Lecture 5 Flashcards
Inflammatory Airway Disease
- Chronic Bronchitis
- Dogs and cats
- Feline Asthma
- “Feline lower airway disease”
(often not differentiated clinically in cats, just called FLAD)
- “Feline lower airway disease”
Airflow limitation
Impedance to air movement in the airways caused by inflammation, secretions, and smooth muscle contraction
- Chronic bronchitis
- Little to no spontaneous bronchoconstriction
- Feline asthma
- REVERSIBLE spontaneous bronchoconstriction
- can be reverse w/ Beta-2 agonists
- REVERSIBLE spontaneous bronchoconstriction
Inflammatory airway disease
- Canine Chronic Bronchitis
- Middle aged to older
- Small breeds over-represented
- Feline asthma and bronchitis
- Young to middle-aged adult
- Siamese
Inflammatory airway disease: clinical signs
- Chronic cough
- Usually non-productive (initially)
- Expiratory WHEEZES
- expiratory push (using abdominal effort)
- Tachypnea at rest
IAD: diagnostics
- CBC
- Parasite testing
- Bronchial lung patteran (donuts and railroad tracks for airways on radiographs)
- +/- interstitial pattern
- TTW, ETW, or BAL*
- Pre-med cats w/ bronchodilator
Feline Lungworm
- Aleurostrongylus abstrusus
- Ingest L3 larva (snail, slug, reptile, bird, rodent)
- Adult worms live in terminal bronchioles/alveolar ducts ==> inflammation
- can be eosinophilic and look like feline asthma!
- Dx: identify L1 larvae in airway fluid or feces (Baermann or zinc sulfate)
- Tx: mild cases self-limiting; fenbendazole
“Classic” Feline Asthma Radiographs
- Bronchointerstitial lung pattern
-
Pulmonary hyperinflation
- increased lucency = air trapping (lungs look abnormally dark on rads)
- flattened diaphragm
- Atelectasis of the RIGHT MIDDLE LUNG LOBE
- mucous plugging
Feline IAD: bronchoscopy
- hyperemia
- irregularity in mucosa
- increased mucus
- lower airway collapse
Feline IAD: respiratory wash cytology
- Bronchitis ==> Neutrophilic
2. Asthma ==> Eosinophilic
Feline IAD: treatment
- Corticosteroids*
- Cornerstone of treatment, taper to lowest effective dose
- Oral (prednisone/prednisolone)
- Inhaled (fluticasone)
- Bronchodilators
- Decrease airway constriction in acute asthma attacks
- NO effect on airway inflammation
- +/- cough suppressants (dogs)
- break inflammatory cycle (dogs w/ a cough can develop into a quality of life issue, not really w/ cats)
Inhaled therapies
Delivered via metered dose inhaler into a spacer
- Fluticasone, albuterol
IAD: Treatment
- weight loss
- harness vs. a collar
- environmental trigger avoidance (smoke, perfume, etc.)
IAD: Treatment goals
- minimize clinical signs
- SLOW AIRWAY REMODELING
- bronchiectasis
- pulmonary fibrosis
- pulmonary hypertension
Long-term management disease
Interstitial disease: eosinophilic bronchopneumopathy
- interstitial lung disease characterized by infiltration with eosinophils
- peripheral eosinophilia common
- Most cases iodiopathic
- Most commonly affects young dogs, arctic breeds, and Rottweilers predisposed*
- MUST rule out other causes of eosinophilic lung inflammation: parasites, neoplasia
- Responds well to corticosteroids
Idiopathic Pulmonary Fibrosis
- West Highland White Terriers
- Diffuse inspiratory CRACKLES
- Diffuse broncho-interstitial lung pattern
- Dx: biopsy, rule out causes of secondary fibrosis
- Prognosis: poor long-term (it’s not reversible)
NOTE: pulmonary fibrosis can occur with any untreated lung disease
Bacterial Pneumonia
RARELY A PRIMARY DISEASE
- Immunocompromised host
- young/old patient
- therapeutic steroids
- systemic disease (diabetes, Cushing’s, FeLV/FIV)
- Lung disease (bronchitis, viral infection)
- Recombency (can’t protect their airway or cough)
- illness/sedation
- Impaired host defenses
- congenital/acquired
Bacterial Pneumonia: causes
- Respiratory tract not sterile to level of carina!!
- may be some normal flora past the carina too
- Route of infection
- ASPIRATION*
- Hematogenous
- Traumatic/penetrating
Bacterial isolates:
#1 = E. coli* (then Pasteurella)
Aerobes > Anaerobes
Mycoplasma sp. common
Diagnose: airway wash w/ culture (look for bacteria, may be in PMN’s, along w/ septic inflammation)
Bordetella Bronchiseptica
1 cause of community acquired infectious pneumonia in dogs <1 YEAR OF AGE
Bordetella is contagious!!!
Pneumonia Radiographs
INTERSTITIAL TO ALVEOLAR PATTERN
- Only interstitial = early or less severe disease
Distribution:
1. Aspiration: cranioventral*
2. Hematogenous: dorsal-diffuse
- Viral pneumonias
(but it's not clear cut..)
Aspiration pneumonia
MOST COMMON CAUSE OF BACTERIAL PNEUMONIA IN ADULT* DOGS
Initial problem = airway irritation/injury (ie. pneumonitis, NOT infection)
==> injury allows for bacterial colonization
Aspiration pneumonia
Out of 125 dogs, history of:
- Vomiting (64%)
- Recent anesthesia (16%)
- causes laxity of esophagus and LES
Commonly associated w/ regurgitation, megaesophagus, largyngeal paralysis (glottis can’t always close properly), myastenia gravis
Localization trend of Aspiration Pneumonia
- Right Middle Lung Lobe
- Right Cranial Lung Lobe
- Caudal segment of Left Cranial lobe
BUT, normal rads in a suspicious patient does not rule aspiration pneumonia out
Bacterial Pneumonia - Empiric treatment
- Uncomplicated disease
- NARROW spectrum, SINGLE therapy
Duration: 1-2 weeks post radiographic resolution (3-4 weeks)
- Complicated/severe disease
- BROAD spectrum, combination therapy
- aerobic and anaerobic coverage, G+ and G- coverage
- Parenteral administration initially
- BROAD spectrum, combination therapy
Duration: 1-2 weeks post radiographic resolution (4-6weeks)
Nebulization
- Loosens and moistens airway secretions
2. Improves expectoration
Fungal Pneumonia
#1 cause: Blastomyces dermatidis* #2 cause: Histoplasma capsulatum
- Coccidiodes immitis
- Cryptococcus neoformans
- feline
- nasal infection more common than true pneumonia (doesn’t cause true pneumonia often)
Fungal Pneumonia: Dx and Tx
Diagnosis:
- CYTOLOGY
- Wash (TTW/BAL)
- LN/Lung FNA
- Look elsewhere for lesions (skin, LN)
- Urine antigen
- Blasto/Histo
- Sensitive! Doesn’t differentiate between the two..
- Rads: may appear as a “snowy” pattern in lungs - very suggestive of fungal pneumonia, but neoplasia and bacterial pneumonia CAN look like this too (if have snowy pattern => guarded prognosis)
Treatment:
- LONG-TERM antifungals (itraconazole/fluconazole)
- +/- anti-inflammatory steroids
Pulmonary Neoplasia
- Metastatic*: most common!
- Primary
- Commonly solitary/large nodule
- Tx: surgical excision +/- chemotherapy
