nutritional assessment

Nutritional AssessmentBy

Ahmed Abudeif Abdelaal

Assistant Lecturer of Tropical Medicine & Gastroenterology

Sohag Faculty of MedicineJanuary, 2017

Goals of nutritional assessment1) To identify the presence and type of malnutrition.

2) To define health-threatening obesity.

3) To devise suitable diets as prophylaxis against disease later in life.

Nutritional assessment includes the following:- Clinical history.

- Physical examination.

- Composite screening tools.

- Anthropometric measures.

- Laboratory assessment.

- Measuring body composition.

- Miscellaneous tests.

Clinical history1) The timing and amount of weight loss:

- A recent unintended weight loss of > 5% of usual weight should prompt efforts to diagnose the underlying disorder or social circumstance.

2) Medical illnesses, e.g. DM, liver cirrhosis.

3) Medications.

4) Gastrointestinal symptoms: anorexia, nausea, vomiting, dysphagia, abdominal pain, diarrhoea.

Clinical history5) Diet habits:

a) Eating fewer than two meals per day.

b) Following a prescribed diet.

c) Food allergy or intolerance.

d) Alcohol consumption.

e) Dietary supplement intake including vitamins, minerals and herbs.

f) Dental status.

Clinical history6) Social habits: eating alone, needing assistance in self-care.

7) Economic status: having enough money for food.

8) Mental status: especially the presence of depressive symptoms.

Physical examination- The physical findings of deficiency syndromes of vitamins, essential fatty acids, and trace metals are relatively insensitive and nonspecific.

- Only marasmus and cachexia syndromes are evident at examination.

- Loss of subcutaneous fat and skeletal muscle is manifested by sunken temples, thin extremities, wasting of the muscles of the hand, and, rarely, edema.

Physical examination- Kwashiorkor in children is characterized by severe edema and a potbelly appearance from hepatomegaly and ascites. However, these clinical signs can rarely present in cases of hypoalbuminemic malnutrition that develops in the setting of systemic inflammation resulting from disease in industrialized societies.

Clinical signs and symptoms of nutritional inadequacy in adult patients

Composite screening tools- Investigators have made numerous attempts to combine the various components of nutritional assessment, including clinical history, physical examination, anthropometry, and serum proteins, into a single score.

- Some of the more widely used tools include the following:

1) Subjective global assessment.2) Nutritional risk index.3) Mini-nutritional assessment.4) Malnutrition universal screening tool.

Composite screening toolsSubjective global assessment (SGA)

- Simple clinical bedside tool which assess nutritional status based on features of the history and physical examination.

- SGA is highly predictive of nutrition associated complications.


- Value of SGA:

1) Identifying malnutrition.

2) Distinguishing malnutrition from a disease state.

3) Predicting outcome.

4) Identifying patients in whom nutritional therapy can alter outcome.


- Components of SGA:

From history:

1) Weight loss.

2) Dietary intake.

3) Presence of gastrointestinal symptoms.

4) Functional capacity.


- Components of SGA:

From physical examination:

1) Subcutaneous fat.

2) Muscle wasting.

3) Oedema.

4) Ascites.


- The findings of the history and physical examination are used to categorize patients as being:

- Well nourished (category A).

- Having moderate or suspected malnutrition (category B). or

- Having severe malnutrition (category C).

Anthropometric measures1) Body weight

- Is a useful element in the physical examination, it is expressed as a relative value to evaluate the patient in relation to the healthy population.

- Weight and height are easily obtained, and standards for comparison have been established.

Desirable weight in pounds in relation to height for men and women 25 years or older

Anthropometric measures1) Body weight

- The major confounding factor that limits the value of weight as an index of PEM is the tendency for water retention with disease, and thus weight gain may not reflect an increase in lean body mass or protein content.

- Fluid retention confound weight assessment in patients with heart failure, end-stage liver disease and severe renal disease.

Anthropometric measures2) Body mass index (BMI)

- BMI has gained favor as a nutritional measure because of two valuable attributes:

1) It is relatively independent of height.

2) the same standards apply to male and female patients.

- BMI is better correlated with outcome than are weight and height.

Anthropometric measures2) Body mass index (BMI)

CategoryBMI (kg/m2)From To

Very severely underweight 15Severely underweight 15 15.9Underweight 16 18.4Normal (healthy weight) 18.5 24.9Overweight 25 29.9Obese Class I (Moderately obese) 30 34.9Obese Class II (Severely obese) 35 39.9Obese Class III (Very severely obese) 40

Anthropometric measures3) Upper arm anthropometry

- Triceps skinfold thickness (TSF) is the most practical technique to estimate body fat.

- Generally, a value lower than the 5th percentile is used to define abnormality.

- The principal value of the TSF measurement is to determine the arm muscle circumference (AMC) or arm muscle area.

Anthropometric measures3) Upper arm anthropometry

- The AMC is a specific measure of protein-energy malnutrition if the 5th or 10th percentile is chosen as the cutoff point, and it is particularly valuable in patients in edematous states and in amputees, in whom weights are inaccurate or insensitive.

