Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Pediatric Mucormycosis Workup

  • Author: Meera Varman, MD; Chief Editor: Russell W Steele, MD  more...
 
Updated: Aug 25, 2011
 

Approach Considerations

Antemortem diagnosis of mucormycosis has improved, leading to improving patient survival.

Once mucormycosis is suspected, obtaining tissue for culture is vital (see Biopsy and Histologic Features). However, isolating fungus from infected tissue is usually difficult, and analysis of nasal and sputum swabs is rarely helpful.

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.

Because fungi of the order Mucorales contaminate laboratory specimens, use caution when these organisms are isolated from bronchial washings, sinus samples, and sputum obtained from immunosuppressed hosts.

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.

Next

CT Scanning and MRI

Computed tomography (CT) scanning and magnetic resonance imaging (MRI) are valuable in delineating extent of disease for most forms of mucormycosis. These 2 imaging modalities are also helpful in planning surgical debridement when needed.

In rhinocerebral mucormycosis, opacification of the sinuses, bone destruction, and osteomyelitis may be noted. In some patients, images may reveal minimal changes even when extensive tissue destruction is present.

Previous
Next

Biopsy and Histologic Features

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. However, GMS stains may not reveal chlamydospores of Mucor fungi.

Histologic findings

Direct microscopic findings of hyphal elements in tissue biopsy specimens are important for the diagnosis of mucormycosis.

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.

Upon microscopic examination, fungi of the Mucorales order are characterized by aseptate hyphae, which vary in width up to 50 µm. These hyphae are broad and branch from the main hyphal trunk; they are often angled 90°.[4] Identification of most of the Zygomycetes is accomplished by observing the morphology of the sporangia, such as presence or absence of the columellae and apophyses, arrangement and number of sporangiospores, and absence or presence of rhizoids.

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 the following image).

Mucormycosis with broad, aseptate hyphae (hematoxy Mucormycosis with broad, aseptate hyphae (hematoxylin and eosin, original magnification ×40).

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, as can be seen in the first image below. Immunohistochemical methods of staining biopsy material are available in specialized laboratories. Perineuronal invasion can also occur (see the second image below).

Angioinvasion (hematoxylin and eosin, original mag Angioinvasion (hematoxylin and eosin, original magnification ×10).
Perineural invasion (hematoxylin and eosin, origin Perineural invasion (hematoxylin and eosin, original magnification ×20).
Previous
 
 
Contributor Information and Disclosures
Author

Meera Varman, MD Associate 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, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Society for Healthcare Epidemiology of America

Disclosure: Received honoraria from phamaceutical companies for speaking and teaching; Received grant/research funds from phamaceutical companies for clinical trials research.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Mark R Schleiss, MD Minnesota American Legion and Auxiliary Heart Research Foundation Chair of Pediatrics, Professor of Pediatrics, Division Director, Division of Infectious Diseases and Immunology, Department of Pediatrics, University of Minnesota Medical School

Mark R Schleiss, MD is a member of the following medical societies: American Pediatric Society, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Society for Pediatric Research

Disclosure: Nothing to disclose.

Chief Editor

Russell W Steele, MD Clinical Professor, Tulane University School of Medicine; Staff Physician, Ochsner Clinic Foundation

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, Southern Medical Association

Disclosure: Nothing to disclose.

Additional Contributors

Gary J Noel, MD Professor, Department of Pediatrics, Weill Cornell Medical College; Attending Pediatrician, New York-Presbyterian Hospital

Gary J Noel, MD is a member of the following medical societies: Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Acknowledgements

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors Mary Carmen Y Mancao, MD, Christine A Reyes, MD, and Debra Whaley, MD, to the development and writing of the source article.

References
  1. Richardson M, Koukila-Kahkola P, Shankland G. Rhizopus, Rhizomucor, Absidia, and other agents of systemic and subcutaneous zygomycoses. Murray PR, Baron EJ, Jorgensen JH, Pfaller MA , Yolken RH, eds. Manual of Clinical Microbiology. 9th ed. Washington, DC: American Society of Microbiology; 2007.

  2. Sugar A. Agents of mucormycosis and related species. Mandell GL, Bennet JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Churchill Livingstone; 2009. Chapter 259.

  3. Wiedermann BL. Zygomycosis. Feigen RD, Cherry JD, Demmler-Harrison GJ, Kaplan SL, eds. Textbook of Pediatric Infectious Diseases. 6th ed. Philadelphia, Pa: Saunders; 2009.

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

  5. 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].

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

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

  8. Garbino J, Myers C, Ambrosioni J, Gumy-Pause F. Report of a successful treatment of pulmonary Cunninghamella bertholletiae infection with liposomal amphotericin and posaconazole in a child with GvHD and review of the literature. J Pediatr Hematol Oncol. 2010 Mar. 32(2):85-7. [Medline].

  9. Rüping MJ, Heinz WJ, Kindo AJ, Rickerts V, Lass-Flörl C, Beisel C, et al. Forty-one recent cases of invasive zygomycosis from a global clinical registry. J Antimicrob Chemother. 2010 Feb. 65(2):296-302. [Medline].

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

  11. Scheinfeld N. A review of the new antifungals: posaconazole, micafungin, and anidulafungin. J Drugs Dermatol. 2007 Dec. 6(12):1249-51. [Medline].

  12. Ullmann AJ, Lipton JH, Vesole DH, Chandrasekar P, Langston A, Tarantolo SR, et al. Posaconazole or fluconazole for prophylaxis in severe graft-versus-host disease. N Engl J Med. 2007 Jan 25. 356(4):335-47. [Medline].

  13. Kaide CG, Khandelwal S. Hyperbaric oxygen: applications in infectious disease. Emerg Med Clin North Am. 2008 May. 26(2):571-95, xi. [Medline]. [Full Text].

  14. Garg PK, Gupta N, Gautam V, Hadke NS. Gastric zygomycosis: unusual cause of gastric perforation in an immunocompetent patient. South Med J. 2008 Apr. 101(4):449-50. [Medline].

  15. Goel S, Carter JE, Culpepper M, Kahn AG. Primary renal zygomycotic infarction mimicking renal neoplasia in an immunocompetent patient. Am J Med Sci. 2009 Oct. 338(4):330-3. [Medline].

  16. Kontoyiannis DP, Lionakis MS, Lewis RE, Chamilos G, Healy M, Perego C, 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. 2005 Apr 15. 191(8):1350-60. [Medline].

  17. Singh N, Aguado JM, Bonatti H, Forrest G, Gupta KL, Safdar N, et al. Zygomycosis in solid organ transplant recipients: a prospective, matched case-control study to assess risks for disease and outcome. J Infect Dis. 2009 Sep 15. 200(6):1002-11. [Medline].

 
Previous
Next
 
Black eschar on the skin of an immunocompromised patient.
Mucormycosis with broad, aseptate hyphae (hematoxylin and eosin, original magnification ×40).
Angioinvasion (hematoxylin and eosin, original magnification ×10).
Perineural invasion (hematoxylin and eosin, original magnification ×20).
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.