Hypoxia Cyanosis and Dyspnea MCQ Quiz | Respiratory System

Welcome to the specialized MCQ quiz on Hypoxia, Cyanosis, and Dyspnea, a critical topic within the Respiratory System for MBBS students. This quiz is expertly designed to test your understanding of the pathophysiology, clinical differentiation, and underlying causes of these vital clinical signs and symptoms. You will encounter 25 challenging questions that cover everything from the four types of hypoxia to the subtle differences between central and peripheral cyanosis, and the neurophysiological basis of dyspnea. After completing the quiz, submit your answers to receive an instant score, detailed feedback with correct answers highlighted, and an analysis of your choices. For your future revision, you can also download all the questions and their correct answers in a convenient PDF format.

1. Hypoxic hypoxia is primarily characterized by:

2. A classic cause of stagnant (ischemic) hypoxia is:

3. Histotoxic hypoxia, as seen in cyanide poisoning, involves:

4. In a typical case of anemic hypoxia, which of the following parameters is usually NORMAL?

5. Central cyanosis is best observed in which of the following areas due to their rich blood supply and thin epithelium?

6. The minimum amount of deoxygenated hemoglobin required in capillary blood to produce clinically detectable cyanosis is approximately:

7. A patient with severe anemia (e.g., Hb 6 g/dL) is less likely to show cyanosis even with significant hypoxemia because:

8. Which of the following conditions is a well-known cause of central cyanosis with a normal arterial PO2 (PaO2)?

9. Peripheral cyanosis, in the absence of central cyanosis, is typically caused by:

10. The primary and most potent stimulus for the respiratory drive in a healthy individual at sea level is:

11. Dyspnea that occurs when a patient lies flat and is relieved by sitting up is known as:

12. In a healthy, upright individual, the ventilation-perfusion (V/Q) ratio is highest at the:

13. Which type of hypoxia shows the most significant improvement upon administration of 100% oxygen?

14. In a patient with a significant right-to-left shunt, administration of 100% O2 will result in:

15. J-receptors (pulmonary C-fiber endings) are located in the alveolar walls and are stimulated by conditions like pulmonary congestion/edema, leading to:

16. Dyspnea that awakens a patient from sleep, often 1-2 hours after lying down, and is relieved by sitting or standing up is characteristic of:

17. Carbon monoxide (CO) poisoning, where CO binds to hemoglobin with high affinity, is classified as which type of hypoxia?

18. Unlike in other forms of severe hypoxia, a classic clinical sign in carbon monoxide poisoning is:

19. Dyspnea that occurs only when a patient is lying on one particular side is termed:

20. The Alveolar-arterial (A-a) oxygen gradient is significantly increased in all of the following types of hypoxia EXCEPT:

21. The most accurate definition of dyspnea is:

22. Sulfhemoglobinemia, a rare cause of cyanosis, is distinguished by what characteristic clinical finding?

23. Acclimatization to chronic hypoxia at high altitude involves all the following physiological changes EXCEPT:

24. The sensation of “air hunger” in dyspnea is most strongly linked to the stimulation of:

25. A patient presents with cyanosis, has “chocolate brown” colored blood drawn, and shows a saturation gap (low SpO2 on pulse oximetry but normal SaO2 on co-oximetry). The most likely diagnosis is: