Alkalosis MCQs With Answer

Alkalosis MCQs With Answer provides B. Pharm students a focused, exam-ready review of acid-base disturbances, mechanisms, causes, diagnostics and pharmacological management of alkalosis. This concise collection emphasizes metabolic and respiratory alkalosis, arterial blood gas (ABG) interpretation, electrolyte effects (especially hypokalemia and decreased ionized calcium), urine chloride assessment, and drug-induced causes such as diuretics and antacids. Questions target clinical reasoning, laboratory patterns, compensation, and treatment principles including saline therapy, potassium replacement, acetazolamide and mineralocorticoid antagonists. Ideal for revision, practical learning and pharmacy exams. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the defining feature of alkalosis?

• Decrease in arterial pH below 7.35
• Increase in arterial pH above 7.45
• Normal pH with elevated bicarbonate
• Isolated low PaCO2 regardless of pH

Correct Answer: Increase in arterial pH above 7.45

Q2. Which of the following best distinguishes metabolic alkalosis from respiratory alkalosis on ABG?

• Primary change in PaCO2 in metabolic alkalosis
• Primary change in HCO3- in metabolic alkalosis
• Only pH changes in metabolic alkalosis
• Arterial oxygen tension is diagnostic

Correct Answer: Primary change in HCO3- in metabolic alkalosis

Q3. Which common drug class is a frequent cause of metabolic alkalosis in patients?

• Loop diuretics
• Beta blockers
• ACE inhibitors
• Statins

Correct Answer: Loop diuretics

Q4. Persistent vomiting causes metabolic alkalosis primarily due to loss of:

• Chloride-rich gastric fluid
• Pancreatic bicarbonate
• Colonic potassium
• Renal ammonium

Correct Answer: Chloride-rich gastric fluid

Q5. In metabolic alkalosis, which electrolyte disturbance commonly coexists and worsens the alkalosis?

• Hyperkalemia
• Hypokalemia
• Hypernatremia
• Hyponatremia

Correct Answer: Hypokalemia

Q6. Which laboratory test helps differentiate chloride-responsive from chloride-resistant metabolic alkalosis?

• Serum bicarbonate concentration
• Urine chloride concentration
• Serum anion gap
• Serum calcium

Correct Answer: Urine chloride concentration

Q7. A urine chloride <20 mEq/L in metabolic alkalosis suggests:

• Chloride-resistant (saline unresponsive) alkalosis
• Saline-responsive (chloride-sensitive) alkalosis
• Primary respiratory alkalosis
• High aldosterone state

Correct Answer: Saline-responsive (chloride-sensitive) alkalosis

Q8. Which hormone excess is most commonly associated with saline-resistant metabolic alkalosis?

• Antidiuretic hormone (ADH)
• Aldosterone
• Insulin
• Thyroxine

Correct Answer: Aldosterone

Q9. Which of the following is an important pharmacological treatment for saline-responsive metabolic alkalosis?

• Intravenous normal saline
• Loop diuretic therapy
• High-dose bicarbonate infusion
• Calcium supplementation

Correct Answer: Intravenous normal saline

Q10. Acetazolamide corrects metabolic alkalosis by:

• Blocking carbonic anhydrase to promote bicarbonate excretion
• Stimulating aldosterone to increase sodium retention
• Acting as a potassium-sparing diuretic
• Increasing pulmonary ventilation

Correct Answer: Blocking carbonic anhydrase to promote bicarbonate excretion

Q11. Which ECG change may be seen with severe alkalosis-induced hypokalemia?

• Peaked T waves
• Prolonged PR interval and U waves
• Shortened QT interval due to hypercalcemia
• ST-segment elevation typical of infarction

Correct Answer: Prolonged PR interval and U waves

Q12. Respiratory alkalosis is characterized primarily by:

• Increased PaCO2 and increased pH
• Decreased PaCO2 and increased pH
• Decreased HCO3- with normal PaCO2
• Increased HCO3- with increased PaCO2

Correct Answer: Decreased PaCO2 and increased pH

Q13. A common cause of acute respiratory alkalosis is:

• Hypoventilation due to sedatives
• Hyperventilation from anxiety or pain
• Renal failure causing bicarbonate retention
• Excessive antacid ingestion

Correct Answer: Hyperventilation from anxiety or pain

Q14. Early salicylate overdose often causes which acid-base disorder?

