**Pathophysiology - Fluids & Electrolytes, Acids and Bases (PRACTICE QUESTIONS!)

A nurse is reviewing lab reports. The nurse recalls blood plasma is located in which of the following fluid compartments?

a. Intracellular fluid (ICF)

b. Extracellular fluid (ECF)

c. Interstitial fluid

d. Intravascular fluid

d. Intravascular fluid

Rationale: Blood plasma is the intravascular fluid.

ICF is fluid in the cells.

ECF is all the fluid outside the cells.

Interstitial fluid is fluid between the cells and outside the blood vessels.

A 35-year-old male weighs 70 kg. Approximately how much of this weight is ICF?

a. 5 L

b. 10 L

c. 28 L

d. 42 L

d. 42 L

While planning care for elderly individuals, the nurse remembers the elderly are at a higher risk for developing dehydration because they have a(n):

a. Higher total body water volume

b. Decreased muscle mass

c. Increase in thirst

d. Increased tendency towards developing edema

b. Decreased muscle mass

Which of the following patients should the nurse assess for a decreased oncotic pressure in the capillaries? A patient with:

a. A high-protein diet

b. Liver failure

c. Low blood pressure

d. Low blood glucose

b. Liver failure

Rationale: Liver failure leads to lost or diminished plasma albumin production, and this contributes to decreased plasma oncotic pressure.

Water movement between the ICF and ECF compartments is determined by:

a. Osmotic forces

b. Plasma oncotic pressure

c. Antidiuretic hormone

d. Buffer systems

a. Osmotic forces

An experiment was designed to test the effects of the Starling forces on fluid movement. Which of the following alterations would result in fluid moving into the interstitial space?

a. Increased capillary oncotic pressure

b. Increased interstitial hydrostatic pressure

c. Decreased capillary hydrostatic pressure

d. Increased interstitial oncotic pressure

d. Increased interstitial oncotic pressure

When planning care for a dehydrated patient, the nurse remembers the principle of water balance is closely related to _____ balance.

a. Potassium

b. Chloride

c. Bicarbonate

d. Sodium

d. Sodium

Rationale: Because water follows the osmotic gradients established by changes in salt concentration, water balance is tied to sodium balance.

A 70-year-old male with chronic renal failure presents with edema. Which of the following is the most likely cause of this condition?

a. Increased capillary oncotic pressure

b. Decreased interstitial oncotic pressure

c. Increased capillary hydrostatic pressure

d. Increased interstitial hydrostatic pressure

c. Increased capillary hydrostatic pressure

Rationale: Increased capillary hydrostatic pressure would facilitate increased movement from the capillary to the interstitial space, leading to edema.

A 10-year-old male is brought to the emergency room (ER) because he is incoherent and semiconscious. CT scan reveals that he is suffering from cerebral edema. This type of edema is referred to as:

a. Localized edema

b. Generalized edema

c. Pitting edema

d. Lymphedema

a. Localized edema

Rationale: Cerebral edema is a form of localized edema.

Generalized edema is manifested by a more uniform distribution of fluid in interstitial spaces.

Pitting edema is due to a pit left in the skin.

Lymphedema is due to swelling in interstitial spaces, primarily in the extremities.

A nurse is teaching the staff about antidiuretic hormone (ADH). Which information should the nurse include? Secretion of ADH is stimulated by:

a. Increased serum potassium

b. Increased plasma osmolality

c. Decreased renal blood flow

d. Generalized edema

b. Increased plasma osmolality

Which statement by the staff indicates teaching was successful concerning aldosterone? Secretion of aldosterone results in:

a. Decreased plasma osmolality

b. Increased serum potassium levels

c. Increased blood volume

d. Localized edema

c. Increased blood volume

Rationale: Aldosterone promotes renal sodium and water reabsorption and excretion of potassium, thus, increasing blood volume.

A 25-year-old male is diagnosed with a hormone-secreting tumor of the adrenal cortex. Which finding would the nurse expect to see in the lab results?

a. Decreased blood volume

b. Decreased blood K+ levels

c. Increased urine Na+ levels

d. Increased white blood cells

b. Decreased blood K+ levels

Rationale: Aldosterone is secreted from the adrenal cortex. It promotes renal sodium and water reabsorption and excretion of potassium, leading to decreased potassium levels.

A patient has been searching on the Internet about natriuretic hormones. When the patient asks the nurse what do these hormones do, how should the nurse respond? Natriuretic hormones affect the balance of:

a. Calcium

b. Sodium

c. Magnesium

d. Potassium

b. Sodium

Rationale: Natriuretic hormones are sometimes called a "third factor" in sodium regulation.

A 5-year-old male presents to the ER with delirium and sunken eyes. After diagnosing him with severe dehydration, the primary care provider orders fluid replacement. The nurse administers a hypertonic intravenous solution. Which of the following would be expected?

a. Symptoms subside quickly

b. Increased ICF volume

c. Decreased ECF volume

d. Intracellular dehydration

d. Intracellular dehydration

A hypertonic solution would cause fluid to move into the extracellular space, leading to intracellular dehydration.

