Clinical Approach to Respiratory Disease in the Dog and the Cat Philip Padrid DVM Medical Director VCA Vet Care Specialty Referral Center Regional Medical Director VCA SW Region Associate Professor of Molecular Medicine (Ret) University of Chicago Pritzker School of Medicine Associate Professor of Small Animal Medicine (adj) The Ohio State University School of Veterinary Medicine FUNDAMENTAL ISSUES Our patients are exposed to bacteria, viruses, fungi and yeast all the time…….. These organisms are often commensal These organisms may be pathogenic but cleared by our patients natural defenses……… The overwhelming majority of the time! Dec 2009, staph spp
Transcript
Clinical Approach to Respiratory Disease in the Dog and the Cat
Philip Padrid DVMMedical Director
VCA Vet Care Specialty Referral Center
Regional Medical DirectorVCA SW Region
Associate Professor of Molecular Medicine (Ret)University of Chicago Pritzker School of Medicine
Associate Professor of Small Animal Medicine (adj)The Ohio State University
School of Veterinary Medicine
FUNDAMENTAL ISSUES
� Our patients are exposed to bacteria, viruses, fungi and yeast all the time……..
� These organisms are often commensal
� These organisms may be pathogenic but cleared by our patients natural defenses………
The overwhelming majority of the time! Dec 2009, staph spp
FUNDAMENTAL ISSUES� Our patients are exposed to bacteria, viruses, fungi and yeast all the time……..
� These organisms are commensal, or they are cleared by our patients natural defenses………
The overwhelming majority of the time!
So, the real questions are:
1. Does our patient have a respiratory tract infection?
2. Does the infection need to be treated with an anti-infective?
Respiratory internal medicine is cardiology without the ultrasound machine…………
WHY DO WE RADIOGRAPH COUGHING ANIMALS
WHY DO WE TAKE 2 VIEWS
Vomiting?
WHY DO WE TAKE 2 VIEWS?
The middle lobe is hidden on a lateral view
What is this?
What is this?
What is this?
1. neoplasia
2. pneumonia
3. lung collapse
4. mediastinum
5. normal variation
DIAGNOSTIC TECHNIQUES
Implications of RML atelectasis in dogs and cats?
1. Early death
2. Exercise intolerance
3. Chronic cough4. Chronic infection
5. None - will re-expand
THIS IS VERY EXCITING
THE CARINA IS AN UNDERAPPRECIATED AREAOF THE CHEST FILM
DIAGNOSTIC TECHNIQUES
IMPLICATIONS OF A NARROW CARINA?
1. big left atrium
2. chronic bronchitis
3. enlarged lymph node
4. 1-3
5. Doesn’t necessary imply anything
DIAGNOSTIC TECHNIQUES
IMPLICATIONS OF A NARROW CARINA?
1. big left atrium
2. chronic bronchitis
3. enlarged lymph node
4. 1-35. Doesn’t necessary imply anything
This variation represents1. bronchomalacia2. heart failure3. normal variation4. cannot tell from this view
INSPIRATION
EXPIRATION
This variation represents1. bronchomalacia2. heart failure3. normal variation4. cannot tell from this view
INSPIRATION
EXPIRATION
BRONCHO-MALACIA
SECONDARY TO CHRONIC BRONCHITIS
CARDIOMEGALY
“We (dvm’s) correctly guess the true nature of cardiac enlargement exactly 50% of the time…..”
John King DVM, DipACVP
BNP(b type naturetic peptide)
1. B-type natriuretic peptide (BNP) is a 32 amino acid cardiac neurohormone
2. BNP is secreted from the ventricular cardiac muscle into the plasma in response to volume or pressure overload
3. The active BNP hormone (c-terminal brain natriuretic peptide [cBNP]) and the inactive N-terminal fragment of pro-BNP (NT-proBNP) are released through enzymatic cleavage of pro-BNP
Plasma BNP concentration is increased in people and dogs with CHFThe magnitude of plasma BNP concentrations in humans positively correlates with worsening New York Heart Association class and prognosis.
EFFECTS OF BNP
cBNP binds to natriuretic peptide-A receptor, resulting in various biologic effects including:
natriuresis (sodium excretion)vasodilationrenin-angiotensin-aldosterone inhibitioninhibition of myocardial hypertrophyinhibition of smooth muscle proliferationalteration of vago- sympathetic balanceinhibition of bronchoconstriction
WHY IS IT NOT SIMPLE?� Multiple studies in people have demonstrated the impact of
various clinical non-cardiac disease states, especially renal insufficiency, sepsis, pulmonary hypertension, acute respiratory distress syndrome, and obesity, on both cBNP and NT-proBNP concentrations, either because of altered renal elimination or as-yet undetermined reasons (AGE)
� There is a significant degree of interday variation (as much as 50%) in the same animal. This is especially found in animals with no heart disease or mild heart disease.
