GI E1- Disorders of the Large Intestine

What are the functions of the large intestine?

compact intestinal contents & form feces, store feces prior to defecation, absorb water, elytes, & vitamins produced by bacteria

The large intestine is _______ than the small intestine

shorter & wider

What is the blind pouch inferior to the ileocecal sphincter?

cecum

where is the appendix attached?

medial posterior portion of cecum

What is anterior to the sacrum and coccyx and expandable to accommodate feces?

rectum

What is the terminal portion of the rectum?

anal canal

What refers to the presence of diverticula in an asymptomatic individual?

diverticulosis

What refers to the presence of diverticula associated with symptoms?

diverticulitis

what is the most common structural abnormality of the colon and the MCC of a lower GI bleed (95% in sigmoid colon)?

Diverticulosis

What is diverticulosis?

acquired saccular outpouchings of the colon from mucosa/submucosa herniating through weak areas of muscular propia (usually near where vasa recta penetrates)

What studies are done to diagnose diverticulosis?

plain abd films, contrast (barium) enema, abd CT, flex sig or colonoscopy

often discovered incidentally

What is diverticulitis?

inflammation of one or more diverticula; due to fecalith or infx from high intraluminal pressure & rupture

what develops in 5-10% of pts w/ diverticulosis?

diverticular hemorrhage (typically massive but self limiting)

Diverticular bleed/hemorrhage is the MCC of ______

massive lower GI bleed

What condition presents with the following symptoms?

• acute LLQ persistent abd pain/tenderness (MC)

• loose bowel movements or constipation

• N, V, cramping, leukocytosis, +/- fever

• possible urinary sx from irritation of bladder from sigmoid colon

diverticulitis

What is relatively contraindicated in diverticulitis due to risk of perforation?

colonoscopy

Diverticulitis patients should undergo a colonoscopy after they are healed due to ________

increased risk of colon cancer

How would diverticulitis appear on an abdominal CT?

stranding, fatty infiltration, streaking, “dirty fat”, phlegmon, “mural thickening of the colon w/ pericolic fat stranding”

What is the treatment for diverticulitis?

abx: cipro & falgyl or augmentin

clear liquid diet (bowel rest)

surgical resection

what are the 3 main branches of the abdominal aorta?

celiac artery, superior mesenteric artery (SMA), inferior mesenteric artery (IMA)

What condition?

• inadequate delivery of O2 & nutrients due to occlusion, vasospasm, or hypoperfusion

• medical & surgical emergency

• injury ranges from reversible to transmural bowel necrosis

• reperfusion can aggravate injury

intestinal ischemia

Why must intestinal ischemia be corrected quickly?

persistent vasoconstriction will cause progression of injury despite it’s initial relief measures

what condition?

• medical & surgical emergency in small bowel

• risk: afib, recent MI, valvular heart dz, recent cardiac or vascular cath

• sudden onset abd pain out of proportion, N/V/D, bloody stools, guarding, rebound tenderness

acute mesenteric ischemia

what is the most prevalent GI complication from CV surgery?

ischemic colitis

What is the gold standard for acute mesenteric ischemia?

mesenteric angiography

what is the workup for acute mesenteric ischemia?

mesenteric angiography, xray, CT, colonoscopy if ischemic colitis suspected, laporotomy in emergent situations

What is the treatment for acute mesenteric ischemia?

aggressive fluid resuscitation

anticoagulants & broad spectrum abx

surgery - embolectomy, laparotomy, resection

vasodilator to relieve vasoconstriction asap (papvarine)

What should you think of with an elderly patient presenting with an acute abdomen OR if abdominal pain is disproportionate to PE findings?

mesenteric ischemia

What condition?

• chronic (> 3 mos) functional disorder

• late teens - 20s; F > M

• chronic abd pain or discomfort associated with altered bowel habits; sx NOT explained by structural or biochemical abnormalities (idiopathic)

• episodic or constant

• discomfort frequently relieved by defecation

irritable bowel syndrome (IBS)

What are the 4 categories of IBS?

