eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Mucormycosis: Differential Diagnoses & Workup

Author: Meera Varman, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Infectious Diseases, Creighton University Medical Center
Coauthor(s): Debra Whaley, MD, Staff Physician, Department of Pediatrics, University of Nebraska Medical Center, Creighton University Joint Pediatric Residency Program; Mary Carmen Y Mancao, MD, Associate Professor, Department of Pediatrics, University of South Alabama College of Medicine; Christine A Reyes, MD, Medical Director, Medical Technology School, Methodist Hospital; Consulting Staff, Department of Pathology, Methodist Hospital, Children's Hospital
Contributor Information and Disclosures

Updated: Nov 20, 2008

Differential Diagnoses

Aspergillosis

Other Problems to Be Considered

The differential diagnoses of mucormycoses vary and depend on specific organ involvement. For rhinocerebral mucormycosis, the differential diagnoses include cavernous sinus thrombosis, bacterial orbital cellulitis, and CNS aspergillosis.

Workup

Laboratory Studies

  • Premortem diagnosis of mucormycosis has recently improved, improving patients' survival.
  • Once mucormycosis is suspected, obtaining tissue for culture is vital (see Histologic Findings).
    • Specimens should be obtained from areas such as suggestive skin lesions, black eschars found in the nasopharynx, and nasal discharge that may appear like clotted blood. These specimens should be immediately sent to the microbiology laboratory for culturing.
    • Direct microscopic findings of hyphal elements in tissue biopsy specimens are important for diagnosis.
    • Isolating fungus from infected tissue is usually difficult.
    • Although Rhizopus or Mucor species can be contaminants, the laboratory finding of these organisms in specimens from patients who are immunosuppressed or from patients with certain risk factors for mucormycosis should not be ignored.

Imaging Studies

  • CT scanning and MRI are valuable in delineating extent of disease for most forms of mucormycosis.
  • CT scanning and MRI are also helpful in planning surgical debridement when needed.
  • In rhinocerebral mucormycosis opacification of sinuses, bone destruction and osteomyelitis may be noted. In some patients, images may reveal minimal changes even when extensive tissue destruction is present.

Procedures

  • Biopsy of necrotic lesions from pulmonary, rhinocerebral, and mucocutaneous sites is appropriate for obtaining specimens for microscopy and cultures.
    • Sensitivity is better with tissue staining than with culturing, but collecting tissue for studies is critical for diagnosis.
    • Routine stains, such as hematoxylin and eosin (H&E) stains, help in visualizing Mucor hyphae, whereas Grocott methenamine silver (GMS) stain and periodic acid-Schiff (PAS) stains help to demarcate fungal elements in tissue.
    • GMS stains may not reveal chlamydospores of Mucor fungi.
  • Analysis of nasal and sputum swabs is rarely helpful.

Histologic Findings

  • Biopsy material can be examined with potassium hydroxide (KOH), H&E, and GMS stains. Another useful stain is cresyl violet, which colors Mucor fungi walls brick red while coloring other fungi purple or blue.
  • Fungal hyphae of Mucor species can often be differentiated from other fungi, such as Aspergillus and Fusarium species. Hyphae of Mucor species are aseptate or pauciseptate, they are broad and thick (6-25 mm wide), they have nonparallel edges, and they possess irregularly shaped fungal elements with relatively infrequent acute-angle and nonrandom branching (see Media file 2).
  • Characteristic but not pathognomonic histologic findings include angioinvasion, with the Mucor fungi invading the walls of arteries, resulting in the necrosis and thrombosis of surrounding tissue (see Media file 3). Immunohistochemical methods of staining biopsy material are available in specialized laboratories. Perineuronal invasion can also occur (see Media file 4).

More on Mucormycosis

Overview: Mucormycosis
Differential Diagnoses & Workup: Mucormycosis
Treatment & Medication: Mucormycosis
Follow-up: Mucormycosis
Multimedia: Mucormycosis
References
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References

  1. Kline MW. Mucormycosis in children: review of the literature and report of cases. Pediatr Infect Dis. Nov-Dec 1985;4(6):672-6. [Medline].

  2. Simbli M, Hakim F, Koudieh M, Tleyjeh IM. Nosocomial post-traumatic cutaneous mucormycosis: a systematic review. Scand J Infect Dis. 2008;40(6-7):577-82. [Medline].

  3. Dave SP, Vivero RJ, Roy S. Facial cutaneous mucormycosis in a full-term infant. Arch Otolaryngol Head Neck Surg. Feb 2008;134(2):206-9. [Medline].

  4. Scheinfeld N. A review of the new antifungals: posaconazole, micafungin, and anidulafungin. J Drug Dermatol. 2007;12:1249-51. [Medline].

  5. Kaide CG, Khandelwal S. Hyperbaric oxygen: applications in infectious disease. Emerg Med clin north Am. 2008;26:571-95. [Medline]. [Full Text].

  6. Boelaert JR, Van Cutsem J, de Locht M, et al. Deferoxamine augments growth and pathogenicity of Rhizopus, while hydroxypyridinone chelators have no effect. Kidney Int. Mar 1994;45(3):667-71. [Medline].

