Respiratory - Infectious Lung Disease Flashcards
What are the differentials for Pulmonary Parenchymal Disease?
- Infectious
- bacterial, fungal, parasitic, protozoal, viral
- Non-cardiogenic pulmonary edema
- pulmonary thromboembolism
- pulmonary contusions
- lung lobe torsions
- pulmonary fibrosis
- pulmonary hypertension
- Neoplasia
What are the rule outs for hypercalcemia?
- Granulomatous
- Osseous
- Spurious
- Hyperparathyroid
- Vitamin D
- Addisons
- Renal
- Neoplasia
- Idiopathic
- Toxin
How is a lung aspirate completed?
- Sternal recumbency or standing
- Clip and clean area (based on radiographs)
- Needle in, suction back 3x, needle out
- Do NOT redirect needle inside the chest
What are the possible complications of a lung aspirate
- Pneumothorax
- lung laceration
- Introduce infection
- vagal response
- hemorrhage
What is Histoplasmosis?
- Caused by Histoplasma spp
- Infects:
- Lungs
- GI
- Disseminated - Liver, spleen, GI, bone, marrow, skin, eyes
What is Blastomycosis?
- Blastomyces dermatitidis
- Dimorphic Fungus
- Mycelia live on decaying organic matter
- Spores inhaled, become yeast in lungs
- Organs of Choice:
- Lungs
- Nodes
- Eyes
- Bone
- CNS
- Skin
What is Coccidioidomycosis?
- Coccidioides immitis
- Southwestern U.S.
- Inhale conidia (<10 to be infected)
- In alveoli: conidia become spherules
- protected from immune system
- divides, grows, ruptures, releases spores
- Organs of Choice:
- Lung
- Bone
- Pericardium
- Skin (especially cats)
- Can be subclinical
How are fungal pneumonias diagnosed?
- Hypercalcemia
- macrophages produce calcitriol
- Calcitriol ⇡ Ca absorption from GI, ⇡ reabsorption from kidneys, and can increase release from bone
- Some fungal diseases have bone infolvement
- macrophages produce calcitriol
- Hyperglobulinemia
- Protein electrophoresis shows polyclonal gammopathy
- Radiographs
- diffuse nodular or miliary interstitial pattern is most classic
- some will have bronchial pattern
- may have hilar lymphadenopathy
- can see assortment of other radiographic findings
- diffuse nodular or miliary interstitial pattern is most classic
- Serology (antibody)
- Blasto/Histo: positive is likely true, high false negative rate
- Coccidio serology is reliable
- Antigen test - submit urine/blood
- Great for blastomycosis and histoplasmosis if cytology/histopathology is not possible
- can use for diagnosis and monitoring treatment
- Great for blastomycosis and histoplasmosis if cytology/histopathology is not possible
- Cytology/Histopathology
- seeing organism confirms its presence
- allows for search of differentials at the same time
What is the treatment for fungal pneumonias?
- Systemic Antifungals
- Fluconazole
- Itraconazole
- Amphotericin B
- Terbinafine
- Ketoconazole
How is an Endotracheal wash performed?
- Preoxygenate, induce (propofol), sterile intubation
- Submit Fluid:
- Red top - aerobic culture and Mycoplasma PCR
- Purple top - cytology (fluid analysis)
How is a Trans-tracheal Wash performed?
- Sterile Prep, +/- Lidocaine block
- Pass Catheter, Pull Stylet out
- Sterile Saline in
- Coupage/Cough
- Suction fluid out
What is nebulization?
- Delivers water droplets to the lower airways
- Increases hydration of mucociliary system
What is Coupage?
- Physical Therapy
- Firmly patting the chest wall with cupped hands
- Stimulates the cough reflex
- Mobilize airway secretions
What causes aspiration pneumonia?
- Impaired Airway
- Recent anesthesia/recumbency
- Seizures, coma, head trauma
- Laryngeal dysfunction
- Recent vomiting
- Too much food/Impaired GI motility
- Megaesophagus
- Overfeeding though enteral tubes
- Delayed gastric emptying
What diseases are common with Bacterial pneumonia?
- Respiratory Disease
- Bordetella
- tracheal collapse
- foreign body inhalation
- bronchitis
- etc,
- Systemic Disease
- Infections
- Immunosuppressive conditions
What bacteria commonly cause bacterial pneumonia?
- Mostly opportunistic, often from the GI or upper respiratory tract
- E. coli
- Staphylococcus
-
Streptococcus
- Strep equi sub zooepidemicus
- Pasteurella multocida
- Pseudomonas
- Klebsiella pneumoniae
- Mycoplasma
What happens during bacterial pneumonia caused by Streptococcus zooepidemicus?
- Causes a severe, acute hemorrhagic pneumonia in dogs
- Highly contagious between dogs
- May look like kennel cough initially
- Can be fatal within 24 hours
- Fortunately sporadic and rare outbreaks
- Tracheal wash culture when possible
- In shelter, outbreak situation, use necropsy to guide therapy for remaining patients
- Empirical treatment targeting this species: IV ampicillin
How is Bacterial Pneumonia diagnosed?
- CBC: inflammatory leukogram
- Radiographs: air bronchograms, alveolar pattern
- right middle/cranial or left cranial lung lobes
- Tracheal wash for cytology, culture/susceptibility
How is Bacterial pneumonia treated?
- Empirically until culture results are back
- Recheck after 2 weeks
- Optimal duration of treatment unknown
- Supportive care as needed
- O2, nebulize, coupage, nutrition, IV fluids
How can aspiration pneumonia be prevented?
- Extra care during anesthesia
- NPO to keep stomach empty
- Keep cuff inflated when intubated
- Suction any fluid prior to extubating
- Feed megaesophagus patients upright and keep upright for 20-30 minutes after meals
- ID and address underlying cause
What is Mycoplasma spp.?
