Diabetes insipidus is a disease characterized by excretion of large amounts of very dilute urine, which can be reduced by reducing the intake of liquids. This results from an inability of the kidney to concentrate urine. Diabetes insipidus is caused by a deficiency of antidiuretic hormone, or a kidney insensitivity to the hormone.
Signs and symptoms
Clinically, the disease manifests itself in an abrupt or rapidly progressive, with a polyuria which may reach 8 to 10 liters per day. The urine is pale like water, very concentrated, and contain no element pathological neither sugar nor albumen. Accompanying this polyuria, polydipsia there. The patient drinks incessantly, much, day, night, and can never quench his thirst.
Otherwise, the patient is in relatively good condition, unless it is hyper-hydrated (headache, nausea), or dehydrated. Clinical examination is normal.
This picture is very characteristic of diabetes insipidus.
The diagnosis must be made with certainty because there is a disease clinically similar: the potomania psychogenic. This is a behavioral disorder that causes an urge to drink the amount of fluid intake may be greater than that absorbed in diabetes insipidus, polyuria course is also very important, sometimes more than in diabetes insipidus.
Clinically, the beginning of the potomania is often abrupt, following an emotional shock, the patient has psychiatric problems (but not always), and polydipsia is variable from one day to another. None of these signs is absolute, but it remains essential course of an accurate diagnosis because the treatment is very different.
The diagnosis is made by dynamic tests.
The water deprivation test helps determine whether there are still opportunities for secretion of the hormone ADH. The test is performed in hospitals, to compensate for a possible rapid dehydration. The patient urine, then weighed and it lies in a bed. Every 15 minutes, weighed, he takes the tension, and every 30 minutes you collect urine in jars numbered. The test stops when the patient shows signs of discomfort: anxiety, dry mucous membranes, rapid pulse, low blood pressure and weight. The combination of dehydration and the inability of the kidneys to concentrate urine despite the abolition of drinks, makes the diagnosis. It goes without saying that in a true diabetes insipidus can not conduct this trial until its conclusion.
The vasopressin test can recognize the deficiency of DHA. Other tests may be performed, most tests are used therapeutic use antidiuretic property of certain drugs.
The differential diagnosis potomania can be difficult even after these events, because a prolonged potomania can inhibit the secretion of the hormone ADH (diabetes insipidus induced), diabetes insipidus because one can heal the sick but who has the habit of drink lots will continue, and therefore excessive urination (diabetes insipidus self-sustaining), or because there are disruptions of primitive thirst center (with a lesion or tumor in the hypothalamus). Sometimes the doctor uses a test of deconditioning, with appropriate psychotherapy. The goal is to persuade the patient to drink less, with a restricted diet, possibly a drug antidiuretic which is gradually replaced by a placebo. The determination of antidiuretic hormone shows its decline.
The MRI is a great place to diagnose causes tumor.
There are various forms of diabetes insipidus:
* Central: lack of secretion of ADH (= antidiuretic hormone, vasopressin) in the pituitary)
* Nephrogenic: reduction or abolition of the renal response to ADH
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