7 Abnormal Growths

Dr. Suman Dua

Introduction

Growth is the progressive increase in the size of a person or parts of a person. Development is the acquisition of various skills to perform specific functions. Growth and development go together but at different rates. A good state of health and nutrition of a person can be assessed by his growth and development. Measurement of growth therefore is very essential to know whether the growth is taking place at a normal pace or not. Abnormal growth or growth failure indicates symptom of disease. Growth occurs when there is increase in size of bones of the arms, legs, and back. Their is growth plate, at the end of long bones, which is made of cartilage cells which form new bone. These cartilage cells are replaced by spaces. The spaces are filled up by bones (deposition of calcium and phosphorus) which are produced by osteoblasts. Growth is said to have stopped when all the cartilageous tissue has been replaced into bone. This usually occurs before the attainment of 16 to 18 years. The bone age or the maturation of the bone can be assessed by taking the X-ray of the hand or knee. Three are many causes of abnormal growth some are temporary and merely variations of the normal pattern of growth. Abnormal growth may result due genetic factors or may be associated with other physical problems. In order to maintain general health and growth of a child, the parents should regularly get the child examined and measured.

Learning Outcome

There are a number of conditions that may lead to decreased or increased growth rate and / or short or tall stature, which could be detected through growth monitoring. Conditions in which stature outside the normal range is often the only or most significant presenting feature are growth hormone deficiency and Turner’s syndrome (TS) Such conditions justify growth screening in childhood.

Short stature may result from hypothyrodism, psychosocial deprivation, and intrauterine growth retardation or other chronic diseases. Tall stature may be due to Marfan syndrome and Klinefelter syndrome, or a sign of treatable endocrine disorders. Early detection of organic causes of abnormal growth is important.

At birth all children are of the same size. Even then, every individual varies in size and shape. Growth standards i.e. range of normal height and weights for different age groups can be used to monitor growth of children. A growth chart is used to compare a child’s height and growth rate with children of the same age. A standard growth chart refers to one in which a large number of children of different ages are taken and a graph of their heights and weights is made. The most commonly used growth charts are from the National Center for Health Statistics (NCHS) and are age and gender specific. When the height is at the 50th percentile, it means the height at which half of the children of that age are taller and half are shorter. When it is at 25th percentile, it means 75 percent of the children are taller at that age, while 25 percent are shorter. Similarly, 75th percentile means that 75 percent will be shorter and 25 percent taller. As there is a lot of variation, and if children are between the 3rd and 97th percentile but if they are growing at a normal rate, they will be regarded as normal. If children are outside these ranges (over97th percentile or under 3rd percentile. The reasons for such differences are searched for. These children may have inherited “short” or “tall” genes from their parents. In most of the cases, they however, continue to grow at a normal pace. What is the normal growth rate during childhood? Most children establish a pattern of growth by 3 years of age and do not deviate from this pattern until the onset of puberty. During this time, the normal growth rate is 2-2.5 inches/year (5-6.5 cm/year). When patients in this age group cross over or change growth channels, this may signal a growth problem and should be evaluated further.

Mid-parental Height: This calculation provides a target mean and range for the genetic potential of a child based upon the biologic parents’ heights. This calculation alone is not sufficient to predict final height; it only calculates a reference range for assessing growth mid-parental height = (father’s height – 5 in.) + (mother’s height) for girls (inches) 2 mid-parental height = (mother’s height + 5 in.) + (father’s height) for boys (inches) 2 Target height = mid-parental height ± 2 SD (1 SD = 2 in).

Key points

• A child’s growth needs to be regularly monitored. This can be done with the help of growth charts and  the child’s doctor.
• Poor feeding sessions or illness can lead to a slow growth, but this may not be a growth disorder.
• A growth disorder may be present at birth or acquired later.

