Dwarfism
The content of the article:
- Causes and risk factors
- Forms of the disease
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
Dwarfism is a significant lag in physical development and growth due to absolute or relative deficiency of growth hormone (STH, growth hormone).
The corresponding diagnosis is established when an adult woman is less than 120 cm tall, men - 130 cm. Men suffer from dwarfism twice as often as women.
The prevalence of the disease is low, according to various sources, the frequency of occurrence of dwarfism is 1: 3000–1: 30,000. Currently, most patients with confirmed dwarfism receive hormone replacement therapy to enable them to achieve normal growth rates.
Synonyms: nanism (from the Greek nanos - dwarf), somatotropic insufficiency, nanosomy.
Dwarfism is a significant lag in growth and physical development.
Causes and risk factors
The main cause of the disease is a genetic mutation inherited from parents autosomal recessively, dominantly, much less often - linked to the X chromosome, as a result of which there is a violation of the production of somatotropic hormone.
Basically, with this disease, the following genes are damaged:
- the gene for the growth hormone GH-1;
- growth hormone receptor gene GHRH-R;
- a gene that controls the maturation of pituitary cells, PROP-1;
- the gene for the Pit-1 protein (GHF-1), which stimulates the expression of the growth hormone gene, as well as the prolactin gene in the pituitary gland.
The main causal dwarfism is a genetic mutation
The development of nanism is also led by:
- idiopathic growth hormone deficiency;
- pathology of the formation of the organs of the central nervous system (holoproencephaly, septo-optic dysplasia);
- violation of the formation of the pituitary gland at the stage of embryogenesis (a- or hypoplasia, ectopia).
In addition to the congenital nature, dwarfism can be the result of an acquired deficiency in the hubbub of growth. The main reasons in this case are:
- neoplasms of the hypothalamic-pituitary axis (craniopharyngioma, hamartoma, neurofibroma, germinoma, adenoma);
- tumors of brain structures;
- traumatic brain injury;
- iatrogenic damage to the structures of the pituitary gland;
- viral and bacterial infections of brain tissues, meninges;
- autoimmune lesions of the hypothalamus, pituitary gland;
- hydrocephalus;
- transient growth hormone deficiency (constitutional or psychosomatic);
- empty Turkish saddle syndrome (SPTS);
- hemorrhagic or ischemic damage to the pituitary tissue;
- exposure to ionizing radiation;
- toxic damage to brain tissue.
In rare cases, nanism is a consequence of the immunity of peripheral tissues to growth hormone at its normal concentration for the following reasons:
- insufficient concentration of growth hormone receptors;
- biologically intact growth hormone;
- high concentration of somatobinding protein;
- tissue resistance to insulin-like growth factor-1 (somatomedin C), which is the most important endocrine mediator of the action of growth hormone.
Forms of the disease
Depending on the cause of the disease:
- congenital and acquired nanism;
- organic (due to damage to brain structures) and idiopathic (of unknown etiology, makes up about 70% of all cases).
In accordance with the level at which the pathology arose, the following forms are distinguished:
- hypothalamic nanism;
- pituitary;
- peripheral.
Depending on the severity of somatotropic insufficiency:
- isolated (production or assimilation of only growth hormone is impaired);
- combined (STH deficiency is combined with the loss of functions of other hormones of the hypothalamic-pituitary system).
Symptoms
The main symptom of the disease is physical retardation and short stature while maintaining body proportions. Other symptoms:
- small, "doll-like" facial features;
- sinking nose, massive forehead;
- rounded skull, short neck;
- miniature feet and hands;
- high voice;
- sexual infantilism;
- dryness, laxity of the skin, often a marble pattern;
- emotional infantilism.
The main sign of dwarfism is short stature while maintaining body proportions.
In the case of the combined involvement of several hypothalamic-pituitary hormones in the pathological process, symptoms of hypothyroidism, hypogonadism, etc. join the clinical picture of dwarfism.
Diagnostics
Diagnosis of the disease is primarily based on an assessment of the characteristic symptoms:
- lag in growth and physical development, which manifests itself in full by 2-4 years;
- an increase of less than 4 cm per year (usually 1-2 cm);
- maintaining the proportionality of the body structure;
- growth standard deviation coefficient less than 2.
Instrumental and laboratory research:
- magnetic resonance imaging and / or computed tomography (detection of structural changes in the hypothalamus and pituitary gland);
- determination of bone age by the methods of Grolich and Pyle or Tanner and Whitehouse (lagging behind the real age by 2 or more years);
- X-ray examination of the skull (identification of anomalies of the Turkish saddle);
- somatotropin-stimulating tests - identification of the peak of STH release in the blood plasma against the background of drug provocation (insulin, clonidine, levodopa, etc.);
- determination of the level of high molecular weight somatomedin-binding protein;
- determination of the concentration of insulin-like growth factor.
Treatment
Until the mid-80s of the last century, for the treatment of children suffering from dwarfism, growth hormone preparations obtained by an extract from the tissues of the human pituitary gland were used. In 1985, such a long-term practice was officially banned due to the inability to produce the required amount of drugs and the high risk of developing Creutzfeldt-Jakob disease in persons receiving such treatment. Currently, the treatment of dwarfism is carried out with a recombinant growth hormone, obtained in a laboratory way using genetically engineered techniques.
In the course of treatment, there is a clear dose-dependent effect. An indicator of the adequacy of the ongoing hormone replacement therapy is a stable annual increase: up to 13 cm (according to other sources, 8-10 cm) after the start of treatment, somewhat slowing down in the future, fixing at the level of 5-6 cm annually.
Active treatment is carried out until socially acceptable values of linear growth are achieved. After the closure of the growth zones, the drugs are used in maintenance doses (approximately 8-9 times less than growth-stimulating doses) to ensure normal life.
Possible complications and consequences
Dwarfism as an independent disease does not have significant consequences, possible complications are associated with concomitant pathology (neoplasms of the hypothalamic-pituitary system, infectious and viral brain lesions, trauma, etc.).
Forecast
With timely diagnosis and adequate replacement therapy, the prognosis is favorable.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
