, proteus
posterior rectal wall MC site

Question 23

how does an anal fistula form? common CP and Tx for it

Answer 23

its an open tract between two epithelium lined areas, usually seen with deeper abscesses
CP: may cause discharge and pain
Tx: colorectal specialist

Question 24

common CP and Tx for anal abscess?

Answer 24

CP: deep dull pain worse with sitting, coughing and defecation, anorectal swelling, febrile, edema, induration, fluctuance just like typical abscess (think pain out of proportion to exam)
*may not be able to palpate if deeper abscess
Tx: I&D first and then WASH (warm water, analgesia, sitz bath, high fiber diet)
*ABX (vanc or bactrim) only needed for sepsis, extensive cellulitis, immunocompromised- DM!

Question 25

definition of constipation. definition of chronic constipation

Answer 25

``` infrequent BM (<2/wk), straining, hard stool, incomplete evacuation chronic: > 12 weeks (more likely to have complications) ```

Question 26

management of constipation

Answer 26

Fiber: retains water and improves GI transit bulk forming laxative (Metamucil): absorbs water and increases fecal mass osmotic laxatives (miralax): causes water retention in stool (pulls water into the gut) Stimulant laxative (colace): increases ACh regulated GI motility and alters electrolyte transport If severe or chronic constipation: manual disimpaction followed by transrectal enemas

Question 27

what is fecal impaction? what is it usually due to?

Answer 27

copious amount of immovable solid bulk of stool in the rectum due to decreased motility and inability to sense/respond to stool in the rectum

Question 28

dx and management of fecal impaction

Answer 28

Dx: DRE shows a lot of stool, do KUB if DRE is not diagnostic Tx: digital disimpaction followed by warm water enema with mineral oil, can use miralax after disimpaction, patient education on reducing future constipation

Question 29

what are hemorrhoids and what are common risk factors?

Answer 29

engorgement of venous plexus originating from either the superior hemorrhoid vein (internal) prox to dentate line OR inferior hemorrhoid vein (external) distal to dentate line RF: increased venous pressure (straining), pregnancy, obesity, prolonged sitting, cirrhosis

Question 30

CP of hemorrhoids

Answer 30

internal: painless intermittent rectal bleeding (bright red) when defecating * uncomplicated internal are nontender and nonpalpable external: perianal PAIN worsened by defecation, tender skin around area, palpable mass, usually DO NOT bleed

Question 31

Dx and Tx of hemorrhoids

Answer 31

Dx: visual inspection, DRE, or FOBT, Anoscopy helps with visualization of internal Tx: overall high fiber diet, increased fluids, warm sitz bath external = preparation H (vasoconstrict), sitz bath, mild corticosteroids internal = hydrocortisone or suppositories Procedures if = failed medical therapy, debilitating pain, or strangulation (rubber band ligation MC) Hemorrhoidectomy for stage 4 internal or severe external

Question 32

what is the difference between diverticulosis and diverticulitis?

Answer 32

diverticulosis: outpouchings of colon due to herniation of the wall mucosa along natural openings of the vasa recta Diverticulitis: perforation of diverticulum leads to inflammation and focal necrosis (fecaliths get trapped)

Question 33

diverticulosis: MC location, 3 RFs, CP, Dx, and Tx

Answer 33

MC location: right colon RFs: low fiber diet, constipation, obesity CP: usually AS (incidental finding), BUT MC cause of acute lower GI bleed Dx: colonoscopy is test of choice Tx: most cases the bleeding stops on own and management is based on preventing diverticulitis *if active bleed, resuscitation of patient and endoscopic therapy to stop bleed

Question 34

diverticulitis: 4 complications, MC location, CP, Dx, and Tx

Answer 34

complications: fistula, bowel perforation, abscess, or bowl obstruction MC location: sigmoid colon CP: LLQ pain (MC) which transitions to diffuse pain with time (peritonitis), N/V, gas, bloating, maybe fever Dx: CT scan is initial test of choice ("focal thickening of colonic wall and pericolonic fat stranding", diverticula not always seen), NO barium enema or colonoscopy during acute attack Tx: uncomplicated is tx output with clear liquid diet and ABX (cipro or bactrim + flaygl) 7-10 d Pts with complicated diverticulitis are admitted *pts refractory to med therapy, reoccurances, perforation or strictures = surgery

Question 35

which patients are considered "complicated diverticulitis" and what is the tx?

Answer 35

ANY pt with one of the 4 complications | *hospital admission with IV ABX, abcesses > 3cm may need percutaneous drainage

Question 36

toxic megacolon: what is it? 5 common causes

Answer 36

NONOBSTRUCTIVE extreme colon dilation (>6cm) with signs of systemic toxicity causes: complications of IBD (UC), infectious colitis (c. Diff), ischemic colitis, recent travel or ABX use

Question 37

CP for toxic megacolon

Answer 37

CP: PROFOUND, BLOODY diarrhea, abd pain, NV distension + signs of toxicity (AMS, fever, tachy, hypotensive, dehydrated, peritonitis)

Question 38

Dx and Tx for toxic megacolon

Answer 38

Dx: Imaging + 3 (fever > 100.4, pulse > 120, WBC >10.5, or anemia) + 1 (hypotensive, dehydrated, electrolyte prob, AMS) **KUB/abd XR usually first imaging ("dilated colon >6cm), CT can be used to assess for complications Tx: SUPPORTIVE (bowel rest, NG tube bowel decompression, broad spectrum ABX- Ceft + Flaygl, IV fluids) + manage underlying cause

Question 39

what is Hirschsprung disease? MC location? MC gender? PP?

Answer 39

congenital megacolon due to absence of ganglion cells leading to FUNCTIONAL obstruction MC in distal colon and rectum MC males PP: failure of complete neural crest migration leads to absence on enteric ganglion cells

Question 40

CP of Hirschsprung dz

Answer 40

1) . neonatal intestinal obstruction: meconium ileus (failure of meconium to pass for more than 48 hrs), bilious vomiting, abd distension, NO STOOL IN VAULT 2) . older children have more chronic constipation picture

Question 41

how to dx and tx hirshsprung disease

Answer 41