1. A child’s growth and development can be influenced by:

• eating habits and nutrition
• presence or absence of chronic illness
• genetics
• endocrine function (hormones)

1.1  NUTRITION AND SYSTEMIC DISEASES

There are many diseases and disorders that can cause short stature and growth failure. Malnutrition in some parts of the world leads to abnormal growth. Poor nutrition may result into poor growth. There are a number of intestinal disorders which may lead to poor absorption of food. Failure to absorb nutrients and energy from food then leads to growth failure. Children with these conditions may have complaints that involve the stomach or intestines. Treatment of these conditions often involves a special diet. Normal growth usually resumes after proper treatment is taken. Chronic diseases affecting growth are diabetes, congenital heart disorders, sickle cell disease,etc.

1.2 BONE DISORDERS

Several inherited bone diseases influence growh and maturation. In achondroplasia, a dominant inherited abnormality, the cartilage cells mature less rapidly than normal.This leads to short long bones and the skin of limbs tends to hang in folds. Physical performance is not much affected. A recessive abnormality known as Osteochondrodystrophy, results in decreased growth of articular cartilage and consequently metaphysical development is delayed. Degenerative changes in joints, sclerosis may lead to restriction of movement. The underlying causes of most of these skeletel dysplasias are not known. Researches are being done to identify the genetic and biochemical mechanishms.

1.3 INTRAUTERINE GROWTH RETARDATION

Some infants are small at birth, as they are born earlier than usual time. Such babies are premature. Some infants are shorter and weigh less than they should at birth. In other words, they had a chance to grow in the womb, but did not reach the length and weight they should have for their gestational age (length of the time in the womb).

This failure to grow normally in the womb is called intrauterine growth retardation.

A problem with the placenta, the organ in the mother’s womb,through which nutrients and oxygen pass to the baby, may result in such conditions.During pregnancy,German measles a viral infection may affect the placenta , causing intrauterine growth retardation. This condition cannot be identified in some case. Such children will remain small throughout life, whereas some of them may reach normal size. Intrauterine growth retardation may result because of so many reasons. Researches are being done to see if growth hormone is effective in increasing the growth rate and adult height of these children.

1.4  GROWTH AND PUBERTY

Adolescence, is marked by growth spurt . Girls experience growth spurt about two years earlier than boys. Rates of growth and changes during puberty show individual variation.Growth and puberty patterns are passed from parents to their children. If one or both parents had a late puberty, then their children may also have late puberty and experience a late growth spurt. This is what is known as ,constitutional growth delay.

SEX HARMONES

Puberty is marked by the increase in production of sex hormones and hence a increased rate of growth.

The harmones are estrogen from ovaries in girls, and testosterone from the testicles in boys. These hormones are responsible for skeletal growth and maturation. Adrenal glands produce hormones which contribute to the development of secondary hair and under arm hair.Abnormal pubertal development can affect a child’s growth and ultimate height.On the basis of onset of Puberty,it may be grouped into two categories. (i) Precocious or premature puberty. (ii) delayed or late puberty.

1.4.1    PRECOCIOUS PUBERTY

If changes in sexual developmet occour before age eight among girls and before age ten among boys,it is referred to as precocious puberty (early). Children with precocious puberty have symptoms similar to normal puberty. The children with precocious puberty experience growth spurts early.This causes these children to grow taller than children of same age,as well as their skeletons mature rapidly.This results in stopping the growth at an early age. Therefore precocious puberty may lead to a decrease in a child’s ultimate height. Proper treatment is therefore required.

Precocious puberty may result as a result of conditions like, brain tumors or genetic abnormality and other disorders of the central nervous system; conditions that cause the gonads or adrenal glands to overproduce sex hormones. In girls, however,in the majority of cases of precocious puberty,a cause cannot be identified. Precocious puberty can be divided into two categories central precocious puberty and peripheral precocious puberty.

Central Precocious Puberty also known as gonadotropin-dependent precocious puberty, occurs when the abnormality is located in the brain. Central precocious puberty is the most common form of precocious puberty and affects many more girls than boys. The causes of central precocious puberty include: brain tumors, or infection. Often, however, there is no identifiable abnormality in the brain; this is called idiopathic central precocious puberty.

