Lecture 28 Parenchymal disease and PTE Flashcards
(82 cards)
1
Q
What is pneumonia?
A
- 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
2
Q
Ddx for parenchymal diseases
A
Pulmonary hemorrhage
Pulmonary edema
Neoplasia
Pulmonary thromboembolism
3
Q
Possible infectious etiology in dogs
A
Fungal
Bacterial
Viral
Rickettsial
Protozoal
Parasitic
4
Q
Fungal pneumonia in dogs is caused by
A
Common
- Blastomyces dermatitides
- - Histoplasma capsulatum
Uncommon
- Cocifiodes immitus
- Crytpococcus neoformans
5
Q
How do fungi in- fect the lungs?
A
Inhalation of spores
- infection established in lung then disseminated through- out body via blood and lymphatic systems
- Skin penetration is rare (needle/scapel/bite)
6
Q
Location of each fungus?
A
- 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
7
Q
What are the clinical findings of blasto?
A
- 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
8
Q
Where do you find clinical signs of blasto in the body?
A
Lung–> snow storm on rads
Skin
Eye–> early detection of ocular lesion is so important
Bone
CNS
Urogenital
Rare gastrointestinal system
9
Q
What are the clinical findings of histoplasmosis?
A
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
10
Q
Whats the disseminated form of histo?
A
Generalized infection of the RE system
- Severe granulomatous pneumonia
- Liver, spleen
- Eye
- Bone marrow
- Granulomatous enteritis
11
Q
Blasto is a
A
broad based budding yeast
inhaled as a spore and once in lungs at room temp will transform into yeast form
12
Q
Histo is a
A
intracellular yeast
13
Q
Clinical findings of coccidioidomycosis
A
Asymptomatic, mild
Acute-subchronic respiratory dz
Systemic dissemination in small %
-> fever, weight loss
-> skin, eyes, bone, pericardium
-> NOT GI usually
Latent infections can reactivate
14
Q
Clinical findings of crytococcus
A
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
15
Q
How is fungal pneumonia DX?
A
- 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
16
Q
What to look for on hematology DX for fungal infections?
A
- Non-specific
- Histoplasma - leukopenia, thrombocytopenia, anemia
- Histoplasma - organisms in monocytes or neutrophils (buffy
coat)
17
Q
Serum chem DX for fungal infections?
A
Blastomycosis and Histoplasmosis
- Increased globulin, polyclonal
- Decreased albumin
- Increased calcium - rare
18
Q
What fungal diseases can you test for serology Ab?
A
Blasto
Histo
Coccidioid
19
Q
What fungal agents would you want to do Ag testing on?
A
- Cryptococcus (latex agglutination Ag test)
- Urine ag test for blasto or histo instead of Ab test
20
Q
What are the treatment options for fungal pneumonias?
A
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 **
21
Q
Whats the prognosis of fungal pneumonia?
A
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
22
Q
What dog is at high risk for systemic aspergillosis?
A
- GSD
- young to middle age females due to hereditary IgA deficiency that leads to defective mucosal immunity
23
Q
Whats teh prognosis and what kind of lesions can you find in systemic aspergillosis in dogd?
A
Guarded – grave prognosis
+/- Cavitary lung lesions
24
Q
Describe bacterial pneumonia in terms of how bacteria can get there?
A
- 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
25
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?
26
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
27
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
28
How do you DX bacterial pneumonia?
History
Clinical Signs
Radiology and bloodwork
Hematology
Serum biochemistries
Blood gas
Look for underlying disease
TTW or ETW
29
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
30
Caudodorsal lung damage signifies what cause of pneumonia
inhaled foreign body or hematogenous spread of infectious agent
31
If ventral lung lobe is affected what is this mostly caused by?
Aspiration pneumonia
32
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
33
Therapy for bacterial pneumonia
1. Cage rest and O2 (humidify)
2. Bronchodilators
3. Nebulization (to decrease viscosity)
4. Frequent turning of recumbent animals
5. Coupage (loosens resp secretions)
6. Hydration and nutrition (do not overhydrate)
5. Antibiotics (depending on what culture and sensitivity said)
- minimum of 2 weeks
34
What type of antibiotics should you use to TX bacterial pneumonia?
Specific therapy determined by culture
and sensitivity
Use broad spectrum initially
IV or oral
Blood-bronchus barrier
- bronchoalveolar-blood barrier
35
What TX meds should you avoid when treating bacterial pneumonia?
diuretics, cough suppressants, and corticosteroids
36
How do you monitor response to therapy?
Temperature
White blood cell count
Radiographs (usually wait 2-3 wks)
Clinical signs - appetite
Minimum duration of antibiotic
treatment is 2 weeks
Each case must be evaluated
for total duration of treatment
37
What is a surgical TX for bacterial pneumonia and when is it indicated?
Surgical - pulmonary lobectomy
– Localized
–indicated when Aggressive medical treatment
unsuccessful
–Best for foreign body
pneumonia
38
What is aspiration pneumonia?
occurs when foreign material is inspired into the lungs
- can be iatrogenic
- severity depends on frequency, volume, character of aspirate, pH of aspirate, and status of host defense
39
What may make an animal prone/predisposed to aspiration pneumonia?
