250.1 🎓 醫孞生版

250.1.0.1 📌 䞀頁重點

250.1.0.1.1 Pathogens
  • Mucorales order: Rhizopus oryzae / arrhizus (most common), Mucor, Lichtheimia, Rhizomucor, Cunninghamella, Apophysomyces
  • Saprobic environmental fungi (soil + decaying vegetation)
  • Inhalation of spores or direct inoculation
250.1.0.1.2 Microbiology
  • Aseptate hyphae (or sparsely septate) — broad (5-25 µm), irregular wide ribbon-like, 90° branching — distinct from Aspergillus (septate, 45° branching, 3-5 µm)
  • Rapid growth on culture
  • Don’t culture if biopsy used (organism doesn’t grow well from biopsy)
250.1.0.1.3 Risk Factors
  • Diabetes mellitus (especially ketoacidosis) — classic
  • Iron overload + chronic transfusion + hemochromatosis
  • Deferoxamine therapy (iron chelator that ironically makes iron available to mucor)
  • Immunocompromise: neutropenia, HSCT, organ transplant, anti-TNF, chemo
  • High-dose corticosteroids
  • COVID-19 + steroid use (especially India 2021)
  • Burns + trauma
  • Malnutrition
  • HIV CD4 < 100 (less common)
  • Voriconazole prophylaxis (selects out Mucor — “voriconazole-associated mucormycosis”)
250.1.0.1.4 Clinical Forms
250.1.0.1.4.1 Rhinocerebral (#1 in DM ketoacidosis)
  • Sinuses → palate → orbit → cavernous sinus → brain
  • Facial pain, nasal discharge, headache, swelling
  • Black eschar on palate / nasal cavity (pathognomonic — necrotic tissue)
  • Proptosis, ophthalmoplegia (cavernous sinus + orbit)
  • Vision loss
  • Altered mental status (intracranial extension)
  • Multi-cranial nerve involvement
  • Mortality 30-50%+
250.1.0.1.4.2 Pulmonary (Neutropenic + HSCT + Transplant)
  • Fever, cough, hemoptysis
  • Cavitary lesions, infarcts
  • Halo + reverse halo signs on CT
  • Mortality 50%+
250.1.0.1.4.3 Cutaneous
  • Trauma + burns + IV / injection sites
  • Necrotic lesions with raised border + central eschar
  • Direct inoculation
  • Can be locally invasive + disseminate
250.1.0.1.4.4 GI (Rare)
  • Neonatal + malnourished
  • Mucosal necrosis + ulcers + perforation
  • Very high mortality
250.1.0.1.4.5 Disseminated
  • Hematogenous spread
  • Multi-organ
  • Very high mortality
250.1.0.1.4.6 Renal (Rare)
  • IDU + HIV + immunocompromise
  • Mass + necrosis
250.1.0.1.5 Diagnosis
  • Clinical + imaging + histology
  • Imaging: black eschar + sinus opacification + erosions + brain extension
  • Tissue biopsy + GMS / PAS stain: aseptate broad ribbon-like hyphae with 90° branching
  • Don’t rely solely on culture (often negative — handle tissue carefully, don’t grind)
  • NEW: MALDI-TOF identification from culture
  • PCR of tissue emerging (faster than culture)
250.1.0.1.6 Treatment
250.1.0.1.6.1 Emergency Approach (Critical — Time-Sensitive)
  1. Liposomal Amphotericin B 5-10 mg/kg/d IV (high-dose) — drug of choice
  2. EMERGENT surgical debridement — wide local excision of necrotic tissue
  3. Reverse predisposing factors:
    • DM: aggressive glucose + ketoacidosis correction
    • Reduce immunosuppression
    • Stop deferoxamine (if used)
  4. Step-down to isavuconazole or posaconazole PO for consolidation × months
  5. ICU monitoring
250.1.0.1.6.2 Drug Sequence
  • Liposomal AmB induction (2-6 weeks minimum) + surgery
  • → Isavuconazole 200 mg PO TID × 6 doses then 200 mg/d (oral, FDA approved 2015 for mucor)
  • Posaconazole delayed-release tablet alternative
  • Total duration: months (until immune recovery + clinical + radiographic resolution)
250.1.0.1.6.3 Surgery
  • Essential for cure in most cases
  • Multiple debridements often
  • Reconstruction later (cosmetic + functional)
  • For rhinocerebral: ENT + ophth + neuroSx involvement
  • Risk of vision loss + facial disfigurement
250.1.0.1.6.4 Adjunctive (Investigational)
  • Hyperbaric oxygen (some institutions; mechanism: high O2 antifungal + neutrophil function)
  • Granulocyte transfusion (rare)
250.1.0.1.7 Prevention
  • DM control
  • Avoid deferoxamine (switch to deferiprone / deferasirox if iron chelation needed)
  • Reduce immunosuppression
  • Posaconazole prophylaxis in high-risk HSCT + neutropenic (replaces fluconazole for mold coverage)
250.1.0.1.8 COVID-19 Associated Mucormycosis (CAM)
  • 2021 India epidemic — > 45,000 cases reported
  • Risk: severe COVID + DM + corticosteroid use + zinc supplementation
  • Rhinocerebral form predominant
  • Similar treatment as standard mucormycosis
  • Major public health concern during COVID waves