The Question is from neet-zoology breathing-and-exchange-of-gases , and it was created by the author A SUBRAMANYAM

Question

A patient presents with significantly reduced lung compliance, making it difficult to inflate their lungs.  Which of the following conditions is the LEAST likely cause of this decreased compliance?

A SUBRAMANYAM · Accepted Answer

## CORE INFORMATION
✓ **Answer**: C
## CONCEPT FRAMEWORK
 **Primary Concept**: Lung Compliance and Respiratory Diseases
 **Related Topics**: Pulmonary Function Tests, Respiratory Mechanics, Pathophysiology of Lung Diseases
 **Prerequisites**: Understanding of lung mechanics (elastic recoil, surface tension, airway resistance), basic knowledge of respiratory diseases.
## SOLUTION PATHWAY
**Given Information**:
  Reduced lung compliance (difficult to inflate lungs).
  Four possible conditions: Pulmonary fibrosis, Asbestosis, Emphysema, Infant Respiratory Distress Syndrome (IRDS).
**Method & Steps**:
 1. Analyze each condition's effect on lung compliance.
  Reasoning: Lung compliance is the measure of how easily the lungs expand.  Conditions that cause stiffness or scarring reduce compliance, while conditions that destroy lung tissue can also affect compliance, albeit in a different way.
 2. Identify the condition least likely to cause reduced compliance.
  Working: 
		* Pulmonary fibrosis: Characterized by scarring and stiffening of lung tissue, leading to significantly reduced compliance.
		* Asbestosis:  A form of pulmonary fibrosis caused by asbestos inhalation, also resulting in reduced compliance.
		* Emphysema:  A condition where the alveoli (air sacs) are damaged and lose their elasticity.  While this leads to decreased elastic recoil and increased air trapping, it does *not* directly cause the lungs to be difficult to inflate.  Instead, it makes exhalation difficult.  The lungs themselves are easier to inflate.
		* Infant Respiratory Distress Syndrome (IRDS):  A condition affecting premature infants due to a lack of surfactant, which reduces alveolar surface tension and makes lung inflation difficult.
 3. Determine the least likely cause.
  Result: Emphysema is the least likely cause of reduced lung compliance because it primarily affects the elasticity of the lungs during exhalation, not the ability to inflate them.
  Verification: The other three options directly impair the ability of the lungs to expand, leading to reduced compliance.
 ## OPTION ANALYSIS
A :x: Pulmonary fibrosis directly reduces lung compliance.
B :x: Asbestosis, a form of fibrosis, significantly reduces lung compliance.
C ✓: Emphysema primarily affects exhalation, not the ability to inflate the lungs.
D :x: IRDS, due to surfactant deficiency, directly reduces lung compliance.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing reduced compliance with increased airway resistance:  While both can make breathing difficult, they have different underlying mechanisms.
   How to avoid: Understand the definition of compliance and how different diseases affect lung mechanics.
  2.Overlooking the specific effects of emphysema:  Emphysema primarily affects exhalation, not the initial inflation of the lungs.
   How to avoid: Focus on the specific pathophysiological changes caused by each disease.
 **Quick Tips**:
  1.Think about the elastic properties of the lungs and how each disease alters them.
  2.Remember that reduced compliance means the lungs are stiffer and harder to inflate.

A SUBRAMANYAM · Answer

Pulmonary fibrosis

A SUBRAMANYAM · Answer

Asbestosis

A SUBRAMANYAM · Answer

The correct Option is "Emphysema"

A SUBRAMANYAM · Answer

Infant Respiratory Distress Syndrome (IRDS)

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