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Flashcards in Lecture 5 Deck (27):
1

Inflammatory Airway Disease

1. Chronic Bronchitis
- Dogs and cats
2. Feline Asthma
- "Feline lower airway disease"
(often not differentiated clinically in cats, just called FLAD)

2

Airflow limitation

Impedance to air movement in the airways caused by inflammation, secretions, and smooth muscle contraction

1. Chronic bronchitis
- Little to no spontaneous bronchoconstriction
2. Feline asthma
- REVERSIBLE spontaneous bronchoconstriction
- can be reverse w/ Beta-2 agonists

3

Inflammatory airway disease

1. Canine Chronic Bronchitis
- Middle aged to older
- Small breeds over-represented
2. Feline asthma and bronchitis
- Young to middle-aged adult
- Siamese

4

Inflammatory airway disease: clinical signs

1. Chronic cough
- Usually non-productive (initially)
2. Expiratory WHEEZES
- expiratory push (using abdominal effort)
3. Tachypnea at rest

5

IAD: diagnostics

1. CBC
2. Parasite testing
3. Bronchial lung patteran (donuts and railroad tracks for airways on radiographs)
- +/- interstitial pattern
4. TTW, ETW, or BAL*
- Pre-med cats w/ bronchodilator

6

Feline Lungworm

1. 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!
2. Dx: identify L1 larvae in airway fluid or feces (Baermann or zinc sulfate)
3. Tx: mild cases self-limiting; fenbendazole

7

"Classic" Feline Asthma Radiographs

1. Bronchointerstitial lung pattern
2. *Pulmonary hyperinflation*
- increased lucency = air trapping (lungs look abnormally dark on rads)
- flattened diaphragm
3. Atelectasis of the RIGHT MIDDLE LUNG LOBE
- mucous plugging

8

Feline IAD: bronchoscopy

1. hyperemia
2. irregularity in mucosa
3. increased mucus
4. lower airway collapse

9

Feline IAD: respiratory wash cytology

1. Bronchitis ==> Neutrophilic

2. Asthma ==> Eosinophilic

10

Feline IAD: treatment

1. Corticosteroids*
- Cornerstone of treatment, taper to lowest effective dose
- Oral (prednisone/prednisolone)
- Inhaled (fluticasone)
2. Bronchodilators
- Decrease airway constriction in acute asthma attacks
- NO effect on airway inflammation
3. +/- cough suppressants (dogs)
- break inflammatory cycle (dogs w/ a cough can develop into a quality of life issue, not really w/ cats)

11

Inhaled therapies

Delivered via metered dose inhaler into a spacer
- Fluticasone, albuterol

12

IAD: Treatment

1. weight loss
2. harness vs. a collar
3. environmental trigger avoidance (smoke, perfume, etc.)

13

IAD: Treatment goals

1. minimize clinical signs
2. SLOW AIRWAY REMODELING
- bronchiectasis
- pulmonary fibrosis
- pulmonary hypertension

Long-term management disease

14

Interstitial disease: eosinophilic bronchopneumopathy

1. interstitial lung disease characterized by infiltration with eosinophils
- peripheral eosinophilia common
2. Most cases iodiopathic
- Most commonly affects young dogs, arctic breeds, and Rottweilers predisposed*
- MUST rule out other causes of eosinophilic lung inflammation: parasites, neoplasia
3. Responds well to corticosteroids

15

Idiopathic Pulmonary Fibrosis

1. West Highland White Terriers
2. Diffuse inspiratory CRACKLES
3. Diffuse broncho-interstitial lung pattern
4. Dx: biopsy, rule out causes of secondary fibrosis
5. Prognosis: poor long-term (it's not reversible)

NOTE: pulmonary fibrosis can occur with any untreated lung disease

16

Bacterial Pneumonia

RARELY A PRIMARY DISEASE

1. Immunocompromised host
- young/old patient
- therapeutic steroids
- systemic disease (diabetes, Cushing's, FeLV/FIV)
- Lung disease (bronchitis, viral infection)
2. Recombency (can't protect their airway or cough)
- illness/sedation
3. Impaired host defenses
- congenital/acquired

17

Bacterial Pneumonia: causes

1. Respiratory tract not sterile to level of carina!!
- may be some normal flora past the carina too
2. 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)

18

Bordetella Bronchiseptica

#1 cause of community acquired infectious pneumonia in dogs <1 YEAR OF AGE

Bordetella is contagious!!!

19

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..)

20

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

21

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

22

Localization trend of Aspiration Pneumonia

1. Right Middle Lung Lobe
2. Right Cranial Lung Lobe
3. Caudal segment of Left Cranial lobe

BUT, normal rads in a suspicious patient does not rule aspiration pneumonia out

23

Bacterial Pneumonia - Empiric treatment

1. Uncomplicated disease
- NARROW spectrum, SINGLE therapy

Duration: 1-2 weeks post radiographic resolution (3-4 weeks)

2. Complicated/severe disease
- BROAD spectrum, combination therapy
- aerobic and anaerobic coverage, G+ and G- coverage
- Parenteral administration initially

Duration: 1-2 weeks post radiographic resolution (4-6weeks)

24

Nebulization

1. Loosens and moistens airway secretions
2. Improves expectoration

25

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)

26

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

27

Pulmonary Neoplasia

1. Metastatic*: most common!

2. Primary
- Commonly solitary/large nodule
- Tx: surgical excision +/- chemotherapy