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Part II Nutrition Assessment, Consequences, and Implications

Clinical Signs of Hypokalemia and Hyperkalemia

The following are clinical signs of hypokalemia: ●

muscle weakness

● cramps ●

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hypoflexia paresthesia

decreased bowel motility hypotension

cardiac arrhythmia drowsiness lethargy

● coma

The following are clinical signs of hyperkalemia: ●

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confusion irritability nausea

vomiting

intestinal colic paresthesia

● abdominal cramps muscle paralysis

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Sodium, Serum Normal Values ●

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136 to 146 mEq/L; 136 to 145 mmol/L (SI) (5) Nutritional Significance

“The serum sodium level reflects the relationship between total body sodium and extracellular fluid volume. The concentration of sodium serves as a major determinant of extracellular osmolality.” A decreased serum sodium level also results in a decreased extracellu- lar osmolality. An elevated serum sodium level results in increased extracellular osmolality. “Elevated osmolality stimulates secretion of the antidiuretic hormone, which in turn increases tubular reabsorption of water” (1). Clinical signs of hypernatremia include dehydra- tion, thirst, agitation, restlessness, hyperflexia, mania, tachycardia, dry mucous membranes, lethargy, hyper- active reflexes, and seizures. As the fluid shifts to com- pensate for excessive levels of sodium, the serum becomes more dilute. Other laboratory values associ- ated with hypernatremia include urine-specific gravity greater than 1.015 and serum osmolality greater than 295 mOsm/kg (1,5).

All laboratory values will appear less concentrated when hyponatremia is present. The body compensates for hyponatremia by increasing water loss. As water is lost, the serum sodium, as well as other laboratory

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values, becomes more concentrated. Other laboratory values associated with hyponatremia include urine- specific gravity lower than 1.010 and serum osmolality lower than 285 mOsm/Kg. Clinical signs of hyponatre- mia include muscle cramps, muscle twitching, head- ache, dizziness, lethargy, confusion, convulsions, stupor, and coma. The changes in the central nervous system are due to fluid shifts from the extracellular spaces to the intracellular spaces, which cause the cells to swell (1).

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Serum sodium levels increase with (1): excessive intake

primary aldosteronism dehydration

excessive sweating diabetes insipidus

hypercalcemic nephropathy ● hypokalemic nephropathy Cushing’s disease

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Serum sodium decreases with (1): ●

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decreased intake severe diarrhea

excessive water intake overhydration vomiting

excessive use of IVs of nonelectrolyte fluids cirrhosis with ascites

inappropriate secretion of antidiuretic hormone hyperglycemia

hyperproteinemia Addison’s disease

The following drugs may increase serum sodium levels (1): ●

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anabolic steroids antibiotics clonidine

corticosteroids laxatives

● methyldopa

The following drugs may decrease serum sodium levels (1): ●

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carbamazepine diuretics

sulfonylureas triamterene vasopressin