Invasive Aspergillosis (IA)

Assume a profoundly immunocompromised host - Neutropenia, transplant, and chronic steroids are the defining risk factors, so expect all three at once. Aspergillus seeds through venous catheters and surgical sites in exactly this population — strict asepsis on lines and any neuraxial technique is not a formality here.

A normal temperature proves nothing - Fever can be absent in the severely immunocompromised despite progressive infection. Do not let an afebrile chart talk you out of the diagnosis.

Hemoptysis is the bleeding you plan for - Vessel invasion makes hemoptysis a real presenting event; in chronic pulmonary disease it occurs about half the time and is often the first symptom. When a bleeding cavity is the reason for the case, plan lung isolation, large-bore suction, and blood availability up front.

Read the chest CT yourself - The halo sign (central nodule with surrounding ground-glass from perinodular thrombosis and hemorrhage) marks early invasive disease; the air crescent sign appears later, after neutrophil recovery. Chronic necrotizing disease shows upper-lobe consolidation with bronchiectasis evolving to cavitation, and pleural thickening beside a cavity.

What you will be anesthetizing them for - Resection of a lesion sitting near a major vessel to pre-empt pulmonary hemorrhage, resection of an aspergilloma for hemoptysis (best when it is a single lesion, not diffuse disease), bronchial artery embolization for hemoptysis control, and urgent nasal endoscopy or debridement for invasive fungal rhinosinusitis. Tranexamic acid is used medically for hemoptysis.

Invasive fungal rhinosinusitis - This is an emergent otolaryngology problem in the severely immunocompromised. Expect a shared, soiled airway near the skull base. CT of the maxillofacial sinuses underestimates the extent; MRI of the brain characterizes progression better. Exophthalmos, retro-orbital pain, or visual impairment tells you how far it has gone.

Voriconazole and the QT interval - Voriconazole is the drug of choice for invasive disease, and QT prolongation is one of the patient comorbidities that steers antifungal selection. Get a baseline ECG before you add your own QT-prolonging agents.

Amphotericin B and potassium - Liposomal amphotericin B and isavuconazole are the alternatives, and amphotericin is preferred over voriconazole for breakthrough infection on mold prophylaxis. Conventional amphotericin B has precipitated severe hypokalemia under anesthesia in a patient with invasive aspergillosis — check K+ and Mg2+ before induction. Note that A. terreus and A. alliaceus are intrinsically resistant to amphotericin B, and A. calidoustus is intrinsically resistant to azoles.

Severe viral illness is a precursor - Invasive aspergillosis has followed both severe influenza and severe COVID-19 in ICU patients. Incidence in hospitalized patients rose 44% between 2004 and 2013 as transplantation became more common.

Do not undo their environmental protection - High-risk patients are kept in HEPA-filtered private rooms, and nosocomial outbreaks have been traced to hospital showers and facility construction. Keep OR transit and holding time short, and route around active construction zones.

Aspergillus is a ubiquitous environmental mold, and everyone inhales conidia daily. An intact neutrophil response clears them, so invasive aspergillosis is a disease of the host whose response has failed — prolonged neutropenia, hematologic malignancy, allogeneic stem cell or solid organ transplant on anti-rejection drugs, long-term corticosteroids, AIDS, and critically ill patients with underlying COPD or asthma. A. fumigatus predominates.

The mechanism that matters is angioinvasion: growing hyphae break through vessel endothelium, producing thrombosis, infarction, and hemorrhage. That is why the halo sign exists on CT and why these patients bleed into their lungs. Pulmonary disease is the usual form, but the fungus disseminates to brain, eye, skin, liver, heart, and kidney.

Untreated, mortality approaches 100%. Even on appropriate antifungals, invasive pulmonary disease still runs about 20% mortality at six weeks.