Common Respiratory Cases Flashcards
What does cough with tracheal palpation mean?
- Elicits a cough due to any disease below the thoracic inlet
Diseases of the airways below the thoracic inlet
- Chronic obstructive pulmonary disease (canine chronic bronchitis)
- Allergic bronchitis (feline asthma)
- Infectious bronchitis
- Airway collapse or compression or obstruction due to foreign body
- Peribronchial to interstitial fibrosis
Diagnostic tests for lower airway disease
- Thoracic radiographs
- Bronchoscopy
- Bronchial lavage
- Cytology
- CBC
- Fecal
- Culture and sensitivity
What can airway wash rule out?
- Infectious agents
- Neoplasia
- Parasites
- Direct specific therapy
Types of airway wash
- Bronchoalveolar lavage +/- bronchial brush
- Trans-tracheal wash
- She prefers bronchoalveolar lavage
What does cytology from a bronchoalveolar lavage look like for canine obstructive pulmonary disease?
- High neutrophilic component
- +/- High macrophage component
- ALWAYS SUBMIT CULTURES
What is canine chronic bronchitis or canine COPD?
- Long-term airway inflammation, typically some component of irreversible changes
Typical findings of canine COPD
- Mixed inflammatory cell infiltrates (neutrophils +/- macrophages))
- Ciliary dysfunction
- Glandular and epithelial hyperplasia
- Excessive mucus production
- Bronchiectasis
- Airway thickening
Type A COPD characteristics
- Minimal to no coughing until late in the course (more like emphysema)
Type B COPD characteristics
- Chronic coughing
- Predominates in the large airways
Which form of COPD is more common?
- COPD Type B
Who gets canine chronic bronchitis?
- Middle-aged, older small and toy breeds of dogs
- NOTE: THIS IS THE SAME signalment for mitral regurgitation
Characteristics of the canine chronic bronchitis cough
- Loud, resonant, and classically has terminal gag
- Owners may not appreciate the productive cough due to swallowing
- Often may cough MORE at night or first thing in the morning after being recumbent due to settling of airway secretions
Common comorbidities with canine chronic bronchitis
- Collapsing trachea
- Bronchiectasis
- Pulmonary hypertension
- Infectious agents (Bordetella and Mycoplasma spp especially) - may need to put on secondary doxycycline
Incidence of K9 bronchitis, allergic bronchitis, and infectious bronchitis
K9 bronchitis: most common airway disease of small dogs
Allergic bronchitis: more in cats
Infectious bronchitis: more common in young animals or multi animals (kennel cough)
Cytology of k9 chronic bronchitis
- Chronic irritant with mixed inflammation
- Possible 2° opportunistic infections
Cytology of allergic bronchitis
- Eosinophilic component
- Allergic sensitization to allergen
Etiology of infectious bronchitis in dogs
- CA adenovirus 2 +/- parainfluenza +/- Bordetella
Etiology of infectious bronchitis in cats
- Herpesvirus
- Calicivirus
- Bordetella
- Mycoplasma
Clinical scenario of K9 chronic bronchitis
- Coughing (typical bronchitis, type B)
- Non-coughing types (emphysema like, type A)
Clinical scenario of allergic bronchitis in cats
- Acute or chronic
- Can be a component of a chronic bronchitis disorder
Clinical scenario of infectious bronchitis
- Sudden onset, self limiting usually
- Can complicate another airway disorder (to left)
What are the mainstays of therapy for chronic bronchitis (broad categories)
- Bronchodilators
- Corticosteroids
- Combos
Which oral bronchodilators are used for treatment of chronic bronchitis?
- Methylxanthines like theophylline (mucociliary apparatus and mucolytic effects)
- Beta 2 stimulants (Terbutaline)
Which inhaled bronchodilators are used for treatment of chronic bronchitis?
