ChestPulmonary Infections

Mohamed Zaitoun

Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals

EgyptFINR (Fellowship of Interventional

Neuroradiology)-Switzerlandzaitoun82@gmail.com

Knowing as much as possible about your enemy precedes successful battle

and learning about the disease process precedes successful management

Pulmonary Infections1-Lobar Pneumonia2-Round Pneumonia3-Bronchopneumonia4-Atypical Pneumonia5-T.B.6-Abscess7-Fungal Infections : Aspergillosis8-Parasitic Infection : Hydatid Cyst9-Infections in the Immunocompromised

1-Lobar Pneumonia :a) Definitionb) Etiologyc) Pathologyd) Clinical Picturee) Radiographic Featuresf) Complications of Pneumonia

a) Definition :-A radiological pattern associated with

homogenous fibrinosuppurative consolidation of one or more lobes of a lung in response to a bacterial pneumonia

-Also known as a non-segmental pneumonia or focal non-segmental pneumonia  

b) Etiology :-The most common cause of lobar

pneumonia is Streptococcus pneumoniae-Other causative organisms that may cause

a lobar pattern include :1-Klebsiella Pneumoniae2-Legionella Pneumophila3-Haemophilus Influenzae4-Mycobacterium Tuberculosis

c) Pathology :-Consolidation in lobar pneumonia mainly affect

the alveolar air spaces , there is characteristic relative sparing of the bronchi creating the appearance of air bronchograms

-The lobar distribution of consolidation occurs because of spread of infection across segmental boundaries , this is facilitated by the pores of Kohn and the canals of Lambert

d) Clinical Picture :1-Productive cough2-Dyspnea3-High Grade Fever4-Rigors5-Malaise6-Pleuritic pain and occasionally hemoptysis

e) Radiographic Features :1-Plain Radiography :-Homogenous opacification in a lobar pattern-The opacification can be sharply defined at the

fissures although more commonly there is segmental consolidation

-There may be presence of air bronchograms and volume loss in the affected areas

**N.B. :D.D. of acute consolidation :1-Pneumona (by fat the most common cause of acute

consolidation)2-Pulmonary hemorrhage 3-ARDS (noncardiogenic pulmonary edema seen in

critically ill patients and thought to be due to increased capillary permeability)

4-Pulmonary edema (may cause consolidation , although this is an uncommon manifestation)

D.D. of chronic consolidation :1-BAC 2-Organizing pneumonia3-Chronic eosinophilic pneumonia

2-CT :-Lobar pneumonia can have has a pattern of

focal ground-glass opacity in a lobar or segmental pattern , this is due to incomplete filling of alveoli and consolidation

-At other times there can be dense opacification of the entire lobe

f) Complications of Pneumonia :1-Pulmonary abscess2-Empyema3-Pneumatocele4-Bronchopleural fistula :-Abnormal communication between communication

between the airway & the pleural space-It is caused by rupture of the visceral pleura -By far the most common cause of BPF is surgery ,

however , other etiologies include lung abscess , empyema & trauma

-On imaging , new or increasing gas is present in a pleural effusion

5-Empyema necessitans :-Empyema necessitans is extension of an empyema to the

chest wall , most commonly secondary to T.B.

2-Round Pneumonia :a) Definitionb) Etiologyc) Clinical Pictured) Radiographic Features

a) Definition :-Is a type of pneumonia usually only seen in

pediatric patients-They are well defined rounded opacities that

represent regions of infected consolidation-The mean age of patients with round pneumonia

is 5 years and 90% of patients who present with round pneumonia are younger than twelve

b) Etiology :-The infective agent in round pneumonia is

bacterial (Streptococcus pneumoniae)

c) Clinical Picture :-Fever , sweats and cough

d) Radiographic Features :-They most commonly occur in superior

segments of lower lobes and in the majority of cases (98%) , they are solitary

-Round pneumonias are round well circumscribed parenchymal opacities , they tend to have irregular margins

