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GI Exam 1 > SI Pathology > Flashcards

SI Pathology Flashcards

1
Q

3 Congenital Problems

A
  • Omphalocoele - anterior ab wall does not form correctly so intestine herniates into ventral sac
  • Gastroschisis - no ab wall forms at all so gut protrude UNCOVERED
  • Meckel’s Diverticulum - vitelline duct does not involute –> pouch often w/ ectopic tissue (gastric or pancreatic)
    • Asymptomatic or ab pain/bleeding (obstruction)
    • Rule of twos - 2% population, 2 cm long, w/in 2 feet of terminal ileum
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2
Q

Infectious Enterocolitis (6 common causes)

A

VOLUMINUS DIARRHEA

  • Yersinia - (gram neg coccobacillus) usually distal, terminal ileum/cecum/appendix (RLQ pain)
  • Salmonella - (gram neg) punched out ulcers; can also invade to Peyer’s Patches –> hypertrophic patches that protrude into lumen
  • Campylobacter jejuni - crypt abscesses/ulcerations
  • Giardia - may see trophozoites right in lumen (tear-drop shape w/ 2 nuclei - like eyes); ingest cysts –> excyst in small intestine –> release trophozoites –> proliferate/irritate mucosa/disrupt absorption
    • Foul-smelling diarrhea
    • Short/blunted villi
  • Cryptosporidium parvum - attach to epithelial surface (see small blue dots on epithelial surface); usually self-limiting unless immune-comp –> diarrhea
  • Amoeba - can see amoeba w/ ingested RBCs right in it
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3
Q

Necrotizing Enterocolitis

A

(newborns at time of first oral intake)

  • can cause bloody stools, gangrenous necrosis of intestine, shock, bowel perforation
  • may need to remove necrotic bowel –> short bowel syndrome and/or strictures
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4
Q

3 Non-Infectious Causes of Enterocolitis

A
  • HIV enteropathy b/c opportunistic infections or intestinal injury fromHIV itself
  • Drug-Induced (chemo, NSAIDs)
  • Radiation - pink/amorphous lamina propria (becoming fibrous), atypical pattern of epithelial cells, thick-walled blood vessels
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5
Q

Celiac

A
  • Chronic immune reaction to gluten normally in small bowel
  • Gluten = poorly digested, insoluble proteins of wheat endosperm (also in rye and barley)
  • Pathogenesis - gluten into lamina propria b/c leaky then picked up by APC –> helper T cells act –> plasma cells –> antibodies produced (anti-gliadin, anti-endomysial, tissue transglutaminase) AND attract lymphocytes –> cytokine –> chronic inflammation in lamina propria (low-grade)
  • Tissue transglutaminase leads to deamination of gliadin -> further inflammation
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6
Q

Celiac Dx and Presentation and Genetics

A
  • Present w/ ab pain, diarrhea if advanced, wt loss, IBS-like (vague discomfort, bloating), IRON DEF
  • Genetics - HLA-DQ2 (90-95%) or DQ8 (5%); CELIAC1 gene on short arm of chromosome 6
  • Dx - serology (above antibodies) then confirm w/ scope biopsy
    • Usually use anti-tTG IgA first (98% sensitive) but if negative and still suspicious look at total IgA b/c they may just have overall IgA deficiency
    • Can also look at anti-tTG IgG
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7
Q

Celiac on Histo and Grossly

A
  • Histo
    • Blunted villi (get wider and shorter until totally gone)
    • Inc # lymphocytes (in lamina propria and intraepithelial)
    • Crypt lengthening/hyperplasia - crypts get bigger to try to replace blunted villi (trying to replace dying mucosal cells faster)
  • Grossly - muscular atrophy in duodenum and scalloped duodenal folds (lump, irregular surface)
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8
Q

Celiac Tx and Complications if Untreated

A
  • Tx - Reversible w/ GF diet (lifelong) but problems w/ compliance
  • If untreated… malabsorption –> nutritional def; inc cancer risk and inc mortality; derm manifestations of blistering on extensor surfaces and speckeld IgA deposits (dermatitis herpetiformis)
    • Iron absorption affected 1st - anemia
    • Ca absorption - osteoporosis/osteopenia
    • Water/electrolytes affected later - diarrhea
    • If goes awhile then protein and carbs - bloating, wt loss, diarrhea
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9
Q

