GI 229&237 Nutrition and Chronic Diarrhoea Flashcards
What is short bowel syndrome?
A state of malabsorption and malnutrition that occurs following massive anatomical or functional loss of the SI
What is necrotizing enterocolitis?
Ischaemia and necrosis of the SI in neonates causing 22-50% of SBS - a surgical emergency in neonates
What is intusseption of the bowel?
Part of the intestine folds into another part - presents in childhood
What is the function of the ileocaecal valve?
To slow transit time and to prevent bacterial reflux from the large intestine to the small
What happens in ileal adaptation?
Usually when there has been a jejunum resection
epithelial hyperplasia within 24hours, with villi changes resulting in increased macronutrient absorption
What must be given after jejenal resection?
Enteral feeding as it stimulates ileal adaptation
containing: arginine, TG’s, glutamine and AA’s
What diet is recommended after jejenal resection?
Diet higher in fat and protein
What are the main complications that must be managed with an ileal resection?
Massive fluid and electrolyte loss due to malabsorption of bile salts and Vitamin B12
What are some complications of Short Bowel Syndrome?
Hypergastrinaemia, malabsorption of bile acids, therefore fat soluble vitamins, clotting disorders, osteoporosis and nephrolithiasis
What is hypergastrinaemia and why does it occur in SBS?
(mostly in jejenal resection) the negative feedback mechanism for inhibiting gastrin secretion has been removed
can lead to oesophagitis or PUD but is often only transient
Why can gallstones occur in SBS?
A decreased bile acid:cholesterol ratio and stasis allowing gallstone formation
Why can nephrolithiasis occur in SBS?
Bile salts in the colon stimulates increased oxalate absorption giving rise to renal oxalate stones
What are the indications for enteral feeding?
Functioning gut but cannot meet the nutritional requirements with normal food
3 months of >10% unintentional weight loss and a hypermetabolic state e.g. sepsis or trauma
What are the indications for parenteral feeding?
Non-functioning gut, gut rest needed, >7 days inadequate nutrition
e.g. in severe pancreatitis, post chemo, IBD, intestinal atresia and other motility disorders
Use short term only (2/52)
Explain refeeding syndrome
When a state of starvation is quickly reversed the catabolic processes and state of gylcogenolysis and gluconeogenesis switch to anabolic. There is sudden increase in insulin in response to feeding leading to increased protein and glycogen synthesis
This leads to rapid uptake of vitamins into cells with Na and water retention
Can be fatal due to mineral and electrolyte deficiencys
What minerals is there rapid uptake of in refeeding and therefore what problems?
hypoPhosphate = tissue hypoxia hypomagnesium hypokalaemia = cardiac dysrhythmias decreased thiamine = confusion Na+/water = oedema there is also thrombocytopaenia
What are the risk factors for refeeding syndrome?
One of:
BMI 15% weight loss in 3-6 months
Low minerals to begin with
Two of:
BMI 10% in 3-6months
intake decreaed in >5/7
Alcohol/drug abuse
How do you prevent refeeding?
Decrease rate of feeding initially
Vitamin B for the 1st 10 days
Supplement electrolytes assessing daily and comparing to baseline
If refeeding occurs then slow feeding rate
What do you get with a Vitamin A deficiency?
compromised mucosa, night blindness and benign intracranial HTN
What do you get with a Vitamin D deficiency?
Ricketts/Osteomalacia
What do you get with a Vitamin E deficiency?
Increased susceptibility to oxidant stress th. CVS disease
Haemolysis
Neurological symptoms
What do you get with a Vitamin K deficiency?
Coagulopathy - prolonged PT
What happens in lactose intolerance?
There is a lack of digestion of lactose by brush border enzymes resulting in its accumulation in the lumen - has an osmotic effect leading to diarrhoea and it also ferments in the intestine leading to gas, bloating and acidic stools
How would you investigate a suspected lactose intolerance?
Lactose breath test - give lactose to ingest then if there is an intolerance there will be increase hydrogen
What are some causes of lactase deficiency?
Primary - can develop later, often after 5 years of age is an AR disorder
Congenital extremely rare and infant fails to thrive
Secondary to mucosal injury - often transient
What is the breakdown of Lactose?
By lactase into glucose and galactose
What does the SGLT transporter do?
Transports glucose and galactose coupled with Na+
Where is CCK released from?
I cells in duodenum and jejenum
Where does CCK act on and what are its actions?
Pancreas: increase enzyme secretion
Gallbladder: Contraction and sphincter of oddi relaxation
What are the actions of Gastrin?
Parietal cells: H+ release
Where is glucagon released from?
alpha cells of pancreas (islets of langerhans)
What is the action of glucagon?
Opposes insulin: increase production of glucose and breakdown of glycogen
What is ghrelin and where is it released from?
Hormone released from stomach that stimulates appetite
Describe somatostatin
Released from stomach and D cells in pancreas - inhibits secretion and action of most hormones!
What is the action of guanylin?
Stimulates fluid absorption from the SI/LI
Where is VIP released rom?
ENS neurones
What is the action of VIP?
SI/Pancreas = increased secretions SI = relaxes smooth muscle
