Tracheal Collapse

Christina Copple, DVMRadiology ResidentNCSU CVM-VTH

Accession numbers 109894 and 109673

Pooh

• 11yr old M Yorkshire Terrier• Internal Medicine Service for evaluation elevated

liver & kidney enzymes, and cardio consult (hx of ARF due to pyelonephritis and also mitral & tricuspid regurgitation)

• Owner reports cough for 3-4 years, in the Owner reports cough for 3-4 years, in the morning, attempts to cough something upmorning, attempts to cough something up

• Recent weight gainRecent weight gain

Pooh’s Physical Examination

• TPR normal• BCS-7/9 =

overconditionedoverconditioned• Thoracic auscultation:

soft murmur on right side, slightly harsh lung harsh lung soundssounds with inspiratory cracklesinspiratory crackles on right and expiratory expiratory efforteffort

• HepatomegalyHepatomegaly on abdominal palpation http://www.welcometothedoghouse.net/pics/yorkshire_terrier_wallpaper.jpg

Pooh’s Diagnostics

• BP elevated at 210• Inflammatory leukogram• Hypercholesterolemia, moderately elevated

ALT/ALP• Cardio consult: unchanged left/right atrial

enlargement and mitral/tricuspid regurgitation, new- mild right ventricular enlargement and moderate pulmonary hypertension

• Endotracheal wash-suggestive of chronic inflammation

• Thoracic radiographs

Left lateral

Right lateralAccession # 109894

VD thorax Accession # 109894

Tracheal Collapse

• Acquired disease of middle-aged Toy and Miniature breeds with unknown cause; prevalence 0.5-2.9%

• Two types– Dorsoventral = most

common; often associated with a redundant, flaccid dorsal tracheal membrane

– Lateral = rare

• Usually involves cervical region but both cervical & thoracic areas can be involved and may extend into the bronchi

• No loss of tracheal ring size but rings lose ability to remain firm and become weakened= deficiency in organic matrix deficiency in organic matrix of tracheal cartilageof tracheal cartilage

• Hypocellular• Lacking or deficient

glycoproteins and glycosaminoglycans, chondroitin sulfate and calcium

Tracheal Collapse

• Associated problems:– Chronic coughing-long

term airway and/or pulmonary parenchymal disease

– Obesity and increased mediastinal fat

– Chronic cardiac disease with tracheal/bronchial compression

– Also tracheal trauma, denervation of dorsal tracheal membrane, congenital defects

• Increasing respiratory work dynamic collapse of dorsal tracheal membrane into lumen

• Results in further irritation and inflammation of mucous membranes, disruption of mucociliary apparatus, increased risk of small airway disease

Tracheal Collapse (“Respiratory Distress Syndrome”)-History and

Physical Examination• Paroxysmal, chronic coughchronic cough for long period of time• Cough elicited on tracheal palpation: chronic, harsh, dry,

“goose honk”• Toy and miniature breeds: Chihuahuas, Pomeranians,

Toy Poodles, Shih Tzus, Lhasa apsos, and Yorkshire Yorkshire TerriersTerriers

• ObeseObese• Varying degrees of inspiratory or expiratory dyspneaexpiratory dyspnea,

inspiratory noises, expiratory grunt with abdominal effort• Lung sounds-normal to rattling, stridorous, wheezing• HepatomegalyHepatomegaly-relationship to syndrome unclear

Tracheal Collapse-Diagnostics

• Radiographs: during both phases or respiration to demonstrate dynamic nature; inspiratory-cervical region collapse, expiratory-thoracic region collapse with unchanged or slightly dilated cervical region

• Fluoroscopy-assess severity; may only see collapse during forced expiration of coughing

• Tracheoscopy/Bronchoscopy with wash -decreased dorsoventral tracheal diameter and pendulous dorsal tracheal membrane

http://i180.photobucket.com/albums/x146/ciethe529/YorkshireTerrier.jpg

Tracheal Collapse-Chronic Medical Therapy

• Bronchodilators (Aminophylline or Theophylline): reduction in spasm of smaller airways-reduces intrathoracic pressures and thus decreases tendency of larger airways to collapse; improves mucociliary clearance; reduces diaphragmatic fatigue

• Beta-agonists (Terbutaline or Albuterol)• Antitussives (Butorphanol)• WEIGHT REDUCTION• No neck collars, remove noxious irritants such

as gas, smoke, or dust

Tracheal Collapse-Surgical Therapy

• Last resort!-does not resolve mainstem or distal bronchial collapse if present

• Plication of dorsal tracheal membrane

• Placement of external tracheal ring prostheses

• Intraluminal stents

http://cvm.msu.edu/hospital/services/interventional-radiology/ir-media/Tracheal%20Stent.jpg

A Retrospective Study of the Relationship Between Tracheal Collapse and Bronchiectasis

in DogsVetRadUS, Vol. 48.3, 2007:199-203

• Thoracic radiographs fundamental to diagnosis-detects tracheal collapse in 60-84% esp. with inspiratory/expiratory views

• Fluoroscopy-imaging modality of choice for dynamic airway changes

• Bronchoscopy-when former are inconclusive, evaluate diameter and grade luminal changes

• Tracheal narrowing = ratio of tracheal diameter:thoracic inlet width <0.2

• Thoracic radiographs-first line assessment of bronchiectasis– Bronchial wall thickening

and alveolar disease– Cylindrical (failure to taper

peripherally) and saccular (distal bronchi dilated with rounded, cyst-like structures) bronchial wall dilation

Tracheal Collapse and Bronchiectasis cont’d

VetRadUS, Vol. 48.3, 2007:199-203

• 60 patients included, all had tracheal collapse (No control group)– 90% small breed dogs– Most commonly affected breed = Yorkshire TerrierYorkshire Terrier

• 30% had both tracheal collapse and bronchiectasis; all were cylindrical– Most commonly affected breed = Yorkshire TerrierYorkshire Terrier– Evidence of link between tracheal collapse &

bronchiectasis and patients with both conditions should be further evaluated for chronic lower airway disease

References

• Ettinger, Stephen J. and Edward C. Feldman. Textbook of Veterinary Internal Medicine. 6th ed. Volume 2. Elsevier. St. Louis, MO. 2000:1224-1228.

• Marolf, Angela, Margaret Blaik, and Andrew Specht. A Retrospective Study of the Relationship Between Tracheal Collapse and Bronchiectasis in Dogs.Veterinary Radiology & Ultrasound. 48.3, 2007:199-203.

Trach Fluoroscopy during coughing episodeAccession # 109673