-Air bronchograms are often present

3-Bronchopneumonia :a) Definitionb) Etiologyc) Clinical Pictured) Radiographic Features

a) Definition :-Is the acute inflammation of the walls of

the bronchioles-It is a type of pneumonia characterized by

multiple foci of isolated acute consolidation affecting one or more pulmonary lobules

b) Etiology :-Causative organisms include :1-Staphylococcus Aureus2-Klebsiella (often in debilitated patients and/or

alcoholics)3-E.Coli4-Pseudomonas (hospital acquired)5-Haemophilus influenza (in children ,

immunocompromised adults) -Common hospital acquired infection 

c) Clinical Picture :1-Productive cough2-Dyspnea3-Low Grade Fever4-Rigors5-Malaise6-Pleuritic pain and occasionally hemoptysis

d) Radiographic Features :1-Plain Radiography :-Bronchopneumonia is characterized by multiple

small nodular or reticunodular opacities which tend to be patchy and confluent

-This represents areas of lung where there are patches of inflammation seperated by normal lung parenchyma

-The distribution is often bilateral and asymmetric and predominantly involves the lung bases

Bronchopneumonia , confluent/merging parenchymal consolidation with diffuse bilateral pulmonary involvement (multiple areas of consolidation)

2-CT :-Multiple foci of opacity can be seen in a

lobular pattern centered at centrilobular bronchioles

-These foci of consolidation can overlap to create a larger hetrogenous confluent area of consolidation

-Exudates fill airways = no air bronchograms 

 Bilateral extended and exclusively peribronchial dense infiltrations in the right upper lobe and lower lobe as well as in the left lower lobe

Centrilobular nodules in a patient with bronchopneumonia

A: Scattered ill-defined nodules represent peribronchiolar consolidation and may contain a visible bronchiole (arrow)

B: At the lung bases , consolidated lobules surround air-filled bronchioles in several locations

4-Atypical Pneumonia :a) Definitionb) Etiologyc) Clinical Pictured) Radiographic Findings

a) Definition :-Refers to the radiological pattern

associated with patchy inflammatory changes, often confined to the pulmonary interstitium most commonly associated with atypical bacterial etiologies :

1-Mycoplasma Pneumoniae (most common)2-Chlamydophila Pneumoniae3-Legionella Pneumophila

b) Etiology :1-Mycoplasma Pneumoniae :-In pediatric populations and in young adults  2-Chlamydophila Pneumoniae :-In pediatric populations and in young adults3-Legionella Pneumophilia : (Legionnaires Disease)-Associated with immunocompromised patients and

exposure to contaminated aerosolised water (for example , from air conditioning system)

c) Clinical Picture :-The presentation of atypical pneumonia is

often similar to the presentation of more typical bacterial pneumonias

d) Radiographic Findings :1-Plain Radiography :-Because the inflammation is often limited to

the pulmonary interstitium and the interlobular septa , atypical pneumonia has the radiographic features of patchy reticular opacities , these opacities are especially seen in the perihilar lung

A 38 year old patient with Mycoplasma pneumonia , Chest radiograph shows a vague ill-defined opacity in the left lower lobe

A 40 year old patient with Chlamydia pneumonia , Chest radiograph shows multifocal patchy consolidation in the right upper , middle and lower lobes

Chlamydia pneumonia

A 53 year old patient with severe Legionellapneumonia , Chest radiograph shows dense consolidation in both lower lobes

Right hemithorax air space shadowing (Legionnaires Disease)

2-CT :-Focal ground glass opacity in a lobular distribution

, involvement is often diffuse and bilateral-There may also be evidence of pleural effusion-Bronchial wall thickening-Diffuse ground glass nodules in a centrilobular

pattern are often present although they progress to a soft tissue density as the infection and inflammation progresses  

-In Mycoplasma pneumoniae infection , airspace consolidation is common , HRCT is sensitive for nodules which are seen in 89% of patients

-In Legionella Pneumophila infection , residual scarring may persist after resolution of the infection

