Keratomalacia

Definition

Starvation is the result of a serious, or total, lack of nutrients needed for the maintenance of life.

Description

Adequate nutrition has two components--necessary nutrients and energy in the form of calories. It is possible to ingest enough energy without a well-balanced selection of individual nutrients and produce diseases that are noticeably different from those resulting from an overall insufficiency of nutrients and energy. Although all foods are a source of energy for the organism, it is possible to consume a seemingly adequate amount of food without getting the required minimum of energy (calories). For example, marasmus is the result of a diet that is deficient mainly in energy. Children who get enough calories, but not enough protein have kwashiorkor. This is typical in cultures with a limited variety of foods that eat mostly a single staple carbohydrate like maize or rice. These conditions overlap and are associated with multiple vitamin and mineral deficits, most of which have specific names and set of problems associated with them.

• Marasmus produces a very skinny child with stunted growth.
• Children with kwashiorkor have body fat, an enlarged liver and edema--swelling from excess water in the tissues. They also have growth retardation.
• Niacin deficiency produces pellagra characterized by diarrhea, skin rashes, brain dysfunction, tongue, mouth and vaginal irritation, and trouble swallowing.
• Thiamine (Vitamin B₁) deficiency causes beriberi, which can appear as heart failure and edema, a brain and nerve disease, or both.
• Riboflavin deficiency causes a sore mouth and throat, a skin rash, and anemia.
• Lack of vitamin C (ascorbic acid)--scurvy--causes hair damage, bleeding under the skin, in muscles and joints, gum disease, poor wound healing, and in severe cases convulsions, fever, loss of blood pressure and death.
• Vitamin B₁₂ is needed to keep the nervous system working right, and it and pyridoxine (vitamin B₆) are both necessary for blood formation.
• Vitamin A deficiency causes at first loss of night vision and eventually blindness from destruction of the cornea, a disease called keratomalacia.
• Vitamin K is necessary for blood clotting.
• Vitamin D regulates calcium balance. Without it, children get rickets and adults get osteomalacia.

Causes & symptoms

Starvation is caused by a number of factors. They include:

• Anorexia nervosa
• Fasting
• Coma
• Stroke
• Famine
• Severe gastrointestinal disease.

Since the body will combat malnutrition by breaking down its own fat and eventually its own tissue, a whole host of symptoms can appear. The body's structure, as well as its functions, are affected.

Characteristic symptoms of starvation include:

• Shrinkage of vital organs, such as the heart, lungs, and ovaries or testes, and their functions.
• Chronic diarrhea
• Anemia
• Reduction in muscle mass and weakness because of it
• Low body temperature
• Decreased ability to digest food because of lack of digestive acid production
• Irritability
• Immune deficiency
• Swelling from fluid under the skin
• Decreased sex drive.

In children, chronic malnutrition is marked by growth retardation. Anemia is the first sign to appear in an adult. Swelling of the legs is next, due to a drop in the protein content of the blood. Loss of resistance to infection follows next, along with poor wound healing. There is also progressive weakness and difficulty swallowing, which may lead to inhaling food. At the same time, the signs of specific nutrient deficiencies may appear.

Treatment

If the degree of malnutrition is severe, the intestines may not tolerate a fully balanced diet. They may, in fact, not be able to absorb adequate nutrition at all. Carefully prepared elemental diets or intravenous feeding must begin the treatment. The treatment back to health is long and first begins with liquids. Gradually, solid foods are introduced and a daily diet of 5,000 calories or more is instituted.

Prognosis

People can recover from severe degrees of starvation to a normal stature and function. Children may suffer from permanent mental retardation or growth defects if their deprivation was long and extreme.

Key Terms

Anemia

Not enough red blood cells in the blood.

Anorexia nervosa

Eating disorder marked by malnutrition and weight loss commonly occurring in young women.

Cornea

The clear part of the front of the eye, through which vision occurs.

Kwashiorkor

Severe malnutritution in children caused by mainly by a protein-poor diet, characterized by growth retardation.

Marasmus

Severe malnutritution in children caused by a diet lacking mainly in calories. Can also be caused by disease and parasitic infection.

Further Reading

For Your Information

Books

• Baron, Robert B. "Protein and energy malnutrition." In Cecil Textbook of Medicine. Edited by J. Claude Bennett and Fred Plum. Philadelphia: W. B. Saunders, 1996, pp. 1154-1158.
• Denke, Margo and Jean D. Wilson. "Protein and energy malnutrition." In Harrison's Principles of Internal Medicine. Edited by Anthony Fauci, et al. New York: McGraw-Hill, 1998, pp. 452-454.
• Wilson, Jean D. "Vitamin deficiency and excess." In Harrison's Principles of Internal Medicine. Edited by Anthony Fauci, et al. New York: McGraw-Hill, 1998, pp. 480-487.

Gale Encyclopedia of Medicine. Gale Research, 1999.