1. Under-nutrition and hospital nutrition
By:
Dr. Wael Thanoon
C.A.B.M.
College of medicine ,Mosul University.

2. There remain regions of the world, particularly rural Africa, where under-nutrition due to famine is endemic, the prevalence of BMI < 18.5 kg/m2 in adults is as high as 20%, and growth retardation due to under-nutrition affects 50% of children.
under-nutrition is defined as BMI<18.5,and can be graded to 3 stages:
Mild:BMI
Moderate:16-17
Severe : less than 16

3. Causes of under-nutrition and weight loss in adults:
A) Decreased energy intake:
Famine
Persistent regurgitation or vomiting
Anorexia, including anorexia nervosa
Malabsorption (e.g. small intestinal disease)
Maldigestion (e.g. pancreatic exocrine insufficiency)
B) Increased energy expenditure:
Increased BMR (thyrotoxicosis, trauma, fever, cancer cachexia)
Excessive physical activity (e.g. marathon runners)
Energy loss (e.g. glycosuria in diabetes)
Impaired energy storage (e.g. Addison's disease, phaeochromocytoma) .

4. clinical features: weight loss
thirst, craving for food, weakness and feeling cold
nocturia, amenorrhoea or impotence
lax, pale, dry skin with loss of turgor and, occasionally, pigmented patches
cold and cyanosed extremities, pressure sores
hair thinning or loss (except in adolescents)
muscle-wasting, best demonstrated by the loss of the temporalis and periscapular muscles and reduced mid-arm circumference
loss of subcutaneous fat, reflected in reduced skinfold thickness and mid-arm circumference
hypothermia, bradycardia, hypotension and small heart
oedema, which may be present without hypoalbuminaemia ('famine oedema')
distended abdomen with diarrhoea
diminished tendon jerks
apathy, loss of initiative, depression, introversion, aggression if food is nearby
susceptibility to infections: Gastroenteritis and Gram-negative septicaemia,Respiratory infections, especially bronchopneumonia,Certain viral diseases, especially measles and herpes simplex,Tuberculosis,Streptococcal and staphylococcal skin infections,Helminthic infestations .

5. laboratory investigations: severe cases:
plasma free fatty acids are increased and there is ketosis and a mild metabolic acidosis.
Plasma glucose is low but albumin concentration is often maintained because the liver still functions normally.
Insulin secretion is diminished, glucagon and cortisol tend to increase, and reverse T3 replaces normal triiodothyronine
The resting metabolic rate falls, partly because of reduced lean body mass and partly because of hypothalamic compensation.
There may be mild anaemia, leucopenia and thrombocytopenia.
The erythrocyte sedimentation rate is normal unless there is infection.
The electrocardiogram shows sinus bradycardia and low voltage..

6. Management
Whether in a famine or in wasting secondary to disease, the severity of under-nutrition is graded according to BMI. People with mild starvation are in no danger; those with moderate starvation need extra feeding; those who are severely underweight need hospital care.
In severe starvation, there is atrophy of the intestinal epithelium and of the exocrine pancreas, and the bile is dilute. When food becomes available, it should be given by mouth in small, frequent amounts at first, using a suitable formula preparation .
Individual energy requirements can vary by 30%. During rehabilitation, more concentrated formula can be given with additional food that is palatable and similar to the usual staple meal.
Salt should be restricted and micronutrient supplements may be essential (e.g. potassium, magnesium, zinc and multivitamins). Between 6.3 and 8.4 MJ/day ( kcal/day) will arrest progressive under-nutrition, but additional energy may be required for regain of weight.
During refeeding, a weight gain of 5% body weight per month indicates satisfactory progress. Other care is supportive, and includes attention to the skin, adequate hydration, treatment of infections, and careful monitoring of body temperature since thermoregulation may be impaired

7. Under-nutrition in hospital:
Under-nutrition is a common problem in the hospital setting. In the UK, approximately one-third of patients are affected by moderate or severe under-nutrition on admission. The elderly are particularly at risk (Box 5.34). Once in hospital, many patients lose weight due to factors such as poor appetite, poor dental health, concurrent illness and even being kept 'nil by mouth' for investigations. Under-nutrition is poorly recognised in hospital and has serious consequences.

8. Nutritional support of the hospital patient :
Normal diet : As a first step, patients should be encouraged to eat a normal and adequate diet. This is often neglected and there is evidence of substantial wastage in hospital food. In patients at risk of under-nutrition ,quantities eaten should be recorded on a food chart. Hospital staff must identify and overcome barriers to adequate food intake, such as unpalatability of food, cultural and religious factors influencing acceptability of food, difficulty with hand dexterity (arthritis, stroke), immobility in bed, or poor oral health. Hospital catering departments have an important role in providing acceptable and adequate meals.
Dietary supplements :If sufficient nutritional intake cannot be achieved from normal diet alone, then dietary supplements should be used. These are drinks with high energy and protein content, and are available in cartons as manufactured, flavoured products or made in the hospital kitchen from milk products and egg. They should be prescribed, and administered by nursing staff, to ensure that they are taken regularly. Dietary supplements do not significantly affect the patient's consumption of normal food.

9. Enteral tube feeding :Patients who are unable to swallow may require artificial nutritional support: for example, after acute stroke or throat surgery or with long-term neurological problems such as motor neuron disease and multiple sclerosis. The enteral route should always be used if possible, since feeding via the gastrointestinal tract preserves the integrity of the mucosal barrier. This prevents bacteraemia and, in intensive care patients, reduces the risk of multi-organ failure .

10. Parenteral nutrition:
Intravenous feeding should only be used when enteral feeding Is impossible. Parenteral feeding is expensive and carries higher risks of complications. There is little benefit if parenteral feeding is required for less than 1 week.
There are a number of possible routes for parenteral nutrition:
Peripheral venous cannula. This can only be used for low-osmolality solutions due to the development of thrombophlebitis, and is unsuitable for patients with high nutritional requirements.
Peripherally inserted cannula (PIC). A 20 cm cannula is placed in a mid-arm vein. Once again, hyperosmolar solutions cannot be used.
Peripherally inserted central catheter (PICC). A 60 cm cannula is inserted into a vein in the antecubital fossa. The distal end lies in a central vein, allowing hyperosmolar solutions to be used.
Central line. The subclavian route is preferred to the internal jugular vein, due to lower infection rates. Hyperosmolar solutions can be used without difficulty. Lines need to be handled with strict aseptic technique, and a single lumen tube is preferred, to prevent infection.

11. If access has been gained to a central vein, nutritional support is usually given as an 'all in one' mixture. The main energy source is provided by carbohydrate, usually as glucose. The solution also contains amino acids, lipid emulsion, electrolytes, trace elements and vitamins. These are mixed as a large bag in a sterile environment, with the constituents adjusted according to the results of regular blood monitoring. Relevant tests include:
daily: urea and electrolytes, glucose
twice weekly: liver function tests, calcium, phosphate, magnesium
weekly: full blood count, zinc, triglycerides
monthly: copper, selenium, manganese