Question:medium
A diabetic patient presents with bloody nasal discharge, orbital swelling and pain. Culture of the periorbital pus shows branching septate hyphae. Which of the following is the most probable organism involved?
A diabetic patient presents with bloody nasal discharge, orbital swelling and pain. Culture of the periorbital pus shows branching septate hyphae. Which of the following is the most probable organism involved?
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Septate branching hyphae mean Aspergillus; broad aseptate hyphae would mean Mucor or Rhizopus.
Updated On: Jun 24, 2026
- Mucor
- Candida
- Aspergillus
- Rhizopus
Show Solution
The Correct Option is C
Solution and Explanation
A diabetic with a destructive nose and orbit infection screams invasive mould disease, and the laboratory note is the tie breaker.
Setting up the differential: Rhino orbital invasive fungal infection in a diabetic is caused either by the Mucorales group, which includes $Mucor$ and $Rhizopus$, or by $Aspergillus$. Clinically they overlap, so we lean on the microscopy.
Reading the hyphae: The report says branching septate hyphae. Septate means the filaments have regular cross walls. Aspergillus is the mould that shows uniform septate hyphae branching at sharp acute angles around 45 degrees. So septate equals Aspergillus.
Excluding the zygomycetes: Mucor and Rhizopus are aseptate or only rarely septate, with broad ribbon like hyphae that branch widely at right angles. They cannot be the answer when the slide clearly shows septate hyphae.
Excluding the yeast: Candida is not a filamentous mould of this kind. It makes budding yeast cells and pseudohyphae, not true branching septate hyphae, so it is ruled out.
The septate description fits only Aspergillus.
\[\boxed{\text{Aspergillus}}\]
Setting up the differential: Rhino orbital invasive fungal infection in a diabetic is caused either by the Mucorales group, which includes $Mucor$ and $Rhizopus$, or by $Aspergillus$. Clinically they overlap, so we lean on the microscopy.
Reading the hyphae: The report says branching septate hyphae. Septate means the filaments have regular cross walls. Aspergillus is the mould that shows uniform septate hyphae branching at sharp acute angles around 45 degrees. So septate equals Aspergillus.
Excluding the zygomycetes: Mucor and Rhizopus are aseptate or only rarely septate, with broad ribbon like hyphae that branch widely at right angles. They cannot be the answer when the slide clearly shows septate hyphae.
Excluding the yeast: Candida is not a filamentous mould of this kind. It makes budding yeast cells and pseudohyphae, not true branching septate hyphae, so it is ruled out.
The septate description fits only Aspergillus.
\[\boxed{\text{Aspergillus}}\]
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