Congenital Nephrogenic Diabetes Insipidus in an Adult

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Title: Congenital Nephrogenic Diabetes Insipidus in an Adult
Authors: Ishii, Hajime; Mizuno, Kenji; Nimura, Susumu; Haga, Hiroshi; Takahashi, Michihiko; Watanabe, Yukari; Tanaka, Kiyonobu; Ogata, Manabu; Tanaka, Noboru; Fukuchi, Soitsu
Publisher: Internal Medicine
Date Published: February 01, 1993
Reference Number: 139
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Abstract • Translation
A 35-year-old man with congenital nephrogenic diabetes insipidus (NDI) is reported. Renal biopsy revealed miniaturized and rounded mitochondria of the proximal tubular cells and decreased brush-borders. Trichlormethiazide combined with triamterene resulted in an apparent reduction of daily urine volume and concomitant increment in urine osmolarity. The present case seems rare in that some morphological changes in the renal tissues could be demonstrated in an adult case with congenital NDI.

This translation by the NDI Foundation is to assist the lay reader. To provide a clear, accessible interpretation of the original article, we eliminated or simplified some technical detail and complicated scientific language. We concentrated our translation on those aspects of the article dealing directly with NDI. The NDI Foundation thanks the researchers for their work toward understanding and more effectively treating this disorder.
© Copyright NDI Foundation 2007 (JC)

Nephrogenic diabetes insipidus (NDI) is a rare disease characterized by polydipsia (excessive thirst) and polyuria (excessive urination). It is due to the inability of the little tubes in the kidneys (called tubules) to concentrate urine as they should. Congenital NDI is generally inherited as a sex-linked recessive disorder, which means females carry the mutated gene and males are much more likely to have the disorder than females. However, there have been several cases of congenital NDI reported in females. In this case, Ishii, et al., report on a 35-year-old male born with NDI, though there was no family history of the disorder. After it was determined the man had NDI, he consented to a kidney biopsy.

Each kidney contains about a million nephrons, each a combination of a glomerulus (the kidney's primary filtering unit) and a tubule. The biopsy revealed that the glomeruli were almost intact, but an area between the end of the tubules and the kidney collecting duct was atrophied. The bottom of the membranes of the glomeruli were wrinkled and irregularly thickened and the brush borders of the part of the tubules next to the glomeruli were decreased in number and shortened in length. The mitochondria are small spherical to rod shaped components in cells that are the principle sites for the generation of energy. In this patient the mitochondria in the part of the tubules close to the glomeruli were miniaturized and more rounded than normal. In the part of the tubules farther away from the glomeruli there were spottings of dead cells and part of the membranes at the tubule's bottom was thicker than usual.

The researchers could not conclude whether these tubular changes were responsible for their patient's NDI, or whether they were the result of his long-term NDI. It did seem possible that the damage to the mitochondria could have contributed to polyuria because they supply the energy for transporting sodium to play a role in sodium and water reabsorption in the kidney.

Thiazides act to induce sodium loss and extracellular volume depletion. They help the part of the tubule near the glomeruli to reabsorb fluid and in this way help in reducing urine volume. When the authors prescribed a low sodium diet and the diuretic trichlolormethiazide, it had little effect. When they added a potassium-sparing diuretic to be taken along with their previous prescription, it produced more of an impact in reducing the patient's daily urine volume.