• Pure metabolic acidosis
• Respiratory alkalosis
• Metabolic alkalosis with hypokalemia
• Respiratory acidosis

Correct Answer: Respiratory alkalosis

Q15. Renal compensation for acute respiratory alkalosis typically results in:

• Rapid increase in bicarbonate reabsorption
• Renal loss of bicarbonate lowering HCO3-
• Increased ammonium production
• Retention of chloride to increase pH

Correct Answer: Renal loss of bicarbonate lowering HCO3-

Q16. Which clinical sign is associated with severe alkalosis due to low ionized calcium?

• Hyperreflexia and tetany
• Decreased deep tendon reflexes and muscle flaccidity
• Hyporeflexia with bradycardia
• Sensory loss in glove-and-stocking pattern

Correct Answer: Hyperreflexia and tetany

Q17. Chronic vomiting producing metabolic alkalosis typically shows which arterial blood gas pattern?

• Low pH, high PaCO2, low HCO3-
• High pH, high HCO3-, elevated PaCO2 due to compensation
• High pH, low PaCO2, low HCO3-
• Normal pH despite abnormal electrolytes

Correct Answer: High pH, high HCO3-, elevated PaCO2 due to compensation

Q18. Which diuretic is most likely to cause metabolic alkalosis by causing chloride and volume depletion?

• Amiloride
• Hydrochlorothiazide
• Spironolactone
• Amlodipine

Correct Answer: Hydrochlorothiazide

Q19. In the context of alkalosis, “contraction alkalosis” refers to:

• Alkalosis due to primary respiratory hyperventilation
• Alkalosis resulting from reduced extracellular fluid volume
• Alkalosis caused by increased chloride intake
• Alkalosis caused by liver failure

Correct Answer: Alkalosis resulting from reduced extracellular fluid volume

Q20. Which of the following is true about the anion gap in pure metabolic alkalosis?

• Anion gap is typically increased
• Anion gap is typically decreased
• Anion gap is usually normal
• Anion gap is not measurable during alkalosis

Correct Answer: Anion gap is usually normal

Q21. Which pharmacologic agent can be used to treat metabolic alkalosis secondary to hyperaldosteronism?

• Furosemide
• Spironolactone
• Thiazide diuretic
• Metoprolol

Correct Answer: Spironolactone

Q22. Milk-alkali syndrome causes metabolic alkalosis primarily by:

• Excessive ingestion of bicarbonate and calcium leading to alkalosis
• Renal loss of bicarbonate due to hypercalciuria
• Direct stimulation of pulmonary ventilation
• Enhanced renal ammonium production

Correct Answer: Excessive ingestion of bicarbonate and calcium leading to alkalosis

Q23. Which measurement directly indicates respiratory contribution to an acid-base disorder?

• Serum bicarbonate (HCO3-)
• Arterial PaCO2
• Serum sodium
• Serum chloride

Correct Answer: Arterial PaCO2

Q24. In metabolic alkalosis due to loop diuretics, which electrolyte replacement is often required?

• Calcium supplementation only
• Potassium replacement
• Phosphate loading
• Sodium restriction without supplementation

Correct Answer: Potassium replacement

Q25. Which statement regarding respiratory compensation for metabolic alkalosis is correct?

• Compensation occurs by hyperventilation to decrease PaCO2
• Compensation is limited by hypoxia as hypoventilation increases PaCO2
• Renal compensation is rapid and complete within minutes
• There is no respiratory compensation for metabolic alkalosis

Correct Answer: Compensation is limited by hypoxia as hypoventilation increases PaCO2

Q26. A patient on chronic loop diuretics presents with metabolic alkalosis. Urine chloride is 35 mEq/L. This suggests:

• Chloride-responsive alkalosis
• Chloride-resistant alkalosis likely due to continued diuretic effect
• Pure respiratory alkalosis
• Primary metabolic acidosis

Correct Answer: Chloride-resistant alkalosis likely due to continued diuretic effect

Q27. Which of the following best explains why hypokalemia promotes metabolic alkalosis?

