Alimentary - Maldigestion and Malabsorption Flashcards
What are the exocrine functions of the pancreas
Fat, carbohydrate and protein breakdown
What does the pancreas secrete for fat digestion?
Pancreatic lipases - FA + monolycerides
Cholesterol esterases - for cholesterol esters
Phospholipases - splits FA from phospholipids
What does the pancreas secrete for carbohydrate digestion?
Amylase - hydrolyses starch and glycogen into disaccharides
What does the pancreas secrete for protein digestion?
Trypsin and chymotrypsin - to form polypeptides
Carboxypolypeptidases - to form amino acids
What is malassimilation?
Maldigestion of nutrients - often caused by pancreas not working
Malabsorption - where nutrients are digested by something is stopping it getting into body
What is malutilisation?
Where nutrients are digested and absorbed normally but something is stopping it from working as it should in the body e.g. cancer, diabetes
What happens if the pancreas isn’t working properly?
Protein, carb and fat maldigestion
Impaired assimilation of fat soluble vits
Impair absorption of B12/cobalamin
Bacteria build up
What are the fat soluble vitamins?
Vit A - retina and eyesight
Vit D - calcium metabolism
Vit E - protection from toxins
Vit K - activation of clotting factors
How does bacteria build up if the pancreas isnt working as it should?
The undigested chyme sits there and creates an environment for the overgrowth of SI bacterial.
What is the significance of B12?
The pancreas synthesises an intrinsic factor for cobalamin, which is absorbed by the SI. This is also taken up by bacteria.
What is exocrine pancreatic insufficiency?
The pancreas loses its exocrine function, so there is no enzymes or buffer.
Often need loss of 90% to see clinical signs
What breeds are more predisposed to EPI?
German shepherds
Rough coated collies
English setters
Chow Chows
Not confirmed in cats
What causes EPI?
Pancreatic acinar atrophy
Pancreatitis
Pancreatic hypoplasia
Pancreatic neoplasia
What is pancreatic acinar atrophy?
Cells die due to selectie destruction to autoimmune disease. Occurs in two stages:
1- subclinical, inflamed with T-cell infiltration and partial atrophy
2 - clinical, with 90% loss and severe end stage atrophy
Most common in dogs
What is pancreatitis?
Inflamed pancreas leads to both endo- and exocrine function of the pancreas being destroyed with fibrosis.
Show signs of EPI and diabetes
Seen in cats mostly but also dogs (S/M and cocker spaniels)
What is pancreatic hypoplasia?
Genetic and uncommon
An underdeveloped pancreas
What is pancreatic neoplasia?
A rare and total loss of an area of the pancreas
What are the clinical signs of EPI?
Weight loss with a good appetite
Increase faecal volume and decrease in consistency
Abnormal faeces (grey/yellow and cow pat like)
Flatulence
Coprophagia
How is EPI diagnosed?
Tested for trypsin immunoreactivity, as pancreas leaks trypsin when working
How is EPI treated?
No ability to repair so need to minic pancreatic actions
Avoid high fat, with high calorie and low fibre (as can absorb enzymes)
Feet 2+ meals a day
Enzyme replacement life long
Some require ABs
Might need B12, preferred oral as injection stings
What are the three phases of digestion?
Luminal
Mucosal
Transport phase
What causes malabsorption in the luminal stage?
-Dysmotility
- EPI or inactivation due to gastric acid hypersecretion (low pH = enzyme deactivation)
- Fat maldigestion due to EPI or liver disease (bile salt impairment)
What is dysmotility?
Can be caused by hyperthyroidism
Leads to increase metabolic weight and a fast GI time so food passes to quickly to be absorbed
What causes malabsorption in the mucosal stage?
-Brush border enzyme defciency
-Brush border protein transport deficiency
-Enterocyte defects
What is brush border enzyme deficiency?
Enzymes at the enterocytes are no longer produced
Congenital - trehalase in cats with chronic diarrhoea
Acquired - relative lactose deficiency leading to oncotic diarrhoea
What is brush border transport deficiency?
Defects in the transport proteins
Aquired - diffused SI disease from an infection
Congenital - intrinsic factor deficiency with altered transport e.g. E Coli or the structure e.g. Salmonella
What are the enterocyte defects?
Problems with the cell itself.
Often seen in IBS and cancer. Altered structures can be caused by lytic infections e.g. Parvo or Rotovirus or a cell infiltration e.g. Johnes
What causes malabsorption in the transport phase?
-Lymphatic obstruction with primary or secondary lymphangiectasia. Caused by infection, inflammation or neoplasia
- Vascular compromise due to infection or vasculitis. Portal vein hyper tension can lead to hepatopathy.
What are a infiltrative diseases of the gut wall?
Parasitic
IBS
Lymphangiectasia
GI lymphoma
Other diffuse neoplasia
Severe small intestine bacteria overgrowth
Dry feline infectious peritonitis
Deep mycoses
What are clinical signs of malabsorption?
Weight loss with normal/increased appetite
Diarrhoea
Coprophagia
How is malabsorption treated?
Depends on cause
Why are gut issues often seen as a secondary disease?
They are often found due to a primary issue
What are examples of primary issues that cause GI issues
Hepatic disease
Right side cardiac disease
Hyperthyroidism
How does hepatic disease cause secondary gut issues?
Bile acids are integral to digestion and absorption of fats
Caused by inflammation, infection, neoplasia, toxicity and fibrosis of the liver
How does portal vein hypertension cause GI issues?
Right side cardiac disease leads to blood flow issues around the liver/stomach
Caused by valvular disease, cardiac muscle disease or pericardial disease
How does hyperthyroidism cause GI issues?
An increased GI transit time so less time for absorption to occur and weight loss due to increased metabolic rates
Treatments vary
