Download Nocardia

K.Gohari Moghadam MD.
Azar 1394
 1- Increased survival of patients by intense
immunosuppression .
 2-The lung is the most frequently affected
organ .

3- Emergence of resistant microorganisms

4- Unusual and subtle clinical manifestations
( absence of fever , sputum )
More complicated clinical course.
5- The changes in immunosuppression
regimens , prophylactic regimens and
increased graft survival altogether alter the
typical clinical presentation .
6- Unusual and subtle radiography
( Normal CXR in neutropenics)
7-Radiologic abnormalities in the
background of systemic disease ( SLE ,
scleroderma )
8- Progressive and fatal nature of infection
in the context of decreased immunity.
9-Need for prompt diagnosis , decision
( often invasive ) and treatment .
10- Concomitant pulmonary diseases , which
are not infectious ( edema , atelectasis ,
emboli , drug toxicity, radiation )
 11-Presence of simultaneous and sequential
infections ( CMV,Pneumocystis ,Aspergillus
and G- bacteria ) .
 12-Limitation of diagnostic assays and
procedures
13- Significant adverse reactions to
antimicrobial regimens .

 14-Invasive Fungal infections are increased in
spite of prophylaxis and treatment during recent
years .
Risk Factors
( Net state of immunosuppression )
Overally , neutropenia is the most important
risk factor .
Anti TNF ( TB , Fungi)
Corticosteroid ( Nocardia , Pneumocystis ,TB)
Conditioning and engraftment ( CMV ,
pneumocystis ,Aspergillus , Nocardia , TB
,Bacterial )
HSCT (Aspergillus )
SOT ( Candida )
T cell depleting Abs ( CMV , EBV , HIV )
Epidemiologic
Exposure
Net state of
immuno
suppression
Dominant
Clinical
presentation
Epidemiologic Exposure
 Donor-derived ( CMV , TB , Toxoplasma )
 Recipient –derived ( TB , CMV , strongyloides )
 Nosocomial : gram negative , S.aureus , HSV , HBV,
HCV , HIV .
 Community acquired ( Aspergillus , Nocardia )
Role of CT scan
 In patients with febrile neutropenia ,
 Fever and normal CXR with respiratory symptoms
 Greater confidence in DDx
 Improve sampling by precise localization
Pyogenic bacteria
 DM : S.aureus , S.pneumoniae, Klebsiella in the form
of increased frequency and severity
 ESRD : Mortality rates from pulmonary infections are
higher by a factor of # 20 .
A case of SLE following
splenectomy
TB
 Lower Lobe TB
 Mediastinal LAP
 Extrapulmonary involvement
 Less cavitation
 Higher probability of smear negative
samples
 A case of Systemic Sclerosis and LLL cavity ( TB)
Miliary TB
Nocardia
 Nocardia has two characteristics:
1- The ability of invasion to any organ ( as TB )
2-The tendency to relapse or progression despite
appropriate treatment ( as Aspergillus )
 Lungs are affected in 2/3 of cases.
 Risk factors are: BMT,steroid use ,CD4< 100 ,DM ,
Malignancies ,Chronic lung disease ,alcoholism .
 Lung involvement is usually primary rather than metastatic
from skin .
Has acute , subacute or chronic presentation .
Different radiographic patterns.
About 45 days to 1 year delay from clinical onset to
diagnosis .
Recovery of Nocardia from lung samples is
diagnostic .
Nocardia in a case of behcet
Nocardia in a WG
Aspergillus
Prolonged and severe neutropenia is the most
important risk factor .
HSCT ( severity of GVHD ),SOT ( specially in lung
transplantation )
Chronic glucocorticoid use
Advanced AIDS
Chronic Granulomatous disease
Uncommon in HIV
 Hemoptysis ,dyspnea, Pleuritic chest pain in DD of
PTE .
 Fever ,which is unresponsive to broad spectrum
antibiotics and even amphotericin is suggestive of
Aspergillus infection.
Important Radiologic patterns of
Aspergillus
 1-Halo sign is suggestive . (pseudomonas and in
Zygomycosis , neoplasms , Kaposi , WG),
2-Cavitation , crescent sign
3-Wedge shaped peripheral consolidation .
 The best method of diagnosis is smear and culture
from lung tissue .
 Positive smear and specially culture from BAL
specimen in a relevant clinical and radiographic
pattern
 Galactomannan is validated for serum samples .(
about 90% sp.,Se, NPV) . BAL GM has more yield.
 GM in circulation is transient , so it is advised to
measure twice a week .
Bronchial biopsy. Leukemia
and….
© A.J.France 2010
Zygomycosis ( Mucormycosis )
Risk factors include : DM ,Glucocorticoid use
,Leukemia,HSCT,SOT,deferroxamine use ,Iron
overload ,AIDS,IV users ,Malnutrition .
In comparison to Aspergillus :
Numbers of nodules >10 in CT scan ,
Presence of sinusitis ,
Pleural effusion and
Previous prophylaxis with voriconazole are in a
favor of diagnosis of mucormycosis .
The most common cause of reverse halo sign is
mucor infection .
Pneumocystis ( HIV )
Indolent course
Diffuse interstitial-alveolar pattern in CXR
Patchy or nodular GGO in HRCT
HRCT has 100% sensitivity
Associated with CD4< 200 as an AIDS defining
illness
Induced sputum is more diagnostic in HIVs when
compared with non HIVs,who have often low
burden of organism .
 Giemsa
 Gomori
 PCR ( For Non HIV ) (low burden of microorganism )
 Culture : not
 BAL : 50%-90%
Pneumocystis pneumonia.
Lung biopsy, silver stain.
© A.J.France 2010
Pneumocystis ( Non HIV )
Steroid use Hx specially in tapering or increasing
period
Transplantation , Sirolimus
Hematologic malignancies
Progressive course with abrupt respiratory failure
Diffuse reticular pattern in CXR and GGO in HRCT
Sirolimus cause a noninfectious idiosyncratic
pneumonitis mimicing PCP pneumonia .
Radiographic patterns
 Early interstitial
 GGO
 Perhilar or central opacities
 Suspicion of PCP should increase when pneumothorax
is obsereved in a HIV patient .
 Adenopathy and pleural effusion are uncommon .
 A negative HRCT may allow exclusion of PCP.
CMV
CMV infection vs. CMV disease
CMV infection is defined by : Either finding of virus
by culture ,molecular technique or serology
CMV disease is defined by : symptoms and signs
such as fever , leukopenia , liver , lung ,pancreas
,colon ,meningoencephalitis , chorioretinitis (
AIDS )
 CMV DNA by PCR > 500 copies per microgram
DNA in peripheral blood is defined as disease .
 Cytopathic effect in BAL cytology , PP65 quantity
(with limitation of WBC<1000) and TBLB .
CMV pneumonia in a RTx
CMV Pneumonia 1 30/9/91
CMV pneumonia 2/10/91