Which of the following would NOT be likely to produce hypernatremia?
Hypernatremia occurs when there is elevation of serum Na+ of > 146 mEq/L. It occurs under various circumstances which include excessive Na+ ingestion in absence of corresponding water ingestion, an inability to ingest water due to impairment in thirst mechanisms, unconsciousness or lack of water supply, and insufficient intake of water to keep up with water losses. Near drowning in salt water causes considerable intake of hypeonic salt solution either through swallowing or absorption through pulmonary membranes. Diabetes Insipidus is a result of faulty, or insufficient secretion of ADH (anti diuretic hormone). This leads to increased urinary output of dilute urine with subsequent excess water losses, leading to hyperosmolality of serum. Hyperglycemia, however, tends to decrease serum Na+ concentrations as water shifts from intracellular compaments into intravascular fluids in response to the hyperosmolar state of the serum. Watery diarrhea will produce excess water losses in excess of electrolytes, thus increasing serum Na+ concentration. Ref: Howard C., Berl T. (2009). Chapter 3. Disorders of Water Balance: Hyponatremia & Hypernatremia. In E.V. Lerma, J.S. Berns, A.R. Nissenson (Eds), CURRENT Diagnosis & Treatment: Nephrology & Hypeension.
Near drowning in salt water
Hyperglycemia
Diabetes Insipidus
Watery diarrhea