Dwarfism is an endocrine disease based on a violation of the synthesis of growth hormone (somatotropin) in the anterior lobe of the pituitary gland, which leads to a delay in the growth of the skeleton, internal organs and physical underdevelopment. Disease is characterized by abnormal stunting: men’s height is below 130 cm, women’s height is below 120 cm; there is a lag in the development of the musculoskeletal system, hypogonadism, a decrease in the size of internal organs, hypotension, bradycardia, etc. Diagnosis involves determining the basal concentration of STH in blood serum, conducting pharmacological tests, skull x-ray, hands and wrist joints. Treatment includes replacement therapy with somatotropin, anabolic steroids, thyroid medications, and sex hormones.
ICD 10
E23.0
Meaning
Dwarfism is a clinical syndrome caused by absolute or relative somatotropic insufficiency of the pituitary gland (lack of secretion of somatotropic hormone or violation of tissue sensitivity to it). Pathology occurs in the population with a frequency of 1:15 000 -1:20 000, somewhat more often among men. The concept of dwarfism (microsomy, nanosomy, nanism) in a broad sense denotes a number of pathological conditions, expressed in the lag of growth and physical development in comparison with the average age, sex, population and racial norm. Disease can be an independent genetic disease or act as a symptom of a number of endocrine and non-endocrine diseases.
Causes
Somatotropic insufficiency underlying dwarfism can be caused by three groups of causes: congenital deficiency of somatotropic hormone (STH), acquired hyposomatotropic state and peripheral resistance of tissues to the effects of STH.
1. Congenital somatotropin deficiency may be associated with genetic defects (mutation of the growth hormone gene, mutation of the somatoliberin receptor gene, etc.) or abnormalities of the hypothalamic-pituitary system (anencephaly, congenital aplasia, hypoplasia or ectopia of the pituitary gland).
2. Acquired dwarfism develops in:
- Tumors of the hypothalamic-pituitary region (craniopharyngioma, hamartoma, neurofibroma, germinoma, pituitary adenoma) or other parts of the brain (for example, glioma of the visual intersection).
- Brain injuries. In some cases, traumatic brain injury, birth injuries, damage to the pituitary pedicle during surgical interventions can lead to dwarfism,
- Other cerebral diseases: neuroinfections (viral, bacterial encephalitis and meningitis), autoimmune pituitary, hydrocephalus, pituitary vascular aneurysms, etc.
- Toxic damage to the pituitary gland. Dwarfism may be associated with the toxic effects of chemotherapy or radiation (with leukemia, retinoblastoma, bone marrow transplantation, etc.).
3. Dwarfism due to the insensitivity of target tissues to growth hormone can develop with a deficiency of STH receptors, lack of biological activity of somatotropic hormone, resistance to insulin-like growth factor 1.
Along with isolated STH insufficiency, with this disease, there may be a decrease in the synthesis of other pituitary hormones: gonadotropins, TSH, ACTH, which is accompanied by a lack of function of the corresponding peripheral endocrine glands (genital, thyroid, adrenal glands), which also affects growth and physical development. In this case, endocrinology speaks of a panhypopituitary form of dwarfism.
Classification
There are dwarfism with proportional and disproportionate physiques. The group of diseases with a proportional physique includes:
- dwarfism
- myxedematous (thyrogenic)
- adrenal form in adrenogenital syndrome (congenital adrenal hyperplasia)
- associated with thymus gland lesion
- infantile developing under the influence of exogenous factors (alimentary insufficiency or intoxication)
- associated with premature puberty and early closure of growth zones.
Disease with a disproportionate physique is represented by the following forms:
- rickety
- chondrodystrophic
- dwarfism in osteogenesis imperfecta (congenital bone fragility).
Family (constitutional) forms of stunting should be distinguished from cases of dwarfism, which are considered as a variant of individual physical development and are not a pathology.
Symptoms
Children are born with normal weight and height indicators. Growth retardation in congenital form usually becomes noticeable by the age of 2-3 years and increases in the future. The growth rate in children with dwarfism is 1.5-2 cm per year (normal – 7-8 cm). In adult men, the height does not exceed 130 cm, in women – 120 cm. The physique is proportional, but the proportions characteristic of childhood may be preserved.
The skin of patients with dwarfism is pale, dry, wrinkled, with a yellowish or marbled hue, which is due to thyroid insufficiency. The hair on the head is often thin, dry, brittle. The underdevelopment of the bones of the facial skull causes the presence of small facial features (“doll face”), sinking of the bridge of the nose.
The distribution of subcutaneous fat can be different – from poor development to excessive fat deposition according to the “kushingoid” type (on the chest, abdomen, thighs). There is a delay in ossification of the skeleton, a weak development of the muscular system, a violation of the change of teeth. Due to the underdevelopment of the larynx, adults with dwarfism retain a high children’s voice timbre. In accordance with low height and body weight, there is a decrease in the size of internal organs (splanchnomicry). Often, with dwarfism, bradycardia and arterial hypotension are detected.
