Nephrogenic diabetes insipidus
Nephrogenic diabetes insipidus | |
---|---|
Other names | arginine vasopressin resistance; renal diabetes insipidus |
Specialty | Nephrology |
Nephrogenic diabetes insipidus, recently renamed as arginine vasopressin resistance (AVP-R) and also previously known as renal diabetes insipidus, is a form of diabetes insipidus primarily due to pathology of the kidney. This is in contrast to central or neurogenic diabetes insipidus, which is caused by insufficient levels of vasopressin (also called antidiuretic hormone, ADH). Nephrogenic diabetes insipidus is caused by an improper response of the kidney to vasopressin, leading to a decrease in the ability of the kidney to concentrate the urine by removing free water.[citation needed]
Signs and symptoms
The clinical manifestation is similar to neurogenic diabetes insipidus, presenting with polydipsia (excessive thirst) and polyuria (excretion of a large amount of dilute urine). Dehydration is common, and incontinence can occur secondary to chronic bladder distension.[1] On investigation, there will be an increased plasma osmolarity and decreased urine osmolarity. As pituitary function is normal, antidiuretic hormone levels are likely to be abnormal or raised. Polyuria will continue as long as the patient is able to drink. If the patient is unable to drink and is still unable to concentrate the urine, then hypernatremia will ensue with its neurologic symptoms.[citation needed]
Causes
Acquired
Nephrogenic diabetes insipidus 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,[2] polycystic kidney disease,[3] electrolyte imbalance,[4][5] or some other kidney defect.[2]
The major causes of acquired nephrogenic diabetes insipidus that produce clinical symptoms (e.g., polyuria) in the adult are
Osmotic
Other causes of acquired nephrogenic diabetes insipidus include hypokalemia (low blood potassium), post-obstructive polyuria, sickle cell disease or trait, amyloidosis, Sjögren syndrome, renal cystic disease, Bartter syndrome, and various medications (amphotericin B, orlistat, ifosfamide, ofloxacin, cidofovir, vaptans).[citation needed]
In addition to kidney and systemic disorders, nephrogenic diabetes insipidus can present itself as a side effect of some medications. The most common and well known of these medications is lithium,[7] although there are many other medications that cause this effect with lesser frequency.[2]
Hereditary
This form of diabetes insipidus can also be hereditary due to defects in the following genes:
Type | OMIM
|
Gene | Locus |
---|---|---|---|
NDI1 | 304800 | AVPR2
|
Usually, the hereditary form of nephrogenic diabetes insipidus 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.[2][8] |
NDI2 | 125800 | AQP2
|
In more rare cases, a mutation in the " |
Diagnosis
Differential diagnosis includes nephrogenic diabetes insipidus, neurogenic/central diabetes insipidus and psychogenic polydipsia. They may be differentiated by using the water deprivation test. Recently, lab assays for antidiuretic hormone are available and can aid in diagnosis. If the patient is able to rehydrate properly, sodium concentration should be nearer to the maximum of the normal range. This, however, is not a diagnostic finding, as it depends on patient hydration.[citation needed]
Desmopressin can also be used; if the patient is able to concentrate urine following administration of desmopressin, then the cause of the diabetes insipidus is neurogenic diabetes insipidus; if no response occurs to desmopressin, then the cause is likely to be nephrogenic.[citation needed]
Treatment
Persons with nephrogenic diabetes insipidus must consume enough fluids to equal the amount of urine produced. Any underlying cause such as high blood calcium must be corrected to treat nephrogenic diabetes insipidus. The first line of treatment is hydrochlorothiazide and amiloride.[10] Patients may also consider a low-salt and low-protein diet.[citation needed]
Thiazide diuretics are used in treatment because diabetes insipidus causes the excretion of more sodium than water, while maintaining the corticomedullary gradient (not maintained when using loop diuretics). The maintained corticomedullary gradient allows more absorption of water in the collecting duct. This improves the blood osmolarity and prevents hypernatremia. [citation needed]
High serum osmolarity stimulates polydipsia in an attempt to dilute the serum back to normal and provide free water for excreting the excess serum solutes. However, since the patient is unable to concentrate urine to excrete the excess solutes, the resulting urine fails to decrease serum osmolarity and the cycle repeats itself, hence polyuria.[citation needed]
Etymology
The name of the disease comes from:
- diabetes: from Ancient Greek: διαβήτης diabḗtēs "a passer-through; siphon", from Greek διαβαίνειν diabaínein "to pass through", from δια- dia- "through" + βαίνειν baínein "to go".
- insipidus: from Late Latin: insipidus "tasteless," from Latin in- "not" + sapidus "tasty", from sapere "to taste".[citation needed]
This is because patients experience polyuria (an excretion of over 2.5 liters of urine per day), and the urine does not have an elevated
Although they share part of their names, diabetes mellitus and diabetes insipidus are two separate conditions. Both cause excessive urination (hence the similarity in name), but whereas diabetes insipidus is a problem with the production of
References
- ^ "Diabetes Insipidus. Diabetes symptoms and information". www.patient.co.uk. Retrieved 2018-05-18.
- ^ a b c d e Wildin, Robert (2006). "What is NDI?". The Diabetes Inspidus Foundation.
{{cite journal}}
: Cite journal requires|journal=
(help) "Nephrogenic Diabetes Insipidus". Archived from the original on 2009-04-01. Retrieved 2009-04-04. - ^ "Diabetes Insipidus". National Institute of Diabetes and Digestive and Kidney Diseases. Archived from the original on 2011-06-08. Retrieved 2018-05-18.
- PMID 8621781.
- S2CID 29761514.
- S2CID 4552345.
- PMID 2989335.
- ^ Online Mendelian Inheritance in Man (OMIM): Diabetes Insipidus, Nephrogenic, X-linked - 304800
- ^ Online Mendelian Inheritance in Man (OMIM): Diabetes Insipidus, Nephrogenic, Autosomal - 125800
- PMID 10332005.