Malnutrition Flashcards
Definition of malnutrition?
A state of nutrition in which a deficiency, excess or imbalance of energy, protein and other nutrients causes measurable adverse effects on tissue/body form/function/clinical outcome
Causes of malnutrition?
Decreased intake
Increased nutritional requirements
Impaired absorption and/or digestion
Increased nutrient losses/utilisation
Describe the relation between aspects of malnutrition and its impact
Chronic status, e.g: anorexia, asthenia, depression, dysphagia, etc lead to poor food intake
Malnutrition results and this can cause GI dysfunction, e.g: increased infection rate, decreased wound healing and physical weakness
Acute events can also influence the impact of malnutrition
This all leads to hypermetabolism, inflammatory responses and insulin resistance, creating stress-related catabolism than perpetuates GI dysfunction
Eventually, GI dysfunction leads to an increase in the length of stay in hospital
Psychosocial causes of malnutrition?
Inappropriate food provision
Lack of assistance
Poor eating environment
Lack of cooking skills/facilities
etc
Effects of starvation on metabolic rate, nitrogen levels, hormones and water and sodium?
Decreased metabolic rate and slow loss, almost all of which is from fat stores
There are decreased nitrogen losses; there are early small increases in catecholamines, cortisol, GH and then a slow fall. Insulin is decreased
With water and Na+, there is an initial loss and then late retention
Effects of injury on metabolic rate, nitrogen levels, hormones and water and sodium?
Inreased metabolic rate and a rapid loss from fat stores and from some protein stores
There is an increase in nitrogen losses; there are increases in catecholamines, cortisol, GH. Insulin is increased but there is relative insulin deficiency
There is water and Na+ retention
Adverse effects of malnutrition?
Impaired immune responses and wound healing Reduced muscle strength and fatigue Inactivity and pressure sores Water and electrolyte disturbances Impaired thermoregulation Menstrual irregularities Impaired psycho-social function
What different GI diseases cause weight loss?
Intra-abdominal infection Impaired GI motility Acute liver disease Coeliac disease Crohn's disease Colorectal cancer Gastric cancer Oesophageal cancer
What is MUST?
Malnutrition Universal Screening Tool has 5 MUST steps:
Step 1 - measure height and weight to get a BMI
Step 2 - note % unplanned weight loss and score using tables provided
Step 3 - establish acute disease effect and score
Step 4 - add score from steps 1-3 to obtain an overall risk of malnutrition
Step 5 - use management guidelines to develop care plan
Methods of nutritional assessment?
Anthropometry Biochemistry Clinical causes Diagnosis Environment
Examples of anthropometry?
Mid-arm muscle circumference
Triceps
Grip strength
Examples of measurements taken in biochemical tests?
Albumin - could indicate malnutrition due to reduced synthesis when supply of AA is limited but this is affected by many other factors; non-specific marker of illness
Transferrin - synthesis reduced in protein restriction
Transthyretin (pre-albumin) - reflects recent dietary intake rather than overall nutritional status, so it is most useful in monitoring response to nutritional support
Retinol binding protein - reflects recent dietary intake rather than overall nutritional status
Urinary creatinine - if renal function is normal, excretion rate will reflect muscle mass; it requires 24 hrs urine collection
IGF1 - reduced in acute/chronic malnutrition and increases with repletion; serial measurements to monitor response are more useful than single measurements to assess status
Micronutrients - poor correlation between plasma values and intracellular conc, esp. during illness, so measurement of related coenzymes is more useful
What other factors affect the biochemical tests?
Albumin - especially APR (abdominoperineal resection)
Transferrin - affected by APR, iron deficiency and liver disease
Transthyretin - increased in uraemia and dehydration; decreased by APR and fasting
Retinol binding protein - more affected by energy than protein restriction. Levels are increased by and a GFR increase and alcoholism; decreased by chronic liver disorders and Vit A and zinc deficiency
IGF1 - levels reduced in liver disease and renal failure and less affected by APR
Which biochemicals are lower in the high risk group?
Vit A, C, D, E
Albumin and zinc
What does nutritional support involve?
Food fortification & dietary counselling first
Oral nutrition support – e.g. additional snacks and/or sip feeds
Enteral tube feeding – the delivery of a nutritionally complete feed directly into the gut via a tube
Parenteral nutrition – the delivery of iv nutrition
Who needs nutritional support?
BMI 10% within the last 3–6 months
BMI 5% within the last 3–6 months
Have eaten or are likely to eat little or nothing for more than 5 days or longer
Poor absorptive capacity and/or high nutrient losses and/or increased nutritional needs from causes such as catabolism
How is enteral tube feeding allowed?
Nasogastric (NG) Nasojejunal (NJ) Percutaneous endoscopic gastrostomy PEG Percutaneous jejunostomy Surgical jejunostomy
Indications for enteral tube feeding?
Inadequate or unsafe oral intake, and a functional, accessible gastrointestinal tract
‘if the gut works, use it’: Unconscious patients Neuromuscular swallowing disorder Upper GI obstruction GI dysfunction Increased nutritional requirements
Contra-indications for enteral tube feeding?
Lower gastrointestinal obstruction Prolonged intestinal ileus Severe diarrhoea or vomiting High enterocutaneous fistula Intestinal ischaemia
What is parenteral nutrition?
The administration of nutrient solutions via a central or peripheral vein; it is expensive, there are many potential complications and there may be psycho-social disturbances
Indications for parenteral nutrition?
People who are malnourished or at risk of malnutrition and meet either of the following criteria:
Inadequate or unsafe oral and/or enteral nutritional intake
A non-functional, inaccessible or perforated (leaking) GI tract, e.g: IBD with severe malabsorption, radiation enteritis, short bowel syndrome, motility disorders
What is refeeding syndrome?
Potentially fatal shifts in fluids and electrolytes and disturbances in organ function and metabolic regulation that may result from rapid initiation of re feeding after a period of under nutrition
Less likely to occur with oral feeding but excessive feeding in PN/EN can cause this
Pathway leading to refeeding syndrome, starting from malnutrition?
Malnutrition alters glycogenolysis, gluconeogenesis and protein catabolism
Protein, fat, mineral, electrolyte and Vit depletion; there is salt and water intolerance
Refeeding (switch to anabolism)
Fluid, salt, nutrient changes
Insulin secretion increases protein and glycogen synthesis; this can cause hypokalaemia / magnesaemia / phosphataemia, thiamine deficiency and salt and water retiontion (oedema)
Leads to refeeding syndrome
Metabolic features of refeeding syndrome?
Hypokalaemia Hypophosphataemia Hypomagnesaemia Altered glucose metabolism Fluid overload
Physiological features of refeeding syndrome?
Arrhythmias Altered level of consciousness Seizure Respiratory failure Cardiovascular collapse Death
How to prevent refeeding syndrome in moderate risk patients?
Introduce nutrition support at a maximum of 50% of requirements for first 48 hours
Monitor clinical and biochemical parameters
Increase nutrition support to meet full requirements if monitoring reveals no problems
How to prevent refeeding syndrome in high risk patients?
Check PO4, Mg2+, K+ and Ca2+
Provide immediately before and during first 10 days of feeding: thiamin, vitamin B compound and a multi-vitamin and mineral supplement
Start feeding at 5-10 kcal/kg/day; slowly increase feeding over 4-7 days
Rehydrate carefully and supplement/correct levels of
PO4, Mg2+, K+ and Ca2+
Monitor PO4, Mg2+, K+ and Ca2+ for first 2 weeks and
amend supplementation as appropriate
