Malnutrition

Question 1

define malnutrition

Answer 1

state resulting from lack of uptake or intake of nutrition leading to altered body composition and body cell mass leading to diminished physical and mental function and impaired clinical outcome from disease

Question 2

describe the prevalence of malnutrition by age, sex and hospital ward

Answer 2

more common in women than men especially in older age groups

most common in oldest and youngest age groups (18-19 and 90+)

most common in care of elderly and oncology

more common in those with gastrointestinal disease compared to cardio, resp and msk

generally - people over 65 especially if they have been admitted to hospital, people with chronic conditions (diabetes, lung disease, kidney disease) + chronic progressive diseases (cancer, dementia), people who abuse drugs or alcohol, people with any GI dysfunction

Question 3

compared malnutrition in community vs in hospital

Answer 3

1 in 3 admitted to hospital were malnourished on admission → suggests that majority originates in community

but malnutrition is unrecognised and undiagnosed in the acute setting → 70% of patients lost weight (mainly muscle mass) at discharge and the most vulnerable are those who came in malnourished

Question 4

what makes people in hospital particularly vulnerable to malnutrition

Answer 4

disease related anorexia - loss of appetite due to pathophysiological mechanisms + disruption of central regulation feeding behaviour

patients consume less than 80% of food on plate in hospital

belief that it is normal for appetite to decrease in hospital → held especially by older patients

belief by patient + staff that medical treatment is more important than food

Question 5

what is the paradox of the body response to injury

Answer 5

metabolic response to breakdown particularly proteins into substrates necessary for survival e.g. for immune system + tissue repair

but this metabolic response can then threaten survival in extreme cases e.g. due malnutrition + loss of muscle mass it causes

Question 6

how is malnutrition related to being acutely unwell

Answer 6

disease related anorexia - loss of appetite due to pathophysiological mechanisms + disruption of central regulation feeding behaviour

body’s response to stress → muscle breakdown into AA for gluconeogenesis + protein synthesis to supply immune response and tissue repair

increased demand for energy, protein + micronutrients → largest demand is for protein

patients who already are malnourished then become acutely unwell as they have less kilocalorie reserve to face illness

Question 7

how does malnutrition affect clinical outcomes

Answer 7

causes physical and functional decline + worsens clinical outcomes

post operative mortality is 10x greater in people who have lost over 20% of bodyweight preoperatively

inadequate muscle tissue → unable to mobilise adequate amounts of endogenous nitrogen in response to stress → greater morbidity compared to those who have sufficient muscle tissue

people in england + wales still dying in hospital from malnutrition as the primary cause

Question 8

how much does malnutrition cost the NHS

Answer 8

£19.6 billion per year

costs for malnourished patient x3 than well nourished

majority of cost is in secondary care

costs will rise in future as population ages

Question 9

how is malnutrition diagnosed

Answer 9

screening → assess by dietician → diagnose

screen using MUST - used in community + hospital, based on BMI, unplanned weight loss + acute disease, categorises in low, medium + high risk of malnutrition
has to be done within 6 hours of hospital admission and every week thereafter
can miss malnourished clinical populations → especially where overhydration is common e.g. ascites

ASSESS:

dietician - defines nutrition status
anthropometry - physical measurements of body compartments e.g height, weight, mid arm muscle circumference

biochemistry → used to estimate nutrient availability in tissue and fluid to assess for deficiencies
testing for trace elements + micronutrients is expensive → needs justification
results can be skewed due to inflammatory response so not measure until CRP is below 10, results are monitored intensely in parenteral nutrition

history → drug + alcohol, diet, metabolic needs, nutritional loss, chronic disease, major surgery or illness, GI tract surgery, medication
nutrition history - anorexia, loss of taste or smell, excessive alcohol, poor fitting dentures, chewing or swallowing problems, fad diets, allergy, dietary restriction
dietary history - food intake
social history - socioeconomic status, living alone,

indirect calorimetry - most reliable measure of energy expenditure + guide energy prescription → measures resting metabolic rate using respirator gas exchange canopy (not used in clinical practice) so equations are used in clinical practice to determine estimated energy requirement

DIAGNOSE:

based on the dietitian assessment of nutritional status
create plan → implement it → monitor → evaluate

Question 10

what are the limitations of BMI

what are the impacts of these

Answer 10

impact of gender, age ,e thnicity is ignored

cannot distinguish between fat mass and fat free mass

has minimal significance is dietetic assessment unless it is very low

Question 11

what does recent unexplained weight loss specifically suggest in regards to body reserves

