Zygomycosis
Zygomycosis is a severe fungal infection caused by Zygomycetes, a group of fungi commonly found in decaying organic matter, soil, and on various fruits and breads. This rare but potentially fatal infection predominantly affects individuals with weakened immune systems, targeting areas such as the sinuses, brain, and lungs. The most common form, rhinocerebral zygomycosis, manifests through symptoms like fever, facial pain, and visual disturbances, while pulmonary zygomycosis presents with respiratory issues such as cough and chest pain.
Individuals with conditions such as uncontrolled diabetes, malnutrition, or those undergoing treatments like organ transplants are particularly at risk. Diagnosis typically involves imaging studies and culturing the fungus to confirm its presence. Prompt treatment is essential and usually involves antifungal medications like intravenous amphotericin B and surgical intervention to remove necrotic tissue. Despite aggressive treatment, zygomycosis carries a high mortality rate, underscoring the importance of prevention and early detection, especially among immunocompromised populations.
Zygomycosis
- ANATOMY OR SYSTEM AFFECTED: Eyes, lungs, respiratory system, vision
- ALSO KNOWN AS: Mucormycosis
Definition
Zygomycosis is a rapidly spreading fungal infection caused by Zygomycetes, a class of ubiquitous fungi found on fruits and breads and in soil and decaying vegetation. This rare, potentially fatal infection primarily affects the sinuses, brain, and lungs in persons with immune disorders.
Causes
Two orders of Zygomycetes cause human disease: Mucorales and Entomophthorales. Most infections are linked to the Rhizopus species within the Mucorales order. Infection occurs through inhalation of mold spores, through ingestion, or through local skin trauma. These opportunistic fungi grow rapidly, targeting arteries to impede blood flow, causing blood clots (thrombosis), and premature tissue death (necrosis). Rhinocerebral zygomycosis is the most common form of infection affecting the nose, eyes, sinuses, and brain. Infection of the lungs, causing pulmonary zygomycosis, is also common. Cutaneous, gastrointestinal, and widespread (disseminated) zygomycosis occur but with less frequency.
Risk Factors
Exposure to these fungi occurs regularly, but many healthy persons have a natural immunity. Immunocompromised persons are more susceptible to this type of invasive infection. Conditions most commonly associated with a risk for zygomycosis include uncontrolled diabetes, malnutrition, bodily burns, steroid or intravenous drug use, metabolic acidosis, organ or stem-cell transplantation, leukemia or lymphoma, deferoxamine (iron chelator) treatment, and acquired immunodeficiency syndrome.
Symptoms
Rhinocerebral zygomycosis is indicated by fever, face pain, sinus congestion, headaches, eye swelling, visual disturbances, and nasal discharge. Infections affecting the brain are associated with seizures, paralysis, and coma. Symptoms of pulmonary zygomycosis include fever, chest pain, cough, and difficulty breathing. Gastrointestinal zygomycosis is indicated by abdominal pain and swelling, stomach upset, vomiting, diarrhea, and bloody stools, and it typically results in stomach and colon necrosis. Symptoms of cutaneous zygomycosis include a painful hardening of the skin with a blackened center. Disseminated zygomycosis usually begins in the lungs and spreads to the nervous system and includes fever, headaches, visual problems, and changes in brain function.
Screening and Diagnosis
Zygomycosis is a very serious and aggressive fungal infection. Immunocompromised persons should seek immediate medical care if disease symptoms appear. Primary care physicians should consult with an infectious disease or ear-nose-throat specialist for diagnosis and treatment. Diagnostic tests may include computed tomography or magnetic resonance imaging scans. Conclusive diagnosis of zygomycosis requires the isolation, analysis, and identification of the fungus in culture.
Treatment and Therapy
Persons with zygomycosis should be treated promptly to avoid blindness, thrombosis, nerve injuries, extensive surgery, disfigurement, and death. Intravenous amphotericin B is the antifungal therapy of choice, along with surgery to remove dead and infected tissue. Even with intensive treatment, zygomycosis has a high mortality rate, which varies with infection type and with the condition of the infected person’s immune system.
Prevention and Outcomes
The fungi that cause zygomycosis are everywhere in the environment. The best preventive measures involve better management of underlying illnesses associated with the disease, improvement of culture-based detection of the disease, and close monitoring of at-risk persons for the earliest possible diagnosis.
Bibliography
Ahmad, Iqbal, et al. Combating Fungal Infections: Problems and Remedy. New York: Springer, 2010.
Ribes, Julie A., Carolyn L. Vanover-Sams, and Doris J. Baker. “Zygomycetes in Human Disease.” Clinical Microbiology Reviews 13 (2000): 236-301.
Sandhu, Avnish. "Mucormycosis (Zygomycosis)." Medscape, 17 Jan. 2024, emedicine.medscape.com/article/222551-overview?form=fpf. Accessed 4 Feb. 2025.
St. Georgiev, Vassil. Opportunistic Infections: Treatment and Prophylaxis. Totowa, N.J.: Humana Press, 2003.