Acid-base balance and electrolytes: case studies (Proceedings)


Acid-base balance and electrolytes: case studies (Proceedings)

Aug 01, 2011

Water balance

     a. clinical measures of water balance
     b. laboratory measures of water balance
     c. water intake
     d. water loss
1. Dehydration- terms describe resulting state of hydration, not what is lost
     a. isotonic dehydration
     b. hypertonic dehydration
     c. hypotonic dehydration
2. Compensatory mechanisms abnormal water balance
     a. Renal blood flow (eg dehydration)
          • Decreased renal blood flow
          • Decreased GFR
          • Decreased urine production
          • (increased urine specific gravity)
     b. Hormonal changes
          • ADH
          • Renin
          • Angiotensin
          • Aldosterone
          • Atrial natiuretic factor

Sodium balance

1. Hyponatremia (see table 22.4, page 334)
     a. pseudohyponatremia
     b. dilution of total body sodium
     c. loss of sodium
2. Hypernatremia (see table 22.4, page 334)
     a. excessive sodium retention
     b. water loss in excess of sodium (hypertonic dehydration)

Chloride balance

1. Hypochloremia and hyperchloremia
     a. often the same mechanisms as hyponatremia/hypernatremia (table 22.4)
     b. may be a primary: eg secretory diarrhea

Potassium balance

1. Hypokalemia (see table 22.5, page 336)
     a. redistributional
          • insulin
          • catecholamines
          • metabolic alkalosis
     b. absolute
          • secretory diarrhea (Na is reabsorbed instead of K)
          • Renal loss
               √ Increased urine flow
               √ Nonreabsorbable anions
               √ sulfates, phosphates, ketoacids, lactate
               √ metabolic alkalosis
               √ third space syndromes
               √ feline kaliopenic nephropathy-polymyopathy syndrome

2. Hyperkalemia (see table 22.5, page 336)
     a. pseudokyperkalemia
     b. redistributional hyperkalemia
     c. absolute hyperkalemia