- Albuterol (shorter acting/rescue) Beta 2 stimulant
- Combivent (albuterol/ipratropium combo that is longer acting Beta 2 stimulant)
Corticosteroids used for chronic bronchitis
- Fluticasone (inhaled steroid)
Combination drugs for chronic bronchitis
- Advair (fluticasone/salmeterol)
- Symbicort (Budesonide/formoterol)
Additional treatment strategies for canine bronchitis
- Weight loss
- Environment
- Cough suppressants
- Antibiotics
- Antiprostaglandins
- Emergency therapy as needed
Purpose of weight loss in treatment for chronic bronchitis
- Increase lung compliance and volume
Things to look at for environment for chronic bronchitis
- Possible allergens
- Smoking
Cough suppressants to use for chronic bronchitis
- Hycodan
- Butorphanol
- Lomotil
ANtibiotics used for chronic bronchitis secondary infections
- Doxycycline for Bordetella and Mycoplasma
- Base on cultures
Antiprostaglandins that can be used for chronic bronchitis
- COX-2 inhibitors
Emergency therapy for chronic bronchitis
- Epinephrine
- Atropine
- Albuterol inhaler
- Oxygen therapy
What two devices can be used for inhaling aerosolized drugs?
- Aerokat for local therapy
- Can also use a giant Ziploc bag
- Either way, animals need training to use an inhaler device
Prognosis for type B chronic bronchitis
- Good for control, no cure
Prognosis for type A chronic bronchitis
- Guarded to poor, often advanced at the time of diagnosis
Typical presentation, observation, and physical exam for cat with asthma
- Alert
- Open mouth breathing when examined
- Elevated respiratory right
- Prolonged inspiratory pull
- Can hear wheezing, harsh sounds on inspiration
- Cough elicited by tracheal palpation
What is the most appropriate test to look at with the airways with a coughing cat?
- Thoracic radiograph
Do cats generally cough with heart failure?
- Nope, that’s mostly dogs
Appearance of thoracic radiographs in a cat with asthma
- Fine honeycomb type pattern
- Some evidence of railroad tracks and donuts
Cytology with feline allergic bronchitis
- Often an eosinophilic component
- TTW or BAL
Pathophysiology of allergic bronchitis/feline asthma
- Re-exposure releases mediators (histamine, kinins, eosinophilic chemotactic factor)
- Bronchioconstriction occurs
Chronic bronchoconstriction characteristics with feline asthma
- Primarily coughing
- Inspiratory effort and noise
Acute bronchoconstriction
- Status asthmaticus
- Tachypnea, dyspnea
- Inspiratory and expiratory effort (+/- abdominal push) if end-terminal bronchioles are affected
Key therapy for allergic bronchitis
- Bronchodilators
- Corticosteroids (this is even more important with cats, as they are often steroid dependent)
- Combos
Examples of bronchodilators for allergic bronchitis that are oral
- Methylxanthines (theophylline)
- Beta 2 stimulant
Inhaled bronchodilators for allergic bronchitis
- Albuterol (shorter acting/rescue Beta 2 stimulant)
- Combivent which is albuterol and ipratropium (longer acting)
Inhaled corticosteroids for cats
- Fluticasone
Combos for allergic bronchitis
- Same as before
- Fluticasone/salmeterol
- Budesonide/formoterol
Prognosis for feline asthma
- Good for control, no cure
- Identifying environmental allergens is difficult
- Long term steroid use can be challenging, so consider inhaled
Where is the disease:
Coughing >1 year, esp with activity
- No ∆ in behavior or appetite
- G 2/6 systolic murmur, left apex
- Wheezes on inspiration heard with a scope
- Airway disease
- Radiograph the chest
What is tracheal collapse?
- Flattening of tracheal rings and/or redundant dorsal trachealis membrane
Who gets tracheal collapse?
- Toy and small breed
Classic sound of the cough of a dog with tracheal collapse
- Goose honk +/- terminal gag
Concurrent diseases that are common with tracheal collapse
- Mitral valve regurgitation
- Chronic bronchitis
Radiographic appearance of collapsing trachea
- Collapse in cervical or thoracic region
Managing bronchial collapse
- Weight loss**
- Avoid using a collar/leash (use a harness)
- Cough suppressants may be used in severe cases of coughing fits
- Treat concurrent conditions
- Severe cases may require surgery to stent the airway open
- Prognosis for medical management is reasonably good; for cure is poor
What is one of the most important aspects of managing bronchial collapse?
- Weight loss
- Many dogs will palliate with weight loss alone
- Reduces intrathoracic pressures, increases lung compliance and volume, decreases compression of fat
Cough suppressants for treatment of tracheal collapse
- Can be used in severe cases but caution is advised as cough suppressants may predispose already compromised airways to opportunistic infections
Where is the disease process:
- 2 year old DSH
- Obtained from shelter as a kitten
- “Breathing problem” for about 4 months
- Progressively worse
- Eating and drinking normally
- Upper airways
- Can be heard without stethoscope
- Over the nasopharyngeal area
Possibly ways to diagnose an upper airway problem in a kitty
- Sedated oropharyngeal exam
- CT
Who gets nasopharyngeal polyps?
