Unresolved pulmonary infections..radiological highlights

Unresolved pulmonary infections...radiological

highlights

Dr/Ahmed Bahnassy

Consultant Radiologist

MBCHB-MSc-FRCR

• Success is to be measured not so much by the position that one has reached in life... as by the obstacles which he has overcome while trying to succeed.

• - Booker T. Washington

Unresolved pneumonia

failure of pneumonia to resolve can be due to:

1.virulent ,or undiagnosed organism.2.underlying disease process or pathology.3.Occurence of complications.4.Other diagnosis than infection.

roles of Radiology

• Diagnose infection…• Detection of Etiology…• Follow up for response to treatment.• Monitoring of complications.

I-Evaluation of offending organism

Radiological Patterns• Pathologically pulmonary infections can be

divided into infections involving :central air ways ,small air ways and pulmonary parenchyma.

• Pneumonia is subdivided into :lobar ,broncho and interstitial pneumonia .

• Lung abscess is an additional pattern seen with lobar or bronchopneumonia

where the infection?

I- Bronchiolitis• Inflammation of small air

ways (membranous and respiratory bronchioles).

• Caused by viruses (RSV is most common).

• Acute bronchiolitis ,causd by adenovirus ,may cause constrictive bronchiolitis ,chronic bronchiolitis, bronchiectasis. .forming a syndrome called Mc leod syndrome.

Obstructive viral pneumonia –RSV (note air trapping )

Swyer-James Syndrome

Laryngeotracheobronchitis..Croup (church steeple sign)

II-Lobar pneumonia.• Caused by streptococcal

or Klebsiella pneumoniae .

• Begins by a peripheral opacity that evolves into a confluent ,consolidation.

• Expansion of the lobe can cause bulging fissure ( associated with Klebsiella pneumoniae )

Bacterial lobar pneumonia

Bulging fissure sign

III-Bronchopneumonia• Begins with infection of air

way mucosa ,then extends into adjacent alveoli .

• Present as ill defined air space nodules or patchy areas of consolidation.

• Caused by virulent organism …( Staph aureus ,or G –ve organisms )

• Can develop abscess.• Result in scarring .

Broncho -pneumonia

Bronchopneumonia - HRCT

IV-Lung Abscess• Localized infection that

undergoes tissue destruction and necrosis.

• Cavitations and air fluid level can occur due to communication with tracheobronchial tree .

• Caused by mixed anaerobic infections , S.aureus ,and Pseudomonas aeruginosa.

• Multiple abscesses may result from septic emboli .

Lung abscess

what is the organism?

I -Nocardia Asteroids

• Organisms live in soil.

• In immunodeficient state.

• Cavitation may occur .

• Pleural effusion in 50% .

II- Pneumococcal Pneumonia

• Most common G +ve.• Air space

consolidation with air bronchogram.

• Multifocal consistent with bronchopneumonia.

• Pleural effusion in < 50%.

III- Staph Pneumonia• Common cause of

nosocomial infection.• Usually

bronchopneumonia with patchy lower lobe consolidation.

• Cavitation frequent.• Pnematoceles may be

seen.• Septic emboli.• Pleural effusion in

50%,Empyema may result .

IV-Infective endocarditis with septic emboli

V-Tuberculosis :Primary T.B.• Ghon focus-Ranke

Complex-air space consolidation-LNs common in children-P. effusion may be seen without lung disease .

Necrotic LN-TB infection

TB variable examples

Cavitating pneumonia TB

Post Primary TB- cavitating lesion

• Cavitations in 40%.• Pleural effusion and

LNs are uncommon.

Miliary TB• Miliary spread refers

to numerous ,well defined nodules,1-2 mm in size, diffusely distributed throughout the lung.

VI-Mycobacterium Avium Complex

• I-Resembles TB, occurs in old men with COPD or mild immunodepression.

• II-Bronchiectasis and nodules in lingula or middle lobe.

• III-GG opacity and small nodules with hypersensitivity pneumonitis .

Lady Windermere syndrome

Mycobacterium Avium Complex-CT

• Bronchiectasis and centrilobular nodules .

VII- Histoplasmosis• Patchy pneumonia-

Histoplasmoma with Bull’s eye calcification. fibrosing mediastinitis-miliary spread)

VIII- Coccidioidomycosis

• May present as consolidation +/- LN; nodules +/- cavitate ;or miliary pattern often with LN

Coccidioidomycosis -Disseminated

• Miliary pattern

IX- Blastomycosis

X- Cryptococcosis (in AIDS )

XI- Aspegillosis :Invasive Aspergillosis -Halo Sign

• Neutropenia present.

• Patchy consolidations with halo sign in Angio-invasive form

• Centrilobular nodules ,tree in bud in airway invasive form.

Invasive Aspergillosis

• Air way invasive.

• Ill defined nodules.

Angio -invasive Aspergillosis with air crescent sign of Lung Ball.

Semi-Invasive Aspegillosis• Mild immunocompromise

(TB, diabetes,mild corticosteroid use )

• Consolidation,• cavitation ,• Pleural thickening ,• +/-mass within the cavity )

Aspergilloma

• Saprophytic infection with underlying structural lung disease.