CT in a 45 year old patient with Chlamydia pneumonia shows a right upper lobe infiltrate

A 66 year old patient with Legionella pneumonia , CT shows dense alveolar consolidations in both lower lobe

Atypical pneumonia with widespread ill-defined centrilobular nodules with lobular ground glass (hazy) attenuation

5-T.B. :a) Locationb) Radiographic Featuresc) Differential Diagnosis

a) Location :-Primary infection can be anywhere in the

lung in children whereas there is a predilection for the upper or lower zone in adults

-Post primary infections have a strong predilection for the upper zones

-Miliary tuberculosis is evenly distributed throughout both lungs

b) Radiographic Features :1-Primary Tuberculosis2-Post Primary Pulmonary Tuberculosis3-Miliary Pulmonary Tuberculosis

1-Primary Tuberculosis :-Patchy areas or consolidation or even lobar

consolidation (lower lobe (60%) > upper lobes)-Cavitation is uncommon in primary TB -In most cases the infection becomes localized

and a caseating granuloma forms (tuberculoma) which usually eventually calcifies and is then known as a Ghon lesion 

Consolidation in primary tuberculosis, frontal chest radiograph demonstrates consolidation in the right middle lobe (straight arrow) with right hilar adenopathy (curved arrow)

T.B. with consolidation

Pulmonary parenchymal changes and lymphadenopathy in primary tuberculosis, T1+C shows a parenchymal lung cavity in the lingula (solid white arrow) with enlarged necrotic subcarinal lymph nodes (black arrows), there is accompanying collapse of the left lower lobe (open arrow)

Tuberculomas in primary tuberculosis, frontal radiograph of the right lung demonstrates well-defined nodules (arrows), findings that are consistent with tuberculomas

-The more striking finding especially in children is that of ipsilateral hilar and contiguous mediastinal (paratracheal) lymphadenopathy , usually right sided , this pattern is seen in over 90% of cases of childhood primary TB but only 10-30% of adults

-Pleural effusions are more frequent in adults-Calcification of nodes is seen in 35% of cases ,

when a calcified node and a Ghon lesion are present , the combination is known as a Ranke complex

There is a well defined round lesion in left midzone, the lesion shows flecks of calcific foci, the two small white arrows point to the well defined borders with no evidence of malignancy

Mediastinal tuberculous adenopathy, CT+C shows multiple enlarged mediastinal lymph nodes with central areas of low attenuation and peripheral enhancement (arrows)

Pleural effusion, CT+C shows a large, right-sided pleural collection, the enhancing parietal pleura is uniformly thickened (arrows)

2-Post Primary Pulmonary Tuberculosis :-Post-primary TB also known as reactivation

TB or secondary TB occurs years later frequently in the setting of a decreased immune status

-In the majority of cases , post-primary TB within the lungs develops in either :

a) Posterior segments of the upper lobesb) Superior segments of the lower lobes

-Typical appearance of post primary TB is that of patchy consolidation or poorly defined linear & nodular opacities

-Cavitation is seen in 40% of cases-Endobronchial spread along nearby airways

is a relatively common finding resulting in a relatively well-defined 2-4 mm nodules or branching lesions (tree-in-bud appearance) on CT 

Cavitary postprimary tuberculosis, frontal radiograph demonstrates a thick-walled cavity with smooth inner margins in the left upper lobe (arrow)

Cavitary postprimary tuberculosis, (a) CT+C obtained with mediastinal windowing demonstrates an enlarged mediastinal lymph node with a central area of low attenuation (arrow), (b) Axial CT scan obtained with lung windowing demonstrates ill-defined cavities (black arrows) accompanied by endobronchial spread in the right upper lobe (white arrow)

Lobar pneumonia in Mycobacterium tuberculosis infection , there is an extensive consolidation involving the right upper lobe with large areas of cavitation

Postprimary tuberculosis , A nodular area of consolidation with a small area of central cavitation is visible in the superior segment of the left lower lobe

