6. Nutrition in medicine Flashcards
Define ‘malnutrition’
A state of nutrition in which a deficiency or excess of energy, protein and other nutrients causes measurable adverse effects on tissue/body form and function and clinical outcome
What percentage of patients are malnourished upon admission to hospital?
40%
What are some causes of malnutrition?
Decreased energy intake due to e.g. dysphagia, prolonged periods of nil by mouth, side effects of treatment, pain, poor dentition, social, food intolerance, psychological e.g. depression
Increased energy requirements e.g. infections (increased basal metabolic rate), involuntary movements, wound healing
Increased losses of energy e.g. malabsorption from the gut, diarrhoea and vomiting, high stoma output
What are the consequences of malnutrition?
Decreased muscle mass due to a reduced protein intake Decreased respiratory function Decreased cardiac function Decreased mobility Decreased of wound healing
Increased risk of infection
Increased risk of pressure sores
Increased risk of malabsorption
Apathy and depression
What are the consequences of malnutrition on the hospital and treatment?
Increased number of complications
Increased length of stay
Increased mortality
How can nutritional screening be carried out and when should this be done?
Use the MUST (malnutrition universal screening tool) system
Should be completed for all adult patients on admission to hospital and weekly thereafter
What are the five steps of MUST?
1 - BMI 2 - Weight loss? 3 - Acute disease effect? 4 - Add the scores for steps 1-3 5 - Make an action plan
REPEAT THIS WEEKLY
When can malnutrition most commonly be missed?
In the overweight patient can be missed easily
What are the different types of nutritional assessments that can be carried out?
Anthropometrics - weight, height BMI, weight history
Biochemistry - pre-existing malnutrition
Clinical status - diagnosis, medication
Dietary intake
Measure fat mass
If it is difficult to stand a patient up and measure their height, how else can you measure this?
Can instead measure knee height, demispan, ulna length BUT be aware that this may overestimate the height
How can you measure weight in a patient that you cannot measure on a scale?
Can measure the mid upper arm circumference (MUAC) and if this is <23.5 then BMI is likely to be <20 (underweight) and if it is >32 then BMI is likely to be >30 (overweight)
Describe the protein albumin and its function
Large protein synthesised in the liver
Most abundant protein found in the plasma and is usually trapped within the capillaries
It’s function is to maintain oncotic pressure - albumin molecules have an osmotic effect that helps to stop water leaking out through capillary walls
What are the causes of low albumin?
Can be due to inadequate protein intake
Inflammation and sepsis associated with infection - this is because the capillaries become more porous and so the albumin leaks out
What is refeeding syndrome?
Potentially fatal condition characterised by severe fluid and electrolyte shifts and related metabolic implications in malnourished patients undergoing refeeding
Why does refeeding syndrome occur?
As there is consumption of food after starvation, the metabolism changes from fatty acids to carbohydrates
So there is raised insulin secretion
Insulin stimulates the K+, PO4- and Mg2+ to return to cells
So the intracellular stores are replenished but this is at the expense of plasma concentrations which can lead to cardiac arrest, cardiac failure, respiratory depression etc
