10.5 Small Bowel Flashcards
Duodenal Atresia
Failure of the small bowel to canalize
What is duodenal atresia associated with?
Down Syndrome
What are the clinical features of duodenal atresia?
- Polyhydramnios
- Distension of the stomach and duodenum
- Bilious vomiting
Meckel Diverticulum
Outpouching of all 3 layers of the bowel wall due to the failure of the vitelline duct to involute
-> DISEASE OF 2’s
Volvulus
Twisting of the bowel along its mesentery result in obstruction and infarction
What are the common locations of volvulus in the elderly and young adults?
Elderly - sigmoid colon
Young adults - cecum
Intussusception
Telescoping of proximal segment of bowel into a distal segment
Lactose Intolerance
Decreased function of the lactase enzyme in the brush border that causes dissension and diarrhea with ingestion of milk products
Celiac Disease
Immune mediated damage of small bowel
What is the most pathogenic component of gluten?
Gliadin
What the pathogenesis of Celiac’s disease?
Deaminated gladden is presented by APCs via MHC II and helper T cells mediate tissue damage
Dermetitis Herpetiformis
Deposition of IgA at tips of dermal papillae - one of the symptoms of Celiac’s disease that resolves with gluten free diet
What are the Ab found in Celiac disease?
IgA anti-endomysium, tTG or gliadin
What will duodenal biopsy show for Celiac disease?
Flattening of villi with hyperplasia of the crypts
What part of the small intestine is most affected by Celiac disease?
Duodenum
If there is refractory symptoms in a Celiac patient despite a gluten-free diet what are the possible causes?
- Small bowel carcinoma
- T cell lymphoma
Tropical Sprue
Damage to small bowel villi by some unknown agent that results in malabsorption - arises after diarrhea and responds to antibiotics
Where is the damage mostly seen in tropical sprue?
Jejunum and ileum
Whipple Disease
Systemic tissue damage with macrophages loaded with Tropheryma whippelii - organism remains int hem
What is the main site affected by Whipple disease?
Fat malabsorption and steatorrhea
Why does fat malabsorption occur in Whipple disease?
Macrophages block chylomicron absorption in the lamina propria
Abetalipoproteinemia
Autosomal recessive deficiency of apolipoprotein B-48 and B-100 which leads to defective chylomicron and VLDL and LDL formation
Carcinoid Tumor
Low grade malignancy of neuroendocrine cells
What is the most common site for carcinoid tumor?
Small bowel
What do GI carcinoid tumors often secrete?
Serotonin (5-HIAA in the urine)
Carcinoid Heart Disease
Right sided valvular fibrosis which leads to tricuspid
regurgitation and PV stenosis
- Occurs with carcinoid metastasis from the GI to the liver
