Presentation on theme: "Koenraad Vandewoude, MD"— Presentation transcript:
1 Invasive Aspergillosis in Critically Ill Patients A New 21th Century Problem? Koenraad Vandewoude, MDIntensive Care Dpt. – Solid Organ Transplant CentreGhent University HospitalGhent, Belgium
2 Invasive Aspergillosis Extensive data available in distinct high-risk patient populations:Hemato-oncological patientsAllogeneic SCT, graft-vs.-host diseasePersistant neutropeniaSolid organ transplant patients, >> lungImmunosuppressive therapyChronic granulomatous diseaseSevere combined immunodeficiencyHIV…
3 Aspergillus spp. Underestimated Pathogen in the ICU? Epidemiological data on incidence and outcome of Invasive Aspergillosis in Critically Ill patients are scarce …Low index of suspicionPositive cultures often discarded as colonization or contaminationAbsence of feasible diagnostic reference standardNow, the question addressed in this lecture, is whether Aspergillus is an underestimated pathogen in critically ill patients?What we know for sure, is that reliable data on the incidence of invasive aspergillosis in this setting are scarce.Several factors may explain this lack of data.First, the index of suspicion of this opportunistic infection is still low amongst critical care practioners. Respiratory tract samples positive for Aspergillus are often discarded as colonization or contamination, and are not taken into account for treatment.Moreover, in contrast to immunocompromised host, there is no feasible and reliable diagnostic reference standard.And finally, in order to have a good estimate of incidence of this disease, a per protocol necropsy policy is necessary in patients dying with unexplained pneumonia.
4 Invasive Pulmonary Aspergillosis in Critically Ill patients Differentiate betweenPts referred to the ICU with IPAe.g. pt. from Bone Marrow Transplant Unit with proven/probable IPA and respiratory failure100% mortality? 1Pts. with IPA diagnosed in the ICUcommunity acquirednosocomialICU acquiredgrim prognosis 2Of course, one should make a difference between patients, admitted to the ICU, referred from the bone marrow transplant unit with an established diagnosis of aspergillosis. It is known that when such a patient develops respiratory insufficiency, death is impending, and mortality is nearly 100%.On the other hand, there are group of critically ill patients, in whom the diagnosis of invasive pulmonary aspergillosis is made during their ICU stay. They may have acquired the disease in the community, or during there stay in other wards of the hospital, including in the intensive care; studies about health care associated pneumonia have demonstrated that also in this group of patients, the outcome of nosocomially acquired IA is very poor, with a mortality of about 80%.Janssen JJ. Outcome of ICU treatment in Invasive Aspergillosis. Intens Care Med 1996; 22:Vallés J. A 7 year Study of Severe Hospital Acquired Pneumonia requiring ICU Admission. Intens Care Med 2003; 29:
5 Pulmonary Aspergillosis A Spectrum of Clinical Entities Depending on patient immune statusWith tissue invasion 1,2Acute invasive aspergillosisSubacute invasive aspergillosisChronic cavitary and fibrosing pleuropulmonary aspergillosisAcute Tracheobronchitis with tissue invasionWithout tissue invasionTracheobronchial colonizationTracheobronchitisPulmonary AspergillomaThe term invasive aspergillosis, refers to several categories of disease; the severity of disease is mainly dependent upon the host immune defence.Aspergillosis may present as an acute pneumonia, with hefty tissue invasion, leading to demise in 7 to 10 days, even when treated appropriately. However, there also exist more indolent forms of aspergillosis, that evolve over weeks and even months, and that are accompanied with less or more severe systemic and respiratory signs and symptoms.A special entity of invasive pulmonary aspergillosis is acute invasive aspergillus tracheobronchitis. This form of the disease is chararacterized by ulcerative lesions in the tracheobronchial tree, and by the formations of membranes – these membranes may ultimately obstruct the airways, leading to respiratory insufficiency; most patients have severe bronchoconstriction, and mechanical ventilation is very difficult with high ventilatory pressures.On the other end of the disease spectrum, are entities without evidence of tissue invasion: such as innocent colonization of the airways (frequently seen in COPD patients and smokers, non invasive bronchits, and the pulmonary aspergilloma, developing in a pre-existing cavity, with the development of hyphae in that cavity, but without evidence of tissue invasion.Clinical entity may change due immune defence alteration1 Denning DW.Chronic cavitary and fibrosing pulmonary and pleural aspergillosis. Clin Infect Dis 20032 Paterson DL.New clinical presentations of invasive pulmonary aspergillosis in non-conventional hosts. Clin Microbiol Infect 2004
