GI E1- Disorders of Small Intestine

Which region of the small intestine is the shortest & retroperitoneal?

duodenum

Which region of the small intestine begins at the suspensory muscle of the duodenum (ligament of treitz)?

jejunum

Which region of the small intestine is the longest, paler, narrower, thinner, less vascular, fewer circular folds, and has more lymphatic nodules?

ileum

What are finger like mucosal projections that increase surface area for digestion and absorption?

villi

What are visible, mucosal/submucosal ridges that increase SA in the jejunum for absorption and cause spiraling of chem for efficient digestion?

circular folds

What are microscopic projections of apical membrane of absorptive cells (brush border)?

microvilli

Where does 90% of nutrient absorption occur?

small intestine

Which water soluble vitamin is NOT absorbed via simple diffusion, instead absorbed in the ileum by active transport in combo w/ intrinsic factor (IF)?

B12

A disruption of digestion and/or nutrient absorption is ______

malabsorption

What are the 3 phases of normal digestion?

intraluminal, mucosal, post-absorptive

What would a resection of the terminal ileum (TI) result in?

malabsorption of bile salts & vit B12

What are other names for celiac disease?

gluten enteropathy, celiac sprue, sprue

What condition?

• autoimmune disorder caused by exposure to gluten

  • IgA abs against gliadin and tissue transglutaminase → diffuse damage to proximal SI mucosa → malabsorption

• villous atrophy, flattening of SI villi; crypt elongation; lymphoid proliferation in laminated propria

• can present any age; grossly underdiagnosed

celiac disease

What is a protein component of grains such as wheat, rye, and barley?

gluten

What condition?

• malabsorption signs → loss of muscle mass or SC fat, pallor

• sx: dermatitis herpetiformis, easy bruising, bone pain, non-specific GI sx, etc

• dx: serology & bx, 24 hr stool (fecal fat > 7g), IgA tTG (most accurate), antigliadin abs, improvement after gluten free diet

Celiac disease

What should be considered in any patient presenting with unexplained deficiencies of iron, folate, vit B12 or undiagnosed non specific GI complaints?

Celiac Disease

The intensely pruritic papulovesicular rash over extensor surfaces, trunk, scalp, and neck known as dermatitis herpetiformis is a characteristic rash of what condition?

Celiac disease

What is the treatment for celiac disease?

dietary consult & gluten free diet- avoid wheat, rye, barley

what conditions can celiac disease be associated with?

insulin dependent DM, autoimmune thyroid, IgA deficiency

Since the small intestine normally contains a sparse amount of bacteria, what can happen if there is a bacterial overgrowth (SIBO)?

direct damage to bowel mucosa → malabsorption

What condition?

• diarrhea, flatulence, bloating, abd distension, fatigue, steatorrhea (RARE)

• if severe malabsorption → wt loss

• long standing cases (elderly) → B12 deficiency that mimics pernicious anemia

• dx: breath test, stool collection, BA w/ SBFT, CT enterography

• empiric abx trial for dx & tx

SIBO

What is the treatment for SIBO?

abx (diagnostic & therapeutic) → cipro, augmentin, norfloxacin, bactrim & metro combo, or rifaximin (fewer SE)

What broad spectrum antibiotic is used to treat E. coli associated with traveler’s diarrhea, IBS-D, SIBO, and has fewer SE?

Rifaximin (Xifaxan)

What is a brush border enzyme that hydrolyzes lactose into glucose & galactose?

lactase

What happens to malabsorbed lactose?

fermented by intestinal bacteria → produce gas & organic acids → inc stool osmotic load → fluid loss

In lactase deficiency, how soon after ingestion of lactose might bloating, abdominal cramps, flatulence, diarrhea, and nausea appear?

30 min - 2 hr

How is a lactase deficiency diagnosed?

empiric trial of lactose elimination x 2 weeks (diagnostic & therapeutic); slowly reintroduce & assess for resolution of sx

hydrogen breath test

What is the treatment for a lactase deficiency?

restriction of dietary lactose, lactase enzyme supplementation (Lactaid), calcium supplementation

What meds might be hidden sources of lactose?

omeprazole, citalopram, senna, prednisolone

The dumping of stomach contents into the proximal SI that might occur after gastric surgery is _____

dumping syndrome

What condition?

• undiluted chyme dumped into SI → fluid shifts from blood to SI to dilute contents

• food rapidly digested/absorbed → hyperglycemia & inc insulin secretion → hypoglycemia 2-3 hrs later

• hypovolemia occurs, SI distends

• gastric emptying of liquids more rapid → dilution of enzymes & bile acid in duodenum → mismatch of chyme delivery & absorptive capacity

Dumping syndrome

What is the treatment for dumping syndrome?

smaller frequent meals (6-8/day), dec fatty food intake, restrict carb intake

What is neurogenic failure or loss of peristalsis in the intestine without mechanical obstruction?

acute paralytic ileus

What medications can cause acute paralytic ileus?

opioids and anticholinergics

The following sx are seen with what condition?

