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