Invasive Aspergillosis

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Presentation :

Invasive aspergillosis most often occurs in immunosuppressed patients with neutropenia or who are hematopoietic stem cell transplant recipients.
Most common site is pulmonary (60%), but sinusitis, brain abscess, and disseminated infection may also occur.
CT chest can reveal septic emboli (nodules, often with a “halo sign”; ) (Figure 19), thromboembolic pulmonary infarction (wedge-shaped peripheral densities), or necrosis with cavitation (air-crescent sign) are typical findings
“Halo sign,” is an area of low attenuation surrounding a pulmonary nodule that reflects hemorrhage into the adjacent tissues.

Aspergillus fumigatus is the most common species causing disease in humans, followed by A. flavus, A. niger, and the amphotericin-resistant A. terreus.
Aspergillus produces disease after inhalation of airborne spores (90%) and occasionally by traumatic skin inoculation.
Aspergillosis usually begins in the respiratory tract and then enters the circulatory system (angioinvasion).

Blood culture results are generally negative
Serum Galactomannan testing
If invasive pulmonary aspergillosis is suspected, bronchoscopy, bronchoalveolar lavage, and, if possible, tissue biopsy are recommended to establish the diagnosis
Methenamine silver stain reveals septate hyaline hyphae with dichotomous acute angle (45°) branching.

First-line treatment of invasive aspergillosis is voriconazole
- Alternative agents include liposomal amphotericin B, isavuconazole, or other lipid formulations of amphotericin B.
When possible, reversing immunosuppression improves treatment response.