Diagnosis/Progress of Hyponatremia

There are three different types of hyponatremia, and based on the amount of fluid in the cells, we can differentiate between the different types of hyponatremias.  The three types that we can diagnose are all a type of hypotonic hyponatremia.  They are: hypovolemic, euvolemic, and hypervolemic hyponatremia (1).  In all of theses cases, the blood level of sodium decreases to below 135 mEq/L (which is below the normal range of serum sodium).  Hypovolemic hyponatremia is presented with a depletion of ECF (extracellular fluid).  Since this is not easily detectable, the best way to detect hypovolemic hyponatremia is through patient history, physical examination, and laboratory results (1).  The symptoms that the patient may have include vomiting, diarrhea, orthostatic blood pressure decrease, increased pulse, and signs of dehydration (decreased skin turgor and dry mucous membranes) (1).  Laboratory signs include elevations of BUN, creatinine, and uric acid (1).   However, the laboratory signs are non-specific and can apply to other diseases.  Euvolemic hyponatremia occurs because of the high prevalence of SIADH.  It is diagnosed primarily from the patient's history, physical examination, and laboratory results (1).  Laboratory results that are indicative of euvolemic hyponatremia include a low BUN and a low serum uric acid level.  Measuring urine sodium is the most helpful in diagnosing euvolemic hyponatremia.  Hypervolemic hyponatremia is a detectable increased ECF volume.  This is usually caused by the inability of the body to excrete fluid.  With the buildup of fluid in the body, the body can be volume overloaded, thus causing hypo-osmolarity.  The diagnosis of fluid excess from hypervolemic hyponatremia is made through the patients history, physical examination, and laboratory results.  Physical examination can help detect patients with signs of fluid overload (edema, ascites, and pulmonary edema).  Laboratory results to detect hypervolemic hyponatremia include elevation of plasma levels of brain natriuretic peptide and a low urine of fractional sodium excretion due to the activation of the renin-angiotensin-aldosterone system.  In acute hyponatremia, one of the deadliest complications is brain herniation. Symptoms can progress from headache, nausea, vomiting, or confusion to seizures, respiratory arrest, and/or death.  They can also progress to a permanent vegatative state as a complication from severe cerebral edema (1).  These symptoms happen the most to postoperative patients, patients with water intoxication brought on by endurance exercises (like marathons), or use of drugs such as eccstasy (1).  Who knew hyponatremia could be so scary?

Brain Herniation 

Works Cited

1)  Verblis, J., Goldsmith, S., Greenberg, A., Korzelius, C., Schrier, R., Sterns, R., & Thompson, C. (2013). Diagnosis, Evaluation, and Treatment of Hyponatremia: Expert Panel Recommendations. The American Journal of Medicine, 126(10), S1-S42. Retrieved April 22, 2015, from http://www.amjmed.com/article/S0002-9343(13)00605-0/fulltext