Lower Respiratory Disease 1 & 2 Past Paper PDF

Lower respiratory disease 1 & 2 Amber Harris, DVM, DACVIM(SAIM) Assistant Professor LAMS 5333 January 22, 2025 Outline Brief introduction to coughing (respiratory view) Triggers Characteristics Diagnostic tests (overview) Common causes of lower respiratory disease (dogs/cats) Infectious...

Lower respiratory disease 1 & 2 Amber Harris, DVM, DACVIM(SAIM) Assistant Professor LAMS 5333 January 22, 2025 Outline Brief introduction to coughing (respiratory view) Triggers Characteristics Diagnostic tests (overview) Common causes of lower respiratory disease (dogs/cats) Infectious* Viral Bacterial Fungal Inflammatory Feline asthma Canine chronic bronchitis Eosinophilic bronchopneumopathy COUGHING Trigger??? Owner smokes Perfume/cologne Air fresheners Household cleaners Dusty cat litter House construction Stress/exercise Cervical pressure Pollution Mold, pollen, etc. Environmental exposures??? Boarded/Groomed/Daycare/Dog park? Travel history? Sick housemates? Indoor/outdoor status (cats) Heartworm prevention??? Environmental exposure? “Fluffy eats other dogs’ poop.” Filaroides, Eucoleus??? “Rocco travels to Tucson with us every winter.” Coccidiomycosis??? “Mittens loves to bring us dead birds.” Aleurostrongylus??? Non-productive cough Usually loud, harsh, dry, +/- paroxysmal 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 (aka Kennel cough) Non-productive cough Terminal retch Productive cough Expectoration of sputum Fluid / mucus / debris from the lower airways = Commonly associated with: Lower airway or parenchymal diseases Infectious (eg. pneumonia) Inflammatory (eg. bronchitis / asthma) Edema If owner thinks productive… it typically is… Productive cough Typically softer in volume, “huff” Less likely to be paroxysmal (aka “coughing fit”) May be difficult to appreciate: Swallows sputum Owner perceives as “vomiting” Terminal retch = NOT productive typically “Huffing” cough CATS → Coughing is RARE When present should pursue aggressively Most commonly lower airway disease (asthma) Tracheal disease… (uncommon cause) Pleural space disease… (rare cause) Owners often confuse with a sneeze Coughing Diagnostics OVERVIEW DDX list → Diagnostic plan Common “first-tier” tests: Complete Blood Count Thoracic radiographs (+/- cervical) Fecal exam Float, sedimentation, Baermann Heartworm testing Cytology Fine need aspirate (FNA) Skin lesions/masses, lymph nodes nasal discharge 2nd & 3rd Tier Testing Chemistry panel Advanced imaging Fluoroscopy, ultrasound, CT Urinalysis Fungal antigen titers Bronchoscopy Infectious testing Respiratory sampling Respiratory PCR, titers Airway = TTW, ETW, BAL Parenchyma = lung Cardiac testing aspirate Echocardiogram NT-pro-BNP Transtracheal / Endotracheal Wash Diffuse disease Ex. bronchitis, asthma Disease must involve airway! Theory: Push sterile fluid into airway Aspirate out bronchial fluid Analyze Transtracheal wash (TTW) Patient awake or lightly sedated Shave & aseptically prep ventral neck Use sterile saline aliquots for instillation Aspirate saline; patient must cough Endotracheal Wash (ETW)/Blind BAL Patient briefly anesthetized with sterile intubation! Saline aliquot squirted down ET tube Suction catheter inserted down ET tube Patient coupaged during aspiration Sterile intubation ETW / Blind BAL Right-sided pneumonia Proper coupage Bronchoalveolar lavage (BAL) Localized or diffuse disease Can sample a specific location Generally samples deeper in lung Sterile intubation & anesthesia Catheter lodged in lower airway Standard = bronchoscopy-guided Blind = without bronchoscope Requires smaller aliquot volume May require coupage Wash fluid diagnostics Cytology Cellular infiltrate? Bacteria present? Fungal organisms? Infectious testing Reference Ranges Bacterial cultures Aerobic - Neutrophils Upper respiratory tract Purulent bronchitis Canine Influenza virus 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 – secondary bacterial infection) Nasal / ocular discharge Serous to mucopurulent Systemic signs: fever, lethargy, anorexia CIRDC pathogenesis Source of infection: Respiratory secretions Environmental contamination Transmission: Close or direct contact Aerosolization +/- fomites HIGHLY contagious High morbidity… LOW mortality CIRDC pathogenesis Incubation period: Exposure to onset ~7 days post-infection of clinical signs Pathogen shedding: Most < 2 weeks Exceptions (weeks to months): Bordetella Mycoplasma Distemper virus Strep? Herpes??? Can start prior to showing clinical signs!!! As early as 24 hours! Can continue after recovery!  