IBS-D: diarrhea; > 3 daily episodes of loose water stool; urgency or fecal incontinence

IBS-C: constipation; < 3 weekly episodes of hard or lumpy stools; straining

IBS-M: mixed diarrhea & constipation

IBS-A: alternating diarrhea & constipation

what condition?

• intermittent, crampy lower abd pain that usually does NOT occur at night or wake pt up

• abnormal stool passage: straining, urgency, feeling of incomplete evacuation, mucous

• bloating or distension

• > 3 mos duration (continuous or intermittent) w/ atleast 1 episode per wk

• +/-: dyspepsia, fatigue, depression, anxiety

• normal PE besides mild tenderness

IBS

What are the alarm symptoms that suggest a diagnosis other than IBS?

• > 50 y/o

• progressive abd pain

• severe constipation or diarrhea; nocturnal diarrhea

• hematochezia

• unintentional weight loss

• fever

• fhx cancer, IBD, celiac dz

What is the Rome IV criteria that allows a diagnosis of IBS?

recurrent abd pain atleast once a week for the last 3 mos assoc w/ 2 or more of the following

• related to defecation

• change in stool frequency

• change in stool form or appearance

What is the manning criteria for the diagnosis of IBS?

pain relieved w/ defecation, more frequent stools at onset of pain, looser stools at onset of pain, visible abd distension, passage of mucus, sensation of incomplete evacuation

What does IBS treatment focus on?

coping with symptoms (no cure)

What is the non-pharm management for IBS?

diet therapy, r/o lactose intolerance, low - fodmap diet, CBT, psych eval

What are pharmacological treatment options for IBS?

anticholinergic (antispasmodic) agents- levin, bentyl

probiotics- bifidobacterium infantis

xifaxan (rifaximin)

antidiarrheal agents- loperamide, cholestyramine

constipation- osmotic laxatives, lubiprostone

psychotropic agents- TCAs, SSRIs

Which osmotic laxatives should to be used for IBS due to increased flatus and distention?

lactulose or sorbitol

Does abx-associated diarrhea require a lab eval or rx?

no (resolves spontaneously after discontinuation)

What drugs are common causes of abx associated diarrhea?

ampicillin, clindamycin, 3rd gen cephalosporins, FQs

what is a spore forming, toxin producing, gram positive bacteria that is one of the most common health care associated infections?

c diff

what are risk factors for abx associated colitis?

hospilitzation, nursing home, abx use, advanced age, gastric acid suppression

what are sx of abx associated colitis?

profuse watery foul smelling diarrhea → can progress to fulminant colitis and lead to toxic megacolon

what is the tx for abx associated colitis?

PO vanco or fidaxomicin

alt: falgyl

how can abx associated diarrhea be prevented?

probiotics: lactobacillus, bifidobacterium, streptococcus thermophiles, saccharomyces

How long do probiotics last in the GI tract?

no longer than 2 weeks (regular consumption is necessary)

What is the 3rd MC diagnosed cancer in males and 2nd MC in females worldwide?

colorectal cancer

how long does the transition from adenoma to cancer take?

~10 years

Which can progress to cancer, hyperplastic polyps or flat polyps?

flat polyps

what are risk factors for CRC?

• genetics & environment

• IBD

• abd radiation

• > 50

• smoking / alcohol

• African American; M > F

• FAP, Lynch syndrome, obesity, red meat, etc

what is the most common symptom of CRC?

change in bowel habits + blood in stool

Change in bowel habits is more likely to be seen in which tumor location of CRC?

left sided CRC

Rectal cancer can lead to ____

blood in stool and pencil like stools

What is more likely associated with right sided colon caner?

IDA

what is the best test for colon cancer?

colonoscopy

How is CRC staged?

TNM

When should colonoscopy screening for colon cancer begin?

average risk: start at 45

Fhx: start at 40 or 10 yrs prior to relative’s age at dx

repeat every 10 years

What is the treatment for CRC?

localized → surgical resection

poor prognosis with metastasized

What are the MC metastatic sites of CRC?

liver, lung, lymph nodes, peritoneum