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GI II Exam 3 > Intestinal Pathology 2 > Flashcards

Intestinal Pathology 2 Flashcards

1
Q

Malabsorption

A

Hallmark of malabsorption is * steatorrhea

Defective absorption of fats, fat- and water-soluble vitamins, proteins, carbohydrates, electrolytes and minerals, and loss of water.

Malabsorptive disorders most commonly encountered in the * United States are pancreatic insufficiency, celiac disease and Crohn disease

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2
Q

Malabsorption results from disturbance in at least one of the phases of nutrient absorption

A

Intraluminal digestion
- Pancreatic insufficiency
(Chronic pancreatitis, Cystic fibrosis)

Terminal digestion and/or transepithelial transport

  • Celiac disease
  • Disaccharidase deficency
  • Crohns disease
  • Abetalipoproteinemia

Transport into lymphatics

  • Whipple disease
  • Intestinal lymphangiectasia
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3
Q

Whipple Disease

A

Blocks Nutrient Transport into Lymphatics

Chronic, relapsing multisystem illness involving the GI tract (diarrhea, steatorrhea, malabsorption) and distant sites (arthritis, lymphadenopathy)

Disease characterized by * weight loss, diarrhea, and polyarthritis;* occur together at presentation in 75% of cases

Infection of the small intestinal mucosa by the gram positive bacillus Tropheryma whipplei

Usually white males ages 30-49 years (10:1 male predominance)

Treat successfully with antibiotics

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4
Q

histology of whipple disease

A

foamy macrophages

Distended foamy macrophages in lamina propria contain Tropheryma whippeli, a gram positive intracellular actinomycete

PAS-D+ organisms

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5
Q

Celiac Disease

A

Celiac disease is an inflammatory disease of small bowel in * genetically susceptible individuals

Genetic predisposition:* strong association with certain HLA types (HLA-DQ2 and DQ8)

Inciting agent exposure: * gluten (actually, the alcohol-soluble * gliadin) from wheat, barley, oat, rye

T-cell (inflammatory) response:
Altered peptides are presented to CD4+ T cells in mucosa, leading to an increase in CD8+ intraepithelial lymphocytes that produce proinflammatory cytokines

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6
Q

Celiac Disease presentation

A

Adults present usually between the ages of 30-60

Children present usually between the ages of 6 and 24 months.

Can be silent (positive serology and villous atrophy without symptoms)

Can be latent (positive serology and no villous atrophy, may have symptoms)

Systemic effects of malabsorption

10-15% of patients will have dermatitis herpetiformis

Vague abdominal discomfort and especially abdominal bloating can lead to a mistaken diagnosis of irritable bowel syndrome

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7
Q

celiac disease risk associations

A

Increased risk for enteropathy-associated T-cell lymphoma

Increased risk for small intestine adenocarcinoma

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8
Q

new developments in celiac disease

A

In the past,* typical celiac disease denoted a clinical presentation with diarrhea, steatorrhea, weight loss, and nutritional deficiencies.

In contrast, presentations previously described asatypical celiac disease
(e.g., anemia, fatigue, abdominal bloating and discomfort, osteoporosis, or infertility) are now * more common

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9
Q

Celiac Disease: Diagnosis

A

Malabsorption

  • Immunoglobulin A Tissue Transglutaminase

Small bowel biopsy distal duodenum/jejunum

  • Response to gluten-free diet

HLA-DQ2 or HLA-DQ8
(high negative predictor)

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10
Q

Dermatitis herpetiformis

A

a chronic blistering intensely itchy skin condition, characterised by blisters filled with a watery fluid

Celiac Disease–> 15-25% develop dermatitis herpetiformis

Deposition of immunoglobulin A (IgA) in upper papillary dermis

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11
Q

Environmental Enteropathy

A

“Tropical Sprue”

Disorder prevalent in areas and populations with poor sanitation and hygiene

Etiology of tropical sprue remains unknown

Typically affects adults

Typical presentation is with chronic diarrhea, soreness of the tongue
(Vitamin B deficiency), and weight loss

Steatorrhea

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12
Q

Autoimmune Enteropathy

A

Rare

  • Intractable diarrhea and * malabsorption associated with circulating gut autoantibodies and a predisposition to autoimmunity

Affects infants, young children and (rarely) adults

Evidence * suggests a hyperactive immune state due to a defect in regulatory T-cells

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13
Q

Autoimmune enteropathy diagnostic criteria:

A

Presence of chronic diarrhea and malabsorption

Partial or complete villus blunting, deep crypt lymphocytosis, increased crypt apoptotic bodies, and minimal intraepithelial lymphocytosis

Presence of anti-enterocyte antibodies and anti-goblet cell antibodies

  • Absence of antibodies does not exclude the diagnosis
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14
Q

Disaccharidase (Lactase) Deficiency

A

Congenital lactase deficiency is a rare autosomal recessive disorder

Acquired lactase deficiency is common, particularly among Native-Americans and African Americans

Incomplete breakdown of lactose leads to osmotic diarrhea from unabsorbed lactose

May resolve over time

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15
Q

Abetalipoproteinemia

A

Abetalipoproteinemia is a rare, autosomal recessive disorder, characterized by fat malabsorption.

Mutation in the microsomal triglyceride transfer protein (MTP)
** -Failure to assemble and export lipoproteins

Malabsorption

Dietary modification and replacement of fat soluble vitamins

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16
Q

Irritable Bowel Syndrome

A

IBS is characterized by the presence of chronic abdominal discomfort or pain associated with changes in bowel habits.

In GI practices one third of patients have functional GI disorders, IBS being the most common diagnosis.

The diagnosis of IBS rests on a careful history and physical examination.

