ADVANCED PATHOPHYSIOLOGY STUDY GUIDE QUESTIONS WITH
COMPLETE SOLUTIONS
1) What mechanisms cause hypernatremia? -- Answer ✔✔ hyperaldosteronism
- Explanation: More commonly, high sodium levels occur because (1)
inadequate free water intake; (2) inappropriate administration of
hypertonic saline solution (e.g. sodium bicarbonate for treatment of
acidosis during cardiac arrest; (3) high sodium levels as a result of over
secretion of aldosterone (as in primary hyperaldosteronism) or; (4)
Cushing syndrome (caused by excess secretion of adrenocorticotropic
hormone (ACTH), which also causes increased secretion of aldosterone.
2) What causes the clinical manifestations of confusion, convulsions, cerebral
hemorrhage, and coma in hypernatremia? -- Answer ✔✔ the high sodium in the
blood vessels pulls water out of brain cells into the blood vessels, causing brain
cells to shrink.
- Explanation: Hypertonic (hyperosmolar) imbalances result in an ECF
concentration greater than 0.9% salt solution, i.e. water loss or solute gain;
cells shrink in a hypertonic fluid.
3) Which are indications of dehydration? -- Answer ✔✔ Tachycardia and weight
loss
, - Explanation: Marked water deficit is manifested by symptoms of
dehydration: headache, thirst, dry skin and mucous membranes, elevated
temperature, weight loss, and decreased or concentrated urine (with the
exception of diabetes insipidus). Skin turgor may be normal or decreased.
Symptoms of hypovolemia, including tachycardia, weak pulses, and postural
hypotension, may be present.
4) How does SIADH cause excess water? -- Answer ✔✔ The increase in
antidiuretic hormone causes retention of water in the renal tubules.
- Explanation: SIADh is not caused by excess water intake but by increased
renal absorption of water as a result of inappropriate increases in ADH.
Serum sodium and osmolality are reduced by dilution. The kidney
continues to excrete sodium, and urine sodium and urine osmolality are
elevated; water is reabsorbed, increasing body fluid volume, and urine
volume is decreased.
5) How is insulin used to treat hyperkalemia? -- Answer ✔✔ Insulin transports
potassium from the blood to the cell along with glucose.
- Explanation: Insulin contributes to the regulation of plasma potassium
levels by stimulating the Na+/K+ ATPase pump, thereby promoting the
movement of potassium into the liver and muscle cells simultaneously with
glucose transport after eating. The intracellular movement of potassium
prevents an acute hyperkalemia related to food intake. Insulin also can be
used to treat hyperkalemia.
6) During acidosis, the body compensates for the increase in hydrogen ions in the
blood by shifting hydrogen ions into the cell in exchange for which electrolyte? --
Answer ✔✔ Potassium
- Explanation: In states of acidosis, hydrogen ions shift into the cells in
exchange for ICF potassium; hyperkalemia and acidosis therefore often
occur together.
7) What are causes of hyperkalemia? -- Answer ✔✔ Renal failure and Addison
disease (hypoaldersteronism)
COMPLETE SOLUTIONS
1) What mechanisms cause hypernatremia? -- Answer ✔✔ hyperaldosteronism
- Explanation: More commonly, high sodium levels occur because (1)
inadequate free water intake; (2) inappropriate administration of
hypertonic saline solution (e.g. sodium bicarbonate for treatment of
acidosis during cardiac arrest; (3) high sodium levels as a result of over
secretion of aldosterone (as in primary hyperaldosteronism) or; (4)
Cushing syndrome (caused by excess secretion of adrenocorticotropic
hormone (ACTH), which also causes increased secretion of aldosterone.
2) What causes the clinical manifestations of confusion, convulsions, cerebral
hemorrhage, and coma in hypernatremia? -- Answer ✔✔ the high sodium in the
blood vessels pulls water out of brain cells into the blood vessels, causing brain
cells to shrink.
- Explanation: Hypertonic (hyperosmolar) imbalances result in an ECF
concentration greater than 0.9% salt solution, i.e. water loss or solute gain;
cells shrink in a hypertonic fluid.
3) Which are indications of dehydration? -- Answer ✔✔ Tachycardia and weight
loss
, - Explanation: Marked water deficit is manifested by symptoms of
dehydration: headache, thirst, dry skin and mucous membranes, elevated
temperature, weight loss, and decreased or concentrated urine (with the
exception of diabetes insipidus). Skin turgor may be normal or decreased.
Symptoms of hypovolemia, including tachycardia, weak pulses, and postural
hypotension, may be present.
4) How does SIADH cause excess water? -- Answer ✔✔ The increase in
antidiuretic hormone causes retention of water in the renal tubules.
- Explanation: SIADh is not caused by excess water intake but by increased
renal absorption of water as a result of inappropriate increases in ADH.
Serum sodium and osmolality are reduced by dilution. The kidney
continues to excrete sodium, and urine sodium and urine osmolality are
elevated; water is reabsorbed, increasing body fluid volume, and urine
volume is decreased.
5) How is insulin used to treat hyperkalemia? -- Answer ✔✔ Insulin transports
potassium from the blood to the cell along with glucose.
- Explanation: Insulin contributes to the regulation of plasma potassium
levels by stimulating the Na+/K+ ATPase pump, thereby promoting the
movement of potassium into the liver and muscle cells simultaneously with
glucose transport after eating. The intracellular movement of potassium
prevents an acute hyperkalemia related to food intake. Insulin also can be
used to treat hyperkalemia.
6) During acidosis, the body compensates for the increase in hydrogen ions in the
blood by shifting hydrogen ions into the cell in exchange for which electrolyte? --
Answer ✔✔ Potassium
- Explanation: In states of acidosis, hydrogen ions shift into the cells in
exchange for ICF potassium; hyperkalemia and acidosis therefore often
occur together.
7) What are causes of hyperkalemia? -- Answer ✔✔ Renal failure and Addison
disease (hypoaldersteronism)
