10.5 - Small bowel Flashcards
double bubble sign is seen in ______________
duodenal atresia
does duodenal atresia have bilious or nonbilious vomiting?
bilious
is meckel diverticulum a true or false diverticulum?
true
what is the cause of a meckel diverticulum?
failure of vitelline duct to involute
what are the most common sites of volvulus?
- sigmoid
- cecum
in intussusception, which part telescopes?
telescoping of proximal segment forward into distal segment
what is the most common cause of intussusception in children? adults?
- children: lymphoid hyperplasia
- adults: tumor
transmural bowel infarction is due to _________________
thrombosis / embolism of SMA or mesenteric vein
mucosal bowel infarction is due to _________________
marked hypotension
thrombosis / embolism of SMA or mesenteric vein leads to what type of bowel infarction?
transmural
marked hypotension leads to what type of bowel infarction?
mucosal
where is the lactase enzyme located?
brush border of enterocytes
lactase breaks down ____________ into _________ and ____________
- lactose
- glucose and galactose
celiac disease is associated with what HLA haplotypes?
HLA-DQ2 and DQ8
once absorbed, gliadin is deaminated by ____________
tissue transglutaminase (tTG)
what immune cell mediates tissue damage in celiac disease?
helper T cells
deamidated gliadin is presented by APCs via MHC ____
II
dermatitis herpetiformis is seen in what condition? what is the pathophysiology?
- celiac
- deposition of IgA
in celiac disease there are antibodies against ________ (3 antigens)
- tTG
- gliadin
- endomysium
what is the duodenal biopsy histology seen in celiac disease?
- flattening of villi
- hyperplasia of crypts
- increased intraepithelial lymphocytes
in celiac disease, which segment of the GI tract is most heavily involved?
duodenum
what are late complications of celiac disease despite good dietary control?
- small bowel carcinoma
- T cell lymphoma
duoenal biopsy show:
- flattening of villi
- hyperplasia of crypts
- increased intraepithelial lymphocytes
diagnosis?
celiac disease
where is damage most prominent in tropical sprue?
jejunum and ileum
whipple disease is a systemic tissue disease characterized by _________ loaded with tropheryma whippelii
macrophages
what is the classic site of involvement in whipple disease?
small bowel lamina propria
what is the pathophysiology of whipple disease?
- macrophages compress lacteals
- chylomicrons cannot be transferred from enterocytes to lymphatics
- fat malabsorption and steatorrhea
what is the cause of steatorrhea in whipple disease?
- macrophages compress lacteals
- chylomicrons cannot be transferred from enterocytes to lymphatics
PAS positive organisms are observed macrophage lysosomes of the small bowel lamina propria - diagnosis?
whipple disease
what is the inheritance of abetalipoproteinemia?
AR
abetalipoproteinemia is an AR deficiency of _________ and __________
B48 and B100
what are the features of abetalipoproteinemia?
- malabsorption
- absent plasma VLDL and LDL
in abetalipoproteinemia which lipoproteins are absent? why?
- VLDL and LDL
- these require B-100
what is the cause of malabsorption in abetalipoproteinemia? why?
- defective chylomicron formation
- requires B48
carcinoid tumor is a malignant proliferation of what type of cells?
neuroendocrine
carcinoid tumors have tumor cells containing neurosecretory granules that stain positive for _____________
chromogranin
how does carcinoid sydrome arise?
metastasis of carcinoid tumor from GI tract (small bowel) to the liver, bypassing metabolism
what are the findings of carcinoid syndrome?
- bronchospasm
- diarrhea
- flushing
what are the findings in carcinoid HEART disease?
- right sided valvular fibrosis (increased collagen)
- tricuspid regurg
- pulmonary stenosis
why aren’t left sided lesions seen in carcinoid heart disease?
due to presence of MAO (metabolizes serotonin)