Centrilobular nodules and rosettes in a patient with endobronchial spread of tuberculosis , multiple small nodules occurring in clusters (arrows) are common in patients with this disease , the nodules being centrilobular , spare the pleural surfaces

Tree in bud

Multiple small peribronchial nodules in the right upper lobe reflecting the endobronchial spread of the disease

3-Miliary Pulmonary Tuberculosis :-It represents hematogenous dissemination

of an uncontrolled tuberculous infection-It is seen both in primary and post-primary

tuberculosis-Miliary deposits appear as 1-3 mm diameter

nodules which are uniform in size and uniformly distributed (no calcification)

Miliary tuberculosis, frontal radiograph shows fine, discrete nodular areas of increased opacity bilaterally

Miliary tuberculosis, HRCT obtained with lung windowing demonstrates numerous fine, discrete nodules bilaterally in a random distribution

c) Differential Diagnosis :From pulmonary calcificationa) Localized :1-Tuberculosis2-Histoplasmosis3-Coccidioidmycosis4-Blastomycosis

b) Calcification in a solitary nodule :1-Hamartoma2-Lung cancer (engulfing a pre-existing calcified

granuloma , eccentric calcification)3-Solitary calcified metastasis (osteosarcoma ,

chondrosarcoma , mucinous adenocarcinoma of the colon or breast , papillary carcinoma of the thyroid)

4-Primary peripheral squamous cell or papillary adenocarcinoma

c) Diffuse or multiple calcifications :1-Infections :-T.B. (healed miliary)-Histoplasmosis-Varicella2-Chronic pulmonary venous hypertension (especially mitral

stenosis)3-Silicosis4-Metastases5-Alveolar microlithiasis6-Metastatic due to hypercalcaemia (CRF , secondary HPT

and multiple myeloma7-Lymphoma following radiotherapy

d) Interstitial ossification :1-Disseminated pulmonary ossification2-Idiopathic

6-Abscess :a) Etiology b) Clinical Picturec) Locationd) Radiographic Featurese) Differential Diagnosis

a) Etiology :1-Primary abscess :-Is one which develops as a result of primary

infection of the lung-They most commonly arise from aspiration ,

necrotizing pneumonia or chronic pneumonia e.g. pulmonary tuberculosis

-More with staphylococcus , Klebsiella-In immunocompromised more with Candida

albicans , Legionella Pneumophilia

2-Secondary abscess :-Is one which develops as a result of another

condition-Examples include :a) Bronchial obstruction : Bronchogenic carcinoma

, inhaled foreign body b) Hematogeneous spread : bacterial

endocarditis , IVDUc) Direct extension from adjacent infection :

mediastinum , subphrenic

b) Clinical Picture :1-Acute (< 6 weeks) :-Fever , cough and shortness of breath ,

peripheral abscesses may also cause pleuritic chest pain

2-Chronic (> 6 weeks) :-Symptoms are more indolent and include

weight loss and constitutional symptoms

c) Location :-Superior segment of the right lower lobe is

the most common site of infection

d) Radiographic Features :1-Plain Radiography :-The classical appearance of  a pulmonary

abscess is a cavity containing an air-fluid level-Round in shape and appear similar in both frontal

and lateral projections -3 phases :Acute : more pus less airSubacute : less pus & more airChronic : air only

Pneumonia with cavitation

Pneumonia with cavitation

2-CT :-The wall of the abscess is typically thick and the

luminal surface irregular , enhance with contrast-Abscesses vary in size and are generally rounded

in shape-May contain only fluid or have an air-fluid level-Typically there is surrounding consolidation

although with treatment the cavity will persist longer than consolidation

Non-Contrast Contrast

e) Differential Diagnosis :1-From other cavitating lesions2-From Empyema

7-Fungal Infections :-Two broad categories :a) Endemic human mycoses (prevalent

only in certain geographic areas) :1-Histoplasmosis2-Coccidioidomycosis3-Blastomycosis

b) Opportunistic mycoses (worldwide in distribution) occur primarily in immunocompromised patients (aspergillosis and cryptococcosis may also occur in immunocompetent hosts)

