Congenital Lobar Congenital Lobar EmphysemaEmphysemaThe case of the cyanotic The case of the cyanotic

PekingesePekingese

Erica Fields, DVMErica Fields, DVM

Gizmo LaddGizmo Ladd

MRN 140041MRN 140041 3 month old male Pekingese3 month old male Pekingese Acute dyspnea and cyanosis, Acute dyspnea and cyanosis,

multiple transient episodes in the multiple transient episodes in the last 24 hourslast 24 hours

Radiographic FindingsRadiographic Findings

Marked decrease in pulmonary Marked decrease in pulmonary vascular markingsvascular markings

Flattening of the diaphragm, Flattening of the diaphragm, consistent with hyperinflationconsistent with hyperinflation

Thin septae throughout pulmonary Thin septae throughout pulmonary parenchyma, suggestive of saccular parenchyma, suggestive of saccular dilationsdilations

Alveolar pattern, left caudal lung lobeAlveolar pattern, left caudal lung lobe—atelectasis??—atelectasis??

Suter, Thoracic Radiography

Differential DiagnosesDifferential Diagnoses

Pulmonary hyperlucencyPulmonary hyperlucency Tension pneumothoraxTension pneumothorax Metabolic acidosis (compensatory Metabolic acidosis (compensatory

hyperpnea)hyperpnea) Pulmonary cysts (bullae)Pulmonary cysts (bullae) Relative decrease in pulmonary Relative decrease in pulmonary

tissue/vasculaturetissue/vasculature Air trapping Air trapping Compensatory lung expansion (as with Compensatory lung expansion (as with

contralateral lobectomy)contralateral lobectomy) Artifact—overexposed radiographArtifact—overexposed radiograph

Suter, Thoracic Radiography

Differential DiagnosesDifferential Diagnoses Decreased pulmonary vascularityDecreased pulmonary vascularity

Pulmonary thromboembolism (regional Pulmonary thromboembolism (regional oligemia)oligemia)

Hypovolemic shockHypovolemic shock Myocardial disease with reduced RV outputMyocardial disease with reduced RV output Severe pulmonic stenosisSevere pulmonic stenosis Addison’s diseaseAddison’s disease Pulmonary artery hypertensionPulmonary artery hypertension Right to left shunting (reversed PDA, Right to left shunting (reversed PDA,

tetralogy of Fallot, Eisenmenger’s tetralogy of Fallot, Eisenmenger’s syndrome)syndrome)

Amis, et al. 1987

Diagnostic TestingDiagnostic Testing Thoracic Radiographs (inspiratory and Thoracic Radiographs (inspiratory and

expiratory)expiratory) Lab testing, including blood gas—with CLE, Lab testing, including blood gas—with CLE,

often have relatively normal resultsoften have relatively normal results Non-selective pulmonary angiographyNon-selective pulmonary angiography Nuclear medicine—Tc-MAA perfusion scanning Nuclear medicine—Tc-MAA perfusion scanning

and ventilation scanning (N-13 reported)and ventilation scanning (N-13 reported) Computed tomography (CT)Computed tomography (CT) Pulmonary function testingPulmonary function testing Echocardiography (rule out right-to-left Echocardiography (rule out right-to-left

cardiac shunt)cardiac shunt) Bronchoscopy (or bronchogram, as performed Bronchoscopy (or bronchogram, as performed

in one study)in one study)

Diagnostics—Gizmo’s Diagnostics—Gizmo’s casecase

Thoracic radiographsThoracic radiographs CBC/Chem—mild anemia and CBC/Chem—mild anemia and

neutrophilic leukocytosis (would neutrophilic leukocytosis (would expect polycythemia with Rexpect polycythemia with RL L shunt)shunt)

ECG—NSRECG—NSR Blood pressure--WNLBlood pressure--WNL

Echocardiography—cephalic Echocardiography—cephalic injection bubble study performed; no injection bubble study performed; no evidence of intracardiac shunting; evidence of intracardiac shunting; however, bubbles appeared in the however, bubbles appeared in the left atrium and ventricle after left atrium and ventricle after approximately 10-15 cardiac cyclesapproximately 10-15 cardiac cycles—suggestive of AV malformation in —suggestive of AV malformation in pulmonary vasculature??pulmonary vasculature??

