Question

Specifically looking for clinical manifestations of hyponatremia, document your findings below.

• Cardiovascular
• Respiratory
• Neuromuscular
• Gastrointestinal

Answer 1

Hyponatremia is defined as a serum sodium <135 meq/l.

Hyponatremia results from the inability of the kidney to excrete a water load or excess water intake. Water intake depends upon thirst mechanism. Thirst is stimulated by increase in osmolality. Thirst is sensed by osmoreceptors located in the hypothalamus and leads to the release of anti-diuretic hormone (vasopressin) from the posterior pituitary. Antidiuretic hormone acts on the V2 receptors located at the basolateral aspect of the collecting duct cells and leads to increased aquaporin expression on the luminal aspect of the collecting duct cells which increases water absorption and abolishes thirst.

clinical manifestations

cadiovascular- cardiac conduction defects- av block-hyponatremia is due to inappropriate and continued vasopressin activity despite hypoosmolality and volume overload. Hyponatremia is also due to diuretic use in an attempt to manage volume overload. When hyponatremia occurs, it is a marker of heart failure severity and identifies patients with increased mortality

respiratory- non cardogenic pulmonary odema, hyper capnic respiratory failure.

neuromuscular- neurologic symptoms resulting from cerebral edema induced by water movement into the brain. These may include seizures, impaired mental status or coma and death.

gastrointestinal-Mild hyponatremia is characterized by gastrointestinal tract symptoms nausea, vomiting, loss of appetite.