NORCET -3 (Shift-2): Farmer's lung disease caused by?

NORCET -3 (Shift-2)

Medical & Surgical Nursing

Easy

Appeared in: NORCET -3 (Shift-2)

Explanation

Farmer's lung is a classic example of hypersensitivity pneumonitis, an immune-mediated lung disease.
It is specifically caused by inhaling dust from moldy hay that contains spores of thermophilic actinomycetes.
The key causative organism is the bacterium Saccharopolyspora rectivirgula.
The body's immune system reacts to these inhaled organic antigens, leading to inflammation in the alveoli and small airways.

Option B: While moldy straw can also harbor the causative organisms, moldy hay is the most common and classic source for Farmer's lung. Therefore, 'Moldy Hay' is a more precise and accurate answer.
Option C: This option uses biologically inaccurate terminology. Actinomycetes are bacteria that produce spores. The disease is caused by inhaling these microscopic spores, not a 'husk'.
Option D: This is a broad term. While Farmer's lung involves a hypersensitivity reaction and can be caused by moldy grain, 'Grain hypersensitivity' more commonly refers to other conditions like grain handler's lung or occupational asthma, which have different mechanisms and presentations.

Clinical Relevance

Nursing practice connection: Knowing Etiology of Farmer's Lung (Hypersensitivity Pneumonitis) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A thorough occupational history is crucial for diagnosing respiratory symptoms, as many lung diseases, like Farmer's lung, are directly linked to workplace or environmental exposures.
Patient education is a key nursing intervention. It should focus on preventing exposure by ensuring proper drying of hay before storage and advising the use of appropriate respiratory protection (e.g., N95 masks) when handling potentially moldy materials.
What if? If a patient develops wheezing and shortness of breath immediately (within minutes to an hour) after exposure to hay dust, instead of 4-8 hours later, an IgE-mediated asthmatic reaction should be considered rather than the delayed Type III/IV reaction of hypersensitivity pneumonitis.

How to Approach the Question

This is a factual recall question testing knowledge of common occupational lung diseases.
First, identify the key term in the question: 'Farmer's lung disease'. The name itself provides a strong clue about the context.
Recall the classic etiological agent associated with this condition. Farmer's lung is famously linked to farming activities involving hay.
Evaluate the options based on this knowledge. 'Moldy hay' is the most specific and well-known cause.
Critically analyze the distractors. 'Straw' is a possibility but less common than hay. 'Husk of actinomycetes' uses incorrect scientific terminology. 'Grain hypersensitivity' is a related but distinct and less specific category of illness.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 636-638