- Usually young cats
What are nasopharyngeal polyps?
- Secondary to chronic mid-ear inflammation
- Non-cancerous growth
- Space occupying lesion
- Surgical removal
- Sometimes bulla osteotomy
Nasopharyngeal polyps prognosis
- Can recur
- Usually good once removed
Where is the disease process:
- 10 year old Brittany
- Anorexia and vomiting for 3 days
- Acute onset respiratory distress and soft cough
- HR 140, RR 66
- Crackles, late inspiration and expiration
- Parenchymal disease
- Not as much worried about heart disease because not tachypneic enough
Differentials for parenchymal disease
- Pneumonia (bacterial, viral, parasitic, aspiration)
- Pulmonary edema (cardiogenic vs non-cardiogenic)
- Small bronchial diseases (terminal airways)
- Pulmonary parenchymal diseases (parasitic, fungal, neoplasia)
Non-cardiogenic causes of edema
- ARDS
- Electrocution
Diagnostic plan for suspected parenchymal disease
- Thoracic radiographs
Appearance of alveolar disease on radiograph
- Alveolar pattern (very dense interstitial)
- Assess heart for any evidence of congestive heart failure as well
- Severely might see an air bronchogram
Which lung region is most likely to be affected with aspiration pneumonia?
- Cranioventral alveolar pattern generally
- Right cranial lung lobe is the most impacted
Air bronchogram
- Airways are “flooded” which highlights the open airway
Definition of aspiration pneumonia
- Inhalation of food, fluid, +/- bacteria
What are risk factors for aspiration pneumonia?
- Anything that can alter laryngeal-pharyngeal function
- Neuromuscular disease
- Megaesophagus, chronic reflux, chronic vomiting
- Anesthesia or depressed mental states (why we do NPO and blow up the cough)
- Accidental tubing
Treatment for aspiration pneumonia (acute fulminate or chronic insidious)
- Oxygen therapy
- Bronchodilators
- Antibiotics based on cultures (they can aspirate the area)
- Shock therapy if fulminate or septic
- Prevent further aspiration
Fluids with aspiration pneumonia and shock
- Be cautious
- There is lung/capillary injury and worsening edema
Where is the disease?
- Coughing for 1 week, progressive
- Decreased appetite/activity
- Decreased G4/6 systolic murmur, left apex
- End-inspiratory and expiratory crackles (RR =66)
- HR is 220 BPM
- Parenchyma
- Take thoracic radiographs
Hallmarks of left heart congestive heart failure on thoracic radiographs
- congested pulmonary veins
- Left sided heart enlargement
- Hilar region interstitial pattern
Treatment options for endocardiosis and secondary pulmonary edema
- Diuretics (furosemide)
- ACE inhibitor (Enalapril)
- Pimobendan
- +/- Spironolactone, other vasodilators like amlodipine
Where is the disease process?
- 11 year old Lhasa apso with history of mitral regurgitation
- On enalapril as a prophylactic
- Bout of pancreatitis
- 2 days later, acute respiratory distress
- HR 160, RR 80
- Increased expiratory effort
- Crackles, late inspiration and expiration
- Parenchymal disease
- COULD BE HEART FAILURE or something else too
- Thoracic radiographs
Radiographs of a dog with ARDS
- Generalized parenchymal opacity
- Not hilar specific
Treatment for dog that is very sick, with generalized increased lung opacity, and history of heart disease?
- Treat as heart failure in addition to the lung disease
- They weren’t convinced that he had venous congestion
- Gave positive inotropes
- Oxygen therapy
- Furosemide
Cytology of non-cardiogenic pulmonary edema
- mild inflammation
- High protein fluid
- Edema protein:serum protein ratio (~80%)
Non-cardiogenic pulmonary edema protein: serum protein ratio compared to CHF
- 80% compared to <50% in CHF
- Non-cardiogenic edema fluid is protein rich due to a capillary permeability issue
- CHF is protein poor due to a hydrostatic pressure issue
What is acute respiratory distress syndrome or non-cardiogenic edema?
