An elderly immunocompromised patient presents with blood-stained nasal discharge and a black necrotic eschar covering the right nasal cavity, hard palate, and nasal turbinates. Histopathology reveals broad aseptate hyphae. Which organism is the most common causative agent of this life-threatening condition?

1. A

   A. Candida albicans

2. B

   B. Cryptococcus neoformans

3. C

   C. Aspergillus fumigatus

4. D

   D. Rhizopus species

Appeared in: INI-CET EXAM -2026

Explanation

• The patient's presentation of a rapidly progressing black necrotic eschar in the nasal and palatal areas in an immunocompromised host is the classic sign of rhinocerebral mucormycosis.
• Rhizopus species, belonging to the order Mucorales, are the most frequent cause of this life-threatening fungal infection.
• The definitive diagnosis is confirmed by the histopathological finding of broad, non-septate (aseptate) hyphae that branch at wide angles (often 90 degrees), which is characteristic of Rhizopus.

Why Other Options Were Wrong

• Option A: Candida albicans causes candidiasis, which typically presents as white, creamy patches (thrush), not a black eschar. Microscopically, it shows budding yeasts and pseudohyphae.
• Option B: Cryptococcus neoformans is an encapsulated yeast that primarily causes meningitis and pulmonary infections, not rhinocerebral disease with necrosis. It does not form hyphae in tissue.
• Option C: Aspergillus fumigatus can cause invasive sinus infections, but it is less likely to produce a black eschar. Microscopically, it is distinguished by its septate hyphae that branch at acute angles (around 45 degrees).

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Clinical Relevance

• Nursing practice connection: Use the key finding related to Identification of the causative agent for rhinocerebral mucormycosis based on clinical and histopathological findings to guide bedside assessment, documentation, and the next nursing action.
• Nurses must have a high index of suspicion for mucormycosis in at-risk patients (e.g., those with diabetic ketoacidosis, neutropenia, or on immunosuppressants) presenting with facial pain, swelling, or nasal stuffiness, as it is a surgical emergency.
• Rapid escalation to the medical team is critical for patient survival, as delays in diagnosis and treatment (surgical debridement and systemic antifungals) lead to high mortality.
• What if? If the patient had poorly controlled diabetes instead of being generally immunocompromised, the diagnosis would still strongly point to mucormycosis, as diabetic ketoacidosis is the single most common risk factor for this infection.

How to Approach the Question

• First, analyze the patient's profile: 'elderly' and 'immunocompromised'. This points towards an opportunistic infection.
• Next, identify the key clinical sign: 'black necrotic eschar'. This is a highly specific finding that suggests tissue death from vascular invasion.
• Then, correlate with the histopathology report: 'broad aseptate hyphae'. This is the definitive microscopic clue.
• Evaluate the options based on these three key pieces of information. Rhizopus is the only option that fits all three criteria: opportunistic, causes black eschar (mucormycosis), and has broad aseptate hyphae.
• Rule out other fungi by their distinct features: Candida causes white patches, Cryptococcus primarily causes meningitis, and Aspergillus has septate hyphae with acute-angle branching.

Concept Tested & Keywords

• Concept Tested: Identification of the causative agent for rhinocerebral mucormycosis based on clinical and histopathological findings.
• Stem keywords: elderly, immunocompromised, blood-stained nasal discharge, black necrotic eschar, broad aseptate hyphae
• Lead-in keywords: most common causative agent
• Clinical cues: Immunocompromised status: Indicates susceptibility to opportunistic infections.
• Clinical cues: Black necrotic eschar: Hallmark sign of tissue infarction due to fungal invasion of blood vessels.

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QMyEM6U3RCP_WSD89RDAdk

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Reference Book

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 394-396

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 273-275

E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 2 (215-514) p. 48-50