CH10 - Gastrointestinal Pathology Flashcards Preview

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Flashcards in CH10 - Gastrointestinal Pathology Deck (345)
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181

How does lactose deficiency develop?

it may be congenital (rare autosomal recessive disorder) or acquired (often develops in late childhood);

182

How is lactose deficiency related to small bowel infarction?

temporary deficiency is seen after small bowel infection (lactase is highly susceptible to injury).

183

What is celiac disease?

Immune-mediated damage of small bowel villi due to gluten exposure

184

What is celiac disease associated with?

HLA-DQ2 and DQ8

185

In what is gluten present?

in wheat and grains

186

What is the most pathogenic component of gluten?

gliadin

187

What happens to gliadin once absorbed?

gliadin is deamidated by tissue transglutaminase (tTG).

188

What happens to deamidated gliadin?

it is presented by antigen presenting cells via MHC class II where the helper T cells mediate tissue damage.

189

What is the clinical presentation for celiac disease in herpes?

Children classically present with abdominal distension, diarrhea, and failure to thrive

190

What is the clinical presentation for celiac disease in adults?

It classically presents with chronic diarrhea and bloating

191

What is seen on the skin in celiac disease?

Small, herpes-like vesicles may arise on skin (dermatitis herpetiformis).

192

What is dermatitis herpetiformis in celiac diseae due to and how does it resolve?

IgA deposition at the lips of dermal papillae it resolves with gluten-free diet

193

What are the laboratory findings for celiac disease?

1) IgA antibodies against endomysium, tTG (tissue transglutaminase), or gliadin

194

What lab finding for celiac disease is also used in IgA deficiency?

IgG antibodies are also present and are useful for diagnosis in individuals with IgA deficiency

195

What is the relationship between IgA deficiency and celiac disease?

increased incidence of IgA deficiency is seen in celiac disease

196

What does duodenal biopsy reveal in celiac disease?

flattening of villi, hyperplasia of crypts, and increased intraepithelial lymphocyte

197

In celiac disease where is damage most prominent?

in the duodenum (jejunum and ileum are less involved)

198

When would the symptoms of celiac disease resolve?

with gluten-free diet.

199

What are late complications that present as refractory disease despite good dietary control?

Small bowel carcinoma and T-cell lymphoma

200

What is tropical sprue?

Damage to small bowel villi due to an unknown organism resulting in malabsorption

201

How does tropical spure compare to celiac disease?

Its similar to celiac disease except 1. Occurs in tropical regions (e.g., Caribbean) 2. Arises after infectious diarrhea and responds to antibiotics

202

In tropical spure, where is damage most prominent?

in jejunum and ileum (secondary vitamin B12 or folate deficiency may ensue); duodenum is less commonly involved.

203

What is whipple disease?

Systemic tissue damage characterized by macrophages loaded with Tropheryma whippelii organisms; partially destroyed organisms are present in macrophage lysosomes (positive for PAS).

204

What is the classic site of involvement in whipple disease?

the small bowel lamina propria

205

What happens in whipple disease?

1. Macrophages compress lacteals. 2. Chylomicrons cannot be transferred from enterocytes to lymphatics. 3. Results in fat malabsorption and steatorrhea

206

What are the other common sites of involvement for whipple disease?

they include synovium of joints (arthritis), cardiac valves, lymph nodes, and CNS.

207

What is abetalipoproteinemia?

Autosomal recessive deficiency of apolipoprotein B-48 and B-100

208

What are the clinical features for abetalipoproteinemia?

Malabsorption due to defective chylomicron formation (requires B-48), Absent plasma VLDL and LDL (requires B-100)

209

What is carcinoid tumor?

Malignant proliferation of neuroendocrine cells; low-grade malignancy

210

What do the tumor cells in carcinoid tumor contain?

neurosecretory granules that are positive for chromogranin