Answer 11

muscle loss and therefore protein loss

Question 12

what are the anthropometric measurements carried out by dietician during malnutrition diagnosis

what do they indicate

Answer 12

anthropometry - measures body different compartments as they are affected differently by malnutrition

weight - recent unplanned weight loss reflects changes in energy protein status → impacts morbidity and mortality

BMI - has low significance due to its limitations unless very low

mid upper arm circumference and tricep skin fold thickness → used to calculate mid arm muscle circumference → used to assess lean body mass → associated with length of hospital stay and functional ability

multi-frequency bioelectrical impedance analysis - used in renal and haematology patients

CT - muscle distribution + composition, differentiate between visceral + subcutaneous fat, assess levels of fat and fat free mass very accurately (but expensive + radiation exposure so assess body composition mainly in research or when CT is part of clinical treatment pathway already)

hand grip strength → reflects upper extremity muscle strength → responds earlier to nutritional deprivation and repletion than other measurements e.g. muscle or body mass → the muscle strength can predict mortality and morbidity independent of muscle mass (reduced mortality for every 1kg increase in hand grip strength)

Question 13

define estimated energy requirement

how is it determined

how is it used

Answer 13

average dietary energy intake predicted to maintain energy balance in an adult of defined age, gender, weight, height and level of physical activity

related to resting metabolic rate (but this is energy expended at rest)

using predictive equations - but have limited use in practice and have maximum accuracy of 70%

used as starting point to determine baseline set of energy requirements that patient has

Question 14

what are the criteria for nutritional support

Answer 14

Question 15

what is artificial nutrition support

Answer 15

provision of enteral or parenteral nutrients to treat or prevent malnutrition

Question 16

what are the considerations when starting/stopping artificial support

Answer 16

feeding route:
oral is best → then enteral → parenteral

always need continued monitoring + evaluation of nutrition route
change or reconsider number of feeding routes if nutritional intake is sub optimal or long term feeding is required

starting and stopping requires ethical and legal considerations

Question 17

what is enteral artificial feeding

how is it done

Answer 17

delivering directly nutrition to stomach or small intestine

naso-gastric tube is first line = NG tube

if naso-gsastric tube is contraindicated e.g. if gastric outlet is obstructed → so tube needs to be distal to stomach

then naso-duodenal (NDT) or jejunal tube (NJT) is used

long term >3 months = gastrostomy or jejunostomy (tube inserted into stomach or jejunum through abdomen)

nutritional feeds that can be used - renal, low sodium, respiratory, immune, elemental, peptide

Question 18

how do the feeding routes for artificial nutrition compare to each other

Answer 18

oral is the best

enteral is superior to parenteral

when parenteral feeding is used, the aim is to move to enteral and then oral feeding as soon as clinically possible

Question 19

what are the complications of enteral nutrition

Answer 19

mechanical - misplacement of tube, blockage of tube, buried bumper - part of gastronomy tube becomes lodged in gastric wall

metabolic - hyperglycaemia, deranged electrolytes

GI - aspiration, nasopharyngeal pain, laryngeal ulceration, vomiting, diarrhoea

Question 20

what do you have to do to make sure NGT is in correct place

Answer 20

aspirate the contents

if the pH is <5.5 that indicates it is in the stomach as this pH is not found anywhere else in the body

if pH >5.5 then a chest x ray needs to be done and interpreted by professional

Question 21

what is parenteral nutrition

when is it used

Answer 21

delivering of fluids, electrolytes and nutrients directly into venous blood

when there is inadequate oral and or enteral nutritional intake

or

when there is a non-functioning, inaccessible or perforated GI tract

Question 22

where is parenteral nutrition inserted

Answer 22

using central venous catheter

centrally inserted into jugular, subclavian or femoral veins to reach the tip of of superior vena cava

or can be peripherally inserted via antecubital fossa to reach tip of superior vena cava

different central venous catheters are used depending on length of nutrition

Question 23

what are the contents of parenteral nutrition

Answer 23

will either use ready made/bespoke “scratch” bag

dietician liaises with MDT to determine fluid and electrolyte targets for each day

Question 24

what are the complications of parenteral nutrition

Answer 24

mechanical - occur when CVC is inserted, pneumothorax, haemothorax, thrombosis, cardiac arrhythmias, thrombus, catheter occlusion, thrombophlebitis (vein inflammation due to clot), extravasation (leakage of fluid around site)

metabolic - occur once feeding has started, deranged electrolytes, hyperglycaemia, abnormal LFTs, oedema hypertriglyceridemia

catheter related infections - intravascular catheters are one of the main sources of bacteraemia and septicaemia in hospitalised patients, need to keep monitoring to try and prevent these and also remember to switch to enteral when possible, assess patient using nutritional support MDT