** Pathogenesis unknown

Peak prevalence of IBS is between 20 and 40 years of age

Significant female predominance

*** Need to rule out other causes, such as enteric infection or inflammatory bowel disease

17
Q

2 types of IBD

A

Inflammatory bowel disease(IBD) is a chronic condition resulting from inappropriate mucosal immune activation.

Crohn disease may involve any area of the GI tract and is frequently transmural.

Ulcerative colitis is limited to the colon and rectum and extends only into the mucosa and submucosa.

18
Q

Crohn Disease

A

Diagnosed most often among persons 15 to 30 years of age

Intermittent attacks of diarrhea, fever, and abdominal pain

Most commonly affects *distal ileum and colon, but may involve mouth to anus

Risk of GI * adenocarcinoma is increased
5-6x

19
Q

Crohn Disease EPIDEMIOLOGY

A

Primarily Western nations

Incidence 3/100,000 in US, and rising

More common in whites than blacks: Jews than non-Jews

More common in females than males (~2:1)

Disease peaks in 2nd to 3rd decade; minor peak 6th to 7th

20
Q

Pattern of bowel involvement of Crohn disease

A

40% small bowel only (Ileum)

30% small bowel and colon

30% colon only

rarely may involve duodenum, stomach, esophagus, mouth

21
Q

Crohn DiseaseGross Pathologic Features

A

Non-contiguous mucosal inflammation

  • aphthous ulcers
  • serpiginous ulcers
  • fissures
  • cobblestone mucosa

Fibrosing Strictures

Perforation and abscess

Adhesions

Thickened intestinal wall

Fistula

Creeping Fat

Mucosa with Cobblestone Appearance

22
Q

Crohn Disease Histopathologic Features

A

Non-necrotizing * granulomas

  • Transmural lymphoid aggregates

Frequently transmural inflammation with deep ulcers (*fissures)

Crypt destruction/distortion

Submucosal fibrosis

Mucosal ulcers

[crypt distortion resembling animals]

23
Q

Aphthous lesions

A

are small erosions that are associated with a neutrophilic infiltrate

24
Q

Ulcerative Colitis- epidemiology

A

Approximately 800,000 people afflicted with ulcerative colitis in the United States

Common symptoms include diarrhea, rectal bleeding, passage of mucus, urgency, and abdominal pain.

Following the initial flare, 40% to 65% of patients have an intermittent course, and * 5% to 10% of patients have a chronic continuous course

Onset of disease peaks from ages 20-25 yrs

Ulcerative colitis is more common among nonsmokers than among current smokers

  • Systemic disorder with migratory polyarthritis, ankylosing spondylitis, uveitis and * primary sclerosing cholangitis
25
Q

Ulcerative Colitis - what we see in tandem

A

pANCAThis autoantibody is present in 41% to 73% of patients with UC.

Risk of adenocarcinoma of the colon is greatest in those with pancolitis of >10 years duration (20-30-fold increased risk)

26
Q

Ulcerative Colitis Pathology

A

Most severe distally and progressively less * severe more proximally

  • Initial presentation
    45% of patients with UC have disease limited to the rectosigmoid

35% have disease extending beyond the sigmoid

20% of patients have pancolitis.

  • Sharp transition between diseased and uninvolved segments of the colon.
  • Always involves rectum
  • Toxic megacolon occurs in approximately 5% of severe flares of UC
27
Q

Toxic megacolon

A

Complete cessation of colon neuromuscular activity leads to massive dilatation of the colon and black-green discoloration signifying gangrene and impending rupture.

28
Q

Ulcerative Colitis Histopathology

A

Inflammation in UC characteristically is confined to the mucosa

  • Cryptitis/crypt abscess and gland destruction/distortion

Ulcers and * pseudopolyps

Mucosa biopsy uniformly involved by inflammation

  • No granuloma
29
Q

Anti-Saccharomyces cerevisiaeantibodies(ASCAs)

A

antibodiesagainst antigens presented by thecell wallof the yeastSaccharomyces cerevisiae.

30
Q

one more time, ulcerative colitis vs crohn’s disease

A

UC: bloody diarrhea, extends poxially from rectum; no skip lesions. Does not involve ileum. Strictures are rare. Diffuse mucosal inflammation/ ulceration. no granulomas. no serositis/ adhesions. no fisutla.

Crohn’s:
watery diarrhea or constipation, segmental with rectal sparing, frequently involves ileum, strictures are common, focal inflammation and ulceration, granulomas common, serositis/ adhesions. fistula.

31
Q

Indeterminant Colitis

A

Because of the extensive pathologic and clinical * overlap between ulcerative colitis and Crohn disease definitive diagnosis is not possible in approximately 10% of IBD patients.

These cases are termed
* Indeterminate colitis

32
Q

Lymphocytic Colitis

A

Chronic watery diarrhea for months to years

Middle aged patients

Female to male 3:1

Normal endoscopic appearance

33
Q

Collagenous Colitis

A

Chronic watery diarrhea for months to years

Middle aged or older patients

Female to male 8:1

Normal endoscopic appearance

34
Q

Diversion Colitis

A

Surgical treatment –> temporary or permanent ostomy and a * blind distal segment of colon

35
Q

Graft versus Host Disease

A

Occurs following hematopoietic stem cell transplantation

Donor T cells targeting antigens on the recipient’s GI epithelial cells

Intestinal graft-versus-host disease often presents as a watery diarrhea but may become bloody in severe cases

36
Q

Diverticular Disease

A

Refers to acquired pseudo-diverticular outpouchings

Most common in the sigmoid colon

Colonic diverticula are rare under 30 yr

> 80% asymptomatic

Inflammation of diverticula is called diverticulitis(pain, leukocytosis and fever)

Perforation is uncommon but it can result in pericolonic abscesses, sinus tracts, and peritonitis

GI II Exam 3 (14 decks)

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