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In the Know All about… growth hormone deficiency (GHD)

January 26, 2017      

By Mendy Hecht, Hamaspik Gazette

In the Know

All about… growth hormone deficiency (GHD)

Once upon a time, children who were born short remained short—especially if they came from families who were naturally short.

However, modern medicine has known for some time now that many cases of short children (and the resulting short adults), medically referred to as short stature, are caused by the body not producing enough growth hormone during the growing years. 

In typically developing children, the body’s pituitary gland produces enough growth hormone for the child to grow bigger and taller each year within an established normal range, up to full adulthood.

In children with under-producing pituitary glands, though, kids are typically on the low end of (or below) the average height range for their age—growing slower than typical kids and not reaching average height by adulthood.

But thankfully, this deficiency in natural growth hormone can be largely corrected in many children with synthetic (man-made) growth hormone—resulting in children reaching adolescence and full adulthood at average height, or at least significantly closer to it.

Do read on to grow (pun definitely intended) your knowledge of GHD.

Definition

Growth hormone deficiency (GHD) in children is a relatively rare disorder.  It may be defined as short stature and/or global developmental delay resulting from inadequate production of growth hormone (GH) by the pituitary gland.

The pituitary gland is a small gland located at the base of the brain.  It is responsible for the production of several hormones, including growth hormone—which for some reason does not have a fancy medical name but is just called “growth hormone.”

In most cases of GHD, it is present from birth (congenital).  It can show up later in life due to trauma, infection, radiation therapy, or a tumor in the brain in other cases.  

Some adults can develop GHD, too—but that’s a different topic.

Symptoms

The primary and most obvious symptom of childhood GHD is slow overall growth throughout childhood, especially early childhood.

Because of the slowed or stopped growth, the child will be much shorter than most children of the same age and gender.

The child will still have normal body proportions, but may be chubby.  The child’s face often looks younger than other children of the same age, particularly in a smaller/shorter bridge of the nose.

The child will have normal intelligence in most cases.

Cause

The cause of GHD is the pituitary gland not producing enough growth hormone.

The pituitary gland is located at the base of the brain.  It controls the body’s balance of hormones.  It also makes growth hormone, which makes a child grow.

In most cases, it is unknown why the pituitary gland does not produce enough growth hormone.

Diagnosis

The presence of GHD is often noticed during the child’s first two or three years, or as early as infancy, by a competent pediatrician.  The pediatrician will observe that the child’s growth rate, as penciled in on the child’s growth chart, is below normal range.  It may be slow or even flat.

A physical exam, including weight, height, and body proportions, will show signs of slowed growth.  A child eventually diagnosed with GHD will not follow normal growth curves.

Before suspecting GHD, the pediatrician will first rule out malnutrition and/or other family, psychological, or social factors that may be causing poor (or non-existent) growth.

After that, the pediatrician will commonly refer the patient to an endocrinologist, a doctor who specializes in the body’s levels of hormones and other natural chemicals.

To further zero in on a GHD diagnosis, the pediatrician or endocrinologist will typically test the patient for levels of two natural substances in the body: insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP3).

Healthy levels of growth hormone make the body make these two natural substances—so, low levels of growth hormone results in low levels of IGF-1 and IGFBP3.

The so-called stimulation test for these two levels takes several hours.

Tests for levels of other hormones may also be done, because a lack of growth hormone may not be the only problem behind short stature or poor growth.

If called for, an MRI scan can also be used to see if the pituitary gland is of healthy size and function.

At some point in the diagnosis process, an x-ray of the hand and wrist called a bone age test will typically also be done.  Normally, a person’s bones change in size and shape as he or she grows.  These changes can be seen on an x-ray—and most often follow a pattern as a child grows older. 

Based on those patterns, then, a bone age test on a child’s hand can predict how many more years of growth the child has left.  This information, together with all other rest results, will then be used to determine if the child should get growth hormone injections.

Treatment

Children diagnosed with GHD will be given shots (injections) of synthetic growth hormone.

Growth hormone shots are a long-term treatment.  They often go on for several years.

These shots are almost always given at home.  Younger children will get their shots from their parents.  Older children can actually do it themselves.  The shots are usually given once a day. 

The injections involve a thin, short and virtually painless needle and “pen,” a hand-held injection device.  The actual growth hormone comes in the form of liquid medication that must be kept refrigerated. 

Each day, the parent (or older responsible child) inserts a small vial of medication into the pen, attaches a disposable sterile needle to its tip, presses the device against a large muscle in the arm or leg, and pushes down the injector button.  The needle then painlessly pierces the skin and reaches the deep muscle tissue below, where the medication enters. 

Once the shot is given, the needle retracts, and is disposed of in a special container provided to the parents (along with the supply of growth hormone, disposable needles and other items).

The shot should generally be injected in a different part of the body each day.  As general rule, there are eight recommended locations on the body, and parents and child should first agree on four of them, and then rotate them such that each gets “poked” only once every four days.

Throughout the long-term treatment regimen, the child will be seen regularly by the pediatrician and/or endocrinologist to ensure that it is working.  The doctor(s) will change the dosage as necessary.

Note that some children with GHD may not be able to get these injections, often because of other conditions; your endocrinologist will be able to explain exactly why.

Common side effects include headache, fluid retention, muscle and joint aches, and slippage of the hip bones.  Serious side effects of growth hormone treatment are rare.

There are a number of FDA-approved brand-name synthetic growth hormone products that your child’s doctor may prescribe. These include Nutropin, Humatrope, Genotropin, Saizen, Norditropin, Tev-Tropin and Omnitrope.

Which one your child ends up using depends on any of, or any combination of, the following factors, including: your child’s remaining growth years, your child’s specific medical information, doctor opinion(s), and benefits/advantages of specific products.

With insurance plans, you may have to expect an uphill battle.  This is because synthetic growth hormone is very expensive, and insurance companies simply don’t want to pay for it.

Some companies do not cover any growth hormone treatment.  Some will, but only using specific brand name and/or only for relatively short times.  Some will initially reject coverage requests and then relent under doctor appeals.  However, some drug manufacturers also have patient assistance programs that provide growth hormone supplies at low or free cost to qualifying parents.  Speak to your doctor and/or to your insurance company customer service hotline for more information.

Prognosis

The main thing to expect is growth!  Although it takes about three to six months to realize any height differences, the important thing is that your child will grow—probably one to two inches within the first six months of starting treatment.  There may be a few other things you notice:

Your child may outgrow his or her shoes quickly.  Foot growth may occur within six to eight weeks, so you may have to buy new shoes more often.

Your child may want to eat more.  An increase in appetite is common, especially if he or she had a poor appetite before treatment.

Your child may look skinnier for a while once height growth starts.  An increase in lean body mass and decrease of fat mass are common with growth hormone treatment.

Many children can gain as much as four or even more inches during the first year of treatment, and three or more inches over the two years following that.  The growth rate then slowly decreases.

The key to successful treatment of childhood GHD is to catch it early enough so that the child can be started on a regimen of growth hormone injections—a regimen that, if started early enough, can give the otherwise short child as many years of increased growth as possible.

In short (this time, no pun intended), the earlier the condition is treated, the better the chance that a child will grow to near-normal adult height.