Disease of the Pulmonary Parenchyma Flashcards
What are the general clinical signs of pulmonary parenchymal disease?
- cough
- exercise intolerance
- tachypnea
- excessive panting
- increased respiratory effort/ distress (mixed inspiration/ expiration effort)
What are the clinical signs generally associated with upper airway obstruction or pleural space disease?
- increased inspiratory effort
What are the clinical signs generally associated with lower airway/ bronchial disorders?
- increased expiratory effort
What is a potential rapid test to determine cardiogenic vs pulmonary cause of respiratory distress?
NT-pro-BNP
- BNP = brain natriuretic protein
- release when there is volume overload (ex. pulmonary hypertension, esp with cardiac dysfunction and failure
- antagonizes renin-angiotensin, promotes vasodilation, and increases diuresis through the kidneys
- could be one way to rapidly diagnose between cardiac or pulmonary cause respiratory distress (higher in cardiogenic cases)
- in cats, can use pleural fluids –> but also elevated with increased creatinine - can be difficult in patients with azotemia
- overall, still cannot completely replace other diagnostics, such as imaging
What’s the limitation of the tracheal lavage?
- may be negative if the disease is deeper down in the lungs in a patient with non-productive cough
- in those cases, a bronchioalveolar lavage would be more beneficial
What’s the limitation of pulmonary FNA?
- better if there is a discrete/ focal/ consolidated mass/ region
- not helpful if diffuse –> biopsy would be more useful (ex. pulmonary fibrosis)
What are some ddx for pulmonary parasites?
- eosinophilic pneumonia
- asthma
- bronchopneumonia
- pulmonary granulomatosis
- pulmonary neoplasia
What are some examples of pulmonary parasites?
- hookworms (ancylostoma) - young puppies
- lungworms (migrates from GI system)
- usual treatment = fenbendazole or ivermectin
What are some examples of pulmonary parenchymal parasites?
- lung fluke: bullae on rads. Coughing. crayfish ingestion
- filaroides: bronchoinsterstial to alveolar pattern. Coughing, respiratory distress. fecal-oral
What are some examples of airway parasites?
- feline lungworm (A. abstrusus), mimics feline asthma
- C. vupis, nematode, in dogs only
- O. osleri, can lead to secondary bacterial infection
- E. aerophilus, nematode, worldwide
- Troglostrongylus spp., also infects wild cats
What are some other parasites relevant to the lungs?
- heartworm (D. immitis)
- French heartworm (Angiostrongylus vasorum)
- ingestion of mollusk or frog
- similar to heartworm
- inflammatory response, chronic cough, general thriftiness
- bleeding diathesis
- CXR: bronchial, interstitial, and/ or peripheral alveolar lung patterns
- CT is better
What are some common bacteria that causes bacterial pneumonia?
it’s unusual for healthy adults (esp cats) to develop bacterial pneumonia - usually there is another inciting cause (other than kennel cough)
- enteric pathogens (E coli, Klebsiella)
- Pasteurella
- coagulase-positive staphylococci
- streptoccoci
- Mycoplasma spp
- bordetella bronchiseptica
What are common presentations of bacterial penumonia?
- extremes in age, immunocompromised, or other predisposing factors
- coughing, nasal discharge, exercise intolerance, respiratory distress
- anorexia, lethargy
- fever not always present
What are some typical CBC changes that could be noted in patients with bacterial pneumonia?
- neutrophilia +/- left shit, anemia, lymphopenia
- CXR: alveolar pattern, ventral distribution
- caudodorsal distribution – hematogenous spread
- need to identify pulmonary sepsis - tracheal or bronchiolar lavage
- watch for commensal bacteria in tracheal lavage
- Mycoplasma require PCR rather than just culture
- empiric treatment = inappropriate in about 1/4 of patients, almost 2/3 if had previous antibiotic therapy
What are the treatments for bacterial pneumonia?
- Antibiotics
- ideally based on culture & sensitivity results
- empirical can start with Clavamox +/- TMS; may need a flouroquinolone in severe cases
- aim for 10-14 days - O2 supplementation
- start with PaO2 < 80mm Hg or SpO2 < 94% - Fluid therapy
- dehydration makes the cilia “stuck” in the gel layer, therefore reducing the efficacy - Ancillary therapy
- Coupage
- mucolytic, ex. n-acetylcystein (NAC)
- lung lobectomy
What kinds of infection is due to Bordetella bronchiseptica?
tracheobronchitis
- releases entoxins that impairs the mucociliary escalator
- contagious, more common in dogs than cats
- can be difficult to eliminate even with the appropriate antibiotics
What kind of infection is due to steptococcus equi Subspecies Zooepidemicus?
necrotizing hemorrhagic pneumonia
- severe, sometimes fatal
- kennel setting
What kind of infection is due to Mycoplasma?
difficult to culture, PCR is needed
- likely an opportunistic bacteria
- do NOT use beta lactams as it lacks cell wall
What kinds of infection is due to Mycobacterium?
TB and non-TB type infections
- generally granulomatous, with lymphadenopathy, pleural effusions, interstitial to alveolar infiltrates
- zoonotic
- prolonged antibiotic therapy
What kind of infection is due Yersinia pestis?
Plague!
- cats, dogs appear resistant
- must be a ddx for feline pneumonia in endemic areas
- lymphadenitis –> mandibular/ cervical nodes. bubonic plague
- can then develop into pneumonia
- can FNA the affected lymph nodes to get a diagnosis
- universally fatal if pneumonia left untreated
What are some examples of viral penumonia?
Dogs:
- canine distemper
- canine influenza virus (H3N8 and H3N2)
- canine parainfluenza virus
- canine herpes virus
- canine infectious hepatitis
Cats:
- feline calicivirus
- feline herpes virus
- feline infectious peritonitis/ coronavirus
What are some clinical signs associated with the influenza virus?
dogs: H3N2 (avian), H2N8 (equine)
- cough, lethargy, fever
- highly contagious
- marked morbidity but low mortality
Cats: H5N1
- less frequent
- could be life threatening
What’s the most common protozoal pneumonia?
protozoal pneumonia is uncommon in both cats and dogs
- Toxoplasma gondii = most common one in cats
- can involve GI, respiratory, CNS, abdominal viscera, eyes, and heart
- Tx = potentiated sulfonamides or clindamycin
- often see rapid improvement, but recurrence is possible
What are some common mycotic pneumonia?
Blastomycosis, histoplasmosis, coccidiosis
- progressive, lower respiratory disease
- extrathoracic signs also possible – weight loss, anorexia, lymphadenopathy
- Tx = expensive and potentially toxic, therefore, need definitive diagnosis
- Diagnosis can be done with extrathoracic sites