6 IPA diagnosis in ICU patients EORTC/MSG Case Definitions 1Difficult to apply outside high risk populationsNot useful to guide therapyOne of the major problems in ICU patients, is the absence of a reliable diagnostic reference frame. One can argue that is would be feasible to use the EORTC/MSG diagnostic criteria for invasive mould infections – but in fact these guidelines are not applicable outside the severely immunocompromised population; furthermore, these guidelines should not be used to guide therapy and clinical practice – if so, antifungal treatment would be instituted late in the course of the disease, or would not even be considered.1 Ascioglu S. Defining opportunistic invasive fungal infections in immunocompromisedpatients with cancer and hematopoietic stem cell transplants. Clin Infect Dis 2002
7 Consensus Definitions Proven IPAHistopathology + cultureProbable IPA1 host + 1 microbiological +1 clinicalHost: neutropenia, fever, immunosuppressive therapy, steroids, GVHDMicrobiological:positive culture sputum, BALNon-invasive test: galactomannan, -D-glucanCT: halo, air-crescent, cavity within area of consolidationPossible IPA1 host + 1 microbiological OR 1 clinicalMore specific signs / symptomsCT: halo, air-crescent, cavityNew infiltrate + specific pulmonary: pleural rub; pleural pain; hemoptysisThe consensus definitions are well known, and are based upon host risk factors, the results of microbiological examination, and the clinical picture, including the results of medical imaging. Non-invasive markers, such as the galactomannan and glucan, and PCR, in blood or bronchial lavage fluids, can also be used to substantiate the diagnosis. Probable and possible aspergillosis are the most frequent clinical categories of diagnosis in routine practice.
8 Particular Issues in ICU patients Interpretation of Host Factors:not always clearly detectable …(combination of) underlying disease and/or critical illness induced immunosuppression with low or intermediate probability of invasive disease 1, 2Impaired phagocytic functionOrgan dysfunctions, metabolic derangementsCorticosteroids 3, 4:difficult assessment of treshold dose/duration of exposure*However, one should consider some particular issues in the critical care setting.Firstly, the interpretation of host factors is not evident in ICU patiens. These can be easily appreciated in patients referred by the hematology ward, but how should we appreciate the temporary immune deficiency, or immunoparalysis, that can occur after sepsis and during severe critical illness? This immunocompromised state is characterized by deficient phagocytosis, and both innate and acquired immune dysfunctions; a patient immune defence may be further weakenen by multiple organ dysfunction, and metabolic derangements, such as uremia, liver dysfunction, and hyperglycemiaFurthermore, corticosteroid therapy is frequently given to septic patients and in case of COPD exacerbations. It not clear at what dose this kind of treatment should be considered as a major host risk factor – it also known that hydrocortisone enhances the growth of Aspergillus fumigatus in vitro.1 Hartemink KJ. Immunoparalysis as a cause for invasive aspergillosis? Intensive CareMed 20032 Engelich G. Acquired disorders of phagocyte function complicating medical and surgical illnesses. Clin Infect Dis 20013 Lionakis M. Glucocorticoids and Invasive Fungal Infections. Lancet 2003; 362:4 Palmer LB. Corticosteroid Treatment as a Risk Factor for Invasive Aspergillosis in Patients with Lung Disease. Thorax 1991; 46: 15-20
9 Particular Issues in ICU patients Signs and symptoms difficult to appreciatecough, chest pain, pleural rub, hemoptysis, dyspneanon specificevaluation difficult or impossiblefever?clinical examination hampered by mechanical ventilationA second problematic issue is the assessment of clinical signs and symptoms; in patients that are intubated and sedated. One can not rely on fever, as a warning symptom as in the setting of neutropenia; furthermore, clinical examination is hampered by the supportive treatment patients receive on the ICU.