Other Causes of Malabsorption (2)

A
  • Tropical Sprue
    • Looks identical to celiac on histo but in those who live or visit tropical locations; responds to abx but unknown pathophysiology (travel hx)
  • Whipple’s Disease
    • Most often in immune-sup
    • Foamy cells in lamina propria, mucosal macrophages
    • PAS stain of organism (Tropheryma whipplei)
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10
Q

Vascular Pathology (2)

A
  • Ischemia - can lead to clearly demarcated areas of necrosis (hemorrhagic, coagulative necrosis); ulcers; inflammation
  • Angiodysplasia - focal vascular malformation; submucousal vessels bleed into lumen (rare but often seen in R colon of older adults)
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11
Q

SI Cancers (3)

A
  • Carcinoid - well differentiated endocrine cell
    • Stain w/ neuroendocrine markers (chromogranin +)
    • Nests of monotonous, small blue cells w/ little cytoplasm
    • Pucker on serosa layer (projects more into lumen)
  • Adenoma - longer, dark nuclei w/ mitotic figures (dysplasia) then invades into submucosa (carcinoma)
    • Most common at ampulla of Vater
  • Lymphomas
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12
Q

Irritable Bowel Presentation and Eval

A
  • Presentation - ab pain and change in stool habits
  • Clinical Dx of Exclusion
    • Alarm Symptoms - rectal bleeding, anemia, wt loss, anorexia, fever, major change, onset after 50 yo (inc cancer risk), pain awakens them at night (seek other disorder)
  • Usually - relieved by defecation, more frequent stools, looser stools, visible ab distention, sense of incomplete evacuation (need 3+)

++ bowel movements and relaxation
– eating, high fiber, stress

  • Who? women> men (present more), in young, depression/anxiety, hx sexual abuse, hx diarrheal illness (C diff, travel)
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13
Q

2 Major IBS Classifications

A

1-Diarrhea Type
- Frequent small stools, not nocturnal or steatorrhea, esp post-prandial and AM

**check stool for Giardia, C diff and electrolytes, check celiac and thyroid labs, do NOT do colonoscopy

2- Constipation Type
- Sensation of incomplete emptying or pellet stools or excessive straining

**check for hypothyroidism and hypercalcemia

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14
Q

IBS Pathophysiology (7 components)

A
  • Visceral Hypersensitivity - more pain to experimental gut stimulation
  • Inflammation - explains why it often starts after a diarrheal illness; inc TNF-alpha and IL-6; inc lymphocytes in myenteric plexus
  • Abnormal Motility - higher at baseline and inc more w/ eating (hypermotility)
  • Psycho Dysfunction - depression, anxiety and phobias often present; may also inc inflammatory markers; inc corticotropin releasing factor (stress mediator)
  • Non-celiac Gluten Sensitivity - no serology but symptoms worse w/ gluten
  • Also FODMAP sensitivity
  • Bacterial Overgrowth - can evaluate w/ breath test (more hydrogen from inc bacterial breakdown)
    • Tx w/ abx (metro, cipro, rifaximin, neomycin)
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15
Q

IBS Tx

A

Trial and Error (+ good relations ad diet)

For diarrhea… smooth muscle relaxants/ anti-spasmodics (dicyclomine, hyoscyamine, methscopalamine, atropine),
& TCAs (dec motility as well as psych improvement and inc sleep if taken before bed)

For constipation … SSRIS, fiber, laxatives (Mg, polyethylene glycol)

Abx if bacterial overgrowth

CBT, behavioral therapy, hypnotherapy (relaxation, symptom management) - works!

