Overall, mucormycosis remains extremely rare. A review of mucormycosis cases at one US cancer center found that 0.7% of patients were found to have mucormycosis at autopsy, and that 20 patients per 100,000 admissions had the disease.[2,5,6] Mucormycosis was found in 1% of patients with acute leukemia in an Italian multicenter review.
Mucormycosis carries a very high mortality rate of 50%-85%. Pulmonary and gastrointestinal diseases carry an even higher mortality rate because these forms are typically diagnosed late in the disease course. Rhinocerebral disease causes significant morbidity in patients who survive because treatment usually requires extensive—and often disfiguring—facial surgery.
The vast majority of pulmonary mucormycosis infections present with diffuse lung involvement and a rapidly progressive clinical course. Patients report symptoms of rapidly progressive cough, fever, and pleuritic chest pain. Patients are often profoundly ill, with marked gas-exchange abnormalities and rapidly advancing respiratory failure despite therapy with conventional antibiotics.
Reported chest abnormalities found on radiography include nodular, lobar, or wedge-shaped infiltrates, which may be seen in 58% of cases. Other signs include mediastinal widening, bronchopneumonia, solitary nodule, miliary pattern, cavitation, air crescent sign, bronchopleural fistula, pulmonary artery pseudoaneurysm, and pleural effusions. The CT halo sign has been shown to represent pulmonary infarcts with surrounding hemorrhage and edema.
More typical findings seen on chest radiographs are those of fungal vascular invasion. The invasion of large vascular structures leads to thrombosis and infarction of the lung parenchyma. This may begin as a nodular or nonspecific acinar infiltrate, which subsequently develops into a wedge-shaped density. In some instances, it progresses to lobar consolidation. The major complication associated with pulmonary mucormycosis is massive hemoptysis; therefore, treatment of pulmonary Zygomycetes infections is usually surgical. Despite this, the radiographic variability is vast, and pulmonary mucormycosis cannot be diagnosed or excluded on radiographic grounds alone.[3,4,8]
The results of sputum cultures are usually negative, but a positive culture for Mucor from sputum is highly suggestive of invasive infection. A definitive diagnosis requires a histologic investigation. Tissue invasion with characteristic broad (5-50 µm), nonseptate hyphae with right-angle branching and blood vessel invasion must be seen. Culture of histologic material will give variable results as well. Percutaneous needle biopsy, open lung biopsy, and pleural fluid culture have been successful methods to obtain these samples. Bronchoscopic examination is often chosen as a relatively safe and less invasive technique to obtain histologic material for diagnosis; however, the results may be negative in patients with large areas of lung infarction secondary to mucormycosis vascular invasion.[1,3,4]
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Cite this: Arunabh Talwar, Craig E. Devoe, Nick Patel. A 74-Year-Old Man With Easy Bruising and Fatigue - Medscape - Feb 09, 2017.