Colorectal Disorders Flashcards
Colon CA is the ____ most common cause of CA death in the US. what is the 5 yr survival rate. MC site of metastasis?
3rd; 64%
metastasis: LIVER (usually goes to regional lymph nodes prior to liver)
what’s the biggest risk factor for colon cancer? other risk factors?
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)
what % of colon rectal cancer occurs after age 50?
90%
having a first degree relative with colon CA _________ the risk of you having it
doubles
what are two genetic conditions that put people at risk for colon CA?
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
what does most CRC come from?
adenomatous polyps that progress into adenocarcinoma (larger polyps more likely to contain neoplastic cells)
what type of polyps have a higher risk for invasive carcinoma?
villous polyps
what are screening recommendations for CRC for average risk patients? what tool and how often?
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
for people with a prior adenoma or a previous resection of cancer, what screening test should be done?
colonoscopy
what are the screening guidelines for a person with a 1st degree relative with colon CA?
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
how do you dx CRC? common lab finding?
TEST OF CHOICE: colonoscopy w biopsy
*see “apple core lesion” on barium enema = needs colonoscopy after
Labs: usually iron deficiency anemia
what is carcinoembryonic antigen monitoring (CEA)? what two things can it be used for? is increased or decreased levels better?
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
what is usual tx for CRC?
surgical based on staging and metastasis (radiation maybe for rectal CA)
- localized = surgical resection followed by postop chemo
- metastatic = palliative chemotherapy
what is the recurrence rate at 5 yrs for people with localized colon CA?
1.5% (considered “curative”)
what is a potential problem with using only a flex sig for CRC screening?
unable to assess for proximal lesions for which women are more susceptible to
what are five risk factors for rectal cancer? what is the best way to prevent this cancer?
HPV infection, MSM, Age > 50 yo, anal fistula hx, smoking
**prevention is best with HPV vaccine
CP, Dx, and Tx for rectal cancer
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
what are the four types of colon polyps?
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
3 types of adenomatous polyps
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
what are anal fissures and what are the most commonly caused by?
painful linear cracks in the distal anal canal
etiologies: constipation, hard stools, low fiber diets
CP, PE finding, and tx for anal fissures
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
how does an anal abscess form? most common bug and site?
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
how does an anal fistula form? common CP and Tx for it
its an open tract between two epithelium lined areas, usually seen with deeper abscesses
CP: may cause discharge and pain
Tx: colorectal specialist
common CP and Tx for anal abscess?
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!
definition of constipation. definition of chronic constipation
infrequent BM (<2/wk), straining, hard stool, incomplete evacuation chronic: > 12 weeks (more likely to have complications)
management of constipation
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