Fifth, tenth, and fiftieth percentiles for triceps skinfold and mid-upper arm muscle circumference of US men and women

Anthropometric measures4) Waist and hip circumference

a) Waist circumference

- It is measured at the level of the umbilicus.

- It gives and indication of the degree of abdominal obesity.

b) Hip circumference

- It is measured at the level of the greater trochanter.

Anthropometric measuresc) Waist : hip ratio

- To assess body fat distribution whether android (apple shaped, central, visceral, abdominal) obesity or gynoid (pear shaped) obesity.

Apple shape Pear shapeExcess fat on the abdomen (more visceral fat)

Excess fat on the thighs and buttocks (less visceral fat)

Common in men Common in womenSignificant correlation with metabolic syndrome, DM, cardiovascular risk

Non significant correlation

Laboratory assessmentA) Serum proteins

1) Albumin

- Normal value (3.5 – 5.5 g/dl).

- Half life is 18 – 20 days.

- It is the traditional standard for nutritional assessment.

- It is used to separate the two principal forms of PEM.


1) Albumin

- Hypoalbuminemia is a strong predictor of risk for morbidity and mortality.

- In almost all cases, except for hereditary analbuminemia, excessive loss secondary to nephrotic syndrome and protein-losing enteropathy, hypoalbuminemia identifies the recent or ongoing presence of a systemic inflammatory response.


1) Albumin

- A value for serum albumin of less than 3.5 g/dl is considered to indicate a mild systemic inflammatory response, whereas a value of less than 2.4 g/dl represents a severe systemic inflammatory response.

- Factors affecting serum albumin levels:

Increased in Decreased inDehydration Overhydration/ascites/eclampsiaMarasmus Hepatic failureBlood transfusions

Inflammation/infection/metabolic stress

Exogenous albumin

Nephrotic syndrome

Protein losing enteropathyBurnsTrauma/post-operative statesKwashiorkorCollagen diseasesCancerCorticosteroid therapyBed restZinc deficiencyPregnancy


2) Other proteins (prealbumin, transferrin, retinol binding protein)

- These proteins do not reliably identify the presence and severity of the systemic inflammatory response any better than does albumin, but they reflect the nutritional response more quickly when inflammation lessens.


2) Other proteins

a) Prealbumin (transport protein for thyroxine):

- Normal value (20 – 40 mg/dl).

- Half life is 2 days.

- Factors affecting serum prealbumin levels:

Increased in Decreased inSevere renal failure Post-surgeryCorticosteroid therapy Liver disease/hepatitisOral contraceptives Inflammation/infection/stress

DialysisHyperthyroidismSudden demand for protein synthesisPregnancySignificant hyperglycaemia


2) Other proteins

b) Transferrin:

- Normal value (204 – 360 mg/dl).

- Half life is 7 days.

- Factors affecting serum transferrin levels:

Increased in Decreased inIron deficiency Pernicious anaemia/folate deficiency

anaemiaDehydration Anaemia of chronic diseasePregnancy (3rd trimester)

Overhydration

Oral contraception/estrogens

Chronic infection

Chronic blood loss Iron overload/iron Dextran therapyHepatitis Acute catabolic statesHypoxia UraemiaChronic renal failure Nephrotic syndrome

Severe liver disease/hepatic congestionKwashiorkorAgeCancerCorticosteroid therapyZinc deficiency


2) Other proteins

c) Retinol binding protein:

- Half life is 12 hours.

Laboratory assessmentB) 24 hour urinary creatinine

- Normally 500 – 1200 mg/day.

- Low value indicates muscle wasting.

Laboratory assessmentC) Creatinine – height index (CHI)

- It is determined by measuring 24 hour urinary creatinine excretion in relation to the patients height while the patient is consuming a creatine and creatinine free diet.

- It indicates protein depletion.

- CHI = (24 hour urine creatinine × 100) / (expected 24 hour urine creatinine for height).

Laboratory assessmentC) Creatinine – height index (CHI)

Category CHINormal > 80%Mild protein depletion 60 –

80%Moderate protein depletion

40 – 60%

Severe protein depletion

< 40%

Laboratory assessmentD) Quantitative fecal fat measurement

- Is helpful to identify those patients with steatorrhoea, and the loss of fat calories that result.

- Normally it is less than 8% of fat intake.