1-Aspergillosis2-Candidiasis3-Cryptococcosis4-Mucormycosis

-Aspergillosisa) Definitionb) Types

a) Definition :-Is a collective term used to refer to a

number of conditions caused by infection with a fungus of the Aspergillus species , usually Aspergillus Fumigatus

b) Types :-According to immune status :1-Hypersensitivity : ABPA2-Normal : Aspergilloma3-Mild Suppression : Semi-invasive4-Severe Suppression : Invasive form

1-Allergic Bronchopulmonary Aspergillosis (ABPA)

a) Etiologyb) Clinical Picturec) Radiographic Features

a) Etiology :-ABPA represents a complex hypersensitivity

reaction (type 1) to Aspergillus occurring almost exclusively in patients with asthma and occasionally cystic fibrosis

-The hypersensitivity initially causes bronchospasm and bronchial wall edema (IgE mediated) , ultimately there is bronchial wall damage , bronchiectasis and pulmonary fibrosis

 

b) Clinical Picture :-Patients have atopic symptoms (especially

asthma) and present with recurrent chest infection

-They may expectorate orange-coloured mucous plug

c) Radiographic Features :1-Plain Radiography :Early in the disease chest x-rays will appear

normal or only demonstrate changes of asthma-Transient patchy areas of consolidation may be

evident representing eosinophilic pneumonia-Eventually bronchiectasis may be evident-Mucoid impaction in dilated bronchi can appear

mass-like or sausage shaped or branching opacities

Right lower and right middle lobe nodular infiltrations , minimal involvement is also present in the left lower lobe

Glove finger shadow (arrow) and nodular opacities in the right middle third

Glove finger sign , finger like projections from hilum from bronchial mucoid impaction

Typical finger-in-glove appearance of mucoid impaction

2-CT :-Fleeting pulmonary alveolar opacities (common

manifestation)-Central upper lobe saccular bronchiectasis

(hallmark)-Mucus plugging (finger in glove appearance) and

bronchial wall thickening (common)-Chronic disease may progress to pulmonary

fibrosis predominantly in upper lobe (end stage)-Cavitation , 10%

Areas of tubular (A, arrows) and cystic ( A, arrowhead) bronchiectasis predominantly in the upper lobes and bilateral mucous plugging (B, arrows) 

Central bronchiectasis and bilateral signet ring sign

Fibrosis in the right apex and a noncalcified 2 cm solid density in the apical posterior segment of the left lobe

Bronchiectasis and peribronchial thickening

2-Aspergilloma :a) Definitionb) Clinical Picturec) Locationd) Radiographic Features

a) Definition :-Mass like fungus balls that are typically composed

of Aspergillus fumigatus-Aspergillomas occur in patients with normal

immunity but structurally abnormal lungs with pre-existing cavities such as :

1-T.B.2-Sarcoidosis3-Bronchiectasis4-Other pulmonary cavities (bronchogenic cyst ,

pulmonary sequestration)

b) Clinical Picture :-Most aspergillomas are asymptomatic-Occasionally due to surrounding reactive

vascular granulation tissue , hemoptysis may be present

c) Location :-Aspergillomas typically occur in the cavities

of post-primary pulmonary tuberculosis Therefore they most frequently are found in the posterior segments of the upper lobes and the superior segments of the lower lobes

d) Radiographic Features :1-Plain Radiography :-Rounded or ovoid soft tissue attenuating

masses located in a surrounding cavity and outlined by a crescent of air

-Altering the position of the patient usually demonstrates that the mass is mobile thus confirming the diagnosis

2-CT :-Well-formed cavity with a central soft tissue

attenuating rounded mass surrounded by an air crescent sign or a Monod sign

-Small area of consolidation around cavity is typical

-Adjacent pleural thickening common

3-Semi-Invasive Aspergillosis :a) Definitionb) Radiographic Features

a) Definition :-This form of aspergillosis occurs in mildly

immunocompromised patients and has a pathophysiology similar to that of invasive aspergillosis except that the disease progresses more chronically over months