  7. Bogard BN. Pulmonary mucormycosis. N Engl J Med. Mar 16 1972;286(11):606. [Medline].

  8. Bradley JS, Nelson JD. Nelson's Pocket Book of Pediatric Antimicrobial Therapy 2002-2003. 15th ed. 2002:62-5.

  9. De Decker K, Van Poucke S, Wojciechowski M, et al. Successful use of posaconazole in a pediatric case of fungal necrotizing fasciitis. Pediatr Crit Care Med. Sep 2006;7(5):482-5. [Medline].

  10. Frater JL, Hall GS, Procop GW. Histologic features of zygomycosis: emphasis on perineural invasion and fungal morphology. Arch Pathol Lab Med. Mar 2001;125(3):375-8. [Medline].

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  12. Greenberg RN, Scott LJ, Vaughn HH, Ribes JA. Zygomycosis (mucormycosis): emerging clinical importance and new treatments. Curr Opin Infect Dis. Dec 2004;17(6):517-25. [Medline].

  13. Kontoyiannis DP, Lionakis MS, Lewis RE, et al. Zygomycosis in a tertiary-care cancer center in the era of Aspergillus-active antifungal therapy: a case-control observational study of 27 recent cases. J Infect Dis. Apr 15 2005;191(8):1350-60. [Medline].

  14. Parfrey NA. Improved diagnosis and prognosis of mucormycosis. A clinicopathologic study of 33 cases. Medicine (Baltimore). Mar 1986;65(2):113-23. [Medline].

  15. Rex JH, Ginsberg AM, Fries LF, et al. Cunninghamella bertholletiae infection associated with deferoxamine therapy. Rev Infect Dis. Nov-Dec 1988;10(6):1187-94. [Medline].

  16. Richardson M, Koukila-Kahkola P, Shankland G. Rhizopus, Rhizomucor, Absidia, and other agents of systemic and subcutaneous zygomycoses. In: Manual of Clinical Microbiology. 8th ed. Washington, DC: American Society of Microbiology; 2003:1761-80.

  17. Robertson AF, Joshi VV, Ellison DA, Cedars JC. Zygomycosis in neonates. Pediatr Infect Dis J. Aug 1997;16(8):812-5. [Medline].

  18. Sugar A. Agents of mucormycosis and related species. In: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, Pa: Churchill Livingstone; 2005:2973-83.

  19. Wiedermann BL. Zygomycosis. In: Feigen RD, ed. Textbook of Pediatric Infectious Diseases. 5th ed. Philadelphia, PA: Saunders; 2004.

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Further Reading

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Keywords

mucormycosis, Mucorales infection, fungal infection, Rhizopus species infection, Rhizomucor species infection, Absidia corymbifera infection, A corymbifera infection, Apophysomyces elegans infection, A elegans infection, Cunninghamella bertholletiae infection, C bertholletiae infection, Mucor species infection, Saksenaea vasiformis infection, S vasiformis infection, burns, trauma, diabetes mellitus, leukemia, diabetic ketoacidosis, malnutrition

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Contributor Information and Disclosures

Author

Meera Varman, MD, Assistant Professor, Department of Pediatrics, Section of Pediatric Infectious Diseases, Creighton University Medical Center
Meera Varman, MD is a member of the following medical societies: American Academy of Pediatrics, Infectious Diseases Society of America, and Pediatric Infectious Diseases Society
Disclosure: phamaceutical companies Honoraria Speaking and teaching; phamaceutical companies Grant/research funds clinical trials

Coauthor(s)

Debra Whaley, MD, Staff Physician, Department of Pediatrics, University of Nebraska Medical Center, Creighton University Joint Pediatric Residency Program
Debra Whaley, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Mary Carmen Y Mancao, MD, Associate Professor, Department of Pediatrics, University of South Alabama College of Medicine
Mary Carmen Y Mancao, MD is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Southern Society for Pediatric Research
Disclosure: Nothing to disclose.

Christine A Reyes, MD, Medical Director, Medical Technology School, Methodist Hospital; Consulting Staff, Department of Pathology, Methodist Hospital, Children's Hospital
Christine A Reyes, MD is a member of the following medical societies: Alpha Omega Alpha, American Society for Clinical Pathologists, College of American Pathologists, and United States and Canadian Academy of Pathology
Disclosure: Nothing to disclose.

Medical Editor

Gary J Noel, MD, Department of Pediatrics, Clinical Associate Professor, Weill Medical College of Cornell University
Gary J Noel, MD is a member of the following medical societies: Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Mark R Schleiss, MD, American Legion Chair of Pediatrics, Professor of Pediatrics, Division Director, Division of Infectious Diseases and Immunology, Department of Pediatrics, University of Minnesota School of Medicine
Mark R Schleiss, MD is a member of the following medical societies: American Pediatric Society, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, and Society for Pediatric Research
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Consulting; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; Novartis Honoraria Speaking and teaching; sanofi pasteur Grant/research funds Unrestricted research grant; sanofi pasteur  Consulting; sanofi pasteur Honoraria Speaking and teaching; Tap Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
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