empyema: an uncommon complication of common...

Empyema: An Uncommon Complication of Common Pneumonia

Heather Hsu, HMS IIIGillian Lieberman, MD

March 2011Heather Hsu, HMS IIIGillian Lieberman, MD

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Overview

Heather Hsu, HMS IIIGillian Lieberman, MD

• Patient presentation– History of present illness and other relevant information– Menu of appropriate radiologic tests and their indications– Review of lung anatomy on chest x-ray– Overview of our patient’s radiographic findings– Differential diagnosis

• A complication of the diagnosis– Definition and epidemiology– Appearance on imaging – Companion patient images– Management overview

• Update on our patient’s clinical course• Summary

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Our Patient: History of Present Illness at First Presentation

• CC: left-sided chest/shoulder pain and dyspnea

• HPI: 70-year-old woman presents with 2 days of increasing, constant, non-radiating left- sided chest and shoulder pain and 1 day of increasing dyspnea and productive cough.

• PMH: type 2 DM, HTN, hypothyroid, chronic pain, hyperlipidemia, breast CA (1989, s/p mastectomy), thyroid CA (2005, s/p thyroidectomy and I-125)

Heather Hsu, HMS IIIGillian Lieberman, MD

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Our Patient: First Presentation Vital Signs, Physical Exam, and Labs

• Vitals: T 99.6, HR 127, BP 134/70, RR 16, O2 sat 98% RA

• Physical Exam: crackles in left lung base, pain with movement of left shoulder

• Labs: WBC 13 (90% PMNs)

Heather Hsu, HMS IIIGillian Lieberman, MD

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At this point, acute respiratory illness is a likely etiology for our patient’s presentation.

However, the differential diagnosis remains broad.

We will now consider the use of imagingto narrow this differential.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Menu of Radiologic Tests for Adults with Acute Respiratory Illness

• Chest X-ray (CXR)• CT chest

Heather Hsu, HMS IIIGillian Lieberman, MD

www.acr.org; Mandell, et al., Clin Infect Dis 2007

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Indications for Imaging in Adults with Acute Respiratory Illness: Chest X-Ray

• Chest X-ray– Indicated for evaluation of acute respiratory illness

in patients with the following characteristics:• Age >40 years• Hemoptysis• Dementia• Comorbidities (e.g., CAD, CHF, etc.)• Associated abnormalities (e.g., hypoxia, leukocytosis)• Clinical suspicion of pneumonia

• Chest CT

Heather Hsu, HMS IIIGillian Lieberman, MD

www.acr.org; Mandell, et al., Clin Infect Dis 2007

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Indications for Imaging in Adults with Acute Respiratory Illness: Chest CT

• Chest X-ray• Chest CT

– Indicated for evaluation of:• Abnormalities seen on plain x-ray• Recurrent or persistent pneumonia• Suspected pleural abnormality• Suspected lung abscess• Pulmonary embolism• Airway patency• Guidance for thoracentesis when u/s is not sufficient

– Depending on the goal of the study, it may be performed with and/or without contrast

Heather Hsu, HMS IIIGillian Lieberman, MD

www.acr.org; Mandell, et al., Clin Infect Dis 2007

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Given this menu of potential tests, their indications, and our patient’s clinical

presentation, a chest x-ray was obtained.

Before we examine our patient’s current chest x-ray, we will review some basic anatomy

using prior films.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Review of Lung Anatomy on CXR

Heather Hsu, HMS IIIGillian Lieberman, MD

Our patient: Prior PA CXR Prior lateral CXR

BIDMC, PACS

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Anatomy Review: Right Lung Fissures

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

Right major fissure

Minor fissureMinor fissure

BIDMC, PACS

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Anatomy Review: Right Upper Lobe

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

RUL RUL

BIDMC, PACS

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Anatomy Review: Right Middle Lobe

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

RML RML

“Silhouette sign”: On the PA film, an opacity in the right middle lobe may obscure the right heart border ( )

