Invasive Aspergillosis in the Intensive Care Unit: Beyond the Typical Haematological Patient

Data about incidence of invasive aspergillosis in intensive care units (ICU) are scarce and variable. Incidences ranging from 2 to 24% have been reported, which might reflect different autopsy policies amongst centres. Recent studies have shown that many patients with invasive aspergillosis do not have a haematological diagnosis. Instead, conditions such as chronic obstructive pulmonary disease and liver failure became recognized as important risk factors. The diagnosis remains difficult in these patients, since diagnostic tests have not been widely validated outside the haematological boundaries. Mechanical ventilation precludes the interpretation of clinical signs and radiological diagnosis is clouded by underlying lung pathology. Respiratory cultures lack sensitivity and specificity. At the moment, diagnosis is best made by testing for galactomannan in bronchoalveolar fluid samples (sensitivity and specificity of > 87%). Testing galactomannan in sera has limited sensitivity for the non-neutropenic. Modern diagnostic tests such as PCR and beta-glucan have never been validated in an ICU population. Due mostly to major delays in the diagnosis, mortality exceeds 50%. Although our therapeutic armamentarium against invasive aspergillosis has improved in recent years, data concerning safety and efficacy of new antifungal agents in the ICU setting are lacking.