Value of CT in Early Pneumonia in Immunocompromised Patients Nantaka Kiranantawat, PSU Preventative Factors Phagocyts Cellular immunity Humoral immunity Predisposing Factors Infection, Stress, Poor nutrition, Systemic illness 1 2 Immunocompromised patients Pulmonary complication: infection 75% Persistent infections during neutropenia: Mortality rate up to 100% Rosenow EC, et al. Mayo Clin Proc 1985 Heussel CP, et al. AJR 1997 3 Immunocompromised patients Invasive aspergillosis Mortality 90% : treated >10 days after clinical or radiological sign Mortality 40%: early treatment von Eiff M, et al. Ann Hematol 1995 4 Immunocompromised patients Localization of infection or microorganism Appropriate Rx Life saving Aisner J, et al. Ann Intern Med 1977 5 Fever & neutropenia >48 hr Normal HRCT Abnormal BAL CXR Abnormal Specific findings Medical Rx Fail Rx BAL Book: Imaging of Pulmonary Infection 6 Nonspecific findings HRCT Nonspecific BAL 1
CXR vs CT Value of CT 2 wk later 7 8 48%: Normal CXR, Abnormal HRCT CT show findings suggestive of pneumonia about 5 days earlier than CXR Heussel CP, et al. AJR 1997 9 Heussel CP, et al. AJR 1997 10 Value of CT Septic emboli 33% Negative CXR Heussel CP, et al. J Clin Oncol 1999 11 Kuhlman JE, et al. Radiology. 1990 12 2
Role of Imaging Identify pulmonary abnormality Location, Extension Course of pneumonia Associated complications Additional or alternative diagnosis Muller NL, et al. Imaging of Pulmonary Infections 13 Role of Imaging 14 HIV Allen CM, et al. Ann Thorac Med 2010 CT Findings CT Findings HIV Febrile neutropenia 15 Hartman TE, et al. AJR 1994 Heussel CP, et al. J Clin Oncol 1999 16 CT Findings Term Pneumonia = Pulmonary infection Pneumonitis = Pulmonary inflammation or Noninfectious pneumonia Kim EA, et al. Radiographic 2002 17 18 3
Classification Etiology: Bacteria, virus, etc. Environment: CAP, HAP Patient status Symptoms: Typical, Atypical 19 Classification Morphology Lobar pneumonia Bronchopneumonia Interstitial pneumonia Bronchiolitis Septic emboli Miliary infiltration 20 Pathophysiology Microaspiration from infected oropharyngeal secretion Aerosolization, directly inhaled Hematogenous spread 21 Classification Morphology Lobar pneumonia Bronchopneumonia Interstitial pneumonia Bronchiolitis Septic emboli Miliary infiltration 22 Ventilation 5-10 µm Mucociliary system Principle Patterns of Infection 1-2 µm Phagocytic defense 23 24 4
Lobar pneumonia Lobar Pneumonia Initial: Periphery, subpleura Muller NL, et al. Diseases of the lung: Radiologic and pathologic correlation 25 26 Ground-glass opacity PCP Dark bronchus sign: Early PCP Marchiori E, et al. AJR 2005 Yadav P, et al. Ann Thorac Med 2007 27 28 Ground-glass opacity AIDS Extensive bilateral GGO: PCP HRCT Sensitivity 100% Specificity 89% Accuracy 90% Gruden JF, et al. AJR 1997 29 Ground-glass opacity Non-AIDS CMV Drug-induced lung disease Pulmonary hemorrhage Organizing pneumonia 30 5
Bronchopneumonia Initial: Involve bronchioles 31 Tree-in-bud pattern Bronchiolitis: Inflamed bronchiolar wall and intraluminal exudate 32 Bronchopneumonia Bronchopneumonia 1 mo 33 34 Bronchopneumonia Bronchopneumonia Early bronchopneumonia: Itoh H, et al. AJR 1978 Centrilobular nodules Marchiori E, et al. AJR 2005 35 36 6
Bronchopneumonia: Aspergillosis Angioinvasive Aspergillosis Neutropenia Halo sign: Early Angioinvasive aspergillosis Marchiori E, et al. AJR 2005 Kuhlman JE, et al. Radiology 1985 Caillot D, et al. Clin Oncol 2001 37 Angioinvasive Aspergillosis Occlusion of small to medium pul. a. Infected infarct 39 Septic Emboli Septic emboli Early: Well-defined nodules with feeding vessel signs 54-67% Huang RM, et al. AJR 1989 Kuhlman JE, et al. Radiology 1990 Iwasaki Y, et al. Eur J Radiol 2001 41 38 Angioinvasive Aspergillosis Halo sign Air-crescent sign 40 Septic emboli vs lung metastases Subpleural consolidation: Lung infarct Septic emboli: 50%-73% Lung metastases: Case report Huang RM, et al. AJR 1989 Kuhlman JE, et al. Radiology 1990 Iwasaki Y, et al. Eur J Radiol 2001 Lew JW, et al. J Med Imaging Radiat Oncol. 2012 42 7
Pulmonary Host Defense 43 Immune System Phagocyte: Neutrophil, Macrophage Cell-mediated immunity: Helper T cell T cells Humoral immunity: B cell 44 B cell Killer T cell www.nobelprize.org Memory cell Plasma cell Immune System B cell 45 Killer T cell Activated Helper T cell Virus infected cell Bac. infected cell Cancer cell www.nobelprize.org Mechanism of Immune Compromise Phagocyte: Decrease amount Acute leukemia Bone marrow failure Chemotherapy 46 Bacteria, Fungi Mechanism of Immune Compromise Phagocyte: Impair function Hypoxia Alcoholism Tobacco smoke Corticosteroid therapy 47 Mechanism of Immune Compromise T Cells: CD4, CD8 Viral infection, HIV Lymphoma Advanced age 48 Malnutrition Drug, steroid All, Intracellular organism 8
Intracellular organisms TB, Nocardia, Legionella species C neoformans, H capsulatum, PCP VZV, HSV, CMV, EBV T gondii 49 Mechanism of Immune Compromise B Cells Splenectomy Chronic lymphocytic leukemia Encapsulated bacteria: S pneumoniae, H influenzae, and S aureus 50 51 52 Conclusions CXR: Recommend for all patients with suspected pulmonary infection CT/HRCT: Detection of occult lung diseases 53 54 9
Conclusions Patterns of infection Localized consolidation (Patchy, segmental, lobar) Nodules Diffuse pattern 55 10