small bowel from pathoma continued

Question 1

tropical sprue: definiton

Answer 1

damage to the small bowel villi due to an unknown organism that results in malabsorption

Question 2

how is tropical sprue different from celiac disease?

Answer 2

1. occurs in tropical regions
2. arises after infectious diarrhea
3. it responds to abx
4. damage is worst at the JEJUNUM and ILEUM (whears in celiac disease, it is in the duodenum). may also get nutritional deficiencies- jejunum absorbs folic acid; ileum absorbs vit B12

Question 3

Whipple disease

Answer 3

systemic tissue damage characterized by macrophages loaded with gram positive tropheryma whippelii organisms. partially destroyed organisms are present in foamy macrophage lysosomes (positive for PAS).

Question 4

classic location and symptoms involved in whipple disease

Answer 4

usually involves the small bowel lamina propria- causes fat malabsorption and steatorrhea. Normally, fats from the enterocytes are repackaged into chylomicrons and put in the lamina propria, where they can be resorbed by lacteels leading to the lymphatics. in whipple disease, macrophages in the lamina propria compress the thin walled lacteels, so the chylomicrons can’t enter the bloodstream.

Question 5

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

Answer 5

synovium of joints, cardiac valves, lymph nodes, and CNS

foamy whippled cream in a CAN: cardiac, arthralgias, neruo symptoms

Question 6

abetalipoproteinemia: definition and symptoms.

Answer 6

AR deficiency of apolipoprotein B48 and B100.
you need B48 for chylomicron formation and proper fat absorption from the gut. Instead, fat accumulates in the enterocytes. you need B100 for VLDL and LDL, so these patients will have absent plasma VLDL and LDL.
presents in early childhood with failure to thrive, steatorrhea, acanthocytosis (spiked RBCs), and night blindness.

Question 7

carcinoid tumor: definition, marker

Answer 7

malignant prolif of neuroendocrine cells. low grade malignancy.
marker: chromogranin

Question 8

Where do carcinoid tumor typically occur? How does it grow?

Answer 8

small bowel is the most common site. grows as a submucosal polyp like nodules.

Question 9

What do carcionid tumors often secrete?

Answer 9

seratonin. dumps to the portal vein. liver processes the serotonin by MAO. MAO breaks it down to 5-HIAA, which is secreted into the tumor. no carcinoid syndrome unless the serotonin gets into the systemic circulation- must have metastasized to the liver

Question 10

What is carcinoid heart disease?

Answer 10

right sided valvular fibrosis. deposition of collagen in valves can lead to tricuspid regurg and pulmonary valve stenosis. no left-sided heart disease because the lung also has MAO, so pts won’t get left-sided valvular fibrosis

Question 11

What is carcionid syndrome?

Answer 11

bronchospasm, diarrhea, and flushin of the skin.

symptoms can be triggered by EtOH or emotional stress

Question 12

why might lactose deficiency be seen after a viral diarrhea? what is a positive lactose tolerance test?

Answer 12

it is seen after a viral diarrhea because lactose is located at the tips of the intestinal villi. this is temporary and lactose function will return.
lactose tolerance test is positive if administration of lactose produces symptoms and glucose rises less than 20 mg/dl.

Question 13

pancreatic insufficiency: causes, tests, manifestations

Answer 13

causes: obstructing tumor, cystic fibrosis, chronic pancreatitis. causes malabsorption of fat soluble vitamins with increased neutral fat in the stool.
D-xylose absorption test: normal urinary excretion of d-xylose in pancreatic insuffiency but decreased excretion with intestinal mucosa defects or bacterial overgrowth