Pulmonary Parenchymal Disease Flashcards
What causes lung sounds seen in lung disease?
lung parenchyma fills with fluid (edema) or inflammatory cells (pneumonia), causing it to become less compliant and harder for the patient to breath
- tachypnea = increased rate
- hyperpnea = deeper breaths
- dyspnea = increased effort
What is the most common cause of pneumonia in dogs? What is the most characteristic sign? What else is seen?
bacterial
deep productive cough
- expiratory dyspnea
- tachypnea
- nasal discharge
- exercise intolerance, cyanosis, collapse
- SYSTEMIC: fever, lethargy, poor appetite
What is commonly seen on physical exams on patients with pneumonia?
- abnormal posture (orthopnea)
- abnormal lung sounds
- fever
- respiratory distress
- mucopurulent nasal discharge
- cyanosis
Diagnostics for lower airway disease:
What is important to note about radiographic changes of diseased lungs?
radiographic changes can lag behind clinical signs. of disease with pneumonia by about 1-2 days
- may not see anything on radiographs with acute disease
What does a vascular pattern on thoracic radiographs indicate? What are 3 causes?
enlarged and/or tortuous blood vessels result in increased soft tissue opacity in the lungs
- enlarged arteries
- elarged veins
- enlarged arteries and veins
What are the 3 causes of enlarged arteries seen on thoracic radiographs? Enlarged veins?
- heartworm disease
- pulmonary thromboembolism
- pulmonary hypertension
left-sided heart failure
What are 4 causes of enlarged arteries and veins (pulmonary overcirculation) seen on thoracic radiographs?
- left-to-right shunts
- patent ductus arteriosus
- ventricular septal defect
- atrial septal defect
What causes bronchial patterns on thoracic radiographs? What are some causes?
inflammation around the airways
- canine chronic bronchitis
- feline idiopathic bronchitis
- allergic bronchitis
- canine infectious respiratory disease complex (kennel cough)
- bacterial/Mycoplasmal infection
- pulmonary parasites
What causes alveolar patterns on thoracic radiographs? What are some causes?
airways stand out and are lined
- pulmonary edema
- severe inflammatory disease
- bacterial/aspiration/fungal pneumonia
- hemorrhage
- pulmonary contusion/thromboembolism
- neoplasia
- systemic coagulopathy
What causes nodular interstitial patterns? What are some examples?
nodular growths on lungs change its opacity
- neoplasia
- mycotic infection
- Blastomycosis/Histoplasmosis/Coccidiomycosis
- pulmonary parasites
- Aelurostrongylus/Paragnimus infection
- abscess/bacterial pneumonia
- FB
- eosinophilic lung disease
- idiopathic interstitial pneumonia
- inactive lesions
What causes interstitial patterns on thoracic radiographs? What are some examples?
subtle pattern on lung tissue
- mild pulmonary edema
- viral/bacterial/mycotic pneumonia
- Toxoplasmosis
- parasitic infection (more often bronchial/nodular)
- neoplasia
- eosinophilic lung disease
- idiopathic pulmonary fibrosis
- mild hemorrhage
How can lung lobe consolidation and atelectasis be differentiated on radiographs?
CONSOLIDATION = soft tissue opacity maintains space that the lobe fills, indicating it is filled with something
ATELECTASIS = opacity is secondary to airway obstruction or absorbed air, causing the lung lobe to collapse and lose volume, which can also cause shifting of the heart
How are cavitary lesions seen on thoracic radiographs?
localized accumulations of air or fluid due to rupture of bullae, blebs, abscesses, or cysts, and emphysema
How can lung lobe torsion be seen on thoracic radiographs?
vesicular gas pattern and alveolar patterns with abrupt truncation near the hilus
- air is trapped in the lung lobe
How is ultrasound used as a diagnostic for lower airway disease?
cannot see through air, but can see fluid-filled or dense tissue
In what situation is CT and MRI a good diagnostic for lower airway disease?
small nodules and suspected fibrosis
In what 2 situations is nuclear imaging especially helpful in diagnosing lower respiratory disease?