Laboratory assessmentE) Assessment of mineral deficiencyMineral Symptoms or signs of

deficiencyTest

Sodium Hypovolemia, weakness - Urinary NaPotassium Weakness, paresthesia,

arrhythmia- Serum K

Magnesium

Weakness, twitching, tetany, arrhythmia, hypocalcaemia

- Serum Mg- 24 hr. urine Mg- Urinary Mg

Calcium Osteomalacia, tetany, arrhythmia

- Serum ionized Ca- DEXA

Phosphorous

Weakness, fatigue, haemolysis, respiratory muscle insufficiency

- Plasma P

Laboratory assessmentE) Assessment of mineral deficiency

Mineral Symptoms or signs of deficiency

Test

Copper Anaemia, neutropenia, osteoporosis

- Serum Cu- Plasma ceruloplasmin

Iodine Hypothyroidism, goiter - Urinary I- TSH

Iron Microcytic hypochromic anaemia

- Serum Fe- TIBC

Manganese

Hypercholesterolemia, dementia, dermatitis

- Serum Mn

Laboratory assessmentE) Assessment of mineral deficiency

Mineral

Symptoms or signs of deficiency

Test

Selenium

Cardiomyopathy, myopathy, pseudoalbinism, macrocytosis

- Serum Se- Blood glutathione peroxidase activity

Zinc Growth retardation, delayed sexual maturation, alopecia, acro-orificial skin lesion, diarrhoea, mental status changes

- Plasma Zn- Leucocyte Zn

Laboratory assessmentF) Assessment of vitamin deficiency

Vitamin Symptoms or signs of deficiency

Test

A (Retinol) Night blindness, Bitot’s spots, keratomalacia, follicular hyperkeratosis, xerosis

- Serum retinol

D (Calciferol) Rickets, osteomalacia, osteoporosis, bone pain muscle weakness, tetany

- Serum 25-hydroxy cholecalciferol

E (α-tocopherol)

Haemolysis, retinopathy, neuropathy

- Serum tocopherol- Serum tocopherol : total lipid ratio

K (Phylloquinone)

Easy bruising and bleeding, abnormal clotting

- Prothrombin time


Test

B1 (Thiamine)

Beriberi (wet, dry), Wernicke’s encephalopathy, fatigue, Korsakoff psychosis

- RBC transketolase activity

B2 (Riboflavin)

Cheliosis, sore tongue and mouth, eye irritation, seborrhoeic dermatitis

- RBC glutathione reductase activity

B3 (Niacin) Pellagra, sore mouth and tongue

- Urinary N-methyl-nicotinamide

B5 (Pantothenic acid)

Fatigue, weakness, paresthia, tenderness of heels and feet

- Urinary pantothenic acid



Test

B6 (Pyridoxine)

Seborrhoeic dermatitis, cheliosis, glossitis, peripheral neuritis, convulsions, hypochromic anaemia

- Plasma pyridoxal phosphate

B7 (Biotin) Seborrhoeic dermatitis, alopecia, change in mental status, seizures, myalgia, hyperesthesia

- Plasma biotin

B9 (Folic acid)

Megaloblastic anaemia, glossitis, diarrhoea

- Serum folic acid- RBC folic acid



Test

B12 (Cyanocobolamine)

Megaloblastic anaemia, SCD, change in mental status, diarrhoea

- Serum cobolamine- Serum methylmalonic acid

C (Ascorbic acid)

Scurvy, weakness, depression

- Plasma ascorbic acid- Leucocyte ascorbic acid


Measuring body composition1) Anthropometry (weight, BMI, skinfold thickness, waist

circumference).2) Isotope dilution.3) Underwater weighing.4) Bioelectrical impedance analysis (BIA).5) Whole body counting.6) In vivo neutron activation.7) Dual energy X-ray absorptiometry (DEXA).8) CT, MRI.

Measuring body composition1) Isotope dilution (hydrometry)

- It is used to measure total body water, allowing estimation of lean body mass.

Measuring body composition2) Underwater weighing (hydrodensitometry, hydrostatic weighing)

- It is used to measure body density, allowing calculation of body fat.

Measuring body composition3) Bioelectrical impedance analysis (BIA)

- Produces estimates of total body water, lean body mass and fat mass by measuring the resistance of the body tissues to the flow of a small electrical current.

- It is performed by applying electrodes to one arm and one leg or by standing on a special scale.

Bioelectrical impedance analysis (BIA)

Measuring body composition4) Whole body counting (total body potassium)

- Measures the amount of naturally radioactive potassium 40 (40K) in the body.

- Because potassium is found almost entirely intracellular, measuring potassium can provide an estimate of body cell mass which in turn can be used to estimate lean body mass.

A stand up and scanning bed whole

body counter

Measuring body composition5) In vivo neutron activation analysis

- By this technique, many elements in the body can be measured, including C, N, Na, Ca, Cl, P.

- Body nitrogen quantified by this method has been used as an indicator of total body protein.

In vivo neutron activation analyzer

Measuring body composition6) Dual energy X-ray absorptiometry (DEXA)

- It is developed originally for the measurement of bone density and mass.

- It differentiates body weight into the components of lean soft tissue, fat soft tissue and bone, based on the differential attenuation by tissues of two levels of X-rays.

DEXA device

Measuring body composition7) CT and MRI

- Both modalities can be used to measure the amounts of fat and lean body tissue and their distribution and further distinguish between intra-abdominal and extra-abdominal fat.

Miscellaneous tests- Hand grip strength (hand dynamometry)

- Several studies have confirmed the importance of muscle strength as a predictive factor for malnutrition.

- It is more useful when taken serially.

nutritional assessment

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