• mild-mod diffuse, continuous abd discomfort → steady & severe pain w/ strangulation

• obstipation, N, V, distension

• hyperactive high pitching “tinkling” bowel sounds; peristaltic “rushes”

• xray: diffuse gas filled loops of small & large bowel +/- air fluid levels (no stack of coins or string of pearls)

acute paralytic ileus

paralytic ileus might be difficult to distinguish from what condition?

partial small bowel obstruction

What is the treatment for acute paralytic ileus?

correct underlying, IV fluids, NPO, NG tube( low intermittent suction), surgery

Is the following SBO functional or mechanical?

• ileus → bowel not moving / contracting

functional

Is the following SBO functional or mechanical?

• something physically blocking the contents from passing through

mechanical

what is the MCC of mechanical SBOs?

adhesions from prior surgeries

What condition?

• abd pain, N, V, bloating, obstipation

• high pitched tinkling & hypoactive bowel sounds, hyper resonance on percussion, listened abd, tachy, signs of dehydration

• dx: plain film & CT → dilated loops of small bowel w/ air fluid levels, free air under diaphragm (indicates perforation)

SBO

what is the treatment for SBO?

emergent surgical consult, IV fluids, NPO, NG tube w/ suction for decompression if persistent N/V/abd distension

A sudden twisting of the bowel on itself causing obstruction and ischemic that can lead to gangrene, necrosis, and perforation is called ______

volvulus

what are the 2 most common sites for volvulus?

cecum and sigmoid colon

what is the treatment for volvulus?

endoscopic reduction & surgery

what causes volvulus?

idiopathic, anomaly of rotation, ingested FB, adhesions

What is telescoping or invagination of a portion of the bowel into a distal portion that can cause constriction, edema, and hemorrhages?

intussusception

What condition?

• M > F, MC in infants

• unknown cause, linked to some rotavirus vaccines

• kids: severe colicky pain, currant jelly stools (blood & mucus), sausage like abd mass

  • BA enema diagnostic and therapeutic

• adults: crampy abd pain

  • abd plain films, CT, & surgery

Intussusception

what is the MCC of bowel obstruction in children 6mo-36mo?

intussusception

what condition?

• extreme dilation and immobility of colon; emergency

• fever, abd cramps/pain/distension, rigid abd, systemic sx

• MC sx is severe bloody diarrhea

• emergency

toxic megacolon

what is toxic megacolon associated with?

ulcerative colitis (esp pancolitis), crohn’s, amoebic colitis, pseudomembranous colitis, infx (shigella, c diff)

what is the tx for toxic megacolon?

emergent→ colon decompression, IV fluids, surgical resection

what condition?

• congenital absence of autonomic smooth muscle ganglia

  • aganglionic bowel segment contracts but needed relaxation does not occur → stasis of stool

• can affect entire colon

• M > F

• coexist w/ other anomalies- down syndrome

• commonly dx in kids and infants, underdx in adults

Hirschsprung Disease

how is Hirschsprung Disease dx?

abd xray, CT, colonic transit studies, sitz mark studies

what is the most common mucosal tumor?

adenocarcinoma

what tumor?

• sx- anemia, bleeding, obstruction, jaundice

• risk: FAP

• most found near ampulla of vater

• tx- segmental resection

adenocarcinoma

what tumor?

• primary or secondary to disseminated dz

• MC type: NHL B cell

• MC site: distal small intestine

• sx: abd pain, distention, wt loss, N, V< anemia, occult blood, fevers unusual

lymphoma

What are treatment options for lymphoma?

surgical resection, surgical debulking, chemo +/- radiation

what is the most common neuroendocrine tumor that’s most frequently in small intestine?

carcinoid tumor

what size carcinoid tumor has a high probability of metastasis?

> 2 cm

what syndrome?

• results form hormones secreted by tumors

• sx: D, abd pain, wheezing, flushing

• may develop into crisis during surgery; somatostatin must be administered pre-op

carcinoid syndrome

how are carcinoid tumors dx?

imaging, 24 hr urine, blood test (CgA)

what is tx for carcinoid tumor

local excision if confined to SI

palliative tx for late dz

what is the most common abdominal surgical emergency?

appendicitis

What condition?

• obstruction of appendix by fecalith, inflammation, etc

• peak incidence: 10-19 yrs

• generalized periumbilical pain → localized RLQ pain

• mcburneys point rebound tenderness, + psoas & obturator signs

• N, V, anorexia, fever, constipiation or diarrhea

Appendicitis

What is the workup for appendicitis?

abd CT > u/s

labs: CBC (mild leukocytosis), U/A (hematuria), CMP normal

What happens if appendicitis left untreated?

gangrene and perforation w/in 36 hrs

What is the treatment for appendicitis?

surgical appendectomy - laparoscopic (MC) or laparotomy

IV abx