1. Anatomic- cleft palate
2. Abnormal consciousness (anesthesia)
3. Neurologic disease
4. Severe debilitation
5. Mega-esophagus
6. Muzzle and vomit
## Footnote
Top 3 in Dogs:
Esophageal disease
Vomiting
Neurologic disease
40
What are some things that dogs aspirate causing pneumonia?
Chemical: gastric acid
- pH (< 3.5)
- volume
- particle present
- bacteria
Presence of food can exacerbate inflammation
Food
- Force-feeding
- Esophageal disease
- Chronically small amounts
- Acute aspiration of large amount
Inert Substance (barium)
Mineral Oil
41
Whats the pathophysiology of aspiration pneumonia?
Phase 1 – Airway response (immediate)
- Direct damage
- Bronchoconstriction
- Airway edema
Phase 2 – Inflamm response (4–6 hr)
- Increase capillary permeability
- Increase neutrophils, pulmonary edema
Phase 3
- +/- Secondary bacterial
infection
## Footnote
Also pulmonary surfactant changes so you get increased surface tension, increased atalectasis, increased respiratory insufficency
42
Clinical signs of acute and chronic aspiration?
Acute aspiration
- Cough, dyspnea, tachypnea
- Cyanosis
Chronic aspiration
- Cough, anorexia
- Depression, weight loss
43
What will you see on radiographs in dog that has aspiration pneumonia?
No immediate changes
Alveolar infiltrate in 12 – 36 hours
Gravity
–Cranial ventral
–Right middle
44
How do you treat aspiration pneumonia?
DO NOT LAVAGE: forces matter deeper
- acids are quickly neutralized
1. Suction/establish airway
2. Oxygen
3. Hydration
4. Bronchodilators
5. +/- Antibiotics
6. NO corticosteroids
Treat underlying cause
Prognosis depends on underlying disease plus what was aspirated
45
What viruses cause viral pneumonia in cats and dogs?
dogs: Distemper, CPI, CAV2 - cats: Calicivirus, FIP
46
What causes protozoal pneumonia in cats and dogs?
dogs: Neospora
cats: Toxoplasmosis
47
What is toxoplasmisus and how does it cause pneumonia?
- Immunocompromised animals
– Lungs are major site of replication
– Pneumonia: main sign of generalized
toxoplasmosis, they can have ARDS and septic shock
Cats are DH
48
What are the agents that cause parasitic pneumonia?
- Lung worms (Aelurostrongylus, Filaroides) - Lung flukes (Paragonimus)
- Larval migration
- Heartworms
- Angiostrongylus vasorum
49
Describe Heartworms in cats?
- Heartworm associated respiratory
disease (HARD)
- Can occur due to infection with immature
larva (L4) that do not mature into adults
- Inflammatory airway and lung
parenchymal reaction (BAL, CBC,
serology and radiographs)
- Lung changes remain after death of L4
- Often misdiagnosed as asthma!
50
In cats what is often misdiagnosed as asthma?
Heartworm disease which causes parasitic pneumonia
51
Inflammatory pneumonia in dogs is often
parenchymal
52
What are the clinical signs of eosinophilic bronchopneumopathy?
Coughing, gagging, retching; dyspnea less
frequent, increased lung sounds
53
Whats the signalment of eosinophilic bronchopneumopathy?
Young adult, medium-large
breeds (Nordic breeds? huskys and malamutes), females>males
54
How do you DX eosinophilic bronchopneumopathy?
Radiographs/CT
- Hard to tell on imaging alone and can have vast presentations
Peripheral
eosinophilia in 60%
Bronchoscopy
BALF: often >50%
eosinophils
Rule out parasites!
55
What will you see on radiographs in eosinophilic bronchopneumopathy?
- Variety of radiographic signs exist dependent on phenotype
- +/- hilar lymphadenopathy
- Diffuse, mixed broncho-interstitial pattern, granulomas, alveolar pattern
- Possible bronchiectasis (chronic)
56
What is the TX for eosinophilic bronchopneumopathy?
- Allergen avoidance
- Treat allergic disease
- Corticosteroids
a. +/- inhaled corticosteroids
- Roughly 25% will relapse if
therapy is discontinued
57
Prognosis of eosinophilic brochopneumopathy?
Good for control
Cure if identify and remove inciting
cause
If eosinophilic pulmonary granulomatosis :
more guarded prognosis and may need cytotoxic drugs
58
What is Idiopathic pulmonary fibrosis in west highland white terriers?
- Chronic, progressive, interstitial lung disease
- Present in middle-old age, with a prolonged history of respiratory signs (coughing, exercise intolerance, dyspnea)
and distinct pulmonary crackles on auscultation
- Etiology unknown, likely arises from interplay between genetic/environmental factors
a. Microaspiration? possible theory
- Mycophenolate?
a. Corcoran group 202; current trial at U Edinburgh
59
Parenchymal neoplasia can be:
Primary- carcinoma
Metastatic- lymphatic or bloodstream spread
60
Signalment of parenchymal neoplasia?
older dogs
Over-rep in boxers, doberman pinchers, aussies, and irish setters
61
On PE of dog with possible parenchymal neoplasia what will you find?