Peripheral precocious puberty is also called gonadotropin-independent precocious puberty can be controlled with medicines which decrease the overproduction of sex hormones .This prevents or decrease the shortening of the child’s ultimate height that would otherwise take place.

1.4.2 DELAYED PUBERTY

Puberty may be delayed if the hormonal changes of puberty occur later than normal range of ages,at which they occur. Puberty, when it has not begun by age 13 in girls or by age 15 in boys,is considered late.Children who experience delayed puberty follow the normal pattern called constitutional growth delay.

Several disorders of brain,pituitary, ovaries, and testicles can result in delayed puberty due to the rise in sex hormones.Chronic disorders of other organs such as the intestines and lungs, or medical treatments o may cause delayed puberty. Children with delayed puberty go through an otherwise normal puberty, just at a late age. This delay is due to the fact that they are maturing slowly than average, also known as constitutional delay of puberty. This condition often runs in families.

Im proper nutrition due to long-term illnesses can delaying puberty strenuous physical training (running or gymnastics) may cause delayed puberty in girls. A medical condition, in which the sex glands (the testes in men and the ovaries in women) produce few or no hormones may cause delayed puberty. Hypogonadism can be divided into two categories: secondary hypogonadism and primary hypogonadism.

Secondary hypogonadism (also known as central hypogonadism is caused by a problem with the pituitary gland or hypothalamus (part of the brain). In secondary hypogonadism, the hypothalamus and the pituitary gland fail to signal the gonads to properly release sex hormones. In primary hypogonadism, the problem lies in the ovaries or testes, which fail to make sex hormones normally. Some causes include, Genetic disorders, especially Turner Syndrome (in women) and Klinefelter syndrome (in men) certain autoimmune disorder, infection surgery etc.

1.5         GENETIC DISORDERS

1.5.1     TURNER SYNDROME

Short stature in girls may be caused by a genetic condition that affects the X chromosome. Chromosomes are small thread-like bodies in the nucleus of each cell; they contain the genetic material that determines the characteristics we inherit. Two of these chromosomes determine sexual development-the X and Y chromosomes. Boys have one X and one Y chromosome, and gilrs have two X chromosomes. In girls with Turner Syndrome, one of the X chromosomes is misshapen or missing in many or all body cells. Because of this, girls with this syndrome are short and may have undeveloped ovaries. Intelligence is normal. Turner Syndrome may be present because of the presence of certain physical features, but poor growth is sometimes the only sign. A special blood test (karypotype) is done to look for damaged or missing sex chromosomes. Replacemtn of the missing ovarian hormones in these girls help to develop normal female sexual characteristics.

1.5.2    MARFAN SYNDROME

Some genetic conditions may result into abnormally tall stature. A hereditary condition affecting connective tissue and associated with tall stature is known as Marfan syndrome. People with Marfan syndrome have very long extremities, eye problems, and differences in facial features. Heart abnormalities, also may be pres.

Abraham Lincoln had Marfan syndrome,as believed. Klinefelter’s syndrome is also oen such example of abnormal tall stature.

1.6 GROWTH DISORDERS DUE TO HORMONES

Growth is controlled by hormones secreted by glands. One of the most important, growth hormone is secreted by the pituitary gland. Other hormones also are essential for growth. The thyroid gland secretes thyroxine, a hormone required for normal bone growth,sex hormones are secreted from the ovaries.

1.6.1    PITUITARY HORMONES

The pituitary gland is attached by a stalk to the hypothalamus, an area of the brain that controls the function of the pituitary. The pituitary gland secretes—Growth hormone to regulate bone growth,,Thyroid-stimulating hormone which controls the production and secretion of thyroid hormones,Gonad-stimulating hormones for development of the sex glands (gonads) and secretion of sex hormones, Adrenal-stimulating hormone which regulates the secretion of adrenal gland hormones.

