Hypopituitarism

What is Hypopituitarism?

Hypopituitarism syndrome is a disease characterized by a decrease and loss of function of the anterior pituitary or adenohypophysis. The pituitary gland or the pituitary gland consists of two lobes of the anterior and posterior. In the anterior pituitary, six hormones are produced (adrenocorticotropin, prolactin, somatotropin, follitropin, lutropin and thyrotropin).

With hypopituitarism, the production of all the pituitary hormones decreases sharply or disappears. As a result, the function of the peripheral endocrine glands decreases, the work of which is controlled by the pituitary hormones

Causes of Hypopituitarism

Hypopituitarism can be primary when hormone-producing cells of the pituitary gland itself are destroyed or absent, and secondary if diseases of the hypothalamus or central nervous system lead to insufficiency of the pituitary gland. Sometimes there is a lack of production of one of the pituitary hormones.

The causes of hypopituitary syndrome may be:

pituitary adenomas
tumors of the pituitary gland and hypothalamus or other parts of the central nervous system
sarcoidosis
Schuller’s disease
tuberculosis
syphilis
blood diseases
inflammatory diseases of the brain
vascular disorders in the arteries of the blood supplying the pituitary and hypothalamus
autoimmune diseases
brain injuries
metabolic disorders with:
– diabetes
– prolonged fasting
– anorexia nervosa
– chronic renal and liver failure.

An abnormality of the pituitary gland can lead to insufficiency of the pituitary gland. In the postpartum period with pathological birth, necrosis of the anterior pituitary gland can occur. With complete necrosis of the anterior lobe, this condition is called Simmonds syndrome, with partial necrosis – Skien syndrome. In hypopituitary syndrome, hormone-producing cells of the anterior pituitary gland are destroyed.

Pathogenesis during Hypopituitarism

The pathogenesis of panhypopituitarism is based on a deficiency of tropic hormones and growth hormone. Depending on the localization, vastness and intensity of the destructive process, loss or decrease of hormone formation in the pituitary gland can be uniform and complete (panhypopituitarism) or partial, in which the production of one or more hormones is preserved.

Congenital deficiency of growth hormone in the most manifest form is manifested by a syndrome of nanism (from lat. Nanos – a dwarf), which is characterized by a sharp lag in digging and physical development. Pituitary dwarfism is not homogeneous in etiology and pathogenesis: in most patients there is a pathology of regulation and secretion of other pituitary hormones, as a rule, there are impaired secretion of FSH, LH, TSH, which is accompanied by various combinations of endocrine and metabolic disorders (panhypopituitary nanism). Hereditary variants of growth hormone deficiency, combined with a deficiency of other tropic hormones, are most often associated with a deficiency of factor Pgor-1 or factor Pit-1. The Pit-1 factor is already present in the early stages of embryogenesis in somatotrophs, lactotrophs and thyrotrophs, where it plays an important role in initiating the expression of the genes responsible for the synthesis of hormones by these adenohypophysis cells. The factor Prop-1 (a harbinger of Pit I) determines the initial bookmark of somato, prolacto, and thyrotrophs, the differentiation of which occurs with the participation of the transcription activator Pit-1. Mutations in these genes cause a combined deficiency of growth hormone, prolactin and TSH. Most cases of pituitary dwarfism occur in idiopathic growth hormone deficiency.

Symptoms of Hypopituitarism

Clinical manifestations of hypopituitarism occur when less than 10% of functioning cells remain. Usually the disease develops gradually over many years.

The earliest sign of the disease is usually insufficiency on the part of the pituitary gonadotropic function – a decrease in the number of pituitary hormones regulating the function of the gonads.

If hypopituitarism arose in childhood or has a hereditary nature, development during puberty is impaired. Puberty is delayed, eunuchoidal body proportions are formed, skeletal bone growth is delayed.

In adults, libido and potency are reduced, secondary sexual characteristics are gradually erased:

hair loss in the armpits and pubis is reduced
slower beard and mustache growth
testicles and prostate gland decrease
muscle tissue atrophies and is replaced by fat.

In women, sexual desire decreases, the menstrual cycle is disrupted, the mammary glands are reduced, the tissues of the genitals are thinning.

One of the early signs of hypopituitarism is a violation of the sense of smell.

Inadequate growth hormone production in childhood is manifested by growth retardation. In adults, growth hormone deficiency can be manifested by muscle weakness, symptoms from the side of the heart, and poor physical exercise tolerance.

A decrease in the production of thyrotropic hormone leads in childhood to insufficient thyroid function and a delay in mental and physical development. In adults, hypothyroidism occurs. Patients usually have a normal diet, sometimes losing weight. There are complaints of weakness. They have low blood pressure, a rare heart rate, and gastrointestinal upsets often occur.

With pituitary tumors, complaints arise from the central nervous system: headache, visual impairment. Narrowing of visual fields and changes in the fundus are detected.

Acute hypopituitarism syndrome is very rare when hemorrhage occurs in the pituitary gland and the following occur:

sharp headache
sudden drop in vision
drop in blood pressure
loss of consciousness.

Diagnosis of Hypopituitarism

For the diagnosis of hypopituitarism in adults, anamnesis data (operations and irradiation of the pituitary gland, complicated by massive bleeding of labor, etc.) are of great importance. In a hormonal study, a combination of low levels of hormones of peripheral endocrine glands (T4, testosterone, estradiol, cortisol) with reduced or low levels of tropic hormones and growth hormone is determined. In most cases, confirmation of the deficiency of tropic hormones and growth hormone in stimulation samples is necessary. All patients are shown an MRI of the brain.

The main methods of clinical diagnosis of pituitary dwarfism are anthropometry and a comparison of its results with percentile tables. To exclude various skeletal dysplasias, body proportions are evaluated. When radiography of the hands and wrist joints is determined by the bone (radiological) age, while pituitary nanism is characterized by a significant delay in ossification. Growth hormone deficiency must be confirmed by a breakdown with insulin hypoglycemia. A very valuable study in the diagnosis of growth hormone deficiency is the determination of the level of IRF-1.

Differential diagnosis
In adults, hypothalamic-pituitary insufficiency must be differentiated with a number of diseases leading to weight loss (malignant tumors, tuberculosis, enterocolitis, sprue and spruce-like syndromes, porphyrin disease, etc.), including anorexia nervosa.

Idiopathic pituitary dwarfism is differentiated from other forms of short stature: with congenital hypothyroidism, early puberty, congenital dysfunction of the adrenal cortex, diabetes mellitus (Moriak’s syndrome, Nobekur), against the background of severe somatic diseases, with genetic osteoarthropathies, and also with the so-called (constitutional low-grade stunted growth). In the latter case, as a rule, it is possible to identify similar cases of stunting in one of the parents.

Pituitary dwarfism must be differentiated from a number of rare genetic syndromes, such as progeria (Gatchinson-Guildford syndrome), Laron syndrome (peripheral insensitivity to growth hormone as a result of a defect in its receptor gene), Russell-Silver syndrome (intrauterine growth retardation with asymmetry of the trunk), syndrome Sekkel (bird-headed dwarfs), Prader-Willi syndrome (growth retardation from birth, obesity, cryptorchidism, hypospadias, oligophrenia), Lawrence-Moon-Barde-Beadle syndrome (short stature, pigment degeneration set cattle, atrophy of the optic nerve head, hypogonadism, mental retardation), achondroplasia (growth retardation due to disproportionate shortening of the limbs).