• Low potassium stimulates renal H+ secretion and bicarbonate reabsorption
• Hypokalemia directly increases bicarbonate production in the liver
• Low potassium increases PaCO2 via respiratory depression
• Hypokalemia leads to decreased aldosterone secretion

Correct Answer: Low potassium stimulates renal H+ secretion and bicarbonate reabsorption

Q28. Which clinical scenario is most consistent with chloride-resistant metabolic alkalosis?

• Excessive vomiting with low urine chloride
• Primary hyperaldosteronism with persistent alkalosis despite saline
• Recent high-dose antacid ingestion resolving with saline
• Acute respiratory alkalosis due to anxiety

Correct Answer: Primary hyperaldosteronism with persistent alkalosis despite saline

Q29. Which of the following is a hallmark ABG finding in acute respiratory alkalosis?

• High PaCO2 with low HCO3-
• Low PaCO2 with near-normal HCO3- (early renal compensation minimal)
• Elevated HCO3- with elevated PaCO2
• Normal PaCO2 with high HCO3-

Correct Answer: Low PaCO2 with near-normal HCO3- (early renal compensation minimal)

Q30. In treating metabolic alkalosis with severe hypokalemia, priority medication is:

• Immediate intravenous sodium bicarbonate
• Potassium chloride replacement
• High-dose loop diuretic
• Oral calcium carbonate

Correct Answer: Potassium chloride replacement

Q31. Which laboratory finding often accompanies metabolic alkalosis and contributes to neuromuscular irritability?

• Increased ionized magnesium
• Decreased ionized calcium
• Increased phosphate
• High serum lactate

Correct Answer: Decreased ionized calcium

Q32. Which of the following medications is least likely to cause metabolic alkalosis?

• Thiazide diuretics
• Loop diuretics
• Proton pump inhibitors
• Excessive antacid (carbonate) use

Correct Answer: Proton pump inhibitors

Q33. A mixed disorder with metabolic alkalosis and respiratory acidosis would show:

• Elevated pH with low PaCO2
• Near-normal pH with both elevated PaCO2 and elevated HCO3-
• Low pH with low HCO3-
• High pH with low HCO3-

Correct Answer: Near-normal pH with both elevated PaCO2 and elevated HCO3-

Q34. Which bedside maneuver can transiently treat acute symptomatic respiratory alkalosis from hyperventilation?

• Encourage more deep breaths
• Rebreathing into a paper bag to increase PaCO2
• Immediate intravenous sodium bicarbonate
• Administer high-flow oxygen

Correct Answer: Rebreathing into a paper bag to increase PaCO2

Q35. Which finding suggests metabolic alkalosis rather than simple respiratory alkalosis when pH is elevated?

• Low HCO3- on ABG
• High HCO3- on ABG
• Normal bicarbonate with low PaCO2
• Low PaO2 with normal bicarbonate

Correct Answer: High HCO3- on ABG

Q36. Which of the following clinical conditions can produce respiratory alkalosis?

• Chronic obstructive pulmonary disease exacerbation with hypoventilation
• Pulmonary embolism causing reflex hyperventilation
• Overdose of opioids causing respiratory depression
• End-stage renal failure causing metabolic acidosis

Correct Answer: Pulmonary embolism causing reflex hyperventilation

Q37. During metabolic alkalosis, renal bicarbonate retention is primarily driven by:

• Decreased proximal tubular reabsorption of bicarbonate
• Enhanced bicarbonate reclamation due to volume depletion and aldosterone
• Direct pulmonary excretion of bicarbonate
• Inhibition of carbonic anhydrase in collecting duct

Correct Answer: Enhanced bicarbonate reclamation due to volume depletion and aldosterone

Q38. Which urine electrolyte pattern would you expect in a patient with vomiting-induced metabolic alkalosis?

• High urine chloride (>40 mEq/L)
• Low urine chloride (<20 mEq/L)
• High urine potassium with high urine chloride
• Low urine sodium only

Correct Answer: Low urine chloride (<20 mEq/L)

Q39. Which statement about mixed acid-base disorders is correct?

