The COVID Complication You Might Miss

Brendan R. Jackson, MD, MPH; Pavithra Natarajan, BMBS


November 19, 2020

Editorial Collaboration

Medscape &

COVID-Associated Pulmonary Aspergillosis (CAPA)  

CAPA is a recently recognized complication of COVID-19. Although aspergillosis is classically associated with severely immunocompromised patients, it is increasingly detected in patients who receive mechanical ventilation and corticosteroids, particularly those with severe influenza infections. With this concern, the following additional lab results are obtained:

  • Serum galactomannan: 1.05 (reference range, < 0.5)

  • Tracheal aspirate galactomannan: 3.78 (reference range, < 0.5)

  • Tracheal aspirate culture: Aspergillus fumigatus

Aspergillosis in patients with severe COVID-19 has been identified globally, including in previously healthy patients without preexisting immunocompromising conditions.

Invasive pulmonary aspergillosis is often misdiagnosed. In fact, a 2012 study found that it was one of the most commonly missed serious diagnoses identified on autopsy among patients in the ICU. The true incidence of CAPA is unknown. The number of reported cases is small, although that may reflect underdiagnosis.

A positive serum galactomannan result would be highly suspicious for CAPA, but a negative result should not be used to exclude the diagnosis, in part because CAPA may be less invasive than aspergillosis in severely immunocompromised hosts. Serum beta-D-glucan may be useful too, as might polymerase chain reaction assay for Aspergillus.

Diagnosis of invasive aspergillosis relies on culturing Aspergillus from respiratory samples or positive galactomannan in serum or bronchoalveolar lavage.

Although COVID-19 guidelines advise against routine diagnostic bronchoscopy in patients with COVID-19 because of the risk for aerosol generation, endotracheal sampling or nondirected bronchoalveolar lavage sampling may be done if CAPA is suspected. A positive respiratory galactomannan result is suggestive of CAPA.

Corticosteroid use is a risk factor for invasive aspergillosis, although aspergillosis can occur in mechanically ventilated patients who have not received these medications. With the results of the RECOVERY trial showing a benefit of using dexamethasone in the management of patients with COVID-19, dexamethasone therapy has been adopted in treatment guidelines for severe COVID-19, which might increase risk for invasive pulmonary aspergillosis.