Ross & Wilson Anatomy and Physiology in Health and Illness (128 page)

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Authors: Anne Waugh,Allison Grant

Tags: #Medical, #Nursing, #General, #Anatomy

BOOK: Ross & Wilson Anatomy and Physiology in Health and Illness

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The importance of nutrition is increasingly recognised as essential for health, and illness often alters nutritional requirements.

Malnutrition

This may be due to:

•
protein-energy malnutrition (PEM)

•
vitamin deficiencies

•
both PEM and vitamin deficiencies.

The degree of malnutrition can be assessed from measurement of body mass index (see
Box 11.1
).

Protein-energy malnutrition (
Fig. 11.2
)

This is the result of inadequate intake of protein, carbohydrate and fat. It occurs during periods of starvation and when dietary intake is inadequate to meet increased requirements, e.g. trauma, fever and illness. Infants and young children are especially susceptible as they need sufficient nutrients to grow and develop normally. If dietary intake is inadequate, it is not uncommon for vitamin deficiency to develop at the same time. Poor nutrition (malnutrition) reduces the ability to combat other illness and infection.

Figure 11.2
Features of protein-energy malnutrition.

Kwashiorkor

This is mainly caused by protein deficiency, and occurs in infants and children in some developing countries, especially when there has been serious drought and crop failure. Reduced plasma proteins lead to ascites and oedema (
p. 117
) in the lower limbs that masks emaciation. There is severe liver damage. Growth stops and there is loss of weight and loss of pigmentation of skin and hair accompanied by listlessness, apathy and irritability. Affected individuals are susceptible to infection and recovery from injury and infection takes longer.

Marasmus

This is caused by deficiency of both protein and carbohydrate. It is often caused by incorrect bottle feeding (overdilution of milk) or gastroenteritis, although people of any age can be affected. Marasmus is characterised by severe emaciation due to breakdown (catabolism) of muscle and fat. Growth is retarded, the skin becomes wrinkled due to absence of subcutaneous fat and hair is lost.

Malabsorption

The causes of malabsorption vary widely, from short-term problems such as gastrointestinal infections (
p. 317
) to chronic conditions such as cystic fibrosis (
p. 258
). Malabsorption may be specific for one nutrient, e.g. vitamin B
₁₂in pernicious anaemia (
p. 67
), or it may apply across a spectrum of nutrients, e.g. in tropical sprue (
p. 323
).

Obesity

In developed countries, this is a very common nutritional disorder in which there is accumulation of excess body fat. Clinically, obesity is present when body mass index exceeds 29.9 (see
Box 11.1
). It occurs when energy intake exceeds energy expenditure, e.g. in inactive individuals whose food intake exceeds daily energy requirements.

Obesity predisposes to:

•
gallstones (
p. 326
)

•
cardiovascular diseases, e.g. ischaemic heart disease (
p. 120
), hypertension (
p. 124
)

•
hernias (
p. 321
)

•
varicose veins (
p. 116
)

•
osteoarthritis (
p.424
)

•
type 2 (non-insulin dependent) diabetes mellitus (
p. 227
)

•
increased incidence of postoperative complications.

Conditions with dietary implications

In addition to nutritional disorder there are many conditions where dietary modifications are needed. Some of these are listed in
Box 11.3
.