EM@3AM: Mucormycosis

Author: Rachel Bridwell, MD (@rebridwell, EM Resident Physician, SAUSHEC / San Antonio, TX) // Edited by: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX)  and Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDOCs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.


A 65-year-old male with poorly controlled type 2 diabetes presents for right sided nose/facial discomfort and swelling and fever. He has run out of his insulin 2 weeks ago and has been having increased urination. He has ERSD and requires hemodialysis. Review of systems is remarkable for a recent dental infection of right bottom molar.

Triage vital signs (VS): BP 107/52, HR 128, T 100.2 temporal, RR 24, SpO2 95% on room air. Pertinent physical examination findings: alert and oriented x 2, fruity odor appreciated. Tender, nasal swelling on medial aspect of bridge, necrotic area appreciated on nasal septum. Edema of the right face is present. Infraorbital paresthesias are present on the right. He is tachycardic, but the CV, pulmonary, skin, and GI systems are otherwise normal.

What’s the likely diagnosis, and what are the next steps in your evaluation and treatment?


AnswerMucormycosis1-15

Epidemiology:

  • Risk Factors: immunocompromised state
    • Uncontrolled diabetes (especially diabetic ketoacidosis [DKA]), blood cell malignancies, chronic steroid use, renal failure, AIDS, cirrhosis, burns, protein malnutrition, elevated serum iron1,2
  • Third most common angioinvasive fungal infection behind candidiasis and aspergillosis3
  • Mortality approaches 30%
  • Increasing incidence secondary to:4,5
    • Increasing burden of diabetes worldwide, with concomitant increase in mucormycosis in a variety of developing countries (e.g. India)6,7
    • Increasing hematopoietic stem cell transplantation, more aggressive immunosuppression strategies, voriconazole prophylaxis8

Microbiology and Pathophysiology:

  • Aggressive filamentous fungal infection; angioinvasive involving the paranasal sinuses, lungs, GI system, skin
  • Zygomycetes is avirulent, becoming a potential pathogen only when host immune system is completely compromised9
  • Infection caused by asexual spore formation which settle in nasal or oropharynx
    • If phagocytic response is compromised, spores germinate and hyphae extend into nearby vasculature, leading to thrombosis, ischemia, infarction9
  • Two proposed routes of origin:
    • Inhalational via nasopharynx => palatal ulceration generates necrosis
    • Direct contamination => infection anywhere in oral cavity
      • Mandibular vs maxillary can determine complication risks
        • Maxillary mucormycosis can beget cavernous sinus thrombosis10
      • Hematogenous spread can affect lungs and brain, with respiratory symptoms, septic shock, and/or altered mental status/confusion10
    • Diabetes: immunologic modulation and suppression
      • Hyperglycemia dampens phagocytic efficiency and chemotaxis9,11
      • Rhizopus oryzae produce ketoreductase, which allows this organism to utilize the abundant ketones in DKA12
      • In the setting of DKA, transferrin cannot bind iron, creating an optimal growing condition for Rhizopus13

Clinical Presentation:

  • Several different types which differ in presentation: rhino-orbital-cerebral (most common), pulmonary, GI, cutaneous, disseminated, miscellaneous
  • Initially nasopharyngeal or oropharyngeal infection, progressing to obvious skin changes, and systemic infection

Evaluation:

  • Assess ABCs and obtain VS—may have fever, tachycardia, hypotension
  • Less commonly cases involve maxillary or mandibular area, creating a potentially difficult airway
  • Perform a complete physical examination.
    • Mouth: llesions on hard palate, buccal folds, gum line
    • Nose: lesions with black pigmentation
    • Dental: denuded mucosa can reveal necrotic bone
    • Eyes: If superior spread from maxilla, extraocular movements may be compromised
    • Voice change can be appreciated if nasal tissue involved9
    • Face: erythema and swelling
  • Laboratory evaluation:
    • POC glucose, CBC with differential to include absolute neutrophil count, electrolytes, renal and liver function, VBG with lactate, ketones
    • KOH smears—fungal hyphae can be seen
  • Imaging: Based on areas of suspected involvement.
    • CT face/orbits will likely provide greatest yield, but can obtain paranasal sinus x-ray
    • Chest x-ray to assess for pulmonary involvement
    • Consider MRV for cavernous sinus thrombosis in correct clinical picture with maxillary mucormycosis

Treatment:

  • ABCs
  • Early airway management may be needed based on patient presentation
  • Source control of infection requires surgical debridement
  • Early antifungal agents:
    • Liposomal Amphotericin B + surgical debridement reduces mortality as compared to Amphotericin B alone5
      • 50% of these patients will develop “amphoterrible” induced nephrotoxicity, anemia, and other morbidity;consider need for CRRT11,14
    • Resuscitation—common in patients with DKA, so always consider in DKA
      • For a review of this topic, check out this EM@3AM post

Disposition:

  • Consult ENT and/or OMFS depending on anatomic involvement
  • Consult ID
  • Admit to MICU/STICU
    • Mortality 30% even with optimal treatment11
      • Especially rhino-orbital-cerebral mucormycosis due to angioinvasion and progressive mucormycosis

Pearls:

  • Always evaluate for mucormyosis in patients with immunocompromise and DKA; Uncontrolled diabetes most commonly presents with rhinocerebral Rhizopus15
  • Several types exist: rhino-orbital-cerebral mucormycosis is the most common
  • Cavernous sinus thrombosis is a complication of maxillary mucormycosis
  • Treatment requires debridement and antifungals

From Dr. Katelyn Hanson and Hanson’s Anatomy:


Further Reading:

FOAMed:

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