Lower Respiratory Disease Flashcards
describe non-productive cough
- usually loud, harsh, dry
-can be a goose honk
-often paroxysmal (coughing fits)
-often inducible with cervical palpation - commonly associated with:
-upper airway disease!!
–tracheal or bronchial collapse
–infectious tracheobronchitis (kennel cough)
describe a productive cough
- expectoration of sputum: fluid, mucus, debris from the LOWER airways
- commonly associated with:
-lower airway or parenchymal diseases: infectious (pneumonia) or inflammatory (bronchitis, asthma)
-edema
-if the owner thinks it’s productive, it typically is
- typically softer in volume, like a huff
-may be difficult to appreciate if pet swallows sputum or owner perceives as vomiting - less likely to be paroxysmal
terminal retch = NOT productive typically
describe coughing in cats
- RARE!! when present, pursue AGGRESSIVELY
- most commonly lower airway disease (asthma)
-tracheal disease (uncommon)
-pleural space disease (RARE cause of cough) - owners often confuse with a sneeze
describe common first tier diagnostics for coughing (5)
- CBC
- thoracic rads (+/- cervical)
- fecal exam: float, sedimentation, Baermann
- heartworm testing
- cytology:
-FNA: skin lesions/masses, LNs
-nasal discharge
describe 2nd and 3rd tier diagnostics for coughing (7)
- chem panel
- urinalysis: fungal antigen titers
- infectious testing: respiratory PCR, TITERS
- cardiac testing: echocardiogram, NTproBNP
- advanced imaging: fluoroscopy, US, CT
- bronchoscopy
- respiratory sampling:
-airway: TTW, ETW, BAL
-parenchyma: lung aspirate
describe transtracheal/endotracheal wash
- for DIFFUSE disease diagnosis
-bronchitis, asthma - disease MUST involve AIRWAY
- theory:
-push sterile fluid into airway
-aspirate out bronchial fluid
-analyze - TTW:
-patient awake/lightly sedated
-shave and prep ventral neck
-use sterile saline aliquots for instillation
-aspirate saline, patient must cough - ETW:
-patient briefly anesthetized with sterile intubation!!
-saline aliquot squirt down ET tube
-suction catheter down ET tube
-patient coupaged during aspiration to help clear mucus and secretions
describe BAL
- to diagnosis localized or diffuse disease
-can sample a specific location
-generally samples deeper in the lung - sterile intubation and anesthesia
- catheter lodged in lower airway
-standard: bronchoscopy guided
-blind: without bronchoscope - requires smaller aliquot volume
-may require coupage
describe wash fluid diagnostics
- cytology:
-cellular infiltrate, bacterial or fungal presence - infectious testing:
-bacterial cultures: aerobic and anaerobic
-respiratory PCR: mycoplasma, +/- full panel - reference ranges:
-neutrophils <5%
-eosinophils <17-20%
-mononuclear: 70% macrophages, 5% lymphocytes
describe respiratory PCR
- performed on
-oropharyngeal +/- nasal +/- conjunctival swab
–influenza: deep nasal
–distemper: conjunctival
-airway wash
- IFA for organism ID also
- some organisms can be isolated normally from healthy dogs (commensals)
-presence does NOT always = cause of disease
describe fungal specific diagnostics
- cytology and histology
-blastomyces dermatidis: big blue broad-based budding yeast
-histoplasma capsulatum: small narrow-based budding yeast with halo around the edge
-coccidoides immitis, posadasii:
-round double-walled structure
-may be difficult/costly to perform
- mira vista urine antigen EIA:
-detects wall galactomannan antigen, which is excreted in urine
-cannot distinguish blastomyces from histoplasma
-used to monitor response to therapy or relapse - coccidoides:
-mira vista canine IgG antibody EIA + antibody by immunodiffusion: serum, CSF, plasma
-antigen quantitative EIA for treatment monitoring
list common canine infectious respiratory disease complex (CIRDC) pathogens
most commonly VIRAL origin
- parainfluenza virus
- adenovirus type-2
- herpesvirus-1
- distemper virus
- respiratory corona virus
- pneumovirus
- influenza virus
*kennel cough is NOT synonymous with bordetella infection!!
