Non-diabetes in children

Non-diabetes mellitus - a disease caused by absolute or relative deficiency of antiduyretic hormone, is characterized by polyuria and polydipsia.

Antidiuretic hormone stimulates the reabsorption of water in the collecting tubules of the kidneys and regulates water metabolism in the body.

[1], [2], [3], [4], [5], [6], [7], [8]

Causes of the diabetes insipidus

Non-diabetes mellitus in children refers to the so-called idiopathic form of it, which can begin at any age in both men and women. Other clinical manifestations of hypothalamic dysfunction and pituitary dysfunction or a later addition of hypothalamic-pituitary dysfunctions testify to the fact that, in idiopathic form, the deficiency of antidiuretic hormone depends on the dysfunction of the hypothalamic-pituitary axis. Most likely, there is a congenital biochemical defect of this region, manifested clinically under the influence of various unfavorable external factors.

Post-traumatic diabetes insipidus in children can develop as a result of lesions localized above the pituitary stalk during a trauma to the skull with fracture of the base of the skull and rupture of the pituitary stalk or after neurosurgical intervention.

Sometimes a permanent polyuria can occur even 1-2 years after the injury. In such cases, it may be necessary to reassess the status of patients over the past period with an attempt to elucidate short periods of clinical manifestation. The latter will make a diagnosis of post-traumatic origin reliable.

It should be emphasized that diabetes insipidus due to accidental skull injuries is an extremely rare disease.

The cause of absolute deficiency of antiduyretic hormone (decrease in hormone secretion) can be a lesion of the neurohypophysis of any genesis:

• The tumors localized above the Turkish saddle and in the area of the optic nerve intersection;
• histiocytosis (due to infiltration of the hypothalamus and pituitary with histiocytes);
• infection (encephalitis, tuberculosis);
• trauma (fracture of the base of the skull, surgical intervention);
• hereditary forms (autosomal dominant and recessive, linked to the X chromosome);
• Tungsten syndrome (combination with diabetes, atrophy of optic nerves and sensoro-neural deafness).

In many cases, the exact cause of absolute deficiency of antiduyretic hormone is not established, and diabetes insipidus in children is identified as idiopathic. However, before taking it to an idiopathic form, repeated examination of the child is necessary, as in half of the patients the morphologically visible changes in the hypothalamus or pituitary gland due to the development of the volumetric process appear only a year after the manifestation of the disease, and in 25% of the patients such changes can be detected through 4 of the year.

A special form is diabetes insipidus in children, in which resistance to antiduyretic hormone is observed (relative insufficiency of the hormone). The disease is not associated with insufficient secretion of vasopressin or its increased destruction, but is due to the inherent insensitivity of renal receptors to vasopressin.

[9], [10], [11], [12], [13], [14], [15], [16]

Pathogenesis

Diabetes insipidus in children is associated with insufficient secretion of vasopressin (ADH). In most cases, this is the result of a deficiency of neurosecretory cells in the supraoptic and, to a lesser extent, paraventricular nuclei of the hypothalamus. The resultant lack of antidiuretic hormone depletion of the body causes water to increase plasma osmolarity, which in turn stimulates the mechanisms of thirst and causes polydipsia. In this way, the equilibrium between the release and consumption of water is restored, and the osmolar pressure of the body's liquid media stabilizes at a new, somewhat elevated level. However, polydipsia is not only a secondary compensatory manifestation of excess polyuria. Along with this, there is a dysfunction of the central mechanisms of thirst. So, according to some authors, the debut of the disease is characterized by a compulsive increase in thirst, to which then polyuria with a low relative density of urine is attached.

Non-diabetes mellitus in children of a neurogenic genesis is a disease with the pathology of the hypothalamic-neurohypophysis axis.

Insufficiency of antiduyretic hormone leads to polyuria with low relative density of urine, increased plasma osmolality, polydipsia. Other complaints and symptoms are determined by the nature of the primary pathological process.

[17], [18], [19], [20], [21], [22]

Symptoms of the diabetes insipidus

One of the main symptoms of the disease is a significant increase in the release of diluted urine. Frequent and profuse urination is observed both in the daytime and at night. Diuresis in some cases reaches 40 liters / day, more often the same amount of daily urine ranges from 3 to 10 liters. Relative density of urine is significantly reduced - on average up to 1005, pathological elements and sugar in it are absent. The inability to form concentrated urine and polyuria, as a rule, is accompanied by a strong thirst both in the daytime and at night. Deprivation of patients with fluid leads to an increase in hypovolemia and hyperosmolarity of the plasma, resulting in severe clinical manifestations - agitation, fever, hyperpnoea, stupor, coma and even death (dehydration symptoms).

