Nephrogenic diabetes insipidus
Nephrogenic diabetes insipidus is a form of diabetes insipidus due primarily to pathology of the kidney.
Causes
Acquired
Nephrogenic DI is most common in its acquired forms, meaning that the defect was not present at birth. These acquired forms have numerous potential causes. The most obvious cause is a kidney or systemic disorder, including amyloidosis , polycystic kidney disease , electrolyte imbalance, or some other kidney defect.
In addition to kidney and systemic disorders, nephrogenic DI can present itself as a side-effect to some medications. The most common and well known of these drugs is lithium, although there are numerous other medications that cause this effect with lesser frequency.
Hereditary
This form of DI can also be hereditary. Usually, the hereditary form of nephrogenic DI is the result of an X-linked genetic defect which causes the vasopressin receptor (also called the V2 receptor) in the kidney to not function correctly.
In more rare cases, a mutation in the "aquaporin 2" gene can cause a break in the kidney water channel, which results in the kidney being unable to absorb water.
Presentation
The Clinical manifestation is similar to Neurogenic diabetes insipidus, presenting with excessive thirst and excretion of a large amount of dilute urine. Dehydration is common, and incontinence can occur secondary to chronic bladder distension. On investigation, there will be an increased plasma osmolarity and descreased urine osmolarity. As pituitary function is normal, ADH levels are likely to be a normal or raised.
Treatment
Treat any underlying cause, allow the patient to drink as much as required. Correct metabolic abnormalities. The first line of treatment is desmopressin, a vasopressin analogue, even in vasopressin receptor receptor malfunction. If this is not successful, other options are available, although their efficacy is limited: hydrochlorothiazide
indomethacin
carbamazepine
Translation of "Nephrogenic diabetes insipidus"
Hebrew: סוכרת תפלה נפרוגנית.
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