-co-infections are common with multiple viruses or virus + bacteria (bordetella bronchiseptica, mycoplasma spp., strep equi or zooepidemicus)
-co-infections increase disease severity!!
describe parainfluenza virus (cPiV)
- enveloped ssRNA virus
- paramyxoviridae (distemper and pneumovirus)
- replicate in upper airway
describe adenovirus type-2 (CAV-2)
- non-enveloped dsDNA virus
- replicates in upper and lower airways
describe bordetella bronchiseptica
- aerobic, gram negative coccobacillus
- highly contagious
-dogs to cats to dogs to sick people!! - replicates on ciliated epithelium
- virulence factors/toxins:
-paralyzes cilia
-impairs phagocytosis
-invades intracellularly to avoid immune detection
describe mycoplasma spp.
- fastidious bacteria that lack a cell wall= very difficult to culture/isolate
- colonized ciliated and non-ciliated epithelium
-lower > upper resp tract
-likes to cause purulent bronchitis
describe canine influenza virus
- strains:
-H3N8: minor continued circulation in NE US
-H3N2: reportable in some states!! - often mimic kennel cough:
-majority develop mild signs of illness
-signs:
–non-productive cough (+/- productive if secondary bacterial infection)
–nasal/ocular discharge: serous to mucopurulent
–systemic signs: fever, lethargy, anorexia
describe CIRDC pathogenesis
- source of infection:
-respiratory secretions
-environmental contamination - transmission:
-close or direct contact
-aerosolization
- +/- fomites
-HIGHLY contagious: high morbidity, low mortality - incubation period: approx 7 days post infection
- pathogen shedding:
-most <2 weeks
-exceptions (weeks to months): bordetella, mycoplasma, distemper virus, strep and herpes
-shedding can start PRIOR to showing clinical signs: as early as 24 hours post infection and can continue after recovery!!
describe CIRDC diagnosis
- signalment and history:
-young, immunocompromised, recent exposure, vaccinated - clinical signs:
-harsh, DRY cough: often non productive, typically inducible, paroxysmal
-usually otherwise healthy - canine respiratory PCR
describe CIRDC management
- most cases are:
-mild, uncomplicated, AND self-limiting (resolve within 7 days) - manage as outpatient if possible
- isolation and supportive care if canine influenza!!
- THINK before antibiotic use!
-rarely shown to help! just bc bacteria are found does NOT mean they are a problem - ideally treat when:
-persistent (>7 days) non-productive cough
-complicated/progressive disease
-juveniles (6-8weeks old)
-anytime you feel quality of life is negatively impacted by cough
what should you treat CIRDC with?
- persistent (>7d) NON PRODUCTIVE cough:
-step 1: anti-inflammatory +/- antitussive
-step 2: doxycycline or minocycline - severe, progressive, or complicated disease
-doxycycline or minocycline - juvelines (6-8wks):
-clavamox
-doxycycline: DONT give to pregnant/nursing bitches!
describe CIRDC prevention
- DHPP vx
D = distemper
H = infectious hepatitis (adenovirus type-1); CAV-2 is usually in vaccine so cross-protective
P = parainfluenza virus - +/- influenza vx if at risk population
- will reduce disease incidence, severity, and shedding
describe bordetella bronchoiseptica vaccination
- ML intranasal:
- +/- viral pathogens
-faster immunity: approx 72 hours, occurs with maternal abx
-can initiate younger (approx 3 weeks of age)
-reduces shedding
-accidental injection associated with: severe injection site reaction, hepatic necrosis, death!!!! - parenteral:
-B. bronchioseptica Ag only
-immunity requires booster 1-2 weeks after 2nd injection
-initiate at 6 weeks
when is cough suppression CONTRAINDICATED?