Pathogen shedding Incubation Clinical disease Infection ~7days ~7days Recovery  Hack… cough Incubation ~7 days Exposure & infection Can start shedding Onset of within 24 hours clinical signs I’m going to live forever! Clinical disease Environmental contamination & & persistence Shedding < 7 - 14 days Recovery CIRDC diagnosis Signalment & History Young? Immune-compromised? Recent exposure? Vaccinated? Normal Clinical signs Harsh, dry cough Often non-productive Typically inducible CIRDC Paroxysmal Usually otherwise healthy Canine respiratory PCR CIRDC management Most cases are: Mild, uncomplicated AND Self-limiting Resolve within 7 days Manage as an outpatient If possible Isolation and supportive care – K9 influenza Think Before Antibiotics! 2019 CIRDC surveillance program 1602 sick dogs… 14% Bordetella + Antibiotic use  25% over past 5 years No  in infection rates or poorer outcomes Asymptomatic dogs arriving at U.S. shelter 503 dogs… 30% Mycoplasma + Just because they are there… does NOT mean they are a problem! 19.5% Bordetella + When should I ideally treat??? Persistent (>7 days) non-productive cough Complicated / progressive disease Juveniles (7 days) non-productive cough Step 1: Anti-inflammatory +/- antitussive Step 2: Doxycycline (5mg/kg PO q12h for 7-14d) Minocycline (5-10 mg/kg q12h) Severe, progressive, or complicated disease Doxycycline or minocycline Pneumonia? Juveniles (> Dog Traumatic Penetrating injury Open wound Proulx et al, JVECC 2014 Community-acquired pneumonia Bordetella bronchiseptica Influenza also predisposes to Most common CAP in dogs pneumonia Especially important in dogs > Anaerobes Bacterial pneumonia: clinical findings Lethargy / “ADR” Fever Reduced appetite Cough Productive, huffing Exercise intolerance Tachypnea / dyspnea +/- nasal discharge Most common in cats +/- crackles History is important! Known medical conditions? Recent pathogen exposure? Can present over wide spectrum of clinical severity Bacterial pneumonia: diagnosis CBC Inflammatory leukogram Other testing as Left shift? Toxic change? indicated looking for: causative or Thoracic radiographs contributory disease(s) 3-view (Rt, Lt, VD or DV) HW test? Pulse ox / blood gas FeLV/FIV? Airway wash Culture & sensitivity  Aspiration pneumonia *** RIGHT MIDDLE LUNG LOBE *** Right cranial lobe Caudal subsegment of left cranial lobe  Bacterial pneumonia empiric treatment Uncomplicated (mild) disease Narrow spectrum, single therapy Amoxicillin / Amoxicillin clavulanate Cephalexin KCS Trimethoprim sulfamethoxazole (TMS) Suppress thyroid Doxycycline (Bordetella, Mycoplasma) Hepatopathy Immune reactions Azithromycin (cats) Duration: ~7-14 days No longer until radiographic resolution!! May monitor CRP normalization for treatment duration Bacterial pneumonia empiric treatment Complicated (severe) disease Broad-spectrum, combination therapy Amoxicillin clavulanate / Ampicillin sulbactam Clindamycin Ideally wash + PLUS + & 2nd/3rd generation cephalosporin OR culture/sensitivity Fluoroquinolone (i.e. enro- marbo-, pradofloxacin) OR Metronidazole (aspiration) OR Amikacin (severe or drug-resistant infections) Duration: often 2-4 weeks Empiric Antibiotic Selection Multi-drug resistance present in ~25% of cases Resistance to 3 or more drug classes Recent antibiotic use =  risk Resistance to empiric antibiotic in ~25 - 50% Why culture & sensitivity is so IMPORTANT!!! Overall pneumonia survival = ~ 85% Community-acquired = ~ 96% Aspiration = ~ 83% The more lung lobes involved = the worse the prognosis Black et al, 2009 Infectious FUNGAL PNEUMONIAS Fungal Pneumonia Blastomyces dermatitidis Histoplasma capsulatum Coccidioides immitis Southwest US (esp. Arizona) Cryptococcus neoformans Feline nasal granuloma pathogen Clinical Findings Respiratory signs NOT commonly present! ~60% have NO respiratory signs at time of diagnosis! 