Question

All the following diseases are associated with peripheral blood eosinophilia except:

• A. Allergic bronchopulmonary aspergillosis (ABPA)
• B. Loeffler's syndrome
• C. Pulmonary eosinophilic granuloma
• D. Churg-Strauss syndrome

Hint:

Think about which disease's 'eosinophilic' name refers to tissue findings on biopsy rather than a raised blood eosinophil count.

Answer 1

The Correct Option is C

The question tests which pulmonary or systemic condition, out of the four, does not raise the eosinophil count in the blood. Let's go through each one.

1. Allergic bronchopulmonary aspergillosis (ABPA): This is a hypersensitivity response to Aspergillus colonizing the airways in asthmatics or cystic fibrosis patients. It causes a marked rise in both blood eosinophils and total IgE, so it is linked with eosinophilia.
2. Loeffler's syndrome: This is a short-lived lung infiltrate caused by larvae passing through the lungs, most often Ascaris lumbricoides. It is a classic cause of peripheral blood eosinophilia along with cough and patchy chest X-ray shadows.
3. Pulmonary eosinophilic granuloma: This is another name for pulmonary Langerhans cell histiocytosis, a smoking-related disease of young adults. The word "eosinophilic" here refers to eosinophils seen within the lung granulomas on biopsy, not to a raised blood eosinophil count. Blood eosinophilia is not a usual finding in this disease.
4. Churg-Strauss syndrome: Now called eosinophilic granulomatosis with polyangiitis, this vasculitis has asthma, sinus disease and a very high blood eosinophil count as core diagnostic features.

Three of the four conditions (ABPA, Loeffler's syndrome and Churg-Strauss syndrome) are established causes of peripheral blood eosinophilia. Pulmonary eosinophilic granuloma stands apart because its eosinophils are tissue-based, not blood-based.

Let's summarize:

• ABPA, Loeffler's syndrome and Churg-Strauss syndrome all raise the blood eosinophil count.
• Pulmonary eosinophilic granuloma (Langerhans cell histiocytosis) does not typically raise blood eosinophils despite its name.

So the exception is pulmonary eosinophilic granuloma, option (3).