- Prokaryotic microbes w/out a cell wall
- Normal flora of upper airway
- Almost 50% of dogs with lower airway disease were positive for Mycoplasma spp
- more often occur w/ another bacteria
- Species ID and sensitivity not routinely available
- Need antibiotic that does NOT target the cell wall
- Azithromycin, doxycycline, fluoroquinolones, chloramphenicol, TMS
- Need antibiotic that does NOT target the cell wall
What pulmonary parasites affect dogs/cats?
- Paragonimus kellicotti (lung flukes)
- Nematodes
- Aelurostongylus abstrusus
- capillaia aerophila
- Filaroides
- Toxoplasmoais (protozoal)
What are Paragonimus kellicotti?
- Lung flukes of dogs and cats
- Midwest and South US
Describe the life cycle of Paragonimus kellicotii
- Dog/cats eats crayfish
- Metacercariae migrate from GI through diaphragm
- Adult flukes live paired in cysts in lungs
- Eggs coughed, swallowed, in feces
- Egg hatches, miracidia enter snail
- Mature cercariae penetrate crayfish
How are Paragonimus kellicotti diagnosed?
- Radiographs show cystic lesions in lungs (like bullae)
- Mostly right caudal lung lobe
- Interstitial and bronchial patterns possible
- Tracheal wash - eosinophils and eggs
- Fecal sedimentation or zinc sulfate for eggs
How is a Paragonimus kellicotti infection treated?
- Praziquantel
- Fenbendazole
Who is commonly affected by Aelurostongylus abstrusus?
stray or hunting cats
Who is commonly affected by Capillaria aerophila?
Dogs and cats
Who is affected by filaroides?
young puppies
What is heartworm disease? (symptoms, complications?)
- Symptoms:
- Cough, exercise intolerance, inappetence, weight loss
- Vomiting in cats
- Complications:
- Congestive heart failure
- Caval syndrome
- Allergic pneumonitis
- Diffuse interstitial disease
- Treat with steroids prior to adulticide
What is Caval syndrome
- Caused by a mass of heartworms in the right atrium, ventricle, or vena cava
- interferes with closure of the tricuspid valve and impedes normal flow of blood through the right heart, leading to cardiovascular collapse
- significant tricuspid regurg
- compromised right ventricular filling
- circulatory collapse
- interferes with closure of the tricuspid valve and impedes normal flow of blood through the right heart, leading to cardiovascular collapse
- Requires surgical intervention
How is Heartworm disease treated in dogs/cats?
- Dogs:
- melarsomine - adulticide
- Heartgard for very slow treatment
- Cats:
- Glucocorticoids and Heartgard
- NO melarsomine
What is Toxoplasmosis?
- pneumonia is rare unless immunosuppressed
- Prednisone or chemotherapy
- Retroviral infections
- Distemper Infections
- typically acutely ill
- Other other organs too
How is Toxoplasmosis diagnosed?
- Radiographs - diffuse interstitial to alveolar pattern, can have mild effusion
- Serology:
- high IgM suggests active infection
- 4-fold rise in IgG suggests active infection
- Aspirate/Biopsy to find tachyzoites in macrophages or neutrophils
How is toxoplasmosis treated?
- Clindamycin and supportive care
What causes viral pneumonia in dogs?
- Distemper - Most serious
- Often 2° bacterial and Mycoplasma infections
- May be complicated with GI and neurologic disease
- Canine influenza - can be severe
- Parainfluenza - mild and self-limiting
- can be complicated by Bordetella of other bacterial infections
- No real need to confirm presence of these viruses
- Canine adenovirus-2 - mild and self-limiting
- can be complicated by Bordetella of other bacterial infections
- No real need to confirm presence of these viruses
What causes viral pneumonia in cats
- Calicivirus - rarely cause pneumonia
- Herpesvirus - rarely cause pneumonia
What is the pathophysiology of viral pneumonia?
- Virus gains access and tries to replicate
- Enter bronchial and alveolar cells
- Targets Type I pneumocytes
- Host immune Defenses
- Mucociliary clearance sweeps the viruses out
- IgG, IgA, IgM block attachment, neutralize
- Cytokines destroy virus
- Lymphocytes kill infected cells
- Alveolar macrophages clean up debris
What type of interstitial pattern does viral pneumonia cause?
- Usually a diffuse or caudodorsal pattern
- Not cranioventral like bacterial pneumonia
What is the common signalment of patients with Viral Pneumonia?
- Young animals
- incomplete vaccine series
- ⇡ risk if crowded, stresses, poor ventilation
What are the clinical signs of viral pneumonia?
- Lethargic
- febrile
- URI
- kennel cough
- dyspneic
How is viral pneumonia treated?
- Supportive Care
- IV fluids and nutritional support
- Oxygen if needed
- Humidification/Nebulization (coupage if exudate)
- Isolate to minimize spread
what are the options for administrating oxygen to dogs/cats? (Pros/Cons)
- Face Mask or Flow-by
- Pros: Fast, access to pet 30-70% O2
- Cons: Stressful, only temporary fix
- Oxygen Cage
- Pros: easy, not stressful
- Cons: patient inaccessible, 40% O2, expensive, technical challenges, many clinics don’t have
- Nasal Oxygen
- Pros: Excellent accessibility, cheaper than cage
- Cons: can be stressful to place but most tolerate very well
- Achieve 40% O2 with 1 cannula, 50-60% with 2
How is nasal oxygen placed?
- Awake or sedated dog
- Topical Anesthetic (xylocaine jelly)
- Red-rubber or flexible green catheter
- Insert to medial canthus of eye
- Suture: Chinese finger trap
- need E-Collar