Violation of the gonadotropic function of the pituitary gland leads to a delay and inferiority of sexual development (hypogonadism). In boys with dwarfism, there is a lack of male-type hair loss, testicular hypoplasia, cryptorchidism, micropenis; in girls – amenorrhea, micromastia, hypoplasia of the uterus and ovaries.
Intellectual development with disease, as a rule, is preserved. There may be such psychological features as negativism, isolation, a decrease in self-esteem, infantile behavior. If there are additional complaints of headache, vomiting, visual impairment, intracranial pathology should be suspected. With panhypopituitary form, signs of secondary hypocorticism and hypothyroidism are determined.
Diagnostics
The criteria for the diagnosis of dwarfism are the data of anamnesis, objective examination, laboratory and instrumental studies. Absolute body sizes are determined in patients, as well as the growth deficit indicator – the difference between the actual growth of the patient and the average normative sex and age indicators in the population. With dwarfism, the growth deficit is more than 2-3 quadratic deviations.
The main role in the diagnosis of disease belongs to the determination of the basal level of STH in the blood serum, the circadian rhythm of secretion and reserves against the background of stimulation. In patients with dwarfism, the initial level of STH is significantly reduced when conducting stimulating tests with insulin, thyroliberin, arginine, etc. increases slightly.
Radiography of the Turkish saddle reveals its childish shape (“standing oval”) and a wide (so-called juvenile) back. With an increase in the size of the Turkish saddle and the presence of calcification sites, first of all, you should think about the tumor. Radiography of the wrist joints and hands allows you to determine the radiological (“bone”) age. With pathology, there is a significant slowdown in the processes of ossification of the skeleton.
To determine the form of dwarfism, it is necessary to study insulin-like growth factor (somatomedin-C), TSH, LH, FSH, T3, T4, cortisol in plasma and urine, antibodies to thyroglobulin, microsomal fraction of thyrocytes, etc. To exclude a tumor lesion, CT (MRI) of the brain is performed.
In case of dwarfism, the patient should be consulted by an endocrinologist, gynecologist (women), andrologist (men), neurologist or neurosurgeon, ophthalmologist, geneticist.
Treatment
In young children, in order to exclude diagnostic errors, a follow-up period is maintained for 6-12 months, during which special attention is paid to proper nutrition, restorative therapy, taking vitamins (A and D) and minerals (phosphorus, calcium). The lack of growth dynamics and physical development is the basis for the transition to hormone therapy.
The basis of pathogenetic treatment of dwarfism is growth hormone replacement therapy, which is carried out in intermittent courses (2-3 months at the same intervals). Human somatotropin is prescribed to patients with proven endogenous hormone deficiency and skeletal differentiation that does not exceed the age indicators of 13-14 years. Treatment with STH is carried out until the growth zones are closed or until acceptable growth parameters are reached.
In the therapy, anabolic steroids (methandienone, nandrolone) are used, which have a stimulating effect on the level of endogenous STH, protein synthesis and growth. Treatment with steroid hormones continues for several years with periodic replacement of drugs. It is advisable to start treatment with anabolic agents from the age of 5-7. To stimulate the function of the sex glands over the age of 16, young men are prescribed chorionic gonadotropin and small doses of androgens, girls – small doses of estrogens.
In the future, after the closure of the growth zones, patients are transferred to the constant intake of sex hormones in accordance with their gender. At the same time, women are shown to take combined estrogen-gestagenic drugs, men – androgens of prolonged action.
With hypothyroidism, L–thyroxine, thyroidin is prescribed; with somatoliberin insufficiency, its synthetic analogues; with hypofunction of the adrenal cortex, glucocorticosteroids. In case of organic pathology of the central nervous system, anti-inflammatory, resorption, dehydration therapy may be required. If pituitary tumors are detected, their surgical removal is indicated, sometimes radiation therapy is performed.
Prognosis and prevention
With dwarfism caused by genetic causes, the prognosis is good. Timely and rational HRT allows patients to be sufficiently physically developed, socially active and able-bodied. When choosing a profession, work involving increased physical and neuropsychiatric loads is not recommended. In the absence of the necessary treatment, patients remain small in stature and physical underdevelopment. In the case of organic brain lesions, the prognosis is determined by the underlying disease and the dynamics of its development.
Patients with dwarfism are on lifelong dispensary registration with an endocrinologist and must visit him every 2-3 months. Prevention of dwarfism consists in the prevention of infections, physical and mental injuries in pregnant women; prevention of birth injuries, neuroinfections, TBI, intoxication in children.