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Endocrinology

Hypopituitarism

The hypopituitarism is a clinical syndrome at which functional activity of peripheral closed glands (bark of adrenal glands, a thyroid gland, gonads) in connection with disturbance of activity of an adenohypophysis and the lowered production of tropny hormones decreases. Deficit of one or several hormones of a hypophysis (a partial gipopituatarizm) or full pituitary insufficiency (panhypopituitarism) can be observed.

Etiology.

There are three main mechanisms which lead to development of a hypopituitarism. At the first there is a decrease in production of hypothalamic hormones which stimulate functions of a hypophysis. The reason of functional insufficiency can be inborn or acquired: tumors, inflammations of posttraumatic or infectious character, blood supply disturbance. At the second mechanism of development the adenohypophysis produces tropny hormones in enough, but their delivery to the destination, a basic reason - tumors and injuries is broken. The third mechanism of a hypopituitarism is a damage of cells of gland of a hypophysis with the subsequent loss of products of hormones, the most common cause – tumoral diseases. 
Possible reasons of a hypopituitarism:

  1. Radiation or surgical intervention to the area of a hypophysis and a hypothalamus.
  2. Tumors of the hypophysis or nearby (cranyopharyngioma, metastasises of the remote tumors, angioma, meningioma, etc.).
  3. Hypophysis apoplexy, other names – Shiyena-Simmonds's syndrome, an ischemic or septiko-embolic heart attack. Rather rare reason, is most often observed at women of reproductive age after massive patrimonial blood loss that leads to disturbance of a blood-groove in a hypophysis and to the subsequent its necrosis.
  4. Severe craniocereberal injuries.
  5. Syndrome of a "empty" Turkish saddle. The easy form of pituitary insufficiency which is combined with the increased production of prolactin is observed at 10% of the diseased.
  6. Infiltrative diseases (hemochromatosis, sarcoidosis, histiocytosis, lymphocytic hypophysitis).
  7. Syndromes of hereditary genesis:

- inborn deficit of growth hormones and other tropny hormones (happens because of a mutation of genes of Rgor-1, Pit-1 and a gene responsible for development of hubbub of growth);
- idiopathic insufficiency of tropny hormones;
- defects in development of gipotalamo-pituitary system (an aplasia, a hypoplasia, a goloprozentsefaliya, a dysplasia, etc.).

General principles of diagnosis. The diagnosis is made on the basis of clinic of a disease, data of a magnetic and resonant or computer tomography, and also researches on the content of this or that hormone of glands targets.

Deficit of a gonadotrophin.

Clinical features.
The lack of a gonadotrophin causes infertility and disturbances of periods (an amenorrhea and an oligomenorrhea) in women of reproductive age. Also decrease in a libido, inflow and a dispareuniya, an osteoporosis is observed. The hypogonadism is often diagnosed retrospectively for men and for women after a menopause when patients already have massive symptomatology.
Diagnosis Diagnosis.
Deficit of a gonadotrophin decides at the LG and FSG low level at women of reproductive age on an amenorrhea and in a postmenopause, or at men on the low level of testosterone (less than 200 ng/dl). Measurement of level of gonadotrophins and oestradiol at women of fertile age with irregular periods, as a rule, not informatively for statement of this diagnosis.
Treatment Treatment.
Treatment consists in compensation of missing hormones of gland target. The lack of testosterone can be filled by means of intramuscular injections, transdermalny plasters or gel. Testosterone in the tableted form is not recommended in connection with possible risk of toxic damage of a liver. Transdermalny drugs provide constant concentration of hormone in blood within physiologic norm, but have higher price in comparison with liquid forms. During therapy by testosterone it is necessary to control a lipidic profile, level of the prostates specific antigens (PSA) and a hematocrit. Women of reproductive age with a hypogonadism need treatment by estragenes for prevention of osteoporosis, and also correction of other symptoms.

Deficit of corticotropin (AKTG).

Clinical features.
Symptoms of deficit of AKTG include a chronic indisposition, fatigue, lack of appetite, subfebrile temperature and a hypoglycemia. Acute and heavy insufficiency of AKTG can provoke a vascular collapse.
Diagnosis.
The optimum initial test for cortisol level, test with AKTG, is carried out no later than the 8th morning. Content of hormone less than 3 mkg/dl confirms insufficiency of bark of adrenal glands, and level over 15 mkg/dl calls the diagnosis into question. Cortisol indicators in the range from 3 to 15 mkg/dl are uncertain, and they should be estimated after stimulation kozintropiny (KNT) which can be executed at any time during the day. Level of cortisol is estimated to and in 30 minutes after an injection of a standard dose of a kozintropin (250 mkg). Normal reaction after administration of drug concentration of cortisol in plasma higher than 18 mkg/dl is considered. The gold standard for an assessment gipotalamo - a pituitary and adrenal (HPA) axis is carrying out tests for tolerance to glucose, but they have to be carried out by pilot medical staff, and, as a rule, are not necessary in daily clinical practice.
Treatment.
Therapy by a hydrocortisone according to the scheme is appointed.

Deficit of TTG.

Clinical features.
Symptoms of insufficiency of thyritropic hormone (TTG) are similar to symptoms of primary hypothyroidism which include a febricula, fatigue, spasms of gastrocnemius muscles, a xeroderma and intolerance of cold. Degree of a hypothyroidism depends on duration and weight of deficit of TTG.
Diagnosis.
Research on the maintenance of TTG and free thyroxine is conducted (T 4). As a rule, patients have low or the TTG normal level, and also low indicators T 4.
Treatment.
Therapy of patients with deficit of TTG is similar to treatment of primary hypothyroidism. The dose of left thyroxine is adjusted depending on a clinical condition of the patient, level of free thyroxine and triiodothyronine (T 3), but not TTG.

Deficit of prolactin.

It is observed rather seldom at disturbances in work of a hypophysis, usually at a heart attack of a hypophysis or extensive hemorrhages. As a rule, it is expressed in lack of a lactation at women.

Deficit of a growth hormone.

 Clinical features.
At decrease in secretion of this hormone in the period of physiological immaturity the patient will suffer from deviations of physical development and lag in growth of this or that degree. Extreme degree – dwarfism (or a pituitary nanism) which can be followed by an underdevelopment of a reproductive system, vision disorders and tendency to hypotonia. If insufficiency of a growth hormone arises at the adult, then it is expressed by dominance of fatty tissue over muscular (including at a normal index of body weight), chronic fatigue, the atherosclerosis raised by risk of cardiovascular diseases and depressions.
Diagnosis.
Researches of urine and blood on the growth hormone level, and also specific tests are conducted. At children's age these anthropometries are also indicative.
Treatment of children consists in consecutive therapy by Somatotropinum of the person and anabolic steroids. During puberty (15 - 16 years) to boys the chorionic gonadotrophin, to girls – small doses of estrogen is appointed, further, after closing of regions of growth, therapy by sex hormones continues. At emergence of insufficiency of a growth hormone in adulthood treatment usually is not carried out.

Treatment of a hypopituitarism at a lack of several hormones or a panhypopituitarism consists in replacement therapy by missing hormones of glands targets throughout all life. In certain cases for recovery of activity of a hypophysis it is required to remove a tumor, depending on result of operation hormonal therapy proceeds or cancelled.

 
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