Makindo Medical Notes

⚠️ Mucormycosis (“Black Fungus”) is an aggressive, invasive fungal infection with high mortality (50–80%). Cases surged post-COVID, especially in diabetic patients treated with corticosteroids. It is a medical emergency requiring rapid recognition and multidisciplinary care.

🦠 About

• Opportunistic infection caused by fungi of the order Mucorales, thriving in immunocompromised states (notably diabetes and DKA).
• Mortality remains high unless both antifungal therapy and surgical debridement are initiated promptly.
• Nicknamed the “Black Fungus” due to necrotic tissue caused by angioinvasion and thrombosis.

📚 Aetiology

• Mucorales invade blood vessels → thrombosis → infarction → necrosis.
• Most infections start via inhalation of spores in the paranasal sinuses or lungs.
• Rhizopus species produce ketone reductase, allowing survival in acidic, glucose-rich environments (classic in DKA).
• Iron overload and Desferrioxamine therapy increase susceptibility (fungi exploit the iron shuttle effect).

🔬 Common Organisms

• Genera most often isolated:
  • Rhizopus spp.
  • Mucor spp.
  • Rhizomucor spp.
  • Myocladus spp.

⚡ Risk Factors

• Uncontrolled diabetes ± DKA (most common risk worldwide).
• Post-COVID recovery with high-dose steroids or immune suppression.
• Haematological malignancies, chemotherapy, malnutrition.
• Solid organ transplant, AIDS, severe burns.
• Iron overload or desferrioxamine therapy.

🩺 Clinical Presentation

• Rhino-Orbital-Cerebral: Sinus pain, headache, black necrotic eschar on palate/turbinates, orbital swelling, proptosis, cranial nerve palsies. Can extend to brain causing seizures or hemiplegia.
• Pulmonary: Fever, cough, pleuritic pain, haemoptysis, cavitary necrotic lesions on CT. Often mistaken for TB/aspergillosis.
• Cutaneous: Necrotic ulcers after trauma or burns, progressing rapidly to black gangrenous lesions.
• Disseminated: Spread from lungs/sinuses → brain, spleen, liver. Very poor prognosis.

🧪 Investigations

• Bloods: FBC, glucose, ABG (check for metabolic acidosis in DKA).
• Histopathology: Broad, non-septate hyphae with right-angle branching invading tissue/vessels.
• Culture: Confirms diagnosis but hazardous – requires specialist lab.
• Imaging:
  • CT/MRI sinuses/orbit/brain: Evaluate spread in rhino-orbital disease.
  • HRCT chest: Cavitation, consolidation, halo or reverse-halo signs.

💊 Management

• Immediate combined approach: Antifungals + urgent surgical debridement + reversal of risk factors (e.g. optimise diabetes, reduce steroids).
• Antifungal therapy:
  • Liposomal Amphotericin B (preferred, high dose).
  • Posaconazole or Isavuconazole for step-down/maintenance.
• Surgery: Aggressive debridement of necrotic tissue is often life-saving.
• Supportive care: Glycaemic control, fluids, and electrolyte balance.
• Note: Mucormycosis is not contagious.

⚠️ Poor Prognostic Factors

• Delayed diagnosis (>5 days from symptom onset).
• Antifungal therapy without surgical debridement.
• Intracranial extension (meningitis, hemiplegia).
• Persistent DKA or severe immunosuppression.

📖 References

• Rhino-Orbital-Cerebral Mucormycosis – EyeWiki
• Rodriguez MM et al. Clinical Microbiology Reviews, 2020.
• NICE COVID-19 Rapid Guideline: Fungal Infections (2021).