75% have other systemic signs Fever – lethargy – anorexia – weight loss Other possible findings: Chorioretinitis / uveitis Lameness, bone pain Lymphadenopathy Cutaneous or dermal lesions / nodules Fungal pneumonia work up CBC & Chemistry Thoracic radiographs Non-regen anemia Miliary or nodular pattern Inflammation Solitary mass / granuloma Eosinophilia? Urine antigen testing Low albumin? High globulins? Cytology Airway wash Fine needle aspirate Lymph node Skin lesions, nodules Lung Pulmonary mycoses treatment Itraconazole Hepatotoxicity 5 – 10 mg/kg q24h PO Blood dyscrasias Fluconazole 5 – 10 mg/kg q12h PO Hepatotoxicity Amphotericin B (liposomal) Nephrotoxicity Minimum 3-6 months +! Will often get worse before improving May require intensive supportive care, O2 support! Disease processes INFLAMMATORY AIRWAY DISEASE Inflammatory airway diseases Feline Asthma & Bronchitis Prevalence ~1 - 5% Siamese over-represented? Eosinophilic inflammation Canine Chronic Bronchitis Exact prevalence unknown “Moderately common…” Co-morbid diseases often present Neutrophilic inflammation Often diagnosed in middle-age (median age ~ 4 - 8y)  Why are you sending inflammatory cells to your lungs!?! Pathophysiology? Likely multi-factorial Prior single resp insult? Chronic irritant exposure or repeated injury? Culmination of many small insults overtime? Reinero et al. JVIM 2018  Clinical signs Chronic cough Expiratory dyspnea Starts as non-productive Prolonged expiration (… at least initially) “Expiratory push” Tachypnea at rest Exercise intolerance Problem with cats: 1. Signs may only be intermittent 2. Signs often seem not severe… Acute respiratory distress (emergent presentation) Cats >> Dogs  Chronically untreated = Permanent airway remodeling Problem = Airflow Limitation Smooth muscle hypertrophy & reactivity… Mucosal infiltration & edema Goblet cell hypertrophy & Epithelial cell hypertrophy  mucus production & metaplasia Impeded air movement thru airways caused by: inflammation, secretions, & smooth muscle contraction Bronchiolar disease “Doughnuts/Donuts” “Tramlines” Broncho-interstitial Bronchiolar disease “Doughnuts/Donuts” “Tramlines” Broncho-interstitial Airway Reactivity Chronic Bronchitis Little to no spontaneous bronchoconstriction (static narrowing) Feline Asthma Reversible spontaneous bronchoconstriction (dynamic narrowing) Work Up Physical exam Wheezes? CBC Evidence of inflammation? Diagnosis Eosinophilia? of Thoracic radiographs exclusion Infectious screening Heartworm Ag +/- Ab Fecal float / sedimentation Fecal Baermann Respiratory PCR panel Airway wash + cytology!!  “Donuts” & “Tram lines” Broncho-interstitial “Classic” Asthma Radiographs Can be normal in up to 25%!!! Broncho-interstitial pattern - Increased lucency Pulmonary hyperinflation - Flattened / caudally displaced diaphragm Right middle lobe atelectasis - Mucus plugging Rib fractures? Why?! Airflow limitation Positive intra-thoracic pressure on expiration Air trapping WHEEZE End-stage disease: Pulmonary fibrosis Airway remodeling - Bronchomalacia - Bronchiectasis Pulmonary hypertension Treatment Bronchitis Asthma Glucocorticoids Glucocorticoids Oral/inhaled Oral/inhaled +/- bronchodilators Bronchodilators Maintenance vs. Rescue +/- antitussives Use only if needed May mask response? Break inflammatory cycle Empiric deworming? Fenbendazole 50mg/kg PO q24h for 14 days AeroKat / AeroDawg Training of patient & owner required Patient must acclimate to using mask Owner must practice using device!!! Bronchodilators Reverse spontaneous bronchoconstriction Asthma Other benefits: Anti-inflammatory synergism with steroids Stimulate mucociliary clearance Reduce respiratory effort Prevent respiratory fatigue = methylxanthines Improve pulmonary perfusion Improve expiratory airflow Other Considerations Weight loss Harness vs. collar Environmental trigger avoidance  Treatment Goals Resolve clinical signs Resolved cough resolved inflammation Prevent remodeling: Bronchiectasis Pulmonary fibrosis Pulmonary hypertension Cor pulmonale Monitoring & treatment decisions are ideally based on repeated airway washes & cytology End-stage Airway Disease Eosinophilic Bronchopneumopathy Typically idiopathic Eosinophilic infiltration of pulmonary interstitium Eosinophilic infiltrate on airway wash Over-represented breeds: Rottweiler, Husky, Malamute Radiographic findings variable DDX Localized… Diffuse… Multi-focal Neoplasia Interstitial… Alveolar… Nodular… Mass-like Fungal Treatment: oral steroids (1.0 – 2.0 mg/kg/d) Less responsive to inhaled therapy to control Can often taper to lower dose or eventually stop Can maintain control with inhaler (if needed) Cannone et al. JSAP 2016  5y FS Chow mix Presentation Chief complaint: chronic cough 4 weeks post-pred Questions??? [email protected]