P&P: electrolyte balance; chart

Question 1

Increased Output Not Balanced by Increased Intake of Na+ and Water

Answer 1

• Vomiting
• Acute or chronic diarrhea from any cause, including laxative abuse
• Draining GI fistula, gastric suction, or intestinal decompression
• Hemorrhage or burns
• Overuse of diuretics
• Lack of aldosterone (adrenal insufficiency, Addison’s disease)

Question 2

Rapid Fluid Shift from ECV into a Third Space

Answer 2

• Acute intestinal obstruction

* Ascites that develops rapidly

Question 3

Output Less than Excessive or Too Rapid Intake of Na+ and Water

Answer 3

• Excessive IV infusion of Na+-containing isotonic solution (0.9% NaCl, Ringer’s)
• High oral intake of salty foods and water with renal retention of Na+ and water

Question 4

Decreased Output Not Balanced by Decreased Intake of Na+ and Water

Answer 4

• Oliguria (e.g., acute kidney injury, acute glomerulonephritis, end-stage renal disease)
• Aldosterone excess (e.g., cirrhosis, chronic heart failure, primary hyperaldosteronism)
• High levels of glucocorticoids (e.g., corticosteroid therapy, Cushing’s disease)

Question 5

Hypernatremia

Answer 5

Body Fluids Too Concentrated; Osmolality Too High

Question 6

Normal Output but Deficient Intake of Water

Answer 6

• No access to water or inability to respond to or communicate thirst (e.g., aphasia, coma, infancy)
• Tube feeding without additional water intake

Question 7

Increased Output Not Balanced by Increased Intake of Water

Answer 7

• Vomiting or diarrhea with replacement of Na+ but not enough water
• Diabetes insipidus (lack of antidiuretic hormone)

Question 8

Hyponatremia

Answer 8

Body Fluids Too Dilute; Osmolality Too Low

Question 9

Output Less than Excessive or Too Rapid Intake of Water

Answer 9

• IV 5% dextrose in water (D5W) infusion with excess rate or amount
• Rapid oral ingestion of massive amounts of water (e.g., child abuse, club initiation, psychiatric disorders)
• Overuse of tap water enemas or hypotonic irrigating solutions
• Massive replacement of water without Na+ during vomiting or diarrhea

Question 10

Decreased Output Not Balanced by Decreased Intake of Water

Answer 10

• Excessive antidiuretic hormone

Question 11

Hypokalemia

Answer 11

Plasma K+ Deficit

Question 12

Normal Output but Deficient K+ Intake

Answer 12

• Prolonged anorexia or diet lacking K+-rich foods

* No oral intake plus IV solutions not containing K+

Question 13

Increased Output Not Balanced by Increased K+ Intake

Answer 13

• Vomiting
• Acute or chronic diarrhea from any cause, including laxative abuse
• Use of K+-wasting diuretics or other drugs that increase renal K+ excretion
• Excessive aldosterone effect (e.g., large amounts of black licorice, cirrhosis, chronic heart failure, primary hyperaldosteronism)
• High levels of glucocorticoids (e.g., corticosteroid therapy, Cushing’s disease)

Question 14

Rapid K+ Shift from ECF into Cells

Answer 14

• Alkalosis, excessive beta-adrenergic stimulation, or excessive insulin

Question 15

Hyperkalemia

Answer 15

Plasma K+ Excess

Question 16

Output Less than Excessive or Too Rapid K+ Intake

Answer 16

• IV K+ infusion with excess rate or amount

* Massive transfusion (>8 units) of stored blood

Question 17

Decreased Output Not Balanced by Decreased K+ Intake

Answer 17

• Oliguria (e.g., severe hypovolemia, circulatory shock, acute kidney injury, end-stage renal disease)
• Use of K+-sparing diuretics, angiotensin-converting enzyme (ACE) inhibitors, or other drugs that decrease renal K+ excretion
• Lack of aldosterone (e.g., adrenal insufficiency, Addison’s disease)

Question 18

Rapid K+ Shift from Cells into ECF

Answer 18

• Lack of insulin or acidosis due to mineral acids

* Massive sudden cell death (e.g., crushing injuries, tumor lysis syndrome)

Question 19

Hypocalcemia

Answer 19

Plasma Ca++ Deficit

Question 20

Normal Output but Deficient Ca++ Intake or Absorption

Answer 20

• Diet lacking Ca++-rich foods

* Poor Ca++ absorption (e.g., chronic diarrhea, lack of vitamin D)

Question 21

Increased Output Not Balanced by Increased Ca++ Intake and Absorption

Answer 21

• Steatorrhea (binds Ca++ in GI secretions as well as dietary Ca++)

Question 22

Ca++ Shift from ECF into Bone or Physiologically Unavailable Form

Answer 22

• Hypoparathyroidism
• Large load of citrate from massive blood transfusion (binds Ca++)
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• Alkalosis (more Ca++ binds albumin) or elevated plasma phosphate level
• Acute pancreatitis (Ca++ binds necrotic fat in abdomen)

Question 23

Hypercalcemia

Answer 23

Plasma Ca++ Excess

Question 24

Output Less than Excessive Ca++ Intake and Absorption

Answer 24

• Vitamin D or Ca++ overdose (includes shark cartilage supplements)

Question 25

Decreased Output Not Balanced by Decreased Ca++ Intake

Answer 25

• Use of thiazide diuretics

Question 26

Ca++ Shift from Bone into ECF

Answer 26

• Hyperparathyroidism

* Cancers that secrete bone-resorbing factors

Question 27

Hypomagnesemia

Answer 27

Plasma Mg++ Deficit

Question 28

Normal Output but Deficient Mg++ Intake or Absorption

Answer 28

• Diet lacking Mg++-rich foods

* Poor Mg++ absorption (e.g., chronic diarrhea, ileal resection, chronic alcoholism)

Question 29

Increased Output Not Balanced by Increased Mg++ Intake and Absorption

Answer 29

• Prolonged vomiting, gastric suction, or draining GI fistula
• Steatorrhea (binds Mg++ in GI secretions as well as dietary Mg++)
• Use of diuretics or other drugs that increase urinary Mg++

Question 30

Mg++ Shift into Physiologically Unavailable Form

Answer 30

• Large load of citrate from massive blood transfusion (binds Mg++)
• Alkalosis (more Mg++ binds albumin)

Question 31

Hypermagnesemia

Answer 31

Plasma Mg++ Excess

Question 32

Output Less than Excessive Mg++ Intake and Absorption

Answer 32

• Overuse of Mg++-containing laxatives or antacids

Question 33

Decreased Output Not Balanced by Decreased Mg++ Intake

Answer 33

• Chronic oliguric renal disease