BIDMC, PACS

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Anatomy Review: Right Lower Lobe

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

RLL

RLL

“Silhouette sign”: On a PA film, an opacity in the RLL may obscure the right hemidiaphragm ( )

“Spine sign”: On lateral, a RLL opacity may interrupt the normal progressive increase in lucency of the thoracic vertebral bodies ( )BIDMC, PACS

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Anatomy Review: Left Major Fissure

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

Left major fissure

Left major fissure

BIDMC, PACS

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Anatomy Review: Left Upper Lobe

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

LUL LUL

“Silhouette sign”: On the PA film, an opacity in the lingular portion of the left upper lobe may obscure the left heart border ( )

BIDMC, PACS

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Anatomy Review: Left Lower Lobe

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

LLL

LLL

“Silhouette sign”: On the PA film, an opacity in the left lower lobe may obscure the left hemidiaphragm ( )

“Spine sign”: On lateral, a LLL opacity may interrupt the normal progressive increase in lucency of the thoracic vertebral bodies ( )BIDMC, PACS

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Our Patient: Prior PA and Lateral CXR

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

Please pause to review our patient’s prior films and give your general impression.

BIDMC, PACS

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Our Patient: Prior CXR Findings

Heather Hsu, HMS IIIGillian Lieberman, MD

Prior PA CXR Prior lateral CXR

General impression: Normal chest X-ray, note the absence of the left breast shadow ( ) s/p mastectomy

BIDMC, PACS

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Now back to our patient’s current presentation with left-sided chest pain and dyspnea…

ECG is unchanged from prior.

A portable AP chest X-ray is obtained.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Our Patient: Current AP CXR

Heather Hsu, HMS IIIGillian Lieberman, MD

BIDMC, PACS; Lieberman’s E-Radiology

First admission AP CXR Prior PA CXR

Please pause to compare our patient’s new CXR with the prior film.

Reminder - Systematic Approach to CXR:

-Acknowledge majorabnormalities

-Quality control-Lines + hardware-Heart + mediastinum-Lungs + diaphragm-Pleura-Bones-Soft tissues-Checkpoints

-Apices-Aortic knob-Hila-Retrocardiac regions

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Our Patient: Current AP CXR Findings

Heather Hsu, HMS IIIGillian Lieberman, MD

BIDMC, PACS

First admission AP CXR

Absence of left breast shadow ( ) s/p mastectomy

Small left pleural effusion ( ) obscuring costophrenic angle

Opacity in left mid + lower lung fields with air bronchograms, partially obscuring L hemidiaphragm

Given these findings, what is the differential diagnosis?

Note that we are comparing a current AP CXR with a prior PA film, so changes in heart size cannot be adequately assessed.

Prior PA CXR

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Our Patient: Differential Diagnosis at First Presentation

• Pneumonia• Malignancy

– Primary– Metastasis

• Pleural effusion– Parapneumonic– Malignant

• Atelectasis

Heather Hsu, HMS IIIGillian Lieberman, MD

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Given our patient’s clinical presentation and CXR findings, she is diagnosed with a left lower lobe community-acquired pneumonia, admitted to the

hospital, and started on levofloxacin.

Over the next two days, her white blood cell count, dyspnea, cough, and chest pain improve

and she is discharged.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Our Patient: Second Presentation

After discharge, our patient returns home.

The next morning, she presents again with severe, pleuritic, left-sided chest pain.

She is afebrile, tachycardic, and tachypneic.

Another chest X-ray is obtained.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Our Patient: CXR at Second Presentation

Heather Hsu, HMS IIIGillian Lieberman, MD

Current AP and lateral CXR First admission AP CXR

BIDMC, PACS

Please pause to compare our patient’s current CXR with the film

from her prior admission.

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Our Patient: Findings from CXR at Second Presentation

Heather Hsu, HMS IIIGillian Lieberman, MD

Second admission AP and lateral CXR

BIDMC, PACS

Quality control:Mediastinum appears wide ( ) due to the patient’s rotated position. Poor arm positioning ( ) obscures upper lung fields.