25% have no clinical signs
Respiratory signs
- cough, exercise intolerance, distress
Variable clinical signs with
paraneoplastic syndromes
62
How do you DX parenchymal neoplasia?
1. Imaging (rads/ct)
2. Cytology
3. Biopsy
63
Describe what you will do to get cytology or biospy in a dog with suspected parenchymal neoplasms?
TTW, BAL---> may not be helpfu because some masses dont exfoliate their cells
Fine needle aspirate
- highest yield (sometimes)
Biopsy: transthoracic, surgical
64
Common tumor types:
epithelial
Mesenchymal
Lymphoma
65
What causes metastatic neoplasia?
Any neoplasm can metastasize to lungs
– Oral/nail bed melanoma
– Thyroid carcinoma
– Osteosarcoma
– Hemangiosarcoma
– Mammary carcinoma
66
How do you treat parenchymal neoplasia?
- Dependent on location, type of neoplasia,
patient, owner, primary vs metastatic
- Surgery
- Chemotherapy classically not very effective
- Stereotactic radiation therapy (SRT) in some cases
- Inhaled IL-15? not available rn
67
Describe lung neoplasia in felines?
- Primary less common than dog
- Average age is 11 - 12 years
- History - vague clinical signs,
respiratory signs
- Carcinoma metastasis to digits
- Lymphoma can have variable
presentation on radiographs
68
How do you DX and TX feline neoplasia?
Diagnostic evaluation
- Pleural effusion, cytology
Treatments:
– Dependent on type of cancer, patient,
owner expectations
– Palliative care with chemotherapy,
NSAIDs (carcinomas), or steroids may
be tried
## Footnote
Neoplasia is the 2nd most common cause of pleural effusion in cats
69
General TX of cancers:
- Advanced stage
- Prognosis generally poor
- If primary without mets, surgical removal may offer more favorable prognosis
70
What is a pulmonary thromboembolism?
- Obstruction of vessel by clot from another area in the body
- Problem is with vasculature and **not airway/alveoli**
71
Describe the 3 factors that are critically important in the development of pulmonary thrombosis in relation to Virchow's triad-thrombosis?
- Changes in vessel endothelium
- Impairment of blood flow (stasis)
- Development of prothrombotic tendencies in the blood
72
Describe arterial vs venous PTE?
- Arterial thrombi consist largely of
platelets with fibrin
- Venous thrombi that form under low shear conditions consist largely of fibrin and entrapped erythrocytes
- Depends on underlying cause
- Impacts treatment choice
73
Whats the function of pulmonary vasculature?
Pulmonary vasculature
- Filtration
- Protects other vital structures
74
What is the pathophysiology of PTE?
When thrombus enters circulation it obstructs bloodflow and causes an under perfused but still ventilated alveoli --> this results in V/Q mismatch
PTE
- Most subclinical if small
- Degree of occlusion determines outcome
Response to the thrombus produces
additional pathology
75
Clinical signs of PTE?
Signs are usually non-specific
– Acute onset dyspnea, restlessness,
cough
Normal auscultation
Cyanosis
Dependent on degree of hypoxia:
– Tachypnea, hemoptysis, sudden
collapse, altered mentation
76
Severity of PTE is dependent on:
Extent/size of embolism
Reflex humoral factors
Patient’s prior condition
77
What are some Ddx in a patient with PTE?
Asthma
Pulmonary hemorrhage
Pleural space disease
CHF
ARDS
Airway obstruction
Pneumonia
78
How do you DX PTE?
- No evidence-based, confirmed diagnostic approach for diagnosis of pulmonary thromboembolism (PTE) in dogs.
- Blood gases (hypoxia PaO2 <60 mm Hg)
- Thoracic radiology (may be normal!)
- CT with angiography
- Nuclear medicine scan
- Echocardiogram may support
- Elevated A-a gradient, decreased P:F ratio
A. Alveolar and arterial gradient, P:F is arterial partial pressure of O2 (PaO2/FiO2)
79
What will radiographs look like and why do we do them for PTE?
- Why? to rule out other pulmonary diseases
- Non-specific
* May appear normal initially!
* Pulmonary vessels affected
* Pulmonary infiltrate
* Pleural effusion
## Footnote
Right sided heart changes
80
Why do we measure D-dimers in patients with PTE?
- D-dimers measure fibrin which is cross-linked in a thrombus and then degraded
- Used to determine if thrombus has
formed and is being broken down
- Nonspecific, but sensitive
81
What are some therapeutic options for PTE?
Supportive care: O2 fluids
Prevention of further PTE growth
- Heparin
- Warfarin
Thrombolytic therapy +/- (data lacking)
- Streptokinase
- Tissue plasminogen activator
- Reperfusion injury
82
Describe PTE in felines?
- Rarely diagnosed. Are we just bad at recognizing it?
- 2004 retrospective study: most common
diseases identified in association with PTE
in cats were neoplasia, anemia of
unidentified cause, and pancreatitis
- Most cats with PTE demonstrated dyspnea and respiratory distress before death
