Hypotonic Hyponatremia In most cases of hyponatremia there is an excess of H20 relative to Na in the body. This decreases the tonicity (osmolality) of the serum. Water then moves from the extracellular to intracellular space down this osmotic gradient. This causes cellular swelling. Cellular swelling in the brain explains the adverse CNS
Endocrine disorders are in the differential diagnosis of hyponatremia. These need to be distinguished from SIADH (Syndrome of Inappropriate Antidiuretic Hormone). In the article on the laboratory evaluation of hyponatremia read here and watch here, we learned that in hypotonic hyponatremia if the urine osmolarity is > 100 ADH is present and that
You know or can look up the standard diagnostic algorithm for hyponatremia. Hypovolemic Euvolemic Hypervolemic Not doing this here. Read on to find out what the labs tell you. Knowing this will supplement and deepen your understanding. We’ll be analyzing the following labs: Serum Sodium Serum Osmolarity Urine Osmolarity Urine Sodium Uric acid
