Question
Respiratory acidosis is caused by all except:
| A. |
Chronic bronchitis
|
| B. |
COPD
|
| C. |
Pulmonary hypertension
|
| D. |
Interstitial lung disease
|
Show Answer
|
Correct Answer » C
Explanation
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|
Core Principle
- Respiratory acidosis = hypoventilation → CO₂ retention (↑ PaCO₂)
- Therefore, causes are conditions that impair ventilation, not just gas exchange.
A. Chronic bronchitis
- Obstructive lung disease
- Causes hypoventilation and CO₂ retention
- Leads to respiratory acidosis
B. COPD
- Most common cause of chronic respiratory acidosis
- Includes chronic bronchitis + emphysema
- Causes hypercapnia
C. Pulmonary hypertension
- Primary problem = vascular (increased pulmonary arterial pressure)
- Does not directly impair ventilation
- Patients often hyperventilate → respiratory alkalosis
- Not a direct cause of CO₂ retention
D. Interstitial lung disease
- Restrictive disease
- Early: hyperventilation → respiratory alkalosis
- Late/severe: can lead to respiratory failure and CO₂ retention
- Therefore, can cause respiratory acidosis in advanced stages