- can measure mucociliary clearance by placing a drop of technetium-labeled albumin at the carina and observing its movement with a gamma camera for diagnosing ciliary dyskinesia
- can measure pulmonary perfusion and ventilation for diagnosing pulmonary thomboembolism
For what 7 organisms is serology a helpful diagnostic?
- Histoplasmosis
- Blastomycosis
- Coccidiomycosis
- Toxoplasma
- Feline Coronavirus
- Cryptococcus
- Heartworm tests
For what 2 organisms is urine antigen testing a useful diagnostic?
- Histoplasmosis
- Blastomycosis (more sensitive than serology)
What cardiovascular marker can be used for diagnosing lung disease? Why is it used?
NT-proBNP —> hormone produced by cardiac muscle cells in response to cellular stretch
can be used as an in-house test to tell if an animal with trouble breathing is caused by cardiac or respiratory disease
How are NT-proBNP levels used for diagnosing cardiovascular or respiratory causes of coughing?
- normal/low NT-proBNP = respiratory cause more likely
- elevated NT-proBNP = cardiac disease associated
can have more than one issue, need full assessment still
How is blood gas used as a diagnostic for lung disease?
in severe cases of impeding respiratory failure, there will be hypercarbia with concurrent respiratory acidosis and hypoxemia
What are the most common causes of bacterial pneumonia in younger and older dogs? What does a definitive diagnosis rely on?
- YOUNG = viral infection followed by bacterial invasion
- OLDER = aspiration and foreign bodies
detection of intracellular bacteria in airway cytology or clinically significant bacterial growth from an airway sample
Is primary or secondary bacterial pneumonia most common?
SECONDARY —> resident flora grow out of control due to another issue, rare to see healthy adults get spontaneous pneumonia
What are the 3 most common primary/community-acquired pathogens that cause bacterial pneumonia? What others have been isolated?
- Bordetella
- Mycoplasma
- Streptococcus
E. coli, Klebsiella pneumonia, Pseudomonas, Enterococcus, Pasteurella multocida, Bacillus, Staph, Fusobacterium
What are the 3 most common causes of secondary bacterial pneumonia? What history is most commong?
- aspiration
- foreign bodies
- immune dysfunction
- laryngeal or esophageal dysfunction
- poor upper airway conformation
- neurologic signs
- hospital-acquired from anesthesia or sedation
What are the most common signs of bacterial pneumonia? Why may it not be noticed immediately?
- lethargic, fever
- anorexic
- cough
- exercise intolerance, collapse, respiratory distress
- tachypnea, increased effort
- mucopurulent nasal discharge
- increased lung sounds (crackles)
dogs that do not exercise as much are not moving oxygen as much
What is the most commonly isolated bacteria from lower airway pneumonia? How is it treated?
Streptococcus spp.
Amoxicillin/Clavulanic acid (Clavamox)
What is the most common community-acquired bacterial cause of pneumonia in young dogs? How does it cause infection?
Bordetella bronchiseptica
secretes exotoxins that result in dysfunction of the mucociliary escalator —> tracheobronchitis is more common, but it can progress to pneumonia
What are the 3 most common treatments for Bordetella bronchiseptica pneumonia?
- Amoxicillin/Clavulanic acid (Clavamox)
- Doxycycline
- Enrofloxacin (Baytril)
can be difficult to eliminate, causing a chronic cough
What species of Mycoplasma is associated with pneumonia in dogs and cats? What diagnostic works the best?
Mycoplasma cynos
PCR —> a special culture medium is necessary
What antibiotics do Mycoplasma most commonly respond well to? Which ones do not work?
macrolides, tetracyclines, chloramphenicol, and fluoroquinolones —> Doxycycline!
those that interfere with cell-wall synthesis, which this genus lacks (beta-lactams - penicillins, cephalosporins)
What is most commonly seen in thoracic radiographs with bacterial pneumonia?
alveolar pattern —> air bronchograms are classic
- interstitial pattern is also possible
What bloodwork is recommended for diagnosing bacterial pneumonia? What is seen?
