Growth Hormone Deficiency (GHD)

It is a type of short stature due to growth hormone deficiency. The disorder is relatively rare: it occurs in about 1 in 2000-4000 children.

It is caused by a lack of growth hormone (GH). This hormone is essential for normal growth. Individuals with a complete lack of growth hormone (isolated GH deficiency) are about 30-40 cm shorter than those with normal growth hormone production. If there are also other hormone deficiencies present, such as thyroid hormone deficiency, the difference is even greater. 

Growth hormone deficiency can have many causes. Based on current knowledge, physicians find a real explanation in only 60% of patients. 

• In one group of children (about 10%), growth hormone deficiency is present from birth, for example as a result of abnormalities in the hypothalamic-pituitary region of the brain. These abnormalities often have a genetic cause. 
• Growth hormone deficiency can also develop later in life due to damage to the hypothalamus or pituitary gland caused by infections (meningitis, encephalitis), trauma, infiltration by other cells (histiocytosis, granulomas) or vascular problems. 
• Tumours can also develop in and above the pituitary gland and destroy it, such as craniopharyngiomas, germinomas and tumours of the optic nerves. 
• When tumours in the brain or in the nose are irradiated, the pituitary gland may be in the irradiation field. If the dose is high enough, the patient will almost certainly develop growth hormone deficiency. In most cases there are also deficiencies of other pituitary hormones. 
• A long list of syndromes is also associated with growth hormone deficiency. 
• Many children with this condition have temporary, isolated growth hormone deficiency. The cause of this deficiency is usually unknown. When the growth hormone test is repeated in adulthood, growth hormone levels appears to be sufficient. 

• Physical examination 
• X-Ray of the left hand: Delayed skeletal maturation: the “skeletal age” or “bone age” is often more than 1 year younger than the chronological age. 

• Low blood levels of insulin-like growth factor 1 (IGF-1) 
• Growth hormone tests 

The definitive diagnosis of growth hormone deficiency is based on 2 abnormal growth hormone stimulation tests. 

Blood needs to be drawn at the time of a growth hormone peak. For this, it is necessary to provoke a peak by first injecting a substance that stimulates growth hormone release. There is a long list of substances used for this, but BESPEED members have all decided to use glucagon for the first test and insulin for the second test (if the child is over 4 years of age and does not have epilepsy). The second test is only necessary if the first test is abnormal. 

Physical signs of growth hormone deficiency are: 

• Slow growth rate: the growth curve crosses the percentile lines in a downwards direction: we call this a “deflecting growth curve”. If the growth retardation lasts for a long time, height will fall below the bottom line of the growth curve. 
• Leg length seems rather short compared to torso length 
• Delayed growth of the bones in the face: snub nose, protruding forehead, chubby cheeks (“doll face”) 
• Delayed growth of the vocal cords: high voice 
• Delayed growth of hair and nails 
• Low muscle mass and muscle strength 
• Fat accumulation mainly on the stomach, thighs and upper arms (“Michelin figure”) 
• If the growth hormone deficiency is congenital, children may have low blood sugar levels (hypoglycaemia) after birth and also remain “yellow” for a long time (“prolonged jaundice”). Boys often have a small penis (less than 2.5 cm in length). 

Growth hormone deficiency is treated by administering growth hormone. Growth hormone cannot be taken by mouth because it breaks down in the stomach and intestines. It is therefore administered by injection in the subcutaneous fatty tissue once a day, usually in the evening.  

The results of growth hormone treatment are very good if the treatment is started at the right time and if the injections are administered faithfully on a daily basis. The growth rate increases within 3 months of the beginning of treatment, and during the first year of treatment, children often grow 10 cm or more. Results from all over the world show that adult height after growth hormone treatment is close to target height, which is the height that would be predicted for a child based on his/her parents’ height. The results of children who were irradiated on the spine are not quite as good, because the vertebrae cannot respond properly to the growth hormone treatment due to the irradiation.