-Mortality : 30%-Risk factors : Diabetes , alcoholism ,

pneumoconioses , malnutrition and COPD

b) Radiographic Features :-Appearance similar to that of invasive

aspergillosis-Cavitation occurs at 6 months after infection

Bilateral rounded areas of consolidation with associated cavitation in both upper lobes

4-Invasive Aspergillosis :a) Definitionb) Radiographic Features

a) Definition :-High mortality (70%-90%) and occurs

mainly in severely immunocompromised patients (bone marrow transplants & leukemia)

-The infection starts with endobronchial fungal proliferation and then leads to vascular invasion with thrombosis and infarction of lung (angioinvasive infection)

b) Radiographic Features :1-Plain Radiography :-Typical appearances are those of solitary

or multiple pulmonary nodules-Wedge-like areas of ill-defined opacity may also

be seen most likely representing infarcts due to invasion of proximal pulmonary vessels

-An air crescent may be visible when recovery is beginning although it is seen earlier on CT

Bilateral pulmonary infiltrates (right > left) with ill-defined cavities showing the crescent sign

Areas of cavitation seen within right middle lobe infiltrate

2-CT :-Solitary or multiple pulmonary nodules-A halo of hemorrhage may be seen around the nodule

as a result of invasion into pulmonary vessels and is seen as an area of ground glass opacity

-Peripheral wedge-like areas of consolidation representing hemorrhagic infarcts

-Within 2 weeks , 50% of nodules undergo cavitation which results in the air crescent sign , the appearance of the air crescent sign indicates the recovery phase (increased granulocytic response)

Widespread ground glass opacities

Cavitary lesions with crescent sign within areas of consolidation in the right lung

Multiple thick walled cavitary pulmonary nodules

Recovering Invasive Aspergillosis

8-Parasitic Infection : Hydatid Cysta) incidenceb) Location c) Radiographic Features

a) Incidence :The lung is the second most common site of

involvement with echinococcosis granulosus in adults after the liver

b) Location :-Predominantly in lower lobes , unilateral or

bilateral

c) Radiographic Features :1-Uncomplicated Cysts :-Multiple or solitary cystic lesion (most

common) , water density-Diameter of 1-20 cm-Round or oval mass with well-defined

borders-Enhancement after contrast injection-Hypodense content relative to the capsule

a) Posteroanterior and b) lateral chest radiography showing well-defined rounded opacities in the right lung of a patient with unruptured cystic echinococcosis

Fluid containing giant cyst measuring 14.4 × 9.3 cm (white arrows) with a thick-enhancing wall (1.29 cm), (red arrow)

2-Complicated Cysts :-Meniscus sign or air crescent sign (rupture between the

layers of the cyst)-Cumbo sign or onion peel sign (air lining between the

endocyst and pericyst has the appearance of an onion peel)

-Water-lily sign (Rupture in a bronchus = wavy fluid level) -Serpent sign (internal rupture of the cyst with collapse of

membranes of parasite into the cyst )-Rupture in a pleura = hydropneumothorax-Consolidation adjacent to the cyst (ruptured cyst)

The perivesicular air meniscus between the host adventitia and the parasitic endocyst (the so-called "sign of detachment") (1) is clearly seen, as is a "cyst within a cyst" or "sign of the double arch“ , Cumbo sign (2). The irregular wavy nature of the fluid level produced by the collapsed hydatid membranes floating on top of the residual hydatid fluid produces the pathognomonic "floating water lily sign" or "sign of the camalote" (3)

Air meniscus in the superior aspect of the lesion as a result of the enlarging cyst communicating with an adjacent bronchiole

Crescent sign (arrow in C)

Chest radiography showing a crescent sign (arrows) in a patient with ruptured cystic hydatidosis 