Question 25

does nutritional support actually benefit malnourished patients

Answer 25

strong evidence base for yes malnourished patients who receive nutritional support have lower mortality than ones who don't support decreases non-elective hospital admissions, increases energy+ protein intake and weight gain patients at risk of malnutrition who are given individualised nutrition support have better outcomes than those who are given standard hospital diet and no nutrition intervention

Question 26

what is the most abundant circulating protein in healthy people

Answer 26

albumin 10-15g produced by hepatocytes everyday

Question 27

what predictive effect does albumin have why

Answer 27

low plasma albumin = marker of poor prognosis albumin production is inhibited by pro-inflammatory cytokines e.g. IL-6, TNF → therefore is a negative acute phase protein → levels decrease as inflammation increases also in the acute inflammatory state there is increased degradation and transcapillary losses of albumin

Question 28

how does albumin impact the nutrition status or nutritional support for patient

Answer 28

it doesn't → albumin is not valid marker of nutrition status nor is it an indication for nutritional support albumin is negative acute phase protein → its levels in plasma decrease in response to inflammation dietician will focus on the impact of the inflammatory state on the nutrition status evidence for this is hypoalbuminemia in obese trauma patients → they are not malnourished but their albumin is low due to the inflammation from their trauma

Question 29

what is the body's response to starvation

Answer 29

starvation → reduced insulin secretion, increase in glucagon → gluconeogenesis from AA in muscle and glycogenolysis from liver stores → stores depleted within 24-72 hours → shift to produce energy from ketone production from FFA from lipid stores → FFAs used instead of AA to spare skeletal muscle breakdown → fat free mass is preserved to an extent → decrease in BMR → brain uses ketones over glucose → loss of fat mass action of cellular pumps is reduced to decrease energy expenditure → electrolytes can leak across cell membrane during starvation: increase in extracellular water, total body water and sodium depletion in total body potassium, magnesium and phosphate → serum concentrations of these are maintained but the intracellular stores are depleted Na+ and fluid leak into cells → Na+ and fluid intolerance micronutrient stores become depleted → thiamine deficiency is likely as its stores are limited + its water soluble

Question 30

what effect does carbohydrate introduction have on the body during starvation

Answer 30

insulin secretion → stimulates action of Na+K+ ATPase pump which requires Mg2+ as a co-factor → drives K+ into cells and Na+ out carbohydrate + insulin drive phosphate into cells as it is need to make ATP there is increased cellular uptake of glucose, K+, Mg2+ and phosphate → therefore a decrease in the extracellular concs of glucose, K+ Mg2+ and phosphate thiamine is co enzyme needed for carbohydrate metabolism → therefore deficiency of thiamine can occur on refeeding in a vitamin B depleted patient carbohydrate also reduces Na+ and fluid excretion → expansion of extracellular fluid compartment → refeeding oedema and fluid overload therefore refeeding syndrome

Question 31

what are the main features of refeeding syndrome

Answer 31

hypokalemia - low K+ hypomagnesaemia - low Mg2+ hypophosphatemia - low Phosphate thiamine deficiency Na+ and water retention → fluid overload and refeeding edema due to the shift from catabolic to anabolic reactions when carbohydrate is reintroduced after starvation

Question 31

what are the main features of refeeding syndrome

Answer 31

hypokalemia - low K+ hypomagnesaemia - low Mg2+ hypophosphatemia - low Phosphate thiamine deficiency Na+ and water retention → fluid overload and refeeding edema due to the shift from catabolic to anabolic reactions when carbohydrate is reintroduced after starvation

Question 32

what are the clinical consequences of refeeding syndrome

Answer 32

arrythmia, tachycardia, congestive heart failure → cardiac arrest and sudden death respiratory depression (hypoventilation) encephalopathy - dmage to brain rhabdomyolysis - breakdown of skeletal muscle coma seizures wernicke's encephalopathy - specific to thiamine deficiency, characteristic symptoms are ataxia, confusion, ophthalmoplegia (paralysis/weakness of extraocular muscles)

Question 33

who is at risk of refeeding syndrome

Answer 33

Question 34

what impact do drugs given on ICU have on nutrition

Answer 34

Question 35

why would gastric residual volume be monitored in patient on ICU

Answer 35

to see if gastric motility is still effective → stomach is able to empty if secretions build up then patient is at risk of ulcers atracurium is paralysing agent given to patients on ventilator → but it often decreases gastric motility

