Lecture 14: Diagnostic Procedures for Resp. Problems (Specht) Flashcards
diagnostic plan based on:
problem list and differential dx
diagnostic plan factors
- goal
- probabilities of differentials
- sensitivtiy and specificity
- expense, invasiveness, risk
- significance of problem/usefulness of info
minimum data base is likely/unlikely to provide dx
unlikely. (i.e. chem, cbc, urinalysis)
how should cats be tested for HW?
Ag and Ab tests
T/F: any chronic coughing p should be tested for HW*
T
have infections with FelV/FIV been directly linked to resp CS?*
NO (they cause immunosuppression/opportunistic infection)
run fecal with p with chronic cough? why?*
Yes. multiple parasites cause cough. Use float/Baermann
Baermann test
incubate feces and let larval stage hatch then look for live larvae
types of infectious disease testing
- serology
- PCR
- isolation
- culture, etc.
3 ways to evaluate blood gas
- pulse oximetry
- arterial blood gas (ABG)
- capnography
advantage/disadvantage of blood gas evaluation
advantages:
-help determine severity
-differentiate pulmonary dz from hypoventilation
-monitor response to tx
disadvantage:
-not very specific - resp. compromise must be severe to detect abnormalities
pulse oximetry
device on tongue to measure SATURATION (not total content) of oxygen in the red cells
ABG
collect blood from artery and look at dissolved conc. of oxygen and CO2 to tell how resp. system is functioning
capnography
tells you how much CO2 is getting OUT of the system
steps of evaluating blood gas
1) confirm test accuracy
2) identify abnormalities and interpret in context of case
FiO2:PaO2 ratio
percentage of oxygen patient is breathing compared to percent of oxygen in patient’s blood (simple and helpful way to tell you if patient’s resp. system is working well)
Hgb dissociation curve
Plots PaO2 vs. SaO2. sigmoid shape w/ plateau at higher PaO2. When PaO2 is w/n normal range, Hg completely saturated. PaO2 should be 84 or higher.
rads don’t usually provide specific dx
T
nasal rads insensitive for most nasal dz
:)
dental rads can dx:
tooth root abcess, oronasal fistula
what kind of rad accentuates pulmonary vessels?
D/V
what kind of rads if collapsing airway suspected?
inspiratory/expiratory
basic pulmonary patterns (5)
- alveolar (fluid/tissue w/n alveolar spaces)
- interstitial (inc. tissue in interstitium)
- bronchial (obvious bronchial markings such as donuts)
- nodular
- pleural space
when do cervical rads?
laryngeal or tracheal dz suspected
when do fluoroscopy?
identify dynamic collapse
when do angiography?
help identify PTE or other problems related to lung perfusion. Involves contrast injections
when do scintigraphy?
to assess ventilation and perfusion. radioactive material put into veins and airways to see if they match up.
CT =
computed tomography
disadvantages of CT/MRI
- expensive
- can’t get dx
- requires general anesthesia
- limited availability
advantages/disadvantages of oropharyngeal exam
advantages:
-can identify CS localized to upper resp. tract
-identify palatal problems, oropharyngeal masses, dental or periodontal disease, etc.
disadvantage:
-requires anesthesia
ad/disad. of nasal cytology
ad: -easy -may be helpful for fungal rhinitis or neoplasia disad: -usually of little or no benefit
are bacteria normal in nasal cytology?
yes
3 types of nasal cytology
1) FNA/impression smear of mass
2) FNA of regional lymph nodes
3) nasal flush samples
rhinoscopy def. and uses
direct visualization of nasal cavity using tube or otoscope. Use for: -suspect foreign bodies -nasopharyngeal dz -facilitate sample collection \+/- neoplasia, infections
disad. of rhinoscopy
- gen. anesthesia
- bleeding
- don’t perform before rads/CT/MRI
- can’t provide dx except for foregin bodies and nasal mites
best test to get a specific dx for most primary nasal diseases*
nasal biopsy
advantages/disad. of nasal biopsy
Ad: -specific dx* -little equip. needed -reasonable cost Disad: -gen. anesthesia -invasive, bleeding -could biopsy brain
if no distinct lesion identified prior to nasal biopsy, what should you biopsy?
take multiple biopsies from various areas
what to look for in nasal culture
VERY HIGH colony counts or SINGLE ISOLATES assoc. with neutrophilic inflamm.
-normal individuals yield multiple bacterial isolates and deep cultures may be positive in 50% of normal dogs
nasal virus usually minimally or non-responsive to tx
:)
bronchoscopy def. and ad/disad:
direct visualization of airway interiors ad: -facilitates sample collection from lower RT -allows you to look at dynamic change, such as during different phases of breathing disad: -gen. anesthesia -equipment/skills -still just a pic
tracheal washing def and ad/disad.:
sample of fluid and cells from large airways
ad:
-useful for large airway and severe diffuse alveolar dz
disad:
-limited use in interstitial or focal disease
2 methods of tracheal washing
1) transtracheal wash (saline inserted and withdrawn from trachea through catheter; can do awake)
2) endotracheal lavage (incision b/w tracheal rings, saline in catheter and withdrawn; requires anesthesia)
bronchoalveolar lavage
sample take from small airways and alveoli either by bronchoscopy-guided or endotracheal lavage
only procedure that doesn’t involve anesthesia
TTW
disad. of TTW and BAL
- transient hypoxemia
- crackles
- specimens degrade quickly
what type of cells should predominate in normal TW/BAL cytology?
large mononuclear cells
abnormalities inlcude increased neuts, eos, parasite ova, larvae, fungus, neoplastic cells
T/F: funus is ALWAYS abnormal in the lung
T
T/F: mycoplasma is ALWAYS abnormal in the lung
F. can be normal or abnormal
what type of bacteria predominate in airway isolates?
aerobes (anaerobes found very infrequently)
trans-thoracic aspiration indications
used for cytology and/or culture. Best in patients with solitary lung mass, or diffuse dz. Best to do when mass lies close to chest wall. Complications common and potentially serious.
Thoracocentesis
- useful dx and THERAPEUTIC technique*
- removes fluid/air from thorax
reasons for negative tap
- no fluid/air present
- fluid deeper than needle
- fluid walled-off, or on contralateral side of chest
- fluid very thick
- most commonly, animal is fat and you aren’t in the pleural space
how is thoracocentesis fluid analyzed?
cytologically
- gives info on protein lvls, cell counts/morphology, etc.
- may be able to dx neoplasia or infection*
intra-thoracic biopsy ad./disad.
ad: -may be necessary for definitive dx* -can be therapeutic and diagnostic disad: -invasive -costly
2 main methods of intra-thoracic biopsy
thoracoscopy
thoracotomy