- productive cough
- infectious disease
coughing is a protective mechanism!
describe how bacterial pneumonia occurs
doesn’t just happen! need to consider WHY host defenses impaired
- congenital defect: ciliary dyskinesia
- immune compromise: iatrogenic or comorbidity
- prolonged recumbency: sedation, anesthesia, critical illness
- disease-induced: bronchitis/asthma, viral, laryngeal paralysis, regurgitation
describe bacterial pneumonia routes of infection
respiratory tract is UNsterile to the level of the carina!!
routes:
- aspiration
- community-acquired
-bordetella bronchiseptica most common CAP in dogs!
-esp important in dogs <1 year (CAP avg age approx 5 months) - hematogenous:
-cat > dog - traumatic: penetrating injury, open wound
describe aspiration pneumonia
- MOST COMMON cause of pneumonia in ADULT dogs
- healthy stomach/upper GI is POORLY colonized by bacteria
-initial problem is airway irritation and caustic injury (pneumonitis is NOT pneumonia)
-things that increase number of gastric bacteria: use of antacids, oral disease, intestinal ileus, enteral feeding - many dogs with aspiration pneumonia have a history of vomiting or recent anesthesia
- common co-morbidities:
-regurgitation
-megaesophagus
-laryngeal paralysis
-myasthenia gravis - most commonly isolated oganisms: (aerobes > anaerobes)
-E. COLI!!!!!!!!!
-klebsiella
-strep, staph
-enterobacter
-enterococcus
-mysoplasma
-pasteurella
-pseudomona
-proteus
describe common clinical findings of bacterial pneumonia
- lethargy/ADR
- reduced appetite
- exercise intolerance
- TACHYPNEA/dyspnea
-most common in cats - fever
- cough: productive, huffing
- +/- nasal discharge
- +/- crackles
HISTORY is important!! need to gather known medical conditions and recent pathogen exposure
describe bacterial pneumonia diagnosis
- CBC: inflammatory leukogram, maybe with a left shift or toxic changes
- thoracic radiographs: 3-view
-RIGHT MIDDLE LUNG LOBE!!!
-right cranial love
-caudal subsegment of left cranial lobe - pulse ox with blood gas
- airway wash: C&S
- other testing as indicated looking for causative or contributory disease: HW, FeLV/FIV
describe bacterial pneumonia empiric treatment
- uncomplicated/mild disease:
-narrow spectrum/single therapy
-amoxicillin/clav
-cephalexin
-TMS: remember side effects of KCS, thyroid suppression, hepatopathy, immune reactions
-doxycycline (bordetella, mycoplasma)
-azithromycin (cats)
-for 7-14d (NOT radiographic resolution) - complicated/severe disease:
-broad spectrum/combination therapy; ideally wash and C&S
-amoxi calv/amoxi sulbactam
-clindamycin
PLUS
-2nd or 3rd gen cephalosporin
OR
-fluroquinolone (floxacin)
PR
-metronidazole (aspiration)
OR
-amikacin (severe or drug-resistant infections)
-for 2-4 weeks
the more lung lobes involved, the worse the prognosis, developing resistance to antibiotics :(
list 4 causative agents of fungal pneumonia
- blastomyces dematitidis
- histoplasma capsulatum
- coccidioides immitis: southwest US (esp arizona)
- cryptococcus neoformans
-feline nasal granuloma pathogen
describe clinical findings of fungal pneumonia
- respiratory signs NOT commonly present
-60% have no resp signs at time of dx - 75% have OTHER systemic signs
-fever, lethargy, anorexia, weight loss - other possible findings
-chorioretinitis/uveitis
-lameness, bone pain
-lymphadenopathy
-cutaneous or dermal lesions/nodules
describe fungal pneumonia workup
- CBC and chem
-nonregen anemia
-inflammation - cytology:
-airway wash
-FNA: LNs, skin lesions/nodules, lungs - thoracic rads:
-miliary or nodular pattern
-solitary mass/granuloma - urine antigen testing
describe pulmonary mycoses treatment
- itraconazole: hepatotoxicity, blood dyscrasias
- fluconazole: hepatotoxicity
- amphotericin B (liposomal): nephrotoxicity
for a minimum of 3-6 months!!
