Risk factors
People who are immunocompromised — such as patients undergoing hematopoietic stem cell transplantation, chemotherapy for leukaemia, or AIDS — are at an increased risk for invasive aspergillosis infections. These people may have neutropenia or corticoid-induced immunosuppression as a result of medical treatments. Neutropenia is often caused by extremely cytotoxic medications such as cyclophosphamide. Cyclophosphamide interferes with cellular replication including that of white blood cells such as neutrophils. A decreased neutrophil count inhibits the ability of the body to mount immune responses against pathogens. Although tumor necrosis factor alpha (TNF-α) — a signaling molecule related to acute inflammation responses — is produced, the abnormally low number of neutrophils present in neutropenic patients leads to a depressed inflammatory response. If the underlying neutropenia is not fixed, rapid and uncontrolled hyphal growth of the invasive fungi will occur and result in negative health outcomes. In addition to decreased neutrophil degranulation, the antiviral response against Flu and SARS-CoV-2 viruses, mediated by type I and type II interferon, is diminished jointly with the local antifungal immune response measured in the lungs of patients with IAPA (Influenza-Associated Pulmonary Aspergillosis) and CAPA (COVID-19-Associated Pulmonary Aspergillosis). Diagnosis
On chest X-ray and CT, pulmonary aspergillosis classically manifests as a halo sign, and later, an air crescent sign. In hematologic patients with invasive aspergillosis, the galactomannan test can make the diagnosis in a noninvasive way.
Taken together, the major chronic, invasive, and allergic forms of aspergillosis account for around 600,000 deaths annually worldwide. Signs and symptoms
A fungus ball in the lungs may cause no symptoms and may be discovered only with a chest X-ray, or it may cause repeated coughing up of blood, chest pain, and occasionally severe, even fatal, bleeding. A rapidly invasive Aspergillus infection in the lungs often causes cough, fever, chest pain, and difficulty breathing. Poorly controlled aspergillosis can disseminate through the blood to cause widespread organ damage. Symptoms include fever, chills, shock, delirium, seizures, and blood clots. The person may develop kidney failure, liver failure (causing jaundice), and breathing difficulties. Death can occur quickly. Aspergillosis of the ear canal causes itching and occasionally pain. Fluid draining overnight from the ear may leave a stain on the pillow. Aspergillosis of the sinuses causes a feeling of congestion and sometimes pain or discharge. It can extend beyond the sinuses.In addition to the symptoms, an X-ray or computerised tomography (CT) scan of the infected area provides clues for making the diagnosis. Whenever possible, a doctor sends a sample of infected material to a laboratory to confirm identification of the fungus. Cause
Aspergillosis is caused by Aspergillus, a common mold, which tends to affect people who already have a lung disease such as cystic fibrosis or asthma, or who cannot fight infection themselves. The most common causative species is Aspergillus fumigatus.