229 - Nutrition Flashcards
Who is particularly at risk of malnutrition?
Surgery - gut removal Poor appetite - missed inpatient meals Chronic inflammation Swallowing problems Disabilities Mechanical issues
Why are those who are ill more likely to become malnourished?
Tissue damage activates mechanisms that increase energy needs
How long can you stay alive nil by mouth?
2 months until death If compromised (sepsis, surgery) - 1 month
Why does malnutrition cause death?
Loss in muscle mass and strength (including cardiac muscle)
Loss of proteins
Reduced immune response (low lymphocytes, low helper:supressor T cell ration, low antibody affinity)
Reduced wound healing
Reduced heat production
Multiple organ failure
+ reduced motility - DVT/PE risk
The acronym WAASP is used in assessment of nutrition, what does it mean?
To screen risk - highlight who needs full assesment
W-eight A-ppetite A-bility to eat S-tress factors P-ressure ulcers
Is serum albumin a measure of nutrition?
NO. Shows state of illness.
What nutritional support is available for those with malnutrition / at risk?
Eat more
Eat supplements
Artificial support - enteral and paraenteral
What is enteral feeding?
Delivery of nutritionally complete food to the GI tract - stomach, duodenum, jejenum.
What are the indications for enteral feeding?
- functioning gut
- if unable to meet nutritional requirements
- If sudden, unintentional weightloss >10%
- If hypermetabolic - sepsis, trauma
- If anorexia has caused disease
What are the advantages of enteral feeding?
Nutrients effectively mobilised and utilised Preserves intestinal mucosal structure Comfortable, simple to give day/night Independent of appetite. Inexpensive
What are the side effects of enteral feeding?
Can get GO reflux
Not good if poor gastric emptying
Diarrhoea
How is enteral feed given?
Short term - NG tube or NJ tube
Longer term - PEG tube
What is a PEG tube?
Percutaneous endoscopic gastostomy
- done via an OGD, push stomach to wall, use selldinger technique to tunnel a tube - use as entry port.
Who might need a PEG tube inserted?
Stroke pt
Head and neck malignancy
Neuro problems
Not indicated if unexpected to live for a month
What is TPN?
Total parenteral nutrition
- NOT via the GI tract - into a vein
Who might need TPN?
inadequate or unsafe oral or enteral intake
Non functioning, inaccesable or perforated gut
What is put in TPN?
Use standard bags with all in - roll to mix
Energy - estimate BMR
Proetin - calculated as nitrogen requirment, given as vamin (inc. all esential amino acids)
Electrolytes
Micronutrients - vitamins and trace elements (must be added to giving bag)
Fluid
How is TPN administered?
Via PICC, Hickman line, subcutaneous port…
What complications do you get with TPN?
Metabolic - fluid overload, electrolyte imbalance, refeeding syndrome, liver issues
Mechanical - line occlusion, thrombosis, wrong placement
Infection - s.aureus
How is infection reduced in someone receiving TPN?
Can tunnel the central line -> PICC line
Good training
investigate all high temperatures
What is refeeding syndrome? Why does it occur?
A Potentially fatal complication that occurs when nutritional support is given to a severely malnourished person
When malnourished, catabolic state, breakdown of muscles, low protein, K+, phosphate, Mg, Zn
When refed, anabolic state. Insulin released, this causes cellular uptake of K+, Phosphate, Mg - so what little there was is taken into cells - leaves serum levels too low - causes arrythmias, oeadema, ATP depletion (as phosphate needed), coma, convulsions.
When is someone at risk of refeeding syndrome?
V low BMI (15% in 3-6 months, little/no intake for >10 days, low baseline
Or multiple less severe factors
or GI disease, alcoholism, malignancy, post-bariatic surgery, anorexia, bizarre diets
How can you prevent refeeding syndrome?
Evaluate electrolyte status Supplement them - don't delay refeeding but supplement early on. Give vit B Start with reduced rate of feeding Monitor often
What is Short bowel syndrome?
The state of malabsorption and malnutrition that occurs following a massive anatomical or functional loss of the small intestine - usually due to surgical resection.
What can cause short bowel syndrome?
Newborns - necrotising enterocolitis (ischaimia and necrosis of GI tract, 2-7% of premature babies have it)
- congenital issues - midgut volvulus, jejunoileal astrasia, hirshsprungs
Children/adults: Surgery for intussusception, crohn’s disease, trauma, ischaemia, cancer
What is peadiatric small bowel syndrome?
Children have the potential that their SI will lengthen after resection, as child is born with 200cm, which grows to 350-800cm normally.
Also, rapid GI growth in weeks 26-38 gestation, so newborns have increased capacity for it to carry on growing
What does the duodenum secrete and absorb
Secretes - CCK + secretin
Absorbs - Iron, Ca, Mg, Folate
What does the jejunum absorb?
Glucose amino acids fat thiamine Vit C
What does the ileum secrete and absorb?
Secretes - enteroglucagon
Absorbs - water, electrolytes, bile acids and salts, Vit B12, Vit ADEK (fat soluble), phosphorus, zinc
What does the ileocaecal valve do?
Slows intestinal transit time
prevents bacteria reflux
After a jejunal resection what is affected and what happens?
Temporary reduction of most nutrients occurs
The jejenum itself isn’t very good at adaption, but the ileum adapts to fulfil jejenums role - both structurally and functionally.
Increases in length, diameter, villi change. Characterised by epithelial hyperplasia.
Begins within 24-48hrs of ressection.
How does ileal adaption after jejunal resection occur?
Key genes express mediators
Delivery of enteral food is key, so food stimulates enzyme production (CCK).
GLP-2 induces villus hyperplasia + increased absorption
Prostaglandins involved in intestinal proliferation (? bad if NSAIDS used ??)
Ghrelin levels reduced
What happens after ileal resection?
Jejenum is very leaky + ileum normally reabsorbs most this liquid, so if ileum is lost then fluid and electrolyte loss occurs. Colon adapts to increase fluid and electrolyte absorption. Colon also increases production of gut hormones (eg. peptide YY)
Ileum also primary site for B12 and bile acids and Vit ADEK are absorbed - so must be replaced otherwise deficient.
What happens after the loss of the ileocaecal valve?
Small bowel bacterial overgrowth
Can cause dilation and decreased motility in SI
Harder to wear from parenteral nutrition when missing
What can happen to gut motility after a big resection?
Ileum may have ‘ileal break’ -> slow gastric emptying can delay delivery of food to SI.
This is ? controlled by peptide YY