``` dx: anorectal manometry for screening (shows increased pressure and failure of sphincter relaxation), contrast enema (see transition zone between normal and affected bowel), rectal biopsy is definitive, abd xr shows dilated bowel loops but decreased air in rectum tx: resection of affected bowel ```

Question 42

two types of inflammatory bowel disease and the difference between the two

Answer 42

UC: limited to colon, begins in rectum and ascends; involves only mucosa and submucosa Crohn's: can involve ANY segment of the GI system (MC starts at distal ileum); it is transmural which means it penetrates all mucosal layers

Question 43

CP of UC (hallmark clinical finding), mild-severe classifications

Answer 43

bloody diarrhea, crampy abdominal pain (LLQ) and tenesmus can have mild fever, malaise, weight loss and extraintestinal manifestations (joints, liver, eyes, urinary, skin) mild: <4 loose stools/day moderate: >4/day severe: 6/day

Question 44

how to dx UC? imaging and labs

Answer 44

labs: positive P-ANCA, increased ESR/CRP, anemia of chronic disease Flexible sigmoidoscopy is imaging of choice in acute dz (pseudopolyps, uniform erythema and ulceration) Barium enema: stovepipe or lead pipe sign (loss of haustral markings) colonoscopy: NOT DONE IN ACUTE DISEASE

Question 45

Tx of mild-mod UC, mild-mod pancolitis, severe

Answer 45

mild to moderate: 1st line is topical 5-aminosalicylic acid (ASA) mild-mod pancolitis: oral and topical 5-ASA plus steroids severe: oral glucocorticoids, high dose 5-ASA, and topical ASA surgical resection in some cases

Question 46

maintenance therapy options for UC and CD

Answer 46

6-MP and azathioprine, methotrexate, cyclosporine, tacrolimus, anti-TNF agents

Question 47

CP of Crohn's Dz (ileocolitis, jejunocolitis, colitis/perianal dz)

Answer 47

ileocolitis: crampy RLQ abdominal pain, non bloody diarrhea and weight loss jejunocolitis: malabsorption, steatorrhea, nutritional or electrolyte disorders colitis and perianal dz: diarrhea, perirectal abscess, fistula or fissure formation + extra-intestinal manifestations could occur (rheum, derm, eye, liver, heme)

Question 48

dx and labs of crohn's disease

Answer 48

upper GI series: initial test (string sign: barium flowing through narrowed/inflamed areas) endoscopy/colonoscopy: "skip areas", cobblestoning of mucosa biopsy: transmural inflammation, noncaseating granulomas, creeping fat labs: + anti-saccharomyces cerevisiae antibodies (ASCA), iron and b12 deficiency if severe

Question 49

tx for crohn's disease (limited ileocolonic, ileal and proximal colon dz, severe and refractory)

Answer 49

limited ileocolonic: 5-ASA (mesalamine) or oral GCs ileal and prox colon: GCs severe and refractory: maintenance meds (azathioprine, 6MP, methotrexate, anti TNF)

