Diabetes insipidus
Synonyms in a broader sense
Water clock
definition
Under the disease of Diabetes insipidus one understands the reduced ability of the kidneys when there is a lack of water, i.e. when the body does not have enough fluid to produce concentrated urine. You can choose between a central and renal form (in the kidney located cause).
Summary
At the Diabetes insipidus is it a Hormone deficiency (ADH - hormone)leading to increased fluid loss through the kidney leads. This deficiency can either be due to insufficient production in the brain or due to insufficient utilization in the kidney itself. In both cases, too much of too little concentrated, i.e. very dilute, urine is excreted.
Those affected always have Great thirst and even during the night could not do without drinking. The diagnosis can be made by trying to thirst and by giving ADH-like substances. Therapy depends on the form of the disease.
causes
There are two causes of diabetes insipidus known. A central form, i.e. in the brain caused misdirection of information, and a renal (ren (lat.) = kidney) so in the kidney located malfunction of the hormone ADH.
This hormone is responsible for the regular excretion of fluids through the kidneys. Depending on the water content of the body, it ensures a correspondingly regulating excretion of the liquid. The mechanism lies in that Installation of small channels (aquaporins) into the wall of the renal tubules. The more of these channels that return water from the primary urine in the kidney to the circulatory system, the less fluid can be eliminated via the kidney. If this hormone is missing, fewer of these aquaporins can be incorporated and the body loses fluid.
Diabetes insipidus after alcohol
We are all familiar with this phenomenon Alcohol consumption.
Those who drink alcohol have to urinate more often because the production of the hormone ADH is suppressed / reduced. This is how the increased thirst comes about during the night or the day after. Due to the increased loss of minerals through the ADH deficiency it can also be nocturnal Muscle spasms come.
Every student knows this "problem" and even "doctors" should suffer from this phenomenon from time to time ;-)
Symptoms / complaints
The three main and typical symptoms of Diabetes insipidus are:
- frequent urination (Polyuria)
- constant feeling of thirst with frequent drinking (Polydipsia)
- inability of the urine to concentrate (Asthenuria)
The polyuria (increased urination) can be up to 20 liters per day for patients. The urine is very diluted due to the high water content.
Read more about the topic here: frequent urination
Due to the high fluid loss, the diabetes insipidus patient is always thirsty - even at night he cannot do without drinking. If it is not possible for the patient to take in the amounts that he excretes again, one is created Dehydration and a Desiccosiswhich can quickly become a deadly danger, especially for small children. Exiccosis (internal dehydration) is also dangerous in adults.
Other symptoms that can occur due to the lack of fluids are:
- dry skin and mucous membranes
- constipation
- Sleep disorder
- Muscle spasms
- Irritability
Small children (under 2 years of age) often have polyuria (frequent urination) diarrhea (diarrhea)!!
If the patient does not suffer from the nocturnal urge to urinate, a Diabetes insipidus practically impossible.
diagnosis
There are essentially two options available for the clinical diagnosis of diabetes insipidus. With both the Urine molarity measured, so to speak the Concentration of urine.
On the one hand, the doctors stand the so-called Thirst attempt to disposal. However, this is based on the cooperation of the patient. In the thirst test, which should last a maximum of 24 hours due to the loss of fluid, there is no increased secretion (excretion) of the hormone ADH despite dehydration ("drying out of the body"). This secretion would be important in order to ensure that the blood volume is maintained in the event of insufficient or no fluid intake.
Second, a substance can be called Desmopressin administered. This substance has the same function as the hormone vasopressin (ADH). With the help of this method, a central and renal diabetes insipidus can be distinguished. If no increased urine concentration is found during the thirst attempt, diabetes insipidus can be diagnosed, but the exact sub-form can only be determined by administering the hormone desmopressin.
If the kidney does not react to this, i.e. highly diluted urine is still being excreted, the cause lies in the kidney itself. It cannot build in the water channels. Otherwise, if the urine concentration is now normal, the cause is to be found centrally, i.e. in the pituitary gland (pituitary gland). Here the pituitary gland produces too little or no ADH (A.nti-D.iureticHormon).
Therapy diabetes insipidus
Therapy for one Diabetes insipitus differs depending on the form of the disease. Here there is the Diabetes insipitus centralis and the Diabetes insipitus renalis.
In diabetes insipitus centralis, the cause lies in Hypothalamus or in the Pituitary gland thereby the distribution of ADH (A.ntidiuretic Hormon) is disturbed. In diabetes insipitus renalis, the cause lies in the kidneys or, more precisely, in the distal ones Tubules and Manifolds.
Here can ADH (Antidiuretic hormone) no longer fully develop its effect. Causes of this disorder can be, for example, poisoning or medication as well as kidney failure, inflammation of the kidney pelvis or a genetic defect. Depending on the classification of the disease, the therapies must have different approaches in order to develop their effect.