1.6.1.1Hypopituitarism

Sometimes the pituitary gland does not secrete enough growth hormone,as a result,child grows slowly. The deficiency may be seen any time during infancy or childhood. When other causes of growth failure have been ruled out, special tests for growth hormone (GH) deficiency,can be done. Children with growth hormone deficiency are treated with daily injections of the hormone, often for a period of years. With timely diagnosis and treatment, these children may increase their rate of growth, and catch up to achieve average or near-average height as adults.

Low amounts of growth hormone may result into short stature but the person has normal body proportions – pituitary dwarfism. This is different from other forms of dwarfism . In them, the person with dwarfism is short, and the growth of the arms, legs, torso, and head often is out of proportion. For example, the person’s arms and legs may appear relatively smaller than the head or torso.

1.6.1.Hyperpituitarism

Excessive amounts of growth hormone in the body may result into: acromegaly and gigantism. This cause may be due to tumor in the pituitary,

(i)  Acromegaly, a condition caused by raised levels of growth hormone.Occurs when normal growth has been completed in adults. The condition is rare, occurring in 6 out of 100,000 people. As the adults cannot increase their height after a certain limit, the excess growth hormone in acromegaly causes their bones to thicken as well as other structures and organs to grow larger. This usually takes place in the middle age.

(ii) Gigantism results when excessive secretion of growth hormone takes place in children before normal growth has stopped. Overgrowth of long bones takes place. The growth in height is accompanied by growth in muscle and organs. The person becomes very tall, with a large jaw, large face, large skull, and very large hands and feet. Gigantism may be associated with health problems such as heart disease and vision problems, etc.

1.6.2Too little thyroid hormone (hypothyroidism)

The thyroid gland is at the base of the neck. The thyroid gland makes the hormone thyroxine.

The thyroid is controlled by the pituitary gland, which makes thyroid-stimulating hormone. The hormone thyroxine controls the rate of chemical reactions (or metabolism) in the body. Too much thyroxine, or hyperthyroidism, increases metabolic rate.

Hypothyroidism occurs due to underproduction of thyroid hormone in the body. A child has slow growth and is physically and mentally sluggish. The lack of this hormone may be present at birth, if the thyroid gland did not develop properly in the fetus. Or the problem may develop during childhood or later in life as a result of certain diseases of the thyroid. Mostly, babies are tested for hypothyroidism at birth. Blood tests can detect the problem, and pills may be be given that replaces the missing thyroid hormone. Early diagnosis and treatment may help these children so that normal growth and development can take place.

1.6.3     Cushing’s syndrome.

Cortisol,is secreted by the adrenal glands, which are located on top of the kidneys in the abdomen Large secretion of cortisol by the child’s adrenals, or if, large-doses of the hormone are given to the child in order to treat certain diseases, Cushing’s syndrome may develop. Children with this syndrome grow slowly, gain weight excessively, and may experience delayed puberty due to the effects of the abnormally large amounts of cortisol in the body.

1.6.4     Obesity

The hormones leptin and insulin, sex hormones and growth hormone influence our appetite, metabolism (the rate at which our body burns kilojoules for energy), and body fat distribution. People who are obese have levels of these hormones that encourage abnormal metabolism and the accumulation of body fat.

SUMMARY

Growth may be affected by  Systemic disorders

Such as:

-malnutrition

-renal disease

– growth failure secondary to rickets, acidosis, and nutritional failure

– resistance to GH

-diabetes

– poor control, with significant acidosis, will result in significant growth retardation cardiac

– growth failure may be due to cyanosis and hypoxia

– other unclear underlying mechanisms

-hematologic disease – chronic anemia

-gastrointestinal disorders – chronic liver disease

– celiac disease

– other causes of malabsorption

-respiratory disease

-endocrine disorders

– hypothyroidism

– growth hormone deficiency/inadequacy

– cortisol excess

– congenital disorders

– intrauterine growth retardation

– skeletal dysplasia

– other genetic syndromes (e.g., turner’s syndrome)