- will often get worse before improving
-may require intensive supportive care, O2 support
what are two common inflammatory airway disease?
- feline asthma and bronchitis
-prevalence 1-5%, possible siamese overrepresentation
-eosinophilic inflammation - canine chronic bronchitis
-exact prevalence unknown; moderately common, co-morbid diseases OFTEN present
-neutrophilic inflammation
often diagnosed in middle age (4-8 yrs)
describe pathology and clinical signs of inflammatory airway diseases
pathology: likely multifactorial
-why sending inflam cells to lungs?
-prior single resp insult, chronic irritant exposure or repeated injury, culmination of many small insults over time
clinical signs:
1. chronic cough: starts as non-productive
- tachypnea at rest
- expiratory dyspnea: prolonged expiration, expiratory push
- exercise intolerance
issues with cats:
-signs may only be intermittent and may not seem severe so
-acute respiratory distress emergent presentation much more common in cats than dogs!!
what is the big issue with inflammatory airway diseases?
- if chronically untreated, leads to permanent airway remodeling:
-smooth muscle hypertrophy and reactivity
-mucosal infiltration and edema
-goblet cell hypertrophy and increased mucus production
-epithelial cell hypertrophy and metaplasia
- these changes impede air movement through airways via
-inflammation, secretions, and smooth muscle contraction
compare airway reactivity between chronic bronchitis and feline asthma
chronic bronchitis:
-little to no spontaneous bronchoconstriction
-static narrowing
feline asthma:
-reversible! spontaneous bronchoconstriction
-dynamic narrowing
describe the workup for inflammatory airway disease
a diagnosis of exclusion!
- physical exam: wheezes
-airflow limitation + positive intra-thoracic pressure on expiration causes air trapping = wheezes - CBC: evidence of inflammation or eosinophilia
- thoracic rads
-bronchial pattern: donuts and tram lines - infectious screening:
-heartworm Ag +/- Ab
-fecal float/sedimentation
-fecal baermann
-respiratory PCR panel
5 airway wash + cytology!!
describe classic asthma radiographs
can be normal in 25% of cases!!
- broncho-interstital pattern
- pulmonary hyperinflation: increased lucency, flattened/caudally displaced diaphragm
- right middle lung lobe atelectasis: mucus plugging
- +/- rib fractures
describe end-stage inflammatory airway disease radiographs
- pulmonary fibrosis
- airway remodeling:
-bronchomalacia
-bronchiectasis - pulmonary hypertension
describe treatment of inflammatory airway disease
bronchitis:
1. glucocorticoids: oral/inhaled
2. +/- bronchodilators
3. +/- antiitussives: use only if needed, may mask response, but could break inflammatory cycle
asthma:
1. glucocorticoids: oral/inhaled
2. bronchodilators: maintenance vs. rescue
empiric deworming: fenbendazole for 14 days
-aeroKat/aeroDawg: training of owner and patient required!! patient must acclimate and owner must practice!!
-other considerations:
–weight loss, harness vs collar, environmental trigger avoidance
describe bronchodilators
- reverse spontaneous bronchoconstriction as seen in asthma
- other benefits:
-anti-inflammatory synergism with steroids
-stimulate mucociliary clearance
-reduce respiratory effort: prevent respiratory fatigue via methylxanthines
-improve pulmonary perfusion
-improve expiratory airflow
describe treatment goals of inflammatory airway disease
- resolve clinical signs
-resolved cough does NOT mean resolved inflammation - prevent remodeling:
-bronchiectasis
-pulmonary fibrosis
-pulmonary hypertension
-cor pulmonale - monitoring and treatment decisions are ideally based on repeated airway washes and cytology
describe eosinophilic bronchoopneumonopathy
- typically idiopathic
-eosinophilic inflammation fo pulmonar interstitium
–eosinophilic infiltrate on airway wash
-overrepresented breeds: rottweiler, husky, malamute - radiographic findings variable
- ddx: neoplasia, fungal
- treatment:
-oral steroids
-less responsive to inhaled therapy to control
-can often taper to lower dose or eventually stop
-can maintain control with inhaler if needed