CBC
- neutrophilic leukocytosis with a left shift
- monocytosis if chronic
When should transtracheal, endotracheal, and bronchoalveolar washes be performed to diagnose bacterial pneumonia? What 4 things are most commonly seen on cytology?
before antibiotic therapy is initiated to perform a culture and sensitivity
inflammation, degenerate neutrophils, foamy macrophages, intracellular bacteria
What 2 IV antibiotics are recommended for hospitalized cases of bacterial pneumonia? What is considered when cases are especially severe, lifethreatening situations?
ideally based on culture, but need broad-spectrum drugs with good lung penetration
- Ampicillin sulbactam (similar to Clavamox) - Gram +/- and anaerobes
- Enrofloxacin - Gram +/-
Gentamycin - aerobes, Gram +/-
What 3 drugs should be avoided when treating severe pneumonia?
- diuretics
- cough suppressants (cough evaculates respiratory tract!)
- glucocorticoids
What is recommended for moisturizing airways in cases of severe pneumonia? What should be avoided?
nebulization with sterile saline +/- Gentamycin 15-30 mind 2-6x a day
mucolytics will cause bronchoconstriction since they are irritating
What additional supportive care is important for hospitalized patients with severe pneumonia?
- turn recumbent animals ever 1-2 hours so the lungs can properly expand
- mild exercise of stable animals
- coupage to promote expectoration of exudate
- bronchodilators in cats
- proper nutrition
What are 3 general characteristics of antibiotics in hospitalized patients with pneumonia? What is agreed to be a great place to start?
- parenteral, then oral
- must be broad-spectrum: G +/-, anaerobes, Mycoplasma
- continue oral for 4-6 weeks (can be up to 8)
Clavamox
What is the prognosis of bacterial pneumonia like? What is it influenced by?
fair to good
- severity and chronicity
- underlying condition(s)
- development of complications, like pyothorax, pneumothorax, abscesses, and fibrosis
What causes aspiration pneumonia? What are some risk factors?
inadvertent inhalation of gastric acid, orophayngeal secretions, and/or ingesta
underlying conditions what cause vomiting or regurgitation and loss of normal airway protection
- sedation, anesthesia
- esophageal disease
- seizures
- laryngeal dysfuntion
- megaesophagus
- cleft palate
- laryngeal paralysis
- recent swimming
What 3 things are commonly seen on radiographs with aspiration pneumonia?
- cranioventral bronchoalveolar pattern
- air bronchograms*
- +/- megaesophagus
(megaesophagus, right middle lung lobe consolidation)
What is seen on CBC with aspiration pneumonia? Why are TTW cytology and culture especially important?
neutrophilic leukocytosis with a left shift and monocytosis if chronic
atypical (enteric) bacteria should be seen
What is aspiration pneumonitis? What is a common secondary effect?
irritating chemicals from the stomach acid cause direct chemical burn to the lung caused by the caustic substances (typically polyethylene glycol)
large volumes of more benign substances can cause a drowning effect, obstruction, and inflammation, which is perfect for secondary invaders
Aspiration pneumonia:
megaesophagus!
What is treatment of aspiration pneumonia like?
largely supportive —> efforts should be made to prevent further aspiration by correcting predisposing factors
- oxygen!!
What is the most common cause of viral pneumonia? What is the best way to identify/diagnose?
influenza H3N8 and H3N2
PCR
What do radiographs typically show with Toxoplasmosis? What is the best what to retrieve organisms?
fluffy alveolar, diffuse, and interstitial opacities (it is a multisystemic disease)
bronchoalveolar lavage - tracheal washes are not enough
How is Toxoplasma pneumonia treated?
sulfonamides or clindamycin
How are animals typically infected by fungi that can cause pneumonia? What type of inflammation is caused? What are common non-specific signs?
inhalation of spores
pyogranulomatous
- inappetence and weight loss
- fever
- lameness (bone lesions!)
- enlarged LNs
- draining tracts
- chorioretinitis, anterior uveitis
What regions of the US are most affected by blastomycosis? What animals are most commonly affected?
