Mucormycosis - Causes, Symptoms and Treatment
Mucormycosis is a rare and commonly fatal mycotic infection caused by fungi of the order Mucorales; it is among the most acute and fulminant fungal infections known. The mortality rate is high, with an average survival rate of only 36%. The worst prognosis occurs in disseminated disease, with a mortality rate approaching 100%, and the best prognosis occurs with infections limited to skin and subcutaneous tissues of the extremities.
A disease of the immunocompromised, mucormycosis is associated with diabetic ketoacidosis, renal disease, deferoxamine therapy, leukemia, disseminated cancer, organ transplants, human immunodeficiency virus (HIV), extensive burns, and prolonged immunosuppressive therapy. Six forms of infection have been identified and include rhinocerebral, pulmonary, cutaneous, gastrointestinal, central nervous system, and disseminated disease. Rhinocerehral mucormycosis is the most common form and is usually associated with diabetic ketoacidosis. Usually associated with leukemia, pulmonary mucormycosis is the second most common presentation.
Causes of Mucormycosis
Mucormycosis is caused by saprophytic fungi, which are usually harmless commensals, but under extraordinary circumstances can cause invasive disease. There are four clinically important fungi in the Mucorales order: Ahsida, Mucor, Rhizomucor, and Rhizopus. Usually found in soil, bread and fruit molds, manure, and insects, these fungi derive their energy from breaking down dead organic matter. Infection occurs when the spores become airborne and enter the sinuses or when ingested with foods. In immunocompromised patients, normal body defenses may fail, leading to spore germination and the development of hyphae, which extend into the blood vessels with resultant ischemia and necrosis of adjacent organs.
Signs and Symptoms of Mucormycosis
The pathologic feature most characteristic of mucormycosis is hyphal invasion of the vasculature. Regardless of the area of invasion, a combination of hemorrhage, thrombosis, infarction, and necrosis of the tissue or organ involved is apparent.
Diagnosis for Mucormycosis
A definitive diagnosis is established by histological examination of infected tissue. Because much of the necrotic debris does not contain organisms, it is important that the tissue samples be painstakingly examined for large nonseptate hyphae. The hyphae may be visualized on hematoxylin and eosin stain, the periodic acid-Schiff stain, methenamine silver stain, or with direct immunofluorescence conjugate.
For unknown reasons, cultures may test negative, even when hyphae are visible in the tissues. X-rays and computed tomography scans often miss signs of significant bone destruction. There must be a high index of suspicion in order to diagnose mucormycosis in its earliest stages, when clinical symptoms are the most subtle and the disease is most treatable.
Treatment for Mucormycosis
The initial approach is to reverse the disease state that predisposed the patient to the infection, if at all possible. Immunosuppressive drugs should be reduced or stopped. Anti fungal therapy and removal of all necrotic tissue is essential to eradicate thc infection. Amphotericin B, most effective, is given I.V. or injected directly into the spinal fluid. Since amphotericin B is unable to penetrate avascular areas, surgical debridement of necrotic tissue is performed to cleanse remaining organisms.
Other therapies include rifampin, tetracycline, and the azole antifungals, in combination with amphotericin B. Life saving supportive measures are undertaken according to the patient's condition.
Use of hyperbaric oxygen (HBO) is also recommended. HBO provides fungicidal levels of oxygen to the tissues to slow or inhibit fungal growth and also potentiates amphotericin B.
Special Considerations and Prevention Tips for Mucormycosis
1. This is an opportunistic disease of severely immunocompromised patients.
2. Wash hands before and after patient contact, before and after invasive procedures, dressing changes, and handling food.
3. Dispose of tissues and dressings in moisture-resistant containers.
4. Wear mask and gloves when performing patient care.
5. Dispose of soiled bed linens appropriately.
6. Maintain blood glucose within prescribed limits.
7. Monitor for adverse effects of amphotericin B such as nephrogenic diabetes insipidus and agranulocytopenia.
8. Hemodynamic monitoring and ventilatory assistance may be required.
9. Patients and significant others may require significant emotional and spiritual support and assistance with end-of-life decisions since the morbidity and mortality rate for this disease remains high.
HEALTH CARE | ABOUT US | CONTACT US | BLOG
© 2005 Online-Health-Care.com. All rights reserved.
Disclaimer: Online-Health-Care.com is for informational purposes only and is not intended to act as a substitute for a professional healthcare practitioner advise. For specific medical advice, diagnoses, and treatment, please consult your doctor. We will not be liable for any complications, injuries or other medical accidents arising from or in connection with the use of or reliance upon any information on this web site.