- Aucte pulmonary edema (non-cardiogenic) secondary to lung injury and increased capillary/tissue permeability
What causes ARDS?
- Often idiopathic
- Can occur secondary to electrocution too
Predisposing causes of ARDS
- Sepsis
- Drug reaction
- Pancreatitis - Aspiration
- Inhalant injury
- Major trauma or surgery
Prognosis for ARDS
- Poor in general
Treatment for ARDS
- Treat underlying condition if known
- O2 therapy is essential
- Maintain low-normal circulatory volume with cautious fluid therapy
- Steroids are of unconfirmed benefit
- Diuretics may be helpful initially, but are of no benefit in latter phases of ARDS (>5-7 days)
- Nitric oxide as an endogenous mediator of vascular smooth muscle relaxation under investigation
O2 therapy for ARDS
- Intubation and mechanical ventilation
- Positive end-expiratory pressure (PEEP) methods are ideal
Why is it important to maintain low-normal circulatory volume in ARDS?
- Leaky capillaries
What can you look at the estimate hydration status with ARDS?
- Serial measures of arterial blood pressure, PCV, total protein, electrolytes, renal enzymes
Where is the disease:
- 12 year old DSH
- Presents abnormal breathing and weight loss
- Indoor only; mostly routine vaccines
- HR 160; RR 60
- Quiet lung sounds
- Lung parenchymal disease
- Do chest radiographs
Pleural effusion appearance on radiographs
- Retracted lung edge
- Scalloped, ventral fluid
- Overall white (fluid) opacity
What are the four causes of pleural effusion?
- Increased hydrostatic pressure in the capillaries
- Decreased oncotic pressure (hypoalbuminemia; <1.5 mg/dL)
- Increased capillary permeability
- Impaired lymphatic drainage (granulomatous disease and cancer)
Are pleural effusions usually unilateral or bilateral in dogs and cats?
- Bilateral generally
- Mediastinum of dog and cat is fenestrated or incomplete
What type of disease process is suggested with a unilateral pleural effusion in a dog or cat?
- Inflammatory focus almost always
- Infectious, neoplastic, granulomatous disease
- The fenestration may be plugged up
Management of severe pleural effusion (severe respiratory distress; fragile)
- Oxygen therapy and thoracocentesis should be performed initially before additional diagnostics
- Thoracocentesis is invasive, but benefit outweighs the small chance of complications
Management of mild, stable pleural effusion (stable condition)
- Present in stable condition
- May have chest radiographs taken to confirm presence of pleural effusion before thoracocentesis
How to categorize the pleural effusion?
- Measure protein concentration
- Total cell count
- Cytologic analysis may reveal a specific diagnosis or assist in directing next diagnostic steps
Fluid aspiration tips
- Small volumes just require needle and syringe (+ sterile prep)
- For larger volume, sterile prep, syringe, butterfly catheter, and 3-way stopcock
- Sedate cats
- Can use radiographs or count rib spaces
Pure transudate
- Protein <2.5 g/dL
- Cells <1000/µL
Rule outs for pure transudate
- Hypoalbuminemia
- PLN, PLE
Exudate
Protein >3 g/dL
Cells >5000/µL
Exudate major categories
- Non-septic
- Septic
- Hemorrhagic
- Chylous
Modified transudate
Protein <3.5 g/dL
Cell <5000/µL
Rule outs for modified transduate
- Right sided congestive heart failure
- Diaphragmatic hernia
- Neoplasia
- Lung lobe torsion
Causes of right sided heart failure
- Pulmonary hypertension
- Tricuspid regurgitation
- Pericardial effusion or restriction
- Cardiomyopathy (dilated or hypertrophic)
Non-septic exudate rule-outs
- Neoplasia
- Fungal infection
- Chronic chylothorax (very irritating)
- FIP
- Chronic lung lobe torsion
Septic exudate rule-outs
- Penetrating chest wound
- FOreign body inhalation
- Ruptured esophagus
- Ruptured pulmonary abscess or abscessed tumor
- Hematogenous bacterial infection
Hemorrhagic exudate rule-outs
- Neoplasia
- Coagulopathy
- Trauma
- Lung lobe torsion
Chylous exudate rule-outs
- Neoplasia
- Heartworm disease
- Hypertrophic cardiomyopathy
- Lung lobe torsion
- Diaphragmatic hernia