Which of the following patients is the most at risk for developing hypernatremia? A patient with:

a. Vomiting

b. Diuretic use

c. Dehydration

d. Hypoaldosteronism

c. Dehydration

Rationale: Dehydration leads to hypernatremia because an increase in sodium occurs with a net loss in water.

Vomiting leads to hyponatremia.

Diuretic use would lead to sodium loss.

Hypoaldosteronism leads to hyponatremia.

The most common cause of pure water deficit is:

a. Renal water loss

b. Hyperventilation

c. Sodium loss

d. Insufficient water intake

a. Renal water loss

Rationale: The most common cause of water loss is increased renal clearance of free water as a result of impaired tubular function.

Hyperlipidemia and hyperglycemia are associated with:

a. Hypernatremia

b. Hypertonic hyponatremia

c. Hypokalemia

d. Acidosis

b. Hypertonic hyponatremia

A 52-year-old diabetic male presents to the ER with lethargy, confusion, and depressed reflexes. His wife indicates that he does not follow the prescribed diet and takes his medication sporadically. Lab results indicate hyperglycemia. Which assessment finding is most likely to occur?

a. Clammy skin

b. Decreased sodium

c. Decreased urine formation

d. Metabolic alkalosis

b. Decreased sodium

Rationale: Hypertonic hyponatremia develops with hyperglycemia. Increases in plasma lipids displace water volume and decrease sodium concentration, leading to the symptoms described.

When taking care of a patient with hyperkalemia, which principle is priority? Hyperkalemia causes a(n) _____ in resting membrane potential with _____ excitability of cardiac muscle.

a. Increase; increased

b. Decrease; increased

c. Increase; decreased

d. Decrease; decreased

a. Increase; increased

Which of the following patients is most prone to hypochloremia? A patient with:

a. Hypernatremia

b. Hypokalemia

c. Hypercalcemia

d. Increased bicarbonate intake

d. Increased bicarbonate intake

Rationale: Hypochloremia is the result of elevated bicarbonate concentration, as occurs in metabolic alkalosis.

Which of the following conditions would cause the nurse to monitor for hyperkalemia?

a. Excess aldosterone

b. Acute acidosis

c. Insulin usage

d. Metabolic alkalosis

b. Acute acidosis

Rationale:In acidosis, ECF hydrogen ions shift into the cells in exchange for ICF potassium and sodium; hyperkalemia and acidosis therefore often occur together.

Which organ system should the nurse monitor when the patient has long-term potassium deficits?

a. Central nervous system (CNS)

b. Lungs

c. Kidneys

d. Gastrointestinal tract

c. Kidneys

Rationale: Long-term potassium deficits lasting more than 1 month may damage renal tissue, with interstitial fibrosis and tubular atrophy.

A 42-year-old female presents to her primary care provider reporting muscle weakness and cardiac abnormalities. Laboratory tests indicate that she is hypokalemic. Which of the following could be the cause of her condition?

a. Respiratory acidosis

b. Constipation

c. Hypoglycemia

d. Primary hyperaldosteronism

d. Primary hyperaldosteronism

Rationale: Primary hyperaldosteronism, with excessive secretion of aldosterone from an adrenal adenoma (tumor) also causes potassium wasting.

Acidosis is related to hyperkalemia, not hypokalemia.

Constipation can occur with hypokalemia but does not cause it.

Hypoglycemia is not related to muscle weakness.

A 19-year-old male presents to his primary care provider reporting restlessness, muscle cramping, and diarrhea. Lab tests reveal that he is hyperkalemic. Which of the following could have caused his condition?

a. Primary hyperaldosteronism

b. Acidosis

c. Insulin secretion

d. Diuretic use

b. Acidosis

Rationale: During acute acidosis, hydrogen ions accumulate in the ICF and potassium shifts out of the cell to the ECF, causing hyperkalemia.

Primary hyperaldosteronism is associated with hypokalemia, not hyperkalemia.

Insulin secretion helps reduce potassium levels in the cell, not cause it.

Diuretics would cause hypokalemia, not hyperkalemia.

A 60-year-old female is diagnosed with hyperkalemia. Which assessment finding should the nurse expect to observe?

a. Weak pulse

b. Excessive thirst

c. Oliguria

d. Constipation

c. Oliguria

Rationale: Hyperkalemia is manifested by oliguria.

Hypokalemia is manifested by a weak pulse; it is not caused by hyperkalemia.

Hypokalemia is manifested by excessive thirst.

Diarrhea, not constipation, is a manifestation of hyperkalemia.

Which of the following buffer pairs is considered the major plasma buffering system?

a. Protein/fat

b. Carbonic acid/bicarbonate

c. Sodium/potassium

d. Amylase/albumin

b. Carbonic acid/bicarbonate

Rationale: The carbonic acid/bicarbonate buffer pair operates in both the lung and the kidney and is a major extracellular buffer.

A nurse recalls regulation of acid-base balance through removal or retention of volatile acids is accomplished by the:

a. Buffer systems

b. Kidneys

c. Lungs

d. Liver

c. Lungs

Rationale: The volatile acid is carbonic acid (H2CO3), which readily dissociates into carbon dioxide (CO2) and water (H2O). The CO2 is then eliminated by the lungs.

