While acknowledging that improvements in therapies have led to better care of patients with invasive aspergillosis – a potentially deadly fungal infection – new practice guidelines emphasize that there remains a critical need for early diagnosis.
The Infectious Diseases Society of America (IDSA) have updated guidelines for the diagnosis and management of aspergillosis and published them in the journal Clinical Infectious Diseases.
Aspergillosis is an infection caused by the common mold or fungus Aspergillus that is everywhere, both indoors and outdoors. It can be found, for instance, in air conditioning units, compost heaps, and damp or flood-damaged homes and buildings.
Most of us breathe in Aspergillus spores every day without getting sick. However, for people with lung diseases or weakened immune systems, exposure to Aspergillus can lead to health problems – such as allergic reactions, lung infections, and infections in other organs.
The updated guidelines concern three major forms of aspergillosis: allergic, chronic pulmonary, and invasive. The allergic form is most common and affects millions of people worldwide. Those with asthma and cystic fibrosis are at highest risk of developing allergic aspergillosis.
Chronic pulmonary aspergillosis, which can affect healthy people, occurs in about 400,000 people worldwide.
Although they require treatment, the allergic and chronic forms of aspergillosis rarely kill. However, invasive aspergillosis, which affects about 200,000 people worldwide, kills 40-80 percent of those with widespread infection.
Thomas Patterson, chief of the Division of Infectious Disease and professor of medicine at The University of Texas Health Science Center, and of the South Texas Veterans Health Care System – both in San Antonio – is lead author of the updated guidelines. He explains:
“These are complicated infections with a number of treatment options. Patients really benefit from a multidisciplinary approach, including the expertise of an infectious disease specialist.”
Improved diagnostic tools have enabled doctors to diagnose invasive aspergillosis early. However, the new guidelines – which update the 2008 guidelines – highlight the increased evidence for antifungal therapy recommendations as well as diagnostic tests.
The new diagnostic methods include blood tests, cultures, and computed tomography (CT) imaging. Some of these are invasive, and doctors may be reluctant to use them. For example, cultures require samples taken directly from the lungs. However, Prof. Patterson urges doctors to be aggressive in diagnosing patients suspected of having invasive aspergillosis because the infection could be life-threatening.
The IDSA urge all practitioners using the guidelines to understand they cannot account for individual variation and are not a substitute for their professional judgment. Adherence is voluntary and should be made in the light of each patient’s circumstances, they note.
The guidelines are in sections that cover different aspects of diagnosis and treatment of aspergillosis. They are briefly summarized as follows:
- Section 1 concerns how to protect vulnerable patients, deals with risk factors for infection, sources of exposure, how to decrease exposure, and environmental monitoring
- Section 2 deals with diagnosis of invasive aspergillosis, including how it should be identified (tissue and fluid specimens until molecular tools are more widely available) and the diagnostic value of new methods, such as nucleic acid testing and Serum and BAL galactomannan (GM)
- Section 3 has recommendations about antifungal agents and susceptibility testing
- Section 4 deals with treatments for different clinical types of invasive aspergillosis – including not only types that affect the lungs, but also types that affect all other parts of the body
- Section 5 concerns recommendations about preventing (prophylaxis) invasive aspergillosis – for example, which regimens, who should receive them, and how to manage breakthrough infections
- Section 6 concerns empiric therapy – where, due to incomplete or less than perfect clinical information, doctors have to base decisions on experience or educated guesses
- Section 7 deals with chronic, allergic, and noninvasive aspergillosis.
In each section, each recommendation is accompanied by an indication of its strength – for example, “weak recommendation; low-quality evidence” – followed by a summary of the relevant evidence.
“Invasive aspergillosis often is overlooked, but early diagnosis and treatment are key.”
Prof. Thomas Patterson