• They always normalize pH, so ABG is unhelpful
• Presence of incompatible compensations suggests a mixed disorder
• Mixed disorders only occur with renal failure
• They are easily identified by serum anion gap alone

Correct Answer: Presence of incompatible compensations suggests a mixed disorder

Q40. Which of the following is an appropriate initial pharmacologic approach for metabolic alkalosis caused by primary hyperaldosteronism?

• Immediate normal saline infusion only
• Aldosterone antagonist such as spironolactone or eplerenone
• High-dose loop diuretic without potassium replacement
• Carbonic anhydrase inhibitor alone

Correct Answer: Aldosterone antagonist such as spironolactone or eplerenone

Q41. Which clinical measurement is most useful when deciding to give saline to correct metabolic alkalosis?

• Serum lactate concentration
• Urine chloride level
• Serum magnesium only
• Arterial oxygen saturation

Correct Answer: Urine chloride level

Q42. A patient with chronic liver disease presents with alkalosis. Which mechanism could explain this?

• Excessive acid production by the liver
• Hypoalbuminemia causing metabolic alkalosis
• Increased bicarbonate reabsorption due to diuretic use
• Hyperventilation due to hepatic encephalopathy

Correct Answer: Increased bicarbonate reabsorption due to diuretic use

Q43. Which of the following best describes the renal adaptation to chronic respiratory alkalosis?

• Decreased urinary bicarbonate excretion to conserve HCO3-
• Increased urinary bicarbonate excretion to lower serum HCO3-
• No change in renal bicarbonate handling
• Increased ammonium production to raise HCO3-

Correct Answer: Increased urinary bicarbonate excretion to lower serum HCO3-

Q44. Which acid–base disturbance is commonly seen in patients with Cushing’s syndrome?

• Metabolic acidosis due to lactic acid
• Metabolic alkalosis due to mineralocorticoid effects
• Respiratory acidosis from hypoventilation
• Mixed metabolic acidosis and alkalosis

Correct Answer: Metabolic alkalosis due to mineralocorticoid effects

Q45. Which therapeutic intervention can worsen metabolic alkalosis if used inappropriately?

• Isotonic saline in chloride-responsive alkalosis
• Exogenous bicarbonate infusion without indication
• Potassium repletion in hypokalemia
• Using acetazolamide in volume-overloaded patients

Correct Answer: Exogenous bicarbonate infusion without indication

Q46. Which pharmacologic agent increases renal bicarbonate loss and may be used in refractory metabolic alkalosis?

• Acetazolamide
• Furosemide
• Metformin
• Calcium channel blocker

Correct Answer: Acetazolamide

Q47. Which of the following best characterizes respiratory alkalosis compensation in the kidney over several days?

• No renal compensation occurs
• Renal bicarbonate decreases to match chronic low PaCO2
• Renal bicarbonate increases to worsen alkalosis
• Only sodium is altered, bicarbonate stays fixed

Correct Answer: Renal bicarbonate decreases to match chronic low PaCO2

Q48. When evaluating a patient with alkalosis, why is measurement of serum chloride clinically important?

• Chloride directly increases respiratory drive
• Low chloride suggests chloride-responsive alkalosis amenable to saline
• High serum chloride confirms metabolic acidosis
• Chloride levels are irrelevant in alkalosis

Correct Answer: Low chloride suggests chloride-responsive alkalosis amenable to saline

Q49. A B. Pharm student should remember that drug-induced metabolic alkalosis can result from which OTC used for dyspepsia?

• Acetaminophen
• Aluminum or magnesium hydroxide antacids
• Topical NSAIDs
• Oral antihistamines

Correct Answer: Aluminum or magnesium hydroxide antacids

Q50. Which principle is most important when counseling on prevention of drug-related alkalosis in patients on diuretics?

• Encourage excessive antacid use to prevent GI upset
• Monitor and replace potassium and chloride as needed
• Stop all diuretics immediately to avoid alkalosis
• Only monitor blood pressure without electrolytes

Correct Answer: Monitor and replace potassium and chloride as needed

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