Question 36

what is given to patient with past alcohol or drug abuse why

Answer 36

IV pabrinex - corrects nutritional deficiencies, specifically replaces thiamine thiamine is likely to be low already in patients with history of drug and alcohol abuse

Question 37

what route of feeding would be best for patient with acute pancreatitis being ventilated on ICU why

Answer 37

oral nutrition is not appropriate enteral nutrition as it is superior to parenteral because: maintains gut stability attenuates disease severity the feed will be peptide based and high ratio of medium chain triglycerides → not reliant on proteases or lipases for absorption

Question 38

what happens if an acute pancreatitis patient is not tolerating enteral nutrition what would this look like

Answer 38

diarrhoea and steatorrhea (pancreatic enzymes could be added to feed to see if this improves) start parenteral nutrition and reduce enteral feeding to ta trophic minimal rate → maintains gut integrity as it stimulates the gut to prevent bacterial translocation and gut leakiness which can exacerbate the pancreatitis

Question 39

what indicator would first suggest that patient is receiving adequate nutrition and is improving

Answer 39

better hand grip strength → indicates better muscle functioning → indicates adequate nutritional support

Question 40

what is short bowel syndrome

Answer 40

intestinal failure where you are unable to maintain protein-energy, fluid, electrolyte or micronutrient balance on a conventionally accepted normal diet results from surgical resection, congenital defect or disease related loss of absorption defined as having less than 2m of bowel from the duodenal jejunal flexure

Question 41

why do the effects of small bowel resection vary between patients

Answer 41

depends on the type, length and quality of small bowel left and whether or not they still have colon most absorption happens in jejunum, apart from vitamin B12 and bile salts which are absorbed in the ileum presence of colon is important because it can absorb , water, Na+ and fatty acids and slows intestinal transit → further aids absorption when colon + ileum is not present e.g. in jejunostomy → large amounts of fluid and electrolytes are lost and small bowel transit is very fast the length of jejunum left determines whether nutrition can be supported by diet alone: \<100 cm of jejunum left = long term IV fluid and electrolytes \<75cm jejunum = long term parenteral nutrition, fluid + electrolytes \<50cm jejunum + colon = long term parenteral nutrition, fluid + electrolytes

Question 42

how do the losses between jejunostomy and jejunocolic anastomosis compare

Answer 42

jejunocolic lose much less fluid and electrolytes as they are able to resorb much more as colon is present and it slows down small intestinal transit to all further reabsorption in jejunum there are significant intestinal losses in jejunostomy and small bowel transit is very fast

Question 43

how is high stomal loss managed

Answer 43

fluid restriction → hypotonic solutions e.g. water, alcohol, tea, coffee will cause net influx of Na+ from plasma into gut lumen due to the large concentration gradient between the lumen and the blood, water will follow Na+ → therefore a high stoma output also should reduce hypertonic fluids which contain sorbitol e.g. juice, coca cola and this high concentration induces secretions from enterocytes in order to dilute them give oral rehydration solution: Na+ concentration = 90mmol/l glucose concentration = 111mmol/l No K+ SGLT1 transport will co transport glucose and Na+ across apical membrane Na+ then actively pumped across basolateral membrane into blood via Na/K+ ATPAse H2O follows Na+ large amounts of Na+ and H2O reabsorbed → much lower stomal losses → prevents dehydration

Question 44

if gastric residual volumes in patient on ventilator continue to increase what do you do

Answer 44

prescribe pro-kinetics to increase gastric motility if it doesn't start decreasing investigate where there is an obstruction or stenosis lower down if there is change from naso gastric to naso jejunal tube

Question 45

how are the energy requirements for a patient in intensive care calculated

Answer 45

penn state equation gender, age, height specific includes clinical parameters specific to ICU e.g. temperature and ventilation settings

Question 46

how would a increase in lean body mass be evidenced in patient

Answer 46

increase in hand grip strength increase mid arm muscle circumference

Question 47

what urinary sodium indicates dehydration why would this be measured

Answer 47

\< 20mmol/l earlier indication of dehydration as it falls faster than plasma sodium

Question 48

what are the key features of diet in jejunostomy patient

Answer 48

fluid restriction → to prevent dehydrated add Na+, higher content of fatty acids, higher calorific content than required by body → no colon so there is reduced absorption of Na+ and fatty acids and faster transit low fibre → anecdotally reduces intestinal secretions