Question

A man presents with hemoptysis, fever, and breathlessness. Microscopic analysis of bronchoalveolar lavage reveals septate hyphae with acute angle branching. Which fungal infection is most likely?

• A. Mucormycosis
• B. Histoplasmosis
• C. Aspergillosis
• D. Candidiasis

Hint:

Aspergillus = septate hyphae with acute angle branching. Mucor = broad aseptate hyphae with right angle branching.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The patient has symptoms of a severe pulmonary infection. The microscopic description of the fungal hyphae is pathognomonic for a certain genus.
Step 2: Detailed Explanation:

Aspergillus species: These are molds that cause various pulmonary diseases, including Invasive Pulmonary Aspergillosis (IPA), especially in immunocompromised patients.

Morphology: Under microscopy, Aspergillus appears as thin, septate hyphae that branch at "acute angles" (approximately 45 degrees). This branching is described as "dichotomous."

Clinical Features: In invasive disease, Aspergillus can invade blood vessels (angioinvasion), leading to tissue necrosis, pulmonary infarction, and hemoptysis.

Comparison with Mucormycosis (A): Mucor species (Zygomycetes) appear as thick, non-septate (coenocytic) hyphae that branch at wide angles, often 90 degrees or "right angles."

Other options: Histoplasmosis (Option B) usually appears as small intracellular yeasts within macrophages. Candidiasis (Option D) typically shows budding yeasts and pseudohyphae.

Step 3: Final Answer:
Septate hyphae with acute-angle branching are diagnostic microscopic features of Aspergillosis.