Mucormycosis pathophysiology

Mucormycosis Microchapters
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Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Mucormycosis from other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
Diagnostic Criteria
History and Symptoms
Physical Examination
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Treatment
Medical Therapy
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Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Syed Hassan A. Kazmi BSc, MD [2]

Pathophysiology

• Fungi of the order Mucorales (class Zygomycetes) are causes of mucormycosis, a life-threatening fungal infection affecting immunocompromised hosts in either developing or industrialized countries.
• Species belonging to the family Mucoraceae are isolated more frequently from patients with mucormycosis.
• Among the Mucoraceae, Rhizopus oryzae (Rhizopus arrhizus) is by far the most common cause of infection. Increasing cases of mucormycosis have been also reported due to infection with Cunninghamella spp.
• Neutrophils play a major part in destroying fungal hyphae, once spores germinate. Macrophages and monocytes may also play part in host defense mechanisms against fungi causing mucormycosis (specifically alveolar macrophages prevent germination of spores). Consequently, mucormycosis develops exclusively in immunocompromised patients who lack these defense mechanisms. Hyperglycemia, acidosis and corticosteroid treatment have also been known to hinder immunity (specifically the actions of phagocytic cells), which also puts patients with diabetes and DKA at an increased risk of acquiring mucormycosis.
• In order to cause disease, the agents of mucormycosis must acquire from the host sufficient iron for growth, must evade host phagocytic defense mechanisms, and must access vasculature to disseminate.