Nutrition and diet Flashcards
What is the definition of 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.
List 4 causes of malnutrition?
- Reduced intake when food is available
- Reduced intake due to inadequate availability, quality or presentation of food
- Lack of recognition and treatment
- Nutritional requirement
Name 4 conditions which can lead to a reduction in someones intake of food causing malnutrition
- Dysphagia
- Prolonged periods NBM (Nil by mouth)
- Side effects of treatment
- Pain/constipation
- Psychological e.g. depression
- Social e.g. low income, isolation
- Poor dentition
- Reflux/feeding problems/food intolerance’s
Name 3 conditions which can lead to an increase in requirement causing malnutrition
- Infections
- Involuntary movements
- Wound healing (burns)
Name 4 conditions which can lead to increased loss being the cause of malnutrition
- Malabsorption from gut
- Diarrhoea and vomiting
- High stoma output
Describe the 5 steps in ‘MUST’ which is used to identify those at risk of malnutrition
- Body Mass Index (BMI)
- Weight loss (% unplanned weight loss in 3-6 months)
- Acute disease effect
- Add scores for steps 1-3
- Action plan
Name one major downside of the BMI calculation
-Does not factor muscle
How is the BMI calculated?
Weight in kilograms divided by the square of height in meters
What are the ranges for BMI?
<19 underweight
20 – 25 Normal
> 25 overweight
What is used when weight is difficult to measure?
In what position can it be measured in?
Which other information is needed to obtain BMI?
Which equation is used to determine the weight from the data obtained?
- Mid upper arm circumference - 10% change in MAC will correspond with 10% change in body weight
- Can be measured in supine position
- Height or surrogate height is needed
- Equation- (Weight (kg) = BMI x Height (m2)
What is used when height is difficult to measure?
Do the measurements from this method differ to the reported?
Surrogate measures;
- Knee height
- Demispan
- Ulna length
Yes, reported is superior
- may overestimate height
- underestimate BMI
How is the Demispan measured?
Midline at their sternal notch to the web between their middle and ring fingers along either horizontally outstretched arm.
Wrist in neutral rotation and zero extension or flexion.
Which mid upper am circumference measurements indicate is someone is under or over weight?
If MUAC is <23.5, BMI is likely to be <20 (underweight)
If MUAC IS >32, BMI is likely to be >30 (overweight)
How is dry weight estimated in those with oedema and ascites?
A table of in Kg is used to correct the weight
Ascites-
Minimal 2.2kg
Moderate 6.0kg
Tense (severe) 14.0kg
peripheral oedema
Mild 1.0kg (ankle)
Moderate 5.0kg (up to knee)
Severe 10.0kg (up to sacrum)
What does the BMI reflect?
BMI reflects chronic protein-energy status
What does the fat mass test estimate and how is it conducted?
Indirectly estimate total adiposity
Skin fold test- commonly done on the triceps
What does the free fat mass test estimate and how is it conducted?
- Protein status
- Arm muscle circumference
Derive from MUAC TSF
AMC - MUAC (cm) – (0.314 x TSF)
How is muscle strength and endurance assessed?
Handgrip Dynamometry (HGD) or Grip Strength test
Which body part and in which positions is the Handgrip Dynamometry (HGD) or Grip Strength test conducted in
supine or sitting position
dominant or non-dominant side of the hand
What is albumin? Where is it made? Where is it located? What is the normal range? What is its function?
- Large protein
- Synthesised in the liver
- Most abundant protein found in plasma and is usually trapped within capillaries
- Normal range: 35-50g/l
- Function: Maintains oncotic pressure
i. e. albumin molecules have an osmotic effect that helps to stop water leaking out through capillary walls
What is the name of the condition used to describe low albumin levels? State some causes of this condition.
Name: Hypoalbuminaemia Causes- Inflammation and sepsis associated with infection C-Reactive Protein White Cell Count pyrexia
What is the cause of low plasma albumin in inflammation and sepsis?
capillary walls become more ‘porous’ and albumin drifts out
Name 2 indicaters of mortality
BMI
Albumin
Name one significal clinical symptom of Hypoalbuminaemia and explain the pathophysiology
Oedema
Less albumin in capillaries, oncotic pressure decreases, water leaks out into the interstitial space causing swelling.