In both therapeutic approaches, the aim is to ensure that an impending water deficit in the body is compensated for and the loss of urine is reduced. This is done using different approaches.
1. The therapy in one Diabetes insipitus centralis is considered to be easier because this is a Desmopressin (Vasopressin analog) is administered. Desmopressin is an antidiuretic, a drug that reduces urine output. Desmopressin is an analogue to the antidiuretic hormone, an endogenous hormone that stimulates the tubules of the kidneys to allow more water to pass through. This means that more water is reabsorbed, i.e. less urine is excreted. This urine is then more concentrated. Since in diabetes insipitus centralis due to a disturbance in the hypothalamus and pituitary gland no ADH (antidiuretic hormone) is released, the therapy intervenes here by the administered desmopressin taking over the function of the ADH. This desmopressin can be administered orally (Ingestion as a solution) or nasal (as a nasal spray) can be administered.
2. The therapy for one Diabetes insipitus renalis However, it turns out to be a little more difficult. Thiazide diuretics can be given. Thiazide diuretics are among the so-called diuretics. They act on the distal tubules of the kidneys and cause an increased excretion of sodium. This makes the urine excreted more concentrated. In addition, the increased intake of fluids is mandatory in diabetes insipitus renalis.
laboratory
There are several laboratory tests and urine parameters that allow a differential diagnosis between one Diabtes insipitus renalis or one Diabetes insipitus centralis as well as other urine concentration disorders.
Above all, there is a decreased concentration of sodium and a decreased one in the urine Osmolality of the urine. This is due to the increased excretion of water and the resulting reduced concentration of sodium in the urine.
in the blood In the case of diabetes insipidus centralis, or in the removed serum, there is above all a reduced concentration of the ADHs (antidiuretic Hormons), as this is no longer properly poured out. In the case of diabetes insipitdus renalis, this concentration is the same as in a healthy person. This is also an important distinction between the two forms of diabetes insipidus.
In both classifications, the sodium is more concentrated in the serum and there is a higher osmolality. This can be explained by the reduced excretion of sodium in the urine.
Guidelines
The guidelines for diabetes insipidus neurohormonalis (that is, diabetes insipidus centralis) include definition and basic information about the disease as well as diagnostic and therapeutic options.
According to the guidelines, diagnostics include Confirmation of polyuria (pathologically increased urine excretion) through a 24-hour urine collection.
Other provisions include:
- the serum- such as Urine molarity
- the Serum creatinine and the
- Urea concentration
- the measurement of the Blood sugar as well as possibly
- a ADH- and a ßHCG-Measurement in serum.
A thirst test as the next diagnostic step is recommended in the case of low urinary osmolarity and at the same time increased or highly normal serum osmolarity. A DDAVP test (also called desmopressin test) can differentiate between central and renal diabetes insipidus. Depending on the initial situation and the results, further diagnostic imaging (cMRI) can be recommended. Various other diagnostic options can also be recommended.
The guidelines also provide an evaluation of the results and further, subsequent ways.
If the sodium and chloride concentration and the serum osmolarity are increased while the specific gravity or the osmolarity of the urine is decreased, this confirms the suspicion of diabetes insipidus. The diagnosis can be further confirmed by the fact that the urine has an inability to concentrate with a simultaneous increase in sodium and serum osmolarity in the thirst test. The diagnosis can also be supported by increased sodium and serum osmolarity values with low ADH values at the same time. To between a central and renal diabetes insipidus to distinguish, according to the guidelines DDAVP-Test.
According to the guidelines, diabetes insipidus centralis can be ruled out directly if normal serum electrolytes and normal serum osmolarity are present in the thirst experiment with the ability to concentrate.
The guidelines also give therapy recommendations:
Desmopressin is the drug of choice because it is an analogue to the missing one ADH (antidiuretic hormone) represents. This can be done nasally (via nasal spray), enterally (via oral intake) or parenteral (intravenous) can be administered. The dosage recommendations vary depending on the route of administration and the individual. It is generally recommended to start with a low dosage, which can be adjusted upwards over the course of the day. According to the guideline, surgical removal of a tumor that may be the cause of the disease may be recommended.
prophylaxis
Unfortunately, prevention is not possible as the causes cannot be influenced. If typical symptoms occur (see above), a doctor should be consulted as soon as possible.
Should be about a tumor in the brain are present, the earlier it is recognized, the better it can be operated on. Also a progressing one Inflammation of the kidneys can be stopped.
forecast
The forecast of the central Diabetes insipidus depends on the prognosis of the underlying disease. If the whole thing is based on a tumor, the prognosis is based on the extent of the Tumorwhether it is operable or not, whether it is benign or malignant, etc.
In general, the prognosis is favorable. However, a cure can only be achieved if the causes can be eliminated. A Pituitary tumor can possibly be removed completely.
With the right medication, those affected can lead a completely normal life.
