Metabolism Problems

Metabolism Problems

In a broad sense, a metabolic disorder is any disease that is caused by an abnormal chemical reaction in the body's cells. Most disorders of metabolism involve either abnormal levels of enzymes or hormones or problems with the functioning of those enzymes or hormones. When the metabolism of body chemicals is blocked or defective, it can cause a buildup of toxic substances in the body or a deficiency of substances needed for normal body function, either of which can lead to serious symptoms.

Some metabolic diseases are inherited. These conditions are called inborn errors of metabolism. When babies are born, they're tested for many of these metabolic diseases in a newborn screening test. Many of these inborn errors of metabolism can lead to serious complications or even death if they're not controlled with diet or medication from an early age.

Examples of metabolic disorders and conditions include:

G6PD deficiency. Glucose-6-phosphate dehydrogenase, or G6PD, is just one of the many enzymes that play a role in cell metabolism. G6PD is produced by red blood cells and helps the body metabolize carbohydrates. Without enough normal G6PD to help red blood cells handle certain harmful substances, red blood cells can be damaged or destroyed, leading to a condition known as hemolytic anemia. In a process called hemolysis, red blood cells are destroyed prematurely, and the bone marrow (the soft, spongy part of the bone that produces new blood cells) may not be able to keep up with the body's need to produce more new red blood cells. Kids with G6PD deficiency may be pale and tired and have a rapid heartbeat and breathing. They may also have an enlarged spleen or jaundice — a yellowing of the skin and eyes. G6PD deficiency is usually treated by discontinuing medications or treating the illness or infection causing the stress on the red blood cells.

Galactosemia. Babies born with this inborn error of metabolism do not have enough of the enzyme that breaks down the sugar in milk called galactose. This enzyme is produced in the liver. If the liver doesn't produce enough of this enzyme, galactose builds up in the blood and can cause serious health problems. Symptoms usually occur within the first days of life and include vomiting, swollen liver, and jaundice. If galactosemia is not diagnosed and treated quickly, it can cause liver, eye, kidney, and brain damage.

Hyperthyroidism. Hyperthyroidism is caused by an overactive thyroid gland. The thyroid releases too much of the hormone thyroxine, which increases the person's basal metabolic rate (BMR). It causes symptoms such as weight loss, increased heart rate and blood pressure, protruding eyes, and a swelling in the neck from an enlarged thyroid (goiter). The disease may be controlled with medications or through surgery or radiation treatments.

Hypothyroidism. Hypothyroidism is caused by an absent or underactive thyroid gland and it results from a developmental problem or a destructive disease of the thyroid. The thyroid releases too little of the hormone thyroxine, so a person's basal metabolic rate (BMR) is low. In infants and young children who don't get treatment, this condition can result in stunted growth and mental retardation. Hypothyroidism slows body processes and causes fatigue, slow heart rate, excessive weight gain, and constipation. Kids and teens with this condition can be treated with oral thyroid hormone to achieve normal levels in the body.

Phenylketonuria. Also known as PKU, this condition occurs in infants due to a defect in the enzyme that breaks down the amino acid phenylalanine. This amino acid is necessary for normal growth in infants and children and for normal protein production. However, if too much of it builds up in the body, brain tissue is affected and mental retardation occurs. Early diagnosis and dietary restriction of the amino acid can prevent or lessen the severity of these complications.

Type 1 diabetes mellitus. Type 1 diabetes occurs when the pancreas doesn't produce and secrete enough insulin. Symptoms of this disease include excessive thirst and urination, hunger, and weight loss. Over the long term, the disease can cause kidney problems, pain due to nerve damage, blindness, and heart and blood vessel disease. Kids and teens with type 1 diabetes need to receive regular injections of insulin and control blood sugar levels to reduce the risk of developing problems from diabetes.

Type 2 diabetes. Type 2 diabetes happens when the body can't respond normally to insulin. The symptoms of this disorder are similar to those of type 1 diabetes. Many kids who develop type 2 diabetes are overweight, and this is thought to play a role in their decreased responsiveness to insulin. Some can be treated successfully with dietary changes, exercise, and oral medication, but insulin injections are necessary in other cases. Controlling blood sugar levels reduces the risk of developing the same kinds of long-term health problems that occur with type 1 diabetes.