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16
Q

Chron’s v UC in Presentation

A

Chron’s -anywhere in GI tract (most common = distal ileum/proximal colon); rectum usually spared

  • transmural but patchy (skip lesions)
  • cobblestone mucosa w/ discrete ulcers
  • Histo = epithelioid granulomas, pyloric gland metaplasia (look like stomach glands instead of goblets of intestine)
  • Gross - thick wall and fat wrapping
  • More chronic presentation (longer time to dx)
  • Smoking makes them worse

UC- - starts at anal verge

  • cont and circumferential
  • abrupt normalization (stops suddenly)
  • superficial but diffuse erythema/friable (easily bleeds w/ scope)
  • SI NOT INVOLVED (can have mouth ulcers)
  • Histo = crypt architecture distortion/ crypt abscesses w/ neutrophils
  • Presentation is NOT subtle - bloody diarrhea, tenesmus (quicker time to dx)
  • Smoking is protective
17
Q

Chron’s v UC Complications

A

Chron’s - fibrosis –> strictures (narrow/blockage) and fistulas (hole b/n loops pr to skin) and abscesses

UC- cancer (high risk colon cancer), toxic megacolon (fever and dilation), growth fail in kids

18
Q

Chron’s v. UC Tx

A

Chron’s - no aminosalicylates; go right to immunomodulators and biologics
+ Corticosteroids for flares
Surgery for complications only (not cure)

UC - aminosalicylates (5-ASA)
+ Corticosteroids for flares
Surgery is CURATIVE

19
Q

Inflammatory Bowel Disease Extra-Intestinal Manifestations (5)

A
  • Arthritis (mono, large joints that flares w/ IBD and RF neg), central ankylosing spondylitis, (may occur b/f IBD)
  • Uveitis (does not correlate w/ flare); episcleritis
  • Skin - pyoderma gangrenosum (blistering skin lesion), erythema nodosum (red, raised, on extensors) and mouth ulcers
  • Hypercoaguable
  • Sclerosing Cholangitis - almost everyone w/ sclerosing cholangitis have IBD; does not correlate w/ IBD flares
20
Q

Inflammatory Bowel Disease Pathogenesis (3 components)

A

1 - Genetic Predisposition (Chron’s&raquo_space; UC)

2- Environmental Triggers - infection, diet, stress, smoking (Chron’s), NSAIDs, abx)

3- Immune Dysregulation

- Failure of immune system to down-regulate following infection --> chronic inflammation
- Inc Th1 and Dec Th2 (regulatory T cells) --> more inflammatory/less anti-inflammatory cytokines
    - Inc TNF-alpha, IL-12 and interferon-gamma (leads to certain meds)
21
Q

Inflammatory Bowel Disease Drug Classes

A

Topical corticosteroids - only for temp symptoms relief b/c side effects (acne, insomnia, wt gain, emotional, etc)

Aminosalicylates (5 -aminosalicylic acid or 5-ASA)

Abx - esp Metro, Cipro, Rifaximin (Chron’s only)

Moderate - immunomodulators

- Thiopurine metabolites 
- Methotrexate
- Cyclosporine

Bio Agents

- Anti-TNFs  
- Anti-Adhesion
22
Q

5-ASA

A
  • Mainly UC
  • block prod of AA
  • Side Effects = hypersensitivity (fever, rash, pancreatitis, nephritis, altered spermatogenesis)
23
Q

Thiopurine Metabolites

A

(azathioprine or 6-mercaptopurine)

  • inhibit ribonucleotide synthesis and thus dec lymphocyte proliferation (anti-inflammatory)
  • Side Effects = may induce pancreatitis in first few weeks but resolves if stop drug
24
Q

Methotrexate

A
  • inhibits dihydrofolate reductase and purine synthesis –> dec production of IL-1, IL-2, leukotriene B4, T cell apoptosis
  • NOT SAFE FOR PREG + hepatotoxicity, interstitial pneumonia, myelosuppression
25
Q

Cyclosporine

A
  • inhibits proliferation and act of T helper cells by interfering w/ IL-2 prod
  • FAST (onset w/in days)
  • Used as last resort b/c very toxic
26
Q

Anti-TNFs (3)

A
  • Infliximab ( monoclonal antibody to TNF-alpha)
  • adalimumab (IgG1 antibody for TNF-alpha)
  • certolizumab (anti-TNF Fab monoclonal antibody fragment)
  • Side Effects - reactivate Tb or rare lymphoma or rare infusion reactions
27
Q

Anti-Adhesion Meds (2)

A
  • Natalizumab (IgG antibody against alpha4 integrin to dec trafficking)
  • vedolizumab (antibody against alpha4beta7 integrin to dec gut-specific trafficking)
  • Side Effects = reactivation of JC virus (fatal in brain) if use natalizumab but not vedolizumab

GI Exam 1 (18 decks)

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