Why can albumin be normal in sick malnourished patients
Because there is no inflammatory response & no reduction in vascular permeability
What is Refeeding Syndrome?
A potentially fatal condition characterized by severe fluid and electrolyte shifts and related metabolic implications in malnourished patients undergoing refeeding (via the oral, enteral or parenteral routes)
List the physiological changes which occur in starvation
-Glucagon levels rises
-Insulin levels fall
-Glycogen used up in the first 24-72 hrs of starvation
-Shifts to protein for energy
-Fatty acids are metabolised to produce ketone bodies – become the major source of energy
-Loss of fat and lean body mass, water and minerals.
Intracellular stores of K+, P04-, Mg2 become depleted
List the physiological changes which occur in refeeding
- Metabolism changes from fatty acids to carbohydrates
- Raised insulin secretion
- Insulin stimulates K+, P04-, Mg2+ to return to cells
- ∴ intracellular stores of electrolytes are replenished but at the expense of plasma concentrations
List 5 pathological issues caused by re-feeding syndrome
Hypokalaemia Hypomagnesaemia Hypophosphataemia Thiamine deficiency Salt and water retention- Oedema
List the Neurological, Musculoskeletal , Respiratory, Cardiac and Renal consequences of Hypophosphataemia
Neurological—Seizures, paraesthesia
Musculoskeletal—Rhabdomyolysis, weakness, osteomalacia
Respiratory—Impaired respiratory muscle function
Cardiac—Cardiac failure
Renal—Rhabdomyolysis, fluid and salt retention
List the neurological, cardiac and gastrointestinal consequences of Hypomagnesaemia
Neurological—Tetany, paraesthesia, seizures, ataxia, tremor
Cardiac—Arrhythmias
Gastrointestinal—Anorexia, abdominal pain
List the Musculoskeletal , Respiratory, Cardiac and gastrointestinal consequences of Hypokalaemia?
Neurological—Paralysis, paraesthesia Musculoskeletal—Rhabdomyolysis Respiratory—Respiratory depression Cardiac—Arrhythmias, cardiac arrest Gastrointestinal—Constipation, paralytic ileus
Who is at risk of refeeding syndrome?
-Any patient with ‘very little’ food intake for >5 days
-Any one the following;
BMI <16
Unintentional weight loss >15% in last 3-6 months
Little or no nutritional intake for more than 10 days
Low levels of K, PO, Mg prior to feeding
-OR Any 2 of the following
BMI <18.5
Unintentional weight loss >10% in last 3-6 months
Little or no nutrition for more than 5 days
A history of alcohol abuse or drug use including chemotherapy, antacids or diuretics
Which conditions would require nutritional support? Why is the nutritional support needed?
stress/trauma/sepsis
- Maintain nutritional status
- limit catabolism- break down of muscle
- Preserve lean body mass (LBM)
- Maintain immune function
- Preserve organ function and promote wound healing
- Enhance recovery and improve patient outcomes
Describe the 2 routes used for nutritional support. Which of the two is best
Enteral- GI tract- Oral Nasogastric Orogastric Nasojejunal Gastrostomy Jejunostomy
Paraenteral- Peripheral (veins) and central
Enteral is best
Under what specific conditions would enteral feeding be required?
Malnorished, indequtae oral intake
When is Parenteral Nutrition required?
GIT unable to digest or absorb adequate amount of nutrients (e.g. short bowel syndrome, motility disorders, gastrointestinal ischaemia, bowel perforation, pancreatitis)
GIT cannot be accessed (e.g. obstruction, severe IBD)
What are the Disadvantages of parenteral nutrition?
Risk associated with placement (pneumothorax)
Risk of catheter related sepsis- infection can occure, infective endocarditis.
Disordered liver function (long term)- can lead to liver failure
Risk of gut atrophy- villie can flatten and get destroyed, body will not replace
Psychological
Cost- very expensive
What is short bowel syndrome? How do you treat someone who has developed malnutrition with this condition?
If small bowel is <100cm
-long term IVF and Supplementary PN (parenteral nutrition)