Water Lilly

Water Lily Sign

Water Lilly sign

Water Lilly sign

Water Lilly sign

a) Posteroanterior and b) lateral chest radiography showing a hydropneumothorax in a patient with ruptured cystic hydatidosis with discharge of contents into the pleural space

Ruptured hydatid cyst : floated membrane within the cyst (serpent signs) and pulmonary consolidation adjacent to the cyst

9-Infections in the Immunocompromised :-50% of all AIDS patients have pulmonary

manifestations of infection or tumor-A normal CXR does not exclude the diagnosis of

PCP-CMV is common at autopsy but does not cause

significant morbidity or mortality; CMV antibody titers are present in virtually all patients with AIDS

-Use of chest CT in AIDS patients :*Symptomatic patient with normal CXR; however,

patients will commonly first undergo induced sputum or bronchoscopy or be put on empirical treatment for PCP

*To clarify confusing CXR *Work-up of focal opacities, adenopathy, nodules

1-Spectrum of Chest manifestations2-PCP Infection3-Mycobacterial Infection4-Fungal Infections5-Kaposi Sarcoma6-AIDS-Related Lymphoma7-Lymphoid Interstitial Pneumonia (LIP)

1-Spectrum of Chest manifestations :a) Nodulesb) Large Opacityc) Lymphadenopathyd) Pleural effusion

a) Nodules :1-Kaposi sarcoma (usually associated with

skin lesions)2-Septic infarcts (rapid size increase)3-Fungal: Cryptococcus, Aspergillus

b) Large Opacity : (consolidation & mass)1-Hemorrhage2-NHL3-Pneumonia4-Linear or interstitial opacities5-PCP6-Atypical mycobacteria7-Kaposi sarcoma

c) Lymphadenopathy :1-Mycobacterial infections2-Kaposi sarcoma3-Lymphoma4-Reactive hyperplasia, rare in thorax

d) Pleural Effusion :1-Kaposi sarcoma2-Mycobacterial, fungal infection3-Pyogenic empyema

2-PCP Infection : (Pneumocystits Carinii Pneumonia)

-Interstitial pattern, 80% :CXR: bilateral perihilar or diffuseHRCT: ground-glass appearance predominantly in

upper lobe with cysts-Progression to diffuse consolidation within days-Normal CXR in the presence of pulmonary PCP

infection, 10%-Multiple upper lobe air-filled cysts or

pneumatoceles (10%) causing : Pneumothorax & Bronchopleural fistulas

38-year-old man with AIDS and Pneumocystis jiroveci pneumonia, HRCT image shows patchy but extensive ground-glass opacity throughout both lungs

58-year-old woman with Pneumocystis jiroveci pneumonia and dermatomyositis and undergoing immunosuppressive therapy, transverse (A) and coronal (B) high-resolution CT images show patchy ground-glass opacity with mid and lower lung predominance

29-year-old man with AIDS and Pneumocystis jiroveci pneumonia, ransverse (A) and coronal (B) high-resolution CT images show patchy ground-glass opacity and smooth interlobular septal thickening (arrows)

37-year-old man with AIDS and Pneumocystis jiroveci pneumonia, HRCT shows numerous thin-walled cysts (arrows) on background of patchy ground-glass opacity, mild focal consolidation (arrowhead) is present in left lower lobe

37-year-old man with AIDS and Pneumocystis jiroveci pneumonia. High-resolution CT image shows multiple cysts of varying size, scattered nodules (arrowheads), and mild patchy ground-glass opacity, left pneumothorax (arrow) has developed

3-Mycobacterial Infection :-M. tuberculosis > M. avium-intracellulare (this pathogen

usually causes extrathoracic disease), CD4 cell count usually <50 cells/mm

-Hilar and mediastinal adenopathy common, necrotic lymph nodes (TB) have a low attenuation center and only rim enhance with contrast, adenopathy in Kaposi sarcoma or lymphoma enhances uniformly

-Pleural effusion-Other findings are similar to non-AIDS TB (upper lobe

consolidations, cavitations)