New Findings:More prominent opacity in left mid and lower lung fields, silhouetting out the left heart border and hemidiaphragm.

The left costophrenic angle ( ) is obscured.

Spine sign ( )

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Our Patient: Differential Diagnosis at Second Presentation

• Inadequately treated pneumonia• Complicated pneumonia

– Simple parapneumonic effusion – Complicated parapneumonic effusion– Empyema– Necrotizing pneumonia

• Lung collapse/atelectasis• Mucus plug• Lung malignancy• Malignant effusion• Pulmonary embolism

Heather Hsu, HMS IIIGillian Lieberman, MD

Given this differential diagnosis, what should the next step be?Do we need further imaging?

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Based on the findings from the chest X-ray and the patient’s worsening clinical condition, the decision is made to order a CTA to rule out

pulmonary embolus and further characterize the abnormalities seen on CXR.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Our Patient: Chest CTA from Second Presentation

Heather Hsu, HMS IIIGillian Lieberman, MD

Cross-sectional views, C+ Chest CT, soft tissue window

BIDMC, PACS

Not depicted: Contrast opacification of pulmonary arteries is complete to segmental level and the central airways are patent.

Please pause to evaluate the images.

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Our Patient: Chest CTA Findings

Heather Hsu, HMS IIIGillian Lieberman, MD

Cross-sectional view, C+ Chest CT, soft tissue window

BIDMC, PACS

Left lower lobe collapse with worsening consolidation ( )

Non-hemorrhagic pleural effusion ( ), with pleural fluid measuring ~27 Hounsfield units

Septation within pleural effusion ( ) and non- dependent layering ( ) indicating loculation

Reminder re: Hounsfield units (HU):Air: -1000 HU Fat: -30 HUWater: 0 HU Soft tissue: +30 HUBlood: +40 HU Bone: +1000 HU

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Our Patient: Revised Differential Diagnosis Following Chest CTA

• Complicated pneumonia– Simple parapneumonic effusion– Complicated parapneumonic effusion– Empyema

• Lung collapse/atelectasis• Lung malignancy• Malignant effusion

Heather Hsu, HMS IIIGillian Lieberman, MD

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Based on the findings from the chest CTA and the patient’s clinical presentation, she is diagnosed with a probable empyema and transferred to the

ICU for further management.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Empyema: Definition, Phases, and Epidemiology

• Definition: The presence of pus and/or gram stain/culture-positive fluid in the pleural space

• Three phases:– Exudative: inflammation of visceral pleura results in

exudative effusion and thickening of pleural surfaces – Fibropurulent: inflammatory cells and neutrophils invade the

pleural space, fibrin is deposited on inflamed pleural surfaces

– Organizing: recruitment of fibroblasts and capillaries results in deposition of collagen and granulation tissue on pleural surfaces leading to pleural fibrosis

• Epidemiology: <2% of patients with community- acquired pneumonia develop empyema

Heather Hsu, HMS IIIGillian Lieberman, MD

Ahmed, et al. Am J Med 2006; Kulman and Singha, Radiographics 1997

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Empyema: Appearance on Imaging

• CXR: may see a pleural-based opacity that has an abnormal contour or does not flow freely on lateral decubitus views

• Ultrasonography: may see loculated effusion• C+ CT chest:

– Classic appearance: oblong fluid collection with smooth inner margins that compresses and displaces surrounding lung and airway

– Important to distinguish empyema from lung abscess• CT findings favoring abscess include a thick-walled, spherical cavity that

destroys lung rather than displacing it– “Split pleura” sign on C+ CT:

• Contrast-enhanced thickened visceral and parietal pleura separated by fluid• May be seen in the fibropurulent phase• Indicates exudative effusion (not specific to empyema)

– “Pleural microbubbles”• Small air bubbles within fluid collection• May indicate resistance of the effusion to chest tube drainage