Physiologic pH is maintained around 7.4 because carbonic acid and bicarbonate exist in a ratio of:

a. 20:1

b. 1:20

c. 10:2

d. 2:10

a. 20:1

Which patient is most prone to metabolic alkalosis? A patient with:

a. Retention of metabolic acids

b. Hypoaldosteronism

c. Excessive loss of chloride (Cl)

d. Hyperventilation

c. Excessive loss of chloride (Cl)

Rationale: When acid loss is caused by vomiting, renal compensation is not very effective because loss of Cl stimulates renal retention of bicarbonate, leading to alkalosis.

Retention of metabolic acids would lead to acidosis, not alkalosis.

Hypoaldosteronism leads to hyponatremia and does not cause alkalosis.

Hyperventilation leads to respiratory alkalosis, not metabolic alkalosis.

Which patient should the nurse assess for both hyperkalemia and metabolic acidosis? A patient diagnosed with:

a. Diabetes insipidus

b. Pulmonary disorders

c. Cushing syndrome

d. Renal failure

d. Renal failure

Rationale: Renal failure is associated with hyperkalemia and metabolic acidosis.

Diabetes insipidus results in hypernatremia.

Pulmonary disorders are a cause of respiratory acidosis or alkalosis but do not affect hyperkalemia.

Cushing syndrome results in hypernatremia.

For a patient experiencing metabolic acidosis, the body will compensate by:

a. Excreting H+ through the kidneys

b. Hyperventilating

c. Retaining CO2 in the lungs

d. Secreting aldosterone

b. Hyperventilating

Rationale: In an attempt to compensate for metabolic acidosis, the lungs hyperventilate to blow off CO2.

It is the lungs hyperventilating that would compensate for metabolic acidosis, not the kidneys.

CO2 retention would increase the acidotic state.

Aldosterone would conserve water, but does not help compensate for acidosis.

Which finding would support the diagnosis of respiratory acidosis?

a. Vomiting

b. Hyperventilation

c. Pneumonia

d. An increase in noncarbonic acids

c. Pneumonia

Rationale: Respiratory acidosis occurs with hypoventilation, and pneumonia leads to hypoventilation.

Vomiting leads to loss of acids and then to alkalosis.

Hyperventilation leads to respiratory alkalosis, not acidosis.

Metabolic acidosis is caused by an increase in noncarbonic acids.

A 54-year-old male with a long history of smoking complains of excessive tiredness, shortness of breath, and overall ill feelings. Lab results reveal decreased pH, increased CO2, and normal bicarbonate ion. These findings help to confirm the diagnosis of:

a. Respiratory alkalosis

b. Metabolic acidosis

c. Respiratory acidosis

d. Metabolic alkalosis

c. Respiratory acidosis

Rationale: A decreased pH indicates acidosis. With increased CO2, it is respiratory acidosis.

For a patient with respiratory acidosis, chronic compensation by the body will include:

a. Kidney excretion of H+

b. Kidney excretion of HCO3

c. Prolonged exhalations to blow off CO2

d. Protein buffering

a. Kidney excretion of H+

Rationale: The kidneys excrete H+ to compensate for respiratory acidosis.

A 55-year-old female presents to her primary care provider and reports dizziness, confusion, and tingling in the extremities. Blood tests reveal an elevated pH, decreased PCO2, and slightly decreased HCO3. Which of the following is the most likely diagnosis?

a. Respiratory alkalosis with renal compensation

b. Respiratory acidosis with renal compensation

c. Metabolic alkalosis with respiratory compensation

d. Metabolic acidosis with respiratory compensation

a. Respiratory alkalosis with renal compensation

Rationale: With an elevated pH, the diagnosis must be alkalosis. Since the PCO2 is low, it is likely respiratory with a slight decrease in HCO3 indicating renal compensation.

Outcomes of laboratory tests include an elevated level of natriuretic peptides. Which organ is the priority assessment?

a. Lungs

b. Heart

c. Liver

d. Brain

B. Heart

Rationale: Elevated natriuretic peptides indicate problems with the heart or the vasculature.

A 60-year-old male with a 30-year history of smoking is diagnosed with a hormone-secreting lung tumor. Further testing indicates that the tumor secretes ADH. Which of the following assessment findings should the nurse expect? (Select all that apply.)

a. Confusion

b. Weakness

c. Nausea

d. Muscle twitching

e. Weight loss

A, B, C, D

Rationale: Secretion of ADH leads to water intoxication with symptoms of cerebral edema, with confusion and convulsions; weakness; nausea; muscle twitching; headache; and weight gain, not loss.

The nurse would anticipate the patient with syndrome of inappropriate ADH (SIADH) to demonstrate which of the following symptoms? (Select all that apply.)

a. Weakness

b. Nausea

c. Headache

d. Weight loss

e. Muscle twitching

A, B, C, E

Rationale: Weakness, nausea, muscle twitching, headache, and weight gain, not loss, are common symptoms of chronic water accumulation.