Short stature

Short stature is defined by national standards of growth and centile charts, taking into account mid parental height, and is generally accepted as a standing height >2SD below the mean. The commonest causes are familial short stature and constitutional delay of growth. Growth hormone deficiency, GH resistance, hypothyroidism, Turner and Cushing’s syndrome are rarer endocrine causes, and malnutrition remains the commonest cause worldwide.

Calculate height velocity

Height velocity requires a minimum of 6 months measurements. Age needs to be decimalised ie 10.5 years, not 10 years 6 months. This is expressed cm/year.

Baseline investigations - all patients

Full blood count, ESR and ferritin

Normocytic normochromic anaemia and eosinophilia may be seen with glucocorticoid deficiency. Low ferritin may also be a marker of malnutrition.

ESR is an important screen for inflammatory conditions such as Crohn's disease or juvenile chronic arthritis.

Urea and electrolytes

Important indicator of general health and underlying disease.

Hyperkalaemia and hyponatraemia may occur in glucocorticoid deficiency.

Liver function test

Liver function test may be surprisingly normal in liver disease. Albumin is a marker of malnutrition. 

Bone profile

Useful indicator of general health and underlying disease.

Hypercalcaemia may occur with glucocorticoid deficiency.

Antiendomyseal and antigliadin antibodies

All patients presenting with short stature should be screened for Coeliac disease.

Glycosylated haemoglobin and fasting glucose and lipids

Hypoadrenal patients may have hypoglycaemia. Diabetes mellitus is usually clinically obvious but needs to be ruled out in patients with weight loss.

Baseline assessment of lipids is also useful in patients with Turner syndrome.

Growth hormone

In newborns, a single serum growth hormone level of less than 7 microgram/L (taken between days 3 and 5) confirms a diagnosis of neonatal GHD.

After the newborn period, a single random serum growth hormone level over 7mcg/l is reassuring but does not exclude GH deficiency.

IGF-I and IGF-BP-3

These are useful tests for diagnosing severe GHD. Low IGF-I is in keeping with GH deficiency, in the presence of low GH secretion. 

In mild GHD, peak GH 5-7ng/ml, IGF-I and IGFBP-3 have lower diagnostic sensitivity and may be normal. Patients who have a deficiency of 3 or more pituitary hormones and an IGF-1 level of <50ng/ml can be considered to have GHD and may not require provocative testing.

Low serum IGF-I should be interpreted cautiously as it may be associated with poor nutrition, or chronic illness. Serum IGFBP-3 concentration is generally less helpful that IGF-I for the diagnosis of GHD, except in very young children when IGF-I may be unreliable.

In pubertal children, these tests are less reliable and dynamic testing will be required.

Baseline pituitary function


Estradial/testosterone, sex hormone binding globulin

These should be in the prepubertal range in children presenting with short stature prior to or associated with delayed puberty. This confirms that dynamic testing of GH reserve will require stilboestrol (1.0mg twice daily for the two days prior to the GH provocation test in both boys and girls) priming.


Luteinising hormone, follicle stimulating hormone

Age and pubertal stage related reference ranges are available to aid the interpretation of LH and FSH. Pre puberty, these are expected to be low. Post completion of puberty, if the sex hormones are confirmed as low, then low or normal luteinising hormone (LH) and follicle stimulating hormone (FSH) may indicate pituitary or hypothalamic pathology.

Elevations in LH and FSH indicate gonadal failure, for example primary or auto-immune ovarian failure, or secondary to mumps or testicular trauma in males.


Prolactin

Hyperprolactinaemia in a child with short stature may be suggestive of pituitary or hypothalamic pathology.

Hypoprolactinaemia may also be seen in some genetic causes of hypopituitarism.

Serum prolactin is affected by many factors, for example stress, nipple stimulation, interfering medications and PCOS, and so if elevated, should be repeated on at least two occasions. Elevated prolactin levels should also prompt the PEG precipitation test to determine whether this is biologically active or the inactive 'macroprolactin'.


Thyroid stimulating hormone, free thyroxine

Thyrotoxicosis commonly causes weight loss but thyrotoxic children are almost always tall. 

Thyroid dysfunction is also more common in people with Turner syndrome.

It is essential to assess levels of both thyroxine and TSH in patients suspected of pituitary disease and prior to a GH provocation test.


9am cortisol

Due to the circadian rhythm of ACTH release, cortisol is best assessed early morning (or on waking in patients with irregular hours, for example shift workers).

Levels above 500nmol/l exclude glucocorticoid deficiency.

Patients with pituitary disease and levels below this may require formal assessment for ACTH reserve, for example with an insulin stress test or glucagon test.

Further investigations - selected cases only

MRI pituitary and MRI olfactory bulbs

MRI pituitary should be performed in all patients with confirmed GH deficiency to seek underlying pathology, and in patients presenting later with hypogonadotropic hypogonadism. Patients with suspected Kallman's syndrome also require MRI of the olfactory bulbs in patients. Late onset, mild, isolated hypogonadism may not require imaging however.

Bone age

Consider performing plain radiograph of the left hand and wrist to assess bone age in patients with delayed puberty.

Chest radiograph

A chest XR should be performed in all patients with multiple congenital abnormalities and with Turner’s syndrome.

Electrocardiogram

This is usefully performed at presentation in adults as it is required prior to starting dopamine agonist therapy or testing dynamic pituitary function if necessary.

Echocardiogram

This is performed to seek coarctation of the aorta or bicuspid aortic valve in patients with confirmed Turner's syndrome at diagnosis and subsequently three to five yearly.

Renal ultrasound scan

Ultrasound of the renal system is performed at diagnosis of Turner’s and Kallmann’s syndromes as anatomical abnormalities occur more frequently in people with these conditions.

Pelvic ultrasound scan

This is useful to perform in most patients presenting with absent or delayed puberty to identify and locate the gonads, and to assess uterine size prior to considering pregnancy in female patients.

Visual perimetry and acuity

Formal visual field testing is mandatory if there is clinical or MRI suspicion of chiasmal impingement in patients with pituitary disease.

Insulin stress test

Insulin tolerance testing (ITT) should be performed if GH deficiency is suspected, and will also detect ACTH deficiency subject to the usual safety exclusion criteria. ITT should not be performed in young children, or when there is a history of convulsions, and never in infants. 

Glucagon test

Glucagon testing should be performed as a second confirmatory test of GH deficiency, or if an insulin stress test is contraindicated due to age or the patient's condition.

Arginine-GHRH testing

This is generally considered the second best dynamic test of GH reserve. However, this may also be performed without GHRH (in which case the interpretation is the same as an insulin stress test) in patients with suspected hypothalamic problems eg irradiation, as they may not mount the typical exuberant response to GHRH.

Bone densitometry scan

This should be performed in patients with long standing nutritional deficiency, chronic illness, hypopituitarism or severe delay of puberty. This should also be considered in all patients with long standing hypogonadism and it may be useful to repeat after five years of treatment.

Vitamin D

Low serum vitamin D levels strengthen the case for vitamin D replacement therapy in patients with osteoporosis of any cause.

Parathyroid hormone

Patients with the phenotypic features of pseudohypoparathyroidism should have PTH levels documented to determine their underlying diagnosis.

Levels will be low in hypoparathyroidism, high in pseudohypoparathyroidism, and normal in patients with pseudopseudohypoparathyrdoidism.

Karyotype

This should be performed at presentation in patients with absent puberty, and in all girls presenting with short stature to exclude Turner syndrome.

Hearing test

This is performed every five years in people with Turner's syndrome.