Mediastinal tuberculous adenopathy, CT+C shows multiple enlarged mediastinal lymph nodes with central areas of low attenuation and peripheral enhancement (arrows)

Pleural effusion, CT+C shows a large, right-sided pleural collection, the enhancing parietal pleura is uniformly thickened (arrows)

Consolidation in primary tuberculosis, frontal chest radiograph demonstrates consolidation in the right middle lobe (straight arrow) with right hilar adenopathy (curved arrow)

Cavitary postprimary tuberculosis, frontal radiograph demonstrates a thick-walled cavity with smooth inner margins in the left upper lobe (arrow)

4-Fungal Infections :-Fungal infections in AIDS are uncommon (<5% of

patients)-Cryptococcosis (most common); 90% have CNS

involvement-Histoplasmosis: nodular or miliary pattern most

common; 35% have normal CXR-Coccidioidomycosis: diffuse interstitial pattern,

thin-walled cavities

5-Kaposi Sarcoma :-The most common tumors in AIDS are :a) Kaposi sarcoma (15% of patients); incidence declining; M:F

= 50:1b) Lymphoma (<5% of patients)-Pulmonary manifestations of Kaposi sarcoma (almost always

preceded by cutaneous/visceral involvement) :1-Nodules :-1 to 3 cm-Single or multiple-Virtually always associated with skin lesions2-Coarse linear opacities emanating from hilum3-Pleural effusions (serosanguineous), 40%4-Adenopathy5-Lymphangitic tumor spread

 

Pulmonary KS in a 45-year-old man, (a) Chest radiograph shows multiple bilateral ill-defined nodules (arrowheads indicate nodules on the right side), two indistinct masses (arrows) are identified in the left hemithorax, (b) HRCT shows two irregular flame-shaped nodules (white arrows) in the right apex and an ill-defined mass (black arrows) in the left apex, the diagnosis was confirmed with fine-needle aspiration biopsy of the left upper lobe mass

Thoracic AIDS-related KS in a 45-year-old man, (a) Chest radiograph demonstrates multiple bilateral 3–5-mm micronodules in a peribronchovascular distribution, (b) High-resolution lung CT scan shows innumerable bilateral, poorly defined peribronchovascular micronodules, some of which exhibit coalescence, (c) CT scan (soft-tissue windowing) depicts enlarged lymph nodes in the axillae and mediastinum (thin arrows), note also the bilateral pleural fluid collections as well as some nodularity (thick arrows), skin compromise is also identified in the left hemithorax (arrowhead)

Disseminated AIDS-related KS in a 36-year-old man with thoracic involvement, (a) Chest radiograph shows ill-defined nodular confluent opacities in the left upper lobe, (b) Chest CT scan demonstrates multiple nodules around the bronchus for the apicoposterior segment of the left upper lobe (black arrow), other small nodules are also identified in the posterior segment of the right upper lobe (white arrows), (c) CT scan (soft-tissue windowing) demonstrates enlarged enhancing lymph nodes (arrows) in the left hilum and occupying the azygoesophageal recess

KS in a 40-year-old man with AIDS who presented with weight loss and fever, abdominal CT scan shows a pleural mass (black arrow) with soft-tissue enhancement in the left pleural space associated with bilateral pleural fluid (white arrows), imaging-guided biopsy revealed KS

6-AIDS-Related Lymphoma :-Non-Hodgkin's lymphoma (usually aggressive B-cell

type) > Hodgkin's lymphoma-Poor prognosis-Spectrum includes :1-Solitary or multiple pulmonary masses, air

bronchogram, 25%2-AIDS-related lymphoma is typically an extranodal

disease (CNS, GI tract, liver, bone marrow): adenopathy not very prominent

3-Pleural effusions are common

7-Lymphoid Interstitial Pneumonia (LIP) :-See Diffuse Lung Lesions

LIP in a 47-year-old woman, high-resolution CT image shows diffuse ground-glass opacity (arrow) with multiple perivascular cysts (arrowheads) and reticular abnormalities (*)