It is rare enough to have diabetes insipidus in children without severe thirst. At the same time, if polyuria is severe, and thirst that compensates for the loss of fluid by the tissues is absent, one can expect spontaneous development of the dehydration symptoms described above.

Often, diabetes insipidus occurs without clinical manifestations and is found in laboratory tests (excessive diuresis, low relative density of urine). The clinical picture is usually combined with such neuro-endocrine disorders as menstrual disorders in women, impotence and sexual infantilism in men. Quite often, there is a decrease in appetite and body weight, especially with a mild thirst. Symptoms of diabetes insipidus can be detected in the framework of panhypopituitarism, cerebral forms of obesity, acromegaly. With such a combination of manifestations are often worn out character.

Psychopathological manifestations are quite frequent and are observed in the form of asthenic and anxiety-depressive syndromes.

Non-diabetes mellitus in children has a mildly expressed autonomic disorder. They are often permanent, although vegetative paroxysms of predominantly sympathoadrenal orientation may also occur. Permanent vegetative disorders are mainly manifested by the absence of sweating, dry skin and mucous membranes and usually accompany the symptoms of diabetes insipidus. In addition to them, lability of arterial pressure is often revealed with a certain tendency to increase it and a tendency to tachycardia. Neurological examination reveals only scattered symptoms of diabetes insipidus. On craniograms, it is often possible to see a flattened shape of the base of the skull with small dimensions of the Turkish saddle, which most likely refers to the signs of the dysraphic status. Disturbances of the EEG are similar to those of other neuro-metabolic-endocrine diseases.

[23], [24], [25], [26], [27], [28], [29]

Diagnostics of the diabetes insipidus

• Polyuria and polydipsia with relative density of urine 1001-1005.
• A sample with liquid exclusion for 3 hours: the relative density of urine remains low, plasma osmolality increases. The increase in the relative density of urine with normal osmolality of the plasma suggests a psychogenic polydipsia, often encountered in early childhood.
• The test with vasopressin (5 U. Subcutaneously): with absolute deficiency of antiduyretic hormone (diabetes insipidus hypothalamic-pituitary), the relative density of urine increases, with resistance to antiduyretic hormone (nephrogenic diabetes insipidus), the relative density of urine remains low.

Instrumental research

Visualization of the hypothalamic-pituitary region - CT, MRI, X-ray study of the skull.

[30], [31], [32], [33],

Differential diagnosis

Non-diabetes mellitus in children is differentiated with excessive water intake or primary polydipsia, which is psychogenic. It should be remembered about polydipsia, which is observed in a number of cases in patients with schizophrenia.

In psychogenic polydipsia, a sample with dryness helps to reduce diuresis, increase the relative density of urine to the figures observed in healthy people (up to 1020), without worsening the patient's condition and symptoms of dehydration. The next stage of differential diagnosis should be the elimination of the nephrogenic form of the disease, which is characterized by insensitivity of the renal tubules to vasopressin. One should keep in mind the following forms of nephrogenic diabetes insipidus: the acquired form as a result of somatic, infectious diseases and intoxications; family form with a hereditary defect in the development of renal tubules responsive to antidiuretic hormone.

Before diabetes insipidus in children will differentiate with other pathological conditions, a thorough examination of the genitourinary system, the function of the kidneys and the blood system, the conduct of the above samples is necessary.

Treatment of the diabetes insipidus

Elimination of the cause that caused diabetes insipidus in children is the first step in the treatment of symptomatic forms. In this case, surgical treatment of the tumor or radiation therapy is used.

Substitution therapy is carried out with vasopressin. Desmopressin is administered 3 times a day. The dose is individually selected from 100 to 600 μg per day under the control of the relative density of urine. Patients should avoid situations in which there is a difficulty in supplying water, as limiting the intake of fluid can lead to hyperosmolality and dehydration of the body.

Forecast

Provided a free drinking regime, diabetes insipidus in children does not pose a threat to life. Hormone replacement therapy with antiduyretic hormone medications determines a favorable prognosis for life and work capacity. With volume education in the hypothalamic-pituitary region, the prognosis depends on its location and the possibility of treatment.

[34], [35], [36],