10 Particular Issues in ICU patients Medical Imaging:Concurrent pulmonary injury hampers interpretationresidual infiltrates, atelectasis, ARDS, …CT scan feasible in case of high-grade ventilatory and inotropic dependency?Typical lesions: Halo, Air-crescent …low incidence in non-neutropenic patientsAnother problem is the value of medical imaging. There are so many confounding factors in the interpretation of radiological data, such as residual infiltrates after bacterial pneumonia, atelectasis, pleural fluid effusion, ;Specific features such as the halo sign and the air crescent sign are infrequently seen in ICU patients, moreover it has been shown that this radiological features ar far less common in patients with other immune deficiencies than neutropenia;Greene RA. Radiologic findings in acute invasive pulmonary aspergillosis: utilityof the halo and air-crescent sign for diagnosis and treatment of invasive pulmonaryaspergillosis in high-risk patients. 13th ECCMID, 2002, Glasgow
11 Microbiological sampling … >> lower respiratory tract samplesBAL not always feasibleDirect microscopy is mandatory!*SerologyAspergillus galactomannan? **validation in neutropenic ptssensitive/significant in other patientsß-glucan: ? ***Biopsy procedures …transbronchial biopsy not possiblethoracoscopic procedure preferredcaveats:ventilator and pressor dependencycoagulation disorders …The interpretation of microbiological data is also difficult.Broncho-alveolar lavage is not always feasibleAn important point is always to require for an urgent direct microscopic examination: the demonstration of septate hyphae may be a key indicator for the diagnosis.There is a lot of experience with non-invasive diagnostics such as the galactomannan test, and the demonstration of the beta D glucan, in patients after stem cell transplantation, but the sensitivity and specificity of these test in other patient groups should be further explored.Finally, one could argue to be more aggressive in diagnostic procedures and to have a lung tissue biopsy in case of diagnostic incertitude, however, such quite invasive procedures are often not possible in patients with high grade ventilatory and inotropic support, and in the presence of coagulation abnormalities. Moreover, biopsy can be falsely negative due to sampling error, or after exposure to antifungals.* Uffredi ML. Significance of aspergillus fumigatus isolation from respiratory specimens in non-granulocytopenic patients. Eur J Clin Microbiol Infect Dis 2003* * Maertens J. Screening for circulating galactomannan as a non-invasive diagnostic tool for invasive aspergillosis in prolonged neutropenic patients and stem cell transplantation recipients. Blood 2001; 97:** *Ostrosky-Zeichner L. Multicenter clinical evaluation of the (1-3) beta-D-glucan assay as an aid in diagnosis of fungal infections in humans. Clin Infect Dis 2005; 41: 654-9
12 Invasive Aspergillosis in ICU Patients Fact or Fiction? Isolation of Aspergillus spp. in ‘immunocompetent host’ is often/always interpreted as colonization ….Assessment of clinical signifance most difficult in patient groups with intermediate risk of invasive diseaseLiterature dataVariable diagnostic criteriaWhen you have a positive culture in a patient, a major problem is to estimate the clinical significance of this finding, in patients with an intermediate or low probability of acquiring invasive pulmonary aspergillosis. Differentiating between colonization and infection is a major challenge for the clinician.When reviewing the available literature, there is also some differences in the diagnostic assessment of patients.
13 of Aspergillosis. Clin Infect Diseases 2001 In the setting of stem cell transplantation, it is quite evident to state that a positive culture is clinically relevant, because more then 60 % of these patients do have invasive disease,But the problem is an accurate interpretation of a culture in patients with intermediate risk for aspergillosis, certainly when it concerns patients with non hematological disease, such ase malnutrition, diabetes, chronic lung disease.This has been nicely demonstrated in this paper by Perfect.Perfect J. Impact of culture isolation of Aspergillus species: a hospital-based surveyof Aspergillosis. Clin Infect Diseases 2001
14 AuthorYearType of studyPatient categoryN.IncidenceMortalityLewis1985Case seriesIPA complicating influenza pneumoniaCase report and literature review6-100%Karam1986Cases seriesNon-neutropenic patients - 10 structural lung disease7 steroid treatment32Janssen JJWM1996MonocentricRetrospectiveMedical ICU pts with hematological malignancy, immunosuppression for mixed connective tissue disease, ARDS2592%PittetCOPD patients in MICUAcquisition of IPA during mechanical ventilation due to high grade airborne inoculation2Rello1998Series of COPD patients and literature review24Valles2002Two centresObservational, prospective studyHospital acquired pneumonia requiring ICI admissionAspergillus spp. identified in 17% of ptsMainly COPD pts77%Bulpa2001COPD patients admitted to ICU diagnosed with IPA23Meersseman2004Medical ICU70% cases without malignancy5 pts with IA without known predisposing condition (of whom 3 Child C cirrhosis)1075.8%91%Garnacho-Montero2005MulticentricProspective73 ICU’s in Spainpatients with LOS > 7 days201.1%80%Vandewoude2006Mixed ICU40% haematological pts833.3/1000Now, what about the available literature on invasive aspergillosis in ICU patients?This form of the disease has already been identified more than twenty years ago, as a major complication in patients with existing structural lung disease, and as a complication of influenza pneumonia, as described by Karam and Lewis in the eighties.Case series have also indicated that Aspergillus must be considered as pathogenic in patients with COPD, one should be very alert in these patients if they had exposure to corticosteroid treatment even in low doses and for short courses.In a Dutch study, ICU treatment for hematological patients with invasive aspergillosis was considered futile, because of the high mortality.Bulpa described a series of COPD patients with invasive disease, and also raised the question of therapeutic futility because of poor outcome of these patients.Finally, there are three studies in intensive care, adressing epidemiologic features of pts with IA.
