Lecture 28 Parenchymal disease and PTE Flashcards
What is pneumonia?
- lung inflammation caused by bacterial, viral, or fungal infection
- air sacs are inflamed and may fill with phlegm/pus
- infections occur via airways or blood stream
Ddx for parenchymal diseases
Pulmonary hemorrhage
Pulmonary edema
Neoplasia
Pulmonary thromboembolism
Possible infectious etiology in dogs
Fungal
Bacterial
Viral
Rickettsial
Protozoal
Parasitic
Fungal pneumonia in dogs is caused by
Common
- Blastomyces dermatitides
- - Histoplasma capsulatum
Uncommon
- Cocifiodes immitus
- Crytpococcus neoformans
How do fungi in- fect the lungs?
Inhalation of spores
- infection established in lung then disseminated through- out body via blood and lymphatic systems
- Skin penetration is rare (needle/scapel/bite)
Location of each fungus?
- Blastomycosis - Tennessee and surrounding states, Ohio and Mississippi River valleys, Great Lakes region
- Histoplasmosis - Ohio, Mississippi, and Missouri River valleys, Great Lakes region, Tennessee- found in 31 of 48 continental US states
- Coccioidomycosis - California and Southwest USA
- Cryptococcosis - Pacific NW, Oregon, Cali, Washington, canada
What are the clinical findings of blasto?
- Loss of appetite, weight loss, fever
- Lasts days to months (chronic)
- Cough +/-, respiratory abnormalities
- Lymph node enlargement, draining skin tracts between toes, paw pads, dorsum, forehead
- RARE that it affects GI system
Where do you find clinical signs of blasto in the body?
Lung–> snow storm on rads
Skin
Eye–> early detection of ocular lesion is so important
Bone
CNS
Urogenital
Rare gastrointestinal system
What are the clinical findings of histoplasmosis?
Wide range of signs; varies on host and strain
1. Respiratory signs can be seen (40% of cats show this)
2. Dogs in US seem particularly susceptible to the GI form
Whats the disseminated form of histo?
Generalized infection of the RE system
- Severe granulomatous pneumonia
- Liver, spleen
- Eye
- Bone marrow
- Granulomatous enteritis
Blasto is a
broad based budding yeast
inhaled as a spore and once in lungs at room temp will transform into yeast form
Histo is a
intracellular yeast
Clinical findings of coccidioidomycosis
Asymptomatic, mild
Acute-subchronic respiratory dz
Systemic dissemination in small %
-> fever, weight loss
-> skin, eyes, bone, pericardium
-> NOT GI usually
Latent infections can reactivate
Clinical findings of crytococcus
Predilection for upper respiratory
-> Cryptococcus rhinitis common in cats
Pulmonary signs can occur
-> mediastinal lymphadenopathy or pleural effusion may contribute
Other systems: CNS, eye, skin
-> meningeal involvement
How is fungal pneumonia DX?
- History
- Clinical signs/PE
- Radiology–> blasto can cause many different radiographic patterns
- Cytology:
- Fine needle aspirate of lymph nodes
- Exudate from draining skin lesions
- TTW, ETW
- Nasal exudate
- CSF
- Anterior chamber aspirate (eye)
- rectal scraping for Histoplasmosis - Histopathology
- CBC and Chem
- Culture
- May take days to weeks adn can be dangerous to culture
- CAUTION: need special media and is infx to workers - Serology
- Agar media: Histo, Blasto, Coccidi, or Aspergillosis
- Antigen for Crypto - Antigen testing
- Urine ag test preferred method for Histo and Blasto
- Antigen for Crypto –> latex agglutination Ag test
What to look for on hematology DX for fungal infections?
- Non-specific
- Histoplasma - leukopenia, thrombocytopenia, anemia
- Histoplasma - organisms in monocytes or neutrophils (buffy
coat)
Serum chem DX for fungal infections?
Blastomycosis and Histoplasmosis
- Increased globulin, polyclonal
- Decreased albumin
- Increased calcium - rare
What fungal diseases can you test for serology Ab?
Blasto
Histo
Coccidioid
What fungal agents would you want to do Ag testing on?
- Cryptococcus (latex agglutination Ag test)
- Urine ag test for blasto or histo instead of Ab test
What are the treatment options for fungal pneumonias?
For Histo, Blasto, and Coccioidomycosis:
- Itraconazole or fluconazole
- Amphotericin B/itraconazole if GI involvement or severe cases
For Cryptococcus:
- Fluconazole or itraconazole
** Anti-inflammatory corticosteroids may be required if lung dz is advanced **
Whats the prognosis of fungal pneumonia?
Depends on severity of lung disease
and other systemic signs
Blastomycosis
- Respiratory signs may get worse
before the animal gets better while
on treatment
- May require corticosteroids for
inflammation, hospitalization for
support
What dog is at high risk for systemic aspergillosis?
- GSD
- young to middle age females due to hereditary IgA deficiency that leads to defective mucosal immunity
Whats teh prognosis and what kind of lesions can you find in systemic aspergillosis in dogd?
Guarded – grave prognosis
+/- Cavitary lung lesions
Describe bacterial pneumonia in terms of how bacteria can get there?
- Isolated from healthy lungs (lungs are not a sterile environment)
– May have underlying cause or
comorbidity
– Reach lung through inhalation, aspiration, opportunistic invasion or hematogenously
Clinical presentation of bacterial pneumonia?
Severity?
– Subclinical to fulminant, life-threatening
Acute to chronic signs
Often non-specific signs
What other concurrent clinical signs are
present?
– Can you isolate the predisposing disease?
Common bacterial isolates in bacterial pneumonia?
Streptococcus zooepidemicus and
others
E. coli
Pasturella
Staphylococcus
Pseudomonas
Klebsiella
Some normal inhabitants can become pathogenic if there is overgrowth or the right environment
What are the clinical signs of bacterial pneumonia?
Productive cough (+/- cat)
Fever, depression, anorexia
Dyspnea/ Distress
Nasal discharge
On auscultation:
crackles
Increased breath sounds
Wheezes
Silent areas
How do you DX bacterial pneumonia?
History
Clinical Signs
Radiology and bloodwork
Hematology
Serum biochemistries
Blood gas
Look for underlying disease
TTW or ETW
What can you find on radiographs in a dog with bacterial pneumonia?
Does not give definitive diagnosis
Mixed interstial, alveolar infiltrate
Lobar consolidation
Look at hilar lymph nodes
Caudodorsal lung damage signifies what cause of pneumonia
inhaled foreign body or hematogenous spread of infectious agent
If ventral lung lobe is affected what is this mostly caused by?
Aspiration pneumonia
When should you do TTW or ETW and what should you submit to lab with these samples?
After radiographs!
Prior to antibiotics if possible
Cytology
-Culture
- ask for mycoplasma,
aerobic and anaerobic