Mississippi, Missouri, Ohio river valleys, Mid-Atlantic
dogs > cats (most common mycosis of dogs in endemic regions)
Where in the environment is Blastomyces most commonly found?
in the soil, commonly in decaying material (transmitted by inhalation)
How is blastomycosis diagnosed?
antigen and antibody testing on serum, plasma, and fluids; combine with other tests to verify
- cytology
- rads/CT/MRI
- histopath
- PCR
- culture not ideal due to danger of growing the organism
What is the most common systemic effect of fungal pneumonia?
SKELETAL LESIONS
- long bone osteolysis or periosteal proliferation
- soft tissue swelling
In what region of the US is Histoplasmosis most common? What animals are most affected? How does it appear on cytology?
Mississippi, Missouri, Ohio river valleys
cats > dogs
intracellular capsules within macrophages (H. capsulatum)
What is the main source of Histoplasmosis? How does presentation of disease differ in cats and dogs?
bird and bat feces (environmentally resistant) —> Cave disease in man
- CATS = lung
- DOGS = GI
How is Histoplasmosis diagnosed? How does this differ in dogs?
serology or urine antigen testing and PCR/histopath
rectal cytology is easiest
In what region of the US is Coccidiomycosis more prevalent? What disease does it cause? In what animals is it most common?
Southwestern —> California, Arizona, New Mexico
Valley fever
dogs > cats
How does Coccidiomycosis compare to other fungal pneumonias? How do animals become infected?
can rarely be zoonotic —> culture NOT recommended
organism is found in the soil and can be present in dust following rain in dry seasons
What animals are most affected by Cryptococcus? How do they become infected?
cats > dogs
inhalation of organism primarily residing in weathered pigeon guano
What is the most common sign of Cryptococcus pneumonia in cats?
subcutaneous swelling over the bridge of the nose
What is the best way of diagnosing Cryptococcus pneumonia? What else is commonly done?
cytology
- antigen detection on serology
- histopath
- culture works*
In what animals is disseminated Aspergillosis most common? When is it considered disseminated?
dogs > cats
when active infection is present in 2 or more separate areas of the body or when hematogenous spread occurs (can be ANYWHERE) —> most commonly allowed to occur in immunocompromised
(nasal Aspergillosis =/= disseminated Aspergillosis)
What is the best way to diagnose disseminated Aspergillosis?
cytology/histopath
- antigen detection on serology (can be positive in cases of exposure and no disease)
- rads/CT/MRI
- PCR
In what animals is Pneumocystis carinii pneumonia most common? What 2 breeds specifically? How is it treated?
immunocompromised dogs > cats (+ people with HIV/AIDS)
- Cavalier King Charles Spaniel - IgG deficiency
- Mini Dachshund - common variable immunodeficiency
Trimethoprim / Sulfamethoxazole
How is geographic location or travel history especially common in animals with suspected fungal pneumonia?
- California/Arizona = Coccidiomycosis (Valley fever)
- Ohio river valley = Blastomycosis, Histoplasmosis
How are serum antibody and urine antigen tests used for diagnosing fungal pneumonia?
- serum antibody = Coccidiomycosis, Cryptococcus
- urine antigen = Blastomycosis, Histoplasmosis
NO CULTURE = blasto, histo, coccidiomycosis
How are animals with mycotic pneumonia treated? What are 2 common side effects?
long term (4-12 months) of Fluconazole, Itraconazole, Terbinafine, or Voriconazole until clinical signs resolve, rads look normal, and antibodies stabilize
- inappetence
- liver enzyme elevations (monitor!)
Why must Amphotericin B be carefully used for fungal pneumonia treatment?
NEPHROTOXIC —> must monitor BUN and creatinine
(lipid complex form is safer)
What does the most severe form of mycotic pneumonia involve? What drugs should be avoided?
bones —> if multiple bones are affected, complete recovery is unlikely unless there is amputation
immunosuppressants —> can lead to disatrous fungal dissemination