15 Invasive pulmonary aspergillosis in non-immunocompromised, non-neutropenic hosts* Review of 32 casesUnderlying diseases: lung fibrosis, COPD, Influenza A, diabetes mellitus, alcoholism, ‘short’ course of steroids, …… IPA should be considered when Aspergillus spp. is isolated in resp. secretions and presence of pneumonia ….* Karam G. Invasive pulmonary aspergillosis in non-immunocompromised, non-neutropenic hosts. Reviews of infectious diseases 1986; 8:
16 COPD patients with IPA: benefits of ICU? * 23 pts, 16 proven, 7 probable (repeated isolation)recent steroid treatment, or intensification of steroid treatmentsevere bronchospasm (12/23)all required mechanical ventilationMortality 100%This slide refers to the paper of Bulpa, describing a series op 23 patients with COPD and invasive aspergillosis;All these pts developed respiratory insufficiency requiring mechanical ventilation, and all of them died.* Bulpa P. COPD patients with invasive pulmonary aspergillosis: benefits of intensive care? Intens Care Med 2001; 27: 59-67
17 Invasive pulmonary aspergillosis in COPD patients: an emerging fungal pathogen* 13 cases of IPA in COPD pts admitted to ICUbronchospasm ++steroid treatment often continued in spite of isolation of Aspergillus spp.Mortality 100% - proven IPA by autopsyIn a recent paper by Ader, the importance of Aspergillus as a lethal pathogen in COPD was highlighted; it was stressed Aspergillus isolation should be considered relevant, after steroid treatmentAn important observation in this study, and also in the previous study , is the presence of severe bronchoconstriction, impeding mechanical ventilation in these patients.* Ader F. Invasive pulmonary aspergillosis in COPD patients: an emerging fungal pathogen.Clin Microbiol Infec 2005: Jun;11:427-9.
18 Retrospective cohort study based on prospectively gathered microbiology and autopsy data – UZ KULeuven: 127/1850 ptnAn excellent study from Leuven has learned us important data about invasive aspergillosis in patients in a medical ICUIn this study, EORTC guidelines were strictly applied, and they performed autopsy in 76 patients out of 127 patients with suspicion of invasive aspergillosis.The diagnosis of invasive aspergillosis was made in 107 patients, representing an incidence of more than 5%; the majority of the patients did not suffer from hematologic disease.The mortality of more than eighty percent, and exceeded the mortality as derived from the SAPS score upon admission of these patients, indicating the serious impact of aspergillosis on patient outcome.5.8% van aantal opgenomen ptn!!! met IPAMeersseman W. Invasive Aspergillosis in Critically Ill patients without MalignancyAm J Respir Crit Care Med 2004
19 In a Spanisch multicenter study, the incidence of Invasive disease was about 1.1 % of admissions; Only 10 % of patients had neutropenia as predisposing factorCOPD was the major underlying illness in these patients, and most of them received corticosteroid treatment; Mortality was 80%
20 Clinical relevance of Aspergillus isolation from respiratory tract samples in critically ill patients. Critical Care 2006Retrospective studySole entry criterion = positive lower respiratory tract specimenAdapted criteria to discriminate colonization vs. clinical relevant ‘infection’ (i.e. : relevant to start antifungal treatment)Incidence 3.3/1000 admission
21 Adapted Diagnostic Criteria … Definite IPApositive histology (+culture) of lung tissuepositive culture from normally sterile siteProbable IPALower resp tract sample pos for AspergillusCompatible signs and symptomsAbnormal medical imaging of chestEitherhost risk factors: neutropenia, hemato-oncologic malignancy treated with cytostatics, steroid treatment > 20 mg/day, immunodeficiencyBAL:semiquantitative positive culture +/++andcytologic exam positive (branching hyhae)We performed a retrospective study in ICU patients, with as sole entry criterion a positive culture of Aspergillus in a respiratory specimen, and we used adapted criteria to discriminate colonization from infectionThe criteria were adapted, in a way that we took any evidence of pneumonia into account, and that we considered to presence of a clearly positive microscopic evidence, with septate hyphae, as an information that corroborates the clinical relevance.Vandewoude K. Clinical relevance of Aspergillus isolation from respiratory tract samples in critically ill patients. Critical Care 2006
