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Reset Osmostat in a Healthy Patient
- Joshua H. Lipschutz, MD; and
- Allen I. Arieff, MD
- From the Veterans Administration Medical Center, University of California at San Francisco, San Francisco, California. Requests for Reprints: Joshua H. Lipschutz, MD, Division of Nephrology, University of California, San Francisco, Box 0532, Room 1065 HSE, San Francisco, CA 94121. Acknowledgment: The authors thank Dr. David Lovett for referring this patient and Jenifer Schaten for assisting in manuscript preparation. Grant Support: In part by the research service of the Veterans Administration Medical Center, San Francisco, California; grant RO1AG08575 from the National Institute of Aging; and Academic Nephrology Training grant DK07219 from the Academic Nephrology Training Program from the National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, Maryland.
Reset osmostat is a rare condition in acutely ill patients with severe pulmonary [1, 2], neurologic [3, 4], or malignant processes [5]. When hyponatremia occurs because of “reset osmostat,” renal concentrating and diluting capacities are normal but the regulation of arginine vasopressin to maintain serum tonicity takes place at a lower osmolal threshold.
We report chronic stable hyponatremia secondary to reset osmostat in a healthy middle-aged man who had sustained a grenade explosion to his face 41 years earlier.
Case Report
The 60-year-old man was generally healthy, had an advanced engineering degree, and was a full-time supervisor until he recently retired. His serum sodium levels, documented on multiple occasions at our institution during a 13-year period, ranged from 125 to 130 mmol/L. He denied using cigarettes (since 1968), diuretic agents, and laxatives. He also denied having polydipsia, polyuria, nausea, and emesis. His past medical history was notable for a grenade explosion to the face, in 1951, that resulted in a chronic, low-grade, superficial infection of the orbital area, which persisted until definitive reconstructive surgery was done in 1974. No neurologic sequelae were noted. He also had mild hypertension, treated …
