Many are accustomed to the phrase “diabetes mellitus” and do not even suspect that diabetes is also insipid. What it is? Is it serious? How to recognize? What to do about it? Let’s consider in detail.
Diabetes insipidus (“diabetes”) is a disease that develops when there is insufficient release of antidiuretic hormone (ADH) or a decrease in the sensitivity of the renal tissue to its action. Violation of the secretion of ADH by the hypothalamus (absolute deficiency) or its physiological role with sufficient formation (relative deficiency) causes a decrease in the processes of reabsorption ( reabsorption ) of fluid in the renal tubules and its excretion in the urine of low relative density. With diabetes insipidus, due to the release of a large volume of urine, an unquenchable thirst and general dehydration (dehydration) of the body develop.
Diabetes insipidus is a rare pathology of the endocrine system that develops regardless of gender and age (more often in people 20–40 years old). In every fifth case, the disease develops as a complication of neurosurgical intervention.
Classification of diabetes insipidus
Modern endocrinology classifies diabetes insipidus according to the level at which the disorder occurs:
- central (neurogenic, hypothalamic-pituitary);
- renal ( nephrogenic ).
In the central form, disorders develop at the level of secretion of antidiuretic hormone by the hypothalamus or at the level of its release into the blood.
Central diabetes insipidus is also subdivided into:
- idiopathic (hereditary disease characterized by a decrease in the synthesis of ADH);
- symptomatic (occurs against the background of other pathologies);
- acquired (develops during life after traumatic brain injuries, tumors, infiltrative processes of the brain, meningoencephalitis );
- congenital (diagnosed from birth with a mutation of the ADH gene).
In the renal form, there is a disturbance in the perception of ADH from the cells of the distal tubules of the nephrons. This is a rare form. Its cause is the anatomical inferiority of the nephron or impaired receptor sensitivity to antidiuretic hormone. These disorders can be congenital or develop as a result of drug or metabolic damage to the nephrons.
The causes of diabetes insipidus
The central form of diabetes insipidus associated with hypothalamic-pituitary destruction due to:
- primary or metastatic tumors;
- neurosurgical interventions;
- vascular, tuberculous, malarial, syphilitic lesions and others.
Idiopathic diabetes insipidus is characterized by the absence of organic damage to the hypothalamic-pituitary system, while antibodies to hormone-producing cells appear spontaneously .
The causes of the renal form of diabetes insipidus are congenital or acquired kidney disease (renal failure, amyloidosis, hypercalcemia ) or lithium drug poisoning. Congenital forms of diabetes insipidus often develop with autosomal recessive inheritance of Wolfram syndrome, which in its manifestations can be complete (with diabetes insipidus and diabetes mellitus, optic nerve atrophy, deafness) or partial (combining diabetes insipidus and diabetes insipidus).
Symptoms of diabetes insipidus
Typical manifestations of diabetes insipidus are polyuria and polydipsia. Polyuria is an increase in the daily volume of urine excreted (usually up to 4-10 liters, sometimes up to 20-30 liters). The urine is colorless, with a small amount of salts and other elements and a low specific gravity (1000-1003) in all portions. The feeling of unquenchable thirst in diabetes insipidus leads to polydipsia (the consumption of large amounts of fluids, sometimes equal to that lost in the urine). The severity of diabetes insipidus is determined by the degree of antidiuretic hormone deficiency.
Idiopathic diabetes insipidus usually develops acutely, suddenly, less often – with a gradual increase. Pregnancy can provoke the manifestation of the disease. Frequent urge to urinate (pollakiuria – more than 7 times a day) leads to sleep disturbances, increased fatigue, emotional imbalance, neuroses. In children, diabetes insipidus at an early stage is manifested by enuresis , later growth retardation and puberty are added.
A late indicator of diabetes insipidus is the expansion of the renal pelvis, ureters, and bladder. As a result of water overload, overstretching and prolapse of the stomach occurs , dyskinesia of the biliary tract develops, and chronic irritation of the intestines.
Patients with diabetes insipidus have dry skin, decreased function of sweat and salivary glands, and poor appetite. Later, dehydration, weight loss, vomiting, headache, lowering blood pressure join. With diabetes insipidus, caused by damage to the parts of the brain, neurological disorders and symptoms of pituitary insufficiency develop. In men, a weakening of potency develops, in women – menstrual dysfunction.
Complications
With diabetes insipidus, there is a risk of dehydration (dehydration) of the body – if the loss of fluid in the urine is not adequately replenished. In this case, patients are observed:
- severe general weakness;
- tachycardia;
- vomiting;
- neurological disorders;
- thickening of the blood;
- hypotension (a critical decrease in blood pressure up to collapse);
- mental disorders.
Even with severe dehydration, polyuria persists.
Diagnostics
In typical cases, diabetes insipidus can be suspected by insatiable thirst and the secretion of more than 3 liters of urine per day. To assess the daily amount of urine, the Zimnitsky test is carried out . The study of urine reveals its low relative density (<1005), hyponatriuria ( hypoosmolarity of urine – 100-200 mosm / kg). Plasma hyperosmolarity ( hypernatremia ) (> 290 mosm / kg), hypercalcemia and hypokalemia are detected in the blood .
Diabetes mellitus is excluded by the determination of fasting blood glucose. With the central form of diabetes insipidus, a low content of ADH is determined in the blood.
Indicative are the results of the dry eating test (abstinence from drinking fluids for 10-12 hours).
With diabetes insipidus, a loss of body weight of more than 5% occurs, a low specific gravity and hypo-osmolarity of urine are preserved .
The causes of diabetes insipidus are clarified during X-ray, neuropsychiatric, ophthalmological examinations. Volumetric formations of the brain are excluded by conducting an MRI of the brain. To diagnose the renal form of diabetes insipidus, ultrasound and CT of the kidneys are performed. Nephrologist consultation is also required. Sometimes a kidney biopsy is required to differentiate renal pathology.
Treatment
Treatment for symptomatic diabetes insipidus begins by addressing the cause (such as a tumor). For all forms of diabetes insipidus, substitution therapy with a synthetic analogue of ADH, desmopressin, is prescribed . The drug is administered orally or intranasally (by instillation into the nose). A prolonged-release drug is also prescribed – an oily solution of pituitrin. In the central form of diabetes insipidus, medications are prescribed that stimulate the secretion of antidiuretic hormone ( chlorpropamide , carbamazepine ).
Correction of the water-salt balance is carried out by infusion (droppers) of saline solutions in large volumes. Sulfanilamide diuretics ( hypochlorothiazide ) significantly reduce urine output in diabetes insipidus .
Diet for diabetes insipidus:
- an increase in the frequency of meals;
- restriction of protein (to reduce the burden on the kidneys);
- a sufficient amount of carbohydrates and fats;
- an increase in the number of vegetable and fruit dishes;
- to quench thirst – juices, fruit drinks, compotes.
Forecast
Diabetes insipidus, which develops in the postoperative period or during pregnancy, is often transient (transient) in nature, idiopathic – is persistent. With appropriate treatment, there is no danger to life, although recovery is rarely recorded.
The recovery of patients is observed in cases of successful removal of tumors, specific treatment of diabetes insipidus of tuberculous, malarial, syphilitic origin. With the correct appointment of hormone replacement therapy, the ability to work is often preserved.
The least favorable course of the nephrogenic form of diabetes insipidus in children.