NURS 2050 Lecture Notes - Lecture 18: Central Pontine Myelinolysis, Plasma Osmolality, Saline (Medicine)
19 Jan 2017
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Document Summary
Exam guidelines for the lecture on altered electrolytes. Hyponatremia: an electrolyte abnormality that occurs when serum sodium levels decrease below. It is a condition that occurs very often in hospitalized patients. In healthy people, hyponatremia does not develop unless water intake is greater than renal water excretion (see case study a in the presentation). It is also commonly found in the elderly with comorbidities that can lower serum sodium levels (cardiac, hepatic and renal disorders). It is essential to diagnose and treat because it can be fatal. ***plasma osmolality is primarily determined by plasma sodium concentration; a true decrease in plasma sodium caused by water excess results in hypo osmolality. ***most cases of hyponatremia are caused by impaired renal water excretion in the presence of continued water intake. Case study a: in patients with hyponatremia, urine osmolality and plasma osmolality can be used to distinguish between impaired water excretion and primary polydipsia (excessive drinking of water).