Question 50

complications for crohn's vs UC

Answer 50

crohn's: perianal dz (fistulas, strictures, abscesses, granulomas), Fe and B12 deficiency UC: primary sclerosing choleangitis, colon ca, toxic megacolon

Question 51

what is chronic mesenteric ischemia due to? compare this to acute mesenteric ischemia

Answer 51

1) . Chronic = ischemic bowel disease due to mesenteric artery atherosclerosis (decreased supply during increased demand such as eating) * most patients have atherosclerotic disease 2) . Acute = abrupt onset of small bowel hypoperfusion MC due to acute arterial occlusion

Question 52

CP of chronic vs acute mesenteric ischemia

Answer 52

``` Chronic = dull abdominal pain worse after meals (intestinal angina) which leads to anorexia and weight loss Acute = severe abdominal pain out of proportion to physical findings, may have NV/diarrhea, advanced disease can have signs of peritonitis ```

Question 53

3 different causes of acute mesenteric ischemia

Answer 53

1) . acute arterial embolism (MC) = superior mesenteric artery MC, embolism from A-fib MC, can also be thrombotic 2) . nonocclusive arterial ischemia = hypoperfusion due to shock, vasopressors, cocaine 3) . venous thrombosis = obstruction of intestinal venous outflow

Question 54

how to dx acute vs chronic mesenteric ischemia

Answer 54

``` acute = CT angiography often initial test, conventional arteriography definitive diagnosis chronic = angiography definitive diagnostic test ```

Question 55

what are two elevated labs in acute mesenteric ischemia?

Answer 55

leukocytosis (elevated WBC) and lactic acid

Question 56

tx of acute and chronic mesenteric ischemia

Answer 56

``` acute = depends on cause but MC tx is surgical revascularization (embolectomy, angioplasty with stenting, bypass), surgical resection of bowel if non salvageble, anticoagulation in patients with a-fib chronic = revascularization is definitive ```

Question 57

what is irritable bowel syndrome and PP theories behind it?

Answer 57

chronic, functional idiopathic pain disorder with NO organic cause, often late teens/early 20s - abnormal motility = chemical imbalance in the intestine causing motility and spasm problems - visceral hypersensitivity = lowered pain threshold to intestinal distention - psychosocial interactions and altered CNS processing

Question 58

common CP of IBS and three main alarm sxs

Answer 58

abdominal pain with bouts of constipation and diarrhea, pain often relieved with defecation, may have bloating, nausea, interefere with ADLs *alarm sxs = evidence of GI bleed, anorexia/weight loss, persistent diarrhea causing dehydration

Question 59

how do you diagnose IBS?

Answer 59

DIAGNOSIS OF EXCLUSION Rome criteria can help: recurrent abd pain at least 1 d/wk in the last 3 months with at least 2: a). related to defecation b). onset associated with change in stool frequency c). onset associated with change in stool form (appearance)

Question 60

how to manage IBS?

Answer 60

lifestyle and dietary changes 1st line (low fat, high fiber, unprocessed food diet), avoid beverages containing sorbitol or fructose and gas-producing foods, sleep, smoking cessation, exercise - constipation sxs = prokinetics (fiber, psyllium, miralax after fiber), lubiprostone and linaclotide if prokinetics don't work - diarrhea sxs = loperamide, rifaximin, eluxadoline, anticholinergics (dicyclomine, hyoscyamine)

Question 61

ischemic colitis: what is it, what is it normally due to, and where does it normally occur?

Answer 61

decreased colonic perfusion which leads to inflammation * MC due to transient systemic hypotension or atherosclerosis involving mesenteric arteries * MC at splenic flexure and rectosigmoid junction

Question 62

CP for ischemic colitis

Answer 62

LLQ, crampy abd pain with tenderness, bloody diarrhea or hematochezia (pain not as severe as acute mesenteric ischemia)

Question 63

Dx and Tx for ischemic colitis

Answer 63

``` Dx = CT of abdomen often first imaging ("thumbprinting" seen, segmental wall thickening), colonoscopy afterwards if no bowel perf pr peritonitis Tx = mostly supportive care (restore perfusion, bowel rest, IV fluids), ABX in some pts ```

Question 64

sxs for colon cancer ascending vs decending colon

Answer 64

``` ascending/right = iron deficiency anemia (fatigue/pallor) plus anorexia, malaise, weight loss descending/left = change in bowel habits (constipation) and more likely obstruction signs (abd pain, distention, nausea) ```

Question 65

what is the most common cause of large bowel obstruction?

Answer 65

adenocarcinoma