Suter, Thoracic Radiography

What is Congenital Lobar What is Congenital Lobar Emphysema?Emphysema?

First, what is emphysema?First, what is emphysema? Technically, it refers to Technically, it refers to destructiondestruction of of

alveolar walls and consequent alveolar walls and consequent hyperinflation of airspaces distal to the hyperinflation of airspaces distal to the terminal bronchioliterminal bronchioli

Overinflation or air trapping can look Overinflation or air trapping can look the same, but without destruction of the same, but without destruction of alveolialveoli

Emphysema is irreversible, whereas air Emphysema is irreversible, whereas air trapping is reversibletrapping is reversible

Amis, et al. 1987

Congenital Lobar Congenital Lobar EmphysemaEmphysema

Recognized in humans, dogsRecognized in humans, dogs Probably not technically emphysema in Probably not technically emphysema in

the dog, as no alveolar destruction, but the dog, as no alveolar destruction, but the name stuckthe name stuck

Bronchial cartilage hypoplasia, Bronchial cartilage hypoplasia, dysplasia or aplasiadysplasia or aplasia

Without cartilage support, the bronchi Without cartilage support, the bronchi collapse on expiration, leading to collapse on expiration, leading to gradual air trapping and hyperinflationgradual air trapping and hyperinflation

Voorhout, et al. 1986

Congenital Lobar Congenital Lobar EmphysemaEmphysema

In humans, boys are over-representedIn humans, boys are over-represented Typically cranial lobes or right middle lobeTypically cranial lobes or right middle lobe Most common presentation is dyspnea, Most common presentation is dyspnea,

cyanosis, and exercise intolerancecyanosis, and exercise intolerance Usually recognized as infants or puppies—Usually recognized as infants or puppies—

one case of a 5 yo Pekeone case of a 5 yo Peke Rare, but at least 3 of the reported cases Rare, but at least 3 of the reported cases

are Pekingese, suggesting breed are Pekingese, suggesting breed predilectionpredilection

Billet and Sharpe. 2002

HistopathologyHistopathology

Usually find hypoplasia, dysplasia, or Usually find hypoplasia, dysplasia, or aplasia of bronchial cartilage in aplasia of bronchial cartilage in affected lobeaffected lobe

Hyperinflation of alveoli +/- alveolar Hyperinflation of alveoli +/- alveolar destructiondestruction

Epithelium and secretory cells may Epithelium and secretory cells may be intactbe intact

Billet and Sharpe, 2002. Amis, et al 1987.

Treatment and PrognosisTreatment and Prognosis

Surgical excision of the affected lobeSurgical excision of the affected lobe May treat conservatively (restricted May treat conservatively (restricted

activity) if minimally affected—more activity) if minimally affected—more experience with this in humansexperience with this in humans

In humans, good prognosis if treated In humans, good prognosis if treated surgicallysurgically

In dogs, not so good—all but 1 dog in In dogs, not so good—all but 1 dog in literature either died or were literature either died or were euthanizedeuthanized

ReferencesReferences Amis TC, Hager D, Dungworth DL, Hornof Amis TC, Hager D, Dungworth DL, Hornof

W. Congenital bronchial cartilage W. Congenital bronchial cartilage hypoplasia with lobar hyperinflation hypoplasia with lobar hyperinflation (congenital lobar emphysema) in an adult (congenital lobar emphysema) in an adult Pekingese. JAAHA 1987; 23: 321-329.Pekingese. JAAHA 1987; 23: 321-329.

Billet JPHG and Sharpe A. Surgical Billet JPHG and Sharpe A. Surgical treatment of congenital lobar emphysema in treatment of congenital lobar emphysema in a puppy. J Sm An Pract 2002; 43: 84-87.a puppy. J Sm An Pract 2002; 43: 84-87.

Suter. Thoracic Radiography. Suter. Thoracic Radiography. Voorhout G, Goedegebuure SA, and Nap RC. Voorhout G, Goedegebuure SA, and Nap RC.

Congenital lobar emphysema caused by Congenital lobar emphysema caused by aplasia of bronchial cartilage in a Pekingese aplasia of bronchial cartilage in a Pekingese puppy. Vet Pathol 1986; 23: 83-84. puppy. Vet Pathol 1986; 23: 83-84.