• Normal immunity.• Haemoptysis may be life

threatening.

XII- Pneumocystis jiroveci (carinii)

Pneumocystis

• Associated with AIDS ,LowCD4 cell count.

• Perihilar GG opacity,consolidation,pneumatoceles,

• pneumothorax,

XIII- Mycoplasma Pneumonia

• Community acquired pneumonia.

• Patchy consolidations or GG opacities.

• Effusion in 20%.• LN uncommon

XIV -Amebic Pneumonia

• Extension from amebic liver abscess .

II-Evaluating routes of infection

• Air borne.• Septic embolization.• Extension from neck.• Extension from liver.

Blood borne ..septic embolicommon causes?

by extension mediastinitis

Danger Space• Danger Space

– Anterior border is alar layer of deep fascia

– Posterior border is prevertebral layer

– Extends from skull base to diaphragm and is so named because it contains loose areolar tissue and offers little resistance to the spread of infection.

• Necrotizing MediastinitisA- MDCT of the neck shows two large fluid collections containing gas in both the submandibular spaces (arrows).(B) At the level of the hyoid bone, a large fluid collection is seen in the visceral space (C) Large fluid collection in the visceral space (D) The fluid collection spreads to the anterior mediastinum (E) Sagittal multiplanar reformatted CT image shows spread of descending necrotizing mediastinitis

contiguous infection

• Thoraco-hepatic amebiasis

Take home message..Do ultrasound

nature of effusion

presence of pneumonia

liver evaluation

III-Evaluation of Complications

• Empyema.• Pulmonary

abscess.• Bronchopleural

fistula.• Septic

embolization.

Empyema after staph pneumonia

Empyema necessitans

Bronchopleral fistula after staph pneumonia

Retropharyngeal cellulitis/abscess

Pulmonary abscess

IV-Evauating recurrent/chronic pulmonary problems in pediatrics

Mechanism Causes

1. Aspiration CNS malformation-cerebral tumors-Tracheo-esophageal fistula-Reflux

2.Anomaly Congenital lobar emphysema-Sequestration-Tracheobronchial tree anomalies(tracheal bronchus-stenosis-atresia)-bronchogenic cyst.

3.Allergy. Astham- Loeffler pneumonia-allergic alveolitis

4.Systemic disease. Cystic fibrosis

5.Immunodeficiency. Prematurity-AIDS-Neutropenia

6.Physical agents. Foreign body-Drugs-radiation-Bronchopulmonary dysplasia

7.Neoplasm. Leukemia-Lymphoma-Histiocytosis

8.CVS Left to right shunt -PA stenosis-vascular ring

9.specific Infections. TB-Mycoplasma-Bronchiectasis

10.Miscellaneous Interstitial Pneumonia-Collagen vascular disease-Alveolar proteinosis-sarcoidosis.

special problem

Role of Radiology • The role of radiology is 3 folds :• 1 .Evaluate the present X-ray.• The presence and distribution of opacities,• Pleural involvement ,Lymph nodal swellings ,pulmonary vascularity ,soft

tissue involvement , bony structures .• 2.Review of previous films.• Are the lesion stable in the same location (Sequestration ?)• Are they present always in upper lobe (aspiration ? )• Are they changing in location (Immunodeficiency ?)• 3.Perform esophagogram.• Reflux of gastric contents.• Abnormal peristalsis.• Compression of esophagus by a mass ,vascular ring.• Tracheo-esophageal fistula.• Hiatal Hernia

Recurrent right basal consolidation

• Posteroanterior (top, A) and lateral (bottom, B) chest

• radiographs demonstrate an area of ill-defined consolidation

• involving the medial segment of the right lower lobe.

Lung sequestrationFigure 2. Axial CT images through the

area of apparentconsolidation during the administration

of IV contrast show amass with inhomogenous

enhancement involving the medialaspect of the right lower lobe. There are

focal areas of low densityin keeping with necrotic regions within

the mass. There are no airbronchograms or cavitations within the

mass. A vessel is clearlyseen to arise from the anterior aspect of

the aorta (curved arrow;top, A), running laterally to the right, to

enter the mass

Bronchopulmonary sequestration

Di-George syndrome

absent thymushypocalcaemiachronic /recurrent chest infection

Cystic fibrosis

Immunodeficieny syndromes

Bronchiectasis

HRCT

V-Pulmonary opacities..That are NOT infection

Causes of consolidations

Pulmonary lymphoma

Lung adenocarcinoma

Lung adenocarcinoma with aerogenic spread

Wegener granulomatosis

Wegener cavitating nodules

Cavitating consolidations

Sarcoidosis

Eosinophilic pneumoniaacute

chronic

Summary

• Evaluate offending organism.• Think of other routes of infection.• Look for underlying disease or pathology.• Evaluate occurence of complications.• Turn to other diagnosis.

• Don't judge each day by the harvest you reap, but by the seeds you plant.

• - Robert Louis Stevenson