22 We had 172 pts with a positive culture, and according to the diagnostic algoritm, we could separated two groups of patients, group of pts with IA and another considered as colonization, because of the absence of pneumonia, host risk factors, and because the positive culture was not supported with a positive direct microscopic examination.We identified 83 patients with invasive diseaseAn important fact is that we had 17 patients with suspicion of invasive aspergillosis, and that was ultimately confirmed by histologic examination; the speculation of colonization was confirmed by histology in another 9 ptsThese findings support the positive predictive value of the diagnostic algorithm
23 An important observation was that the majority of patients did have any hematological underlying disease.Underlying diseases were COPD, malnutrition, liver cirrhosis,…
24 When comparing both patient groups, we found that pts with invasive disease had a higher APACHE II score upon admission, that they experienced more hemodynamic instability and acute renal failure than pts considered colonized.An important difference between both pt groups in the outcome, with an in-hospital mortality of 77% in IA pts and 40% in colonized pts
25 Survival curves for ICU patients with IPA vs Aspergillus spp Survival curves for ICU patients with IPA vs Aspergillus spp. colonization…
26 Does Invasive Aspergillosis has an impact on ICU patient outcome? i.e.: is there an attributable mortality?Case-control study1:2 matchingMatching criteriaAPACHE II (admission)Diagnostic categoryAgeTwo cohorts of pts with same ‘expected mortality’Vandewoude K. Invasive aspergillosis in critically ill patients: attributable mortality andexcesses in length of stay and ventilator dependence. J Hosp Infection 2004
27 An important question is whether invasive aspergillosis had an impact on outcome in terms of attributable mortalityWe tried to adress this issue a matched cohort studyPts were matched upon APACHE II score, age, and upon diagnostic category upon admissionWe found that hospital mortality was higher in the patient group with invasive disease, this was not significantly different,An important observation however is that the mortality in pts with IA was clearly higher than mortality as expected upon APACHE II score, in contrast to the data for the colonized pts.We also demonstrated that the use of ICU resources as significantly higher in pts with IA, as indicated by the difference in length of stay and ventilator dependence.Vandewoude K. Invasive aspergillosis in critically ill patients: attributable mortality andexcesses in length of stay and ventilator dependence. J Hosp Infection 2004
28 Conclusion Invasive Aspergillosis in ICU patient is a Fact … Incidence …0.33 – 5.8%Depending on patient mix: MICU > SICULimited patient groups, precluding firm conclusions …Underestimated?Delayed diagnosisDiagnosis post mortem …Grim prognosisMortality exceeding 77%Observed mortality >> predicted mortalityAttributable mortality … ?In conclusion, literature data indicate that invasive aspergillosis is an emerging disease in critically ill patientsData on incidence vary considerably, and are also influenced by type of hospital and type of ICUProven IA is often an autopsy finding, indicating that diagnosis is delayed in most pts
29 ConclusionDo not discard an Aspergillus spp. positive respiratory tract specimen in critically ill patients – consider the clinical significance even in the absence of EORTC/MSG host risk factors
30 ?Epidemiology: prospective multicenter observational studies needed to estimate incidenceBiopsy if possible?Protocol based autopsy policyValidation of clinical diagnostic algorithm,Useful to guide (pre-emptive) therapyDevelopment of criteria for pre-emptive treatmentConsideration of additional host risk factors:COPD, steroid treatment, MOF, ….Explore and measure immunoparalytic stateEvaluation of non-invasive serologic markers in ICU ptsgalactomannanBeta-D-glucanPCR