CHO & Protein Absorption Flashcards
Zollinger-Ellison Syndrome
- gastrin-producing pancreatic tumor
- Because of very high circulating gastrin levels, patients have very high basal acid production.
- erosive esophagitis and several gastric and duodenal ulcers, some in the second portion of the duodenum
Celiac sprue or gluten sensitive enteropathy
- Small intestinal villous atrophy and increases in lamina propria lymphocytes.
- Decreased secretin production, thus leading to increased acid output from stomach.
- Crampy abdominal pain, diarrhea, flatulence, bloating, weight loss, steatorrhea.
- May also experience iron deficiency anemia, osteomalacia (vitamin D malabsorption), peripheral neuropathy (B12 deficiency), easy bruising (vitamin K malabsorption), edema (malabsorption of protein) may be seen in some patients.
adult hypolactasia
- acquired deficiency in the brush border enzyme lactase
- Lactose remains in the intestinal lumen and acts as a strong osmotic substance. This leads to symptoms of flatulence, bloating, and diarrhea
- An oral load of glucose will increase blood levels of glucose with no change in breath hydrogen levels; in contrast, an oral load of lactose will fail to increase blood levels of glucose with a marked increase in breath hydrogen levels due to bacterial action on unabsorbed lactose further down the GI tract.
Sucrase-isomaltase deficiency
Congenital intolerance to sucrose.
- After ingestion of sucrose, an affected child will typically experience stomach cramps, bloating, excess gas production, and diarrhea
- Most affected children are better able to tolerate sucrose as they get older.
Enteropeptidase deficiency
- mutation in the gene that codes for pro-enteropeptidase.
- deficiency causes protein malabsorption during early infancy
- malabsorption syndrome characterized by muscle wasting, failure to thrive, and hypoproteinemia
- protein digestion improves with time and can be adequate in the adult
Glucose-galactose malabsorption
defect in Na+-dependent glucose transporter. This transporter is known as SGLT1. Any carbohydrate source in the diet will lead to diarrhea with a single exception (fructose). Starch, sucrose, lactose, glucose or galactose will lead to diarrhea and in increased breath hydrogen levels.
Fructose malabsorption
defect in GLUT5 transporter, fructose is not absorbed.
fructose intolerance
more severe, defect in aldolase B enzyme
-different from fructose malabsorption
Hartnup disease
- genetic defects in a transporter that is responsible for the intestinal and renal absorption of neutral amino acids (e.g., tryptophan, phenylalanine, leucine, etc.
- associated with decreased plasma levels of tryptophan, especially in developing countries, leading to nicotinic acid (niacin) deficiency, manifested as pellagra (dermatitis, diarrhea, and dementia)
Cystinuria
- genetic defects in a transporter that is responsible for the intestinal and renal absorption of cationic amino acids (lysine, arginine, ornithine, and cystine)
- INCREASED risk for kidney stones consisting of cystine.
- levels of cystine or cysteine are usually normal
Secretion arises from what cells
the crypt cells
absorption takes place in what structures
Villi
Fecal osmotic gap =
Body fluid osmolality (which is 290 mosm/kg H2O) – (minus) fecal osmolality by electrolytes [which is 2 x fecal ([Na+] + [K+])].
Acetazolamide/Diamox (carbonic anhydrase inhibitor) causes
Decrease in electroneutral NaCl uptake
fecal osmotic gap for lactose intolerance
> 100 mOsm
- ACIDIC pH
- defect in carb absorption –> colon bacteria acts on food and produces acidic molecules