Heather Hsu, HMS IIIGillian Lieberman, MD

Kulman and Singha, Radiographics 1997; Smolikov, et al. Clin Radiol 2006

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Empyema: Companion Patient Images

Heather Hsu, HMS IIIGillian Lieberman, MD

BIDMC, PACS

Cross-sectional views, C+ Chest CTA, soft tissue window

Fluid trapped in the minor fissure ( ) Loculated right pleural effusion ( ) that is layering non-dependently

Atelectasis ( ) Liver dome ( )

Middle-aged man with right-sided chest discomfort and shortness of breath

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Empyema: Management Overview

• Thoracentesis– Pleural fluid analysis, gram stain, and culture

• Appropriate antibiotics– Sterilization of empyema cavity with systemic

antibiotics (minimum 4-6 weeks) • Drainage

– Tube thoracostomy– Video-assisted thoracoscopic surgery (VATS)– Open decortication– Open thoracostomy

Heather Hsu, HMS IIIGillian Lieberman, MD

Colice, et al. Chest 2000

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Our Patient: Management of Her Clinical Course

Heather Hsu, HMS IIIGillian Lieberman, MD

• Pleural fluid analysis– Culture-negative, non-malignant exudative effusion with low pH

and positive gram stain– Consistent with empyema

• Antibiotics– Broad spectrum coverage with vancomycin, cefepime, and

azithromycin• Drainage

– VATS and decortication procedures were attempted without success due to difficulty ventilating the right lung during the procedures.

– Ultimately, a chest tube was placed and the effusion drained successfully.

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Our Patient: ICU Course and Outcome

Heather Hsu, HMS IIIGillian Lieberman, MD

• ICU course– Complicated by NSTEMI, serotonin syndrome, blood

transfusion, and benzodiazepine withdrawal• Outcome

– Discharged after ~2 weeks in the ICU– Currently living at home and doing well

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Summary

Heather Hsu, HMS IIIGillian Lieberman, MD

• Patient presentation– History of present illness and other relevant information– Menu of appropriate radiologic tests and their indications– Review of lung anatomy on CXR– Overview of our patient’s radiographic findings– Differential diagnosis

• Empyema– Definition, phases, and epidemiology– Appearance on imaging – Companion patient images– Management overview

• Update on our patient’s clinical course

40

Bibliography

• Ahmed RA, Marrie TJ, Huang JQ. Thoracic empyema in patients with community- acquired pneumonia. Am J Med. 2006;119(10):877-83.

• Colice GL, Curtis A, Deslauriers J, et al. Medical and surgical treatment of parapneumonic effusions : an evidence-based guideline. Chest. 2000;118(4):1158- 71.

• Kuhlman JE, Singha NK. Complex disease of the pleural space: radiographic and CT evaluation. Radiographics. 1997;17:63-79.

• Lieberman G. A systematic approach to evaluating chest X-rays. Lieberman’s E- Radiology. http://eradiology.bidmc.harvard.edu/interactivetutorials/. Accessed March 15, 2011.

• Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44 Suppl 2:S27-72.

• Smolikov A, Smolyakov R, Riesenberg K, et al. Prevalence and clinical significance of pleural microbubbles in computed tomography of thoracic empyema. Clin Radiol. 2006;61(6):513-9.

• Washington L, Kahn A, Mohammed T. American College of Radiology Appropriateness Criteria: Acute respiratory illness. http://www.acr.org/secondarymainmenucategories/quality_safety/app_criteria.aspx. Accessed March 15, 2011.

Heather Hsu, HMS IIIGillian Lieberman, MD

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Acknowledgements

• Gillian Lieberman, MD – for her teaching and guidance

• Veronica Fernandes, MD – for her feedback on the presentation

• Emily Hanson – for technical support and guidance

• Douglas Hsu, MD – for assistance in finding companion patient images

Heather Hsu, HMS IIIGillian Lieberman, MD