Lecture 35: Lower Respiratory Tract Disorders

cough

protective reflex to forcefully expel air and material from airways

characteristics of cough

• productive vs non-productive

• intensity → loud, harsh, paroxysmal, soft

• temporal associations → time of day, activity

productive cough

• moist sound heard during cough

• delivers mucus, exudate, edema fluid, or blood from airways into oral cavity

• most commonly caused by inflammation, infectious disease, or heart failure

non-productive cough

• dry cough

• mostly associated with airway disease such as collapsing trachea

exercise intolerance

• begins with hypoxia from a variety of disease processes

• mild tachypnea and subtly decreased activity → exercise intolerance and dyspnea at rest

• often present in overt distress

evaluating respiratory distress

• resting respiratory rate → upper limit 20-30 breaths per minute

• mucus membrane color → pallor (acute hypoxemia), cyanosis (severe hypoxemia)

• breathing pattern → rate, depth, inspiratory and expiratory efforts, audible sounds

inspiratory respiratory distress

• extrathoracic disease

• pulmonary disease

expiratory respiratory distress

intrathoracic airways

initial evaluation for respiratory distress includes

• PE → complete systematic physical, thoracic auscultation

• radiographs

• bloodwork → CBC

bronchial lung sounds

most prominent in central area of lungs; tubular sounds over large airways

vesicular lung sounds

most prominent in peripheral lung fields → breeze blowing through leaves

auscultation of abnormal lung sounds

• decreased lung sounds (pleural effusion, pneumothorax, mass lesions)

• increased or harsh lung sounds, crackles, wheezes

what is the most helpful diagnostic tool for intrathoracic disease?

radiographs

radiographs for intrathoracic disease

• minimum 2 views → right lateral and ventrodorsal

• right and left laterals increase sensitivity

• dorsoventral views are taken to highlight dorsal pulmonary arteries

• horizontal views to evaluate pleural effusion or cavitary lesions

what phase of respiration is the best for taking thoracic radiographs?

peak inspiration

what is this showing?

inspiratory view

what are the 4 main pulmonary patterns for radiographs?

• vascular pattern

• bronchial pattern

• alveolar pattern

• interstitial pattern

what is blue?

pulmonary artery

what is red?

pulmonary vein

what view is this?

DV

vascular pattern

characterized by an increase or decrease in size of the pulmonary arteries and/or veins

what pattern is this?

vascular

what pattern is this?

bronchial

bronchial pattern

characterized by prominent bronchial walls resulting in thickened end-on and longitudinal bronchi → donuts and tram lines

alveolar pattern

characterized by air bronchogram, lobar signs, and silhouette effect

what pattern is this?

alveolar pattern

interstitial pattern

structured (nodular), unstructured (diffuse) or a combination resulting in an increase in lung opacity

what pattern is this?

interstitial

pleural effusion

characterized by retraction/rounding of lung lobes due to pleural fluid accumulation, dorsal displacement of the trachea

what is this showing?

pleural effusion

what are these showing?

pneumothorax

lung lobe consolidation

entire lobe is soft tissue opacity

atelectasis

collapsed lung lobe due to airway obstruction; lobe is also soft tissue opacity but smaller sized

cavitary lesions

abnormal air accumulation in lung

angiography

used to confirm pulmonary thromboembolism

ultrasonography

used to evaluate pulmonary mass lesions, guide collection of FNA samples, assess pleura, lungs

CT/MRI

advanced imaging to evaluate masses, metastatic disease, PTE, pneumonias, etc

nuclear imaging

used to diagnose ciliary dyskinesia, pulmonary perfusion, and ventilation

parasitology

• direct observation via scoping

• blood tests

• cytological analysis of fluid or respiratory samples

• fecal floatation

serology

• fungal pulmonary disease → histoplasmosis, blastomycoses, coccidioidomycoses

• toxoplasmosis

• cryptococcus

• heartworm disease

tracheal wash

• transtracheal wash technique

• transoral (endotracheal) technique

bronchoalveolar lavage

• bronchoscopic

• nonbronchoscopic

what should cats be pre-treated with for a transoral wash?

terbutaline and lidocaine on arytenoids

transthoracic lung aspiration

• ultrasound guided FNA of pulmonary parenchyma

• potential complications include pneumothorax, hemothorax, and pulmonary hemorrhage

• can be utilized for masses near body wall and diffuse interstitial lung disease

bronchoscopy

• evaluation of major airways

• broncho-alveolar lavage performed routinely

• technique of choice for airway foreign body removal

what is this?

blastomycosis

what are these?

macrophages

thoracotomy/thoracostomy

allows surgical exploration, tissue biopsy and definitive treatment of pulmonary lesions

which clinical sign is most commonly seen in patients with lower respiratory tract disease?

cough