059 Malabsorption Flashcards
Describe vitamin B12 absorption
Vitamin B12 is combined with intrinsic factor. The parietal cell produces intrinsic factor and HCl (so a proton pump inhibitor also inhibits IF release). First, B12 complexes with a binder so that the B12 is not attacked by the acid. Trypsin breaks down the bond between the binder and the B12. It then latches on to intrinsic factor and continues until the terminal ileum, where it is absorbed. Vitamin B12 is only absorbed in the terminal ileum, as there are specific intrinsic factor receptors.
What is pernicious anaemia?
Vitamin B12 anaemia
How may we diagnose pernicious anaemia?
Endoscopy showing lack of folds in stomach due to atrophy.
Histology of glandular structure becomes distorted and there is a blue infiltrate into the mucosa (immune cells present due to autonoimmune disease)
What is glossitis?
Inflammation of the tongue due to high rates of proliferation.
What is the treatment for vitamin B12 malabsorption?
Intramuscular B12, which will resolve problems in 2-3 weeks.
Where is lactase produced?
On the brush border membrane
Why do we get bloating, cramps during lactose intolerance?
Lactose is not absorbed so it will continue down the GI tract and bacteria will use it for metabolism.
How can we diagnose lactase deficiency?
Lactose intolerance patients will have higher level of breath hydrogen.
Where is sucrase located and what does it do?
It is found on the brush border membrane and it is needed to break down sucrose to glucose and fructose.
Where are bile salts absorbed back into the enterohepatic circulation?
Terminal ileum.
Why would someone have bile acid malabsorption?
If someone has lost their terminal ileum due to surgical treatment of Crohns disease.
What is the difference between general malabsorption syndrome and specific malabsorption syndrome??
General malabsorption syndrome occurs when there is a non-functioning pancrease, a problem with interluminal digestion, or a mucosal problem. Specific malabsorption syndrome occurs when a specific nutrient is unable to be absorbed.