� BNP is falsely increased in animals with renal failure, systemic hypertension, and pulmonary hypertension.
� BNP is falsely decreased in animals on cardiac medications and in animals that are dehydrated or hypovolemic.
JUSTINE LEE STUDY� Neither our study, nor the study published previously
examining the same assay, can be used to establish definitive reference intervals for the specific plasma cBNP immunoassay in normal dogs.
� Our findings in normal dogs concur with those of other investigators, who recently showed that a substantial proportion of normal dogs had increased NT-proBNP values at 1 or more time points over a 3-week period, with values exceeding the proposed diagnostic threshold value
� Our data suggest that this cBNP assay would reliably rule out CHF in our study population, but cannot unequivocally rule it in, on a patient- by-patient basis.
JVECC Study Conclusions
JVECC Study Conclusions
WHAT DOES IDEXX RECOMMEND?
� IDEXX suggests that veterinarians include Cardiopet proBNP with their initial workup when any of the following clinical signs are present:
� An audible murmur, arrhythmia, exercise intolerance, lethargy, breathlessness, dyspnea, coughing, pale mucous membranes, visible signs of poor perfusion,
� Certain other situations may also indicate a need for the test. These include all cases of suspect congestive heart failure, to differentiate respiratory disease from heart disease, all patients with murmurs and arrhythmia, all cats over the age of four, all cats with a gallop rhythm, all breeds predisposed to heart disease and showing clinical signs
ANTECH TEST LITERATURE
Love is Blind
THIS IS THE QUESTION WE NEED TO UNDERSTAND
� CAN WE USE BNP TO DISTINGUISH CARDIAC FROM NON CARDIAC CAUSE OF clinically symptomatic animals ie; COUGH OR DYSPNEA?
� Answer: IN THE DOG: likely best use is to rule out CHF as cause of cough/dyspnea in patient with significant clinical signs
THIS IS THE QUESTION WE NEED TO ANSWER
� CAN WE USE BNP TO DISTINGUISH CARDIAC FROM NON CARDIAC CAUSE OF clinically symptomatic animals ie; COUGH OR DYSPNEA?
� Answer: IN THE CAT: asymptomatic but suspected cardiac disease. BNP is often more useful than the physical exam for this group. Many cats with cardiac disease will not have a heart murmur, gallop sound, or arrhythmia to clue-in the veterinarian that their heart is abnormal. The BNP is helpful here. (i.e. Is the cat having a pre-anesthetic evaluation and we want to know if there is significant cardiac disease? ) If the result is abnormal I would recommend an echocardiogram.
AIRWAY CYTOLOGY
- 1. TechniqueTTW
brush
BAL
2. Interpretationmacrophage
neutrophil
eosinophil
4 yr old catwith chronic cough4 yr old healthy cat
BRONCHOALVEOLAR LAVAGESAMPLES FROM CATS
Typical Cytological Finding from TTW,Bronchial wash or BAL from Cats with
Bronchial Disease
AIRWAY CULTURES
1. What is normal?2. What is abnormal?3. How can we tell the
difference?
CCB IS NOT AN INFECTIOUS DISEASE
Padrid et al.
AJVR 1990
Dye et al
JVIM 1996
Peters et al JVIM 2000:14:534-541
� CCB 7/20 + aerobic culture
7/7 < 1 X 103 (100%)
4/7 single organism grown (57%)
(included pseudomonas)
� LRTI
13/14 + aerobic culture
10/13 > 3 X 104 CFU/ml (77%)
9/13 single organism grown (70%)
CCB IS NOT AN INFECTIOUS DISEASE
DIAGNOSTIC TECHNIQUES IN
RESPIRATORY MEDICINE
• Physical Exam
• Radiography
•Pulse Oxymetry
PULSE OXYMETRY
What exactly does it measure1. Oxygen gas pressure in the blood2. Oxygen supply to the lungs3. Oxygen binding by red blood cells4. Oxygen uptake by the heart5. Oxygen supply to the entire body
PULSE OXYMETRY
What exactly does it measure1. Oxygen gas pressure in the blood2. Oxygen supply to the lungs
3. Oxygen binding by red blood cells4. Oxygen uptake by the heart5. Oxygen supply to the entire body
PULSE OXYMETRY
• What is the real value of this measurement
• How can I use it more effectively
What we really want to know………..
PULSE OXYMETRY
So, if oxygen has a pressure of 80 mmHg or greater, about 95% of Hg is saturated
1. That’s enough for dogs and cats to get around
2. Breathing is normal
3. Play behaviour is normal
4. Routine leash walks are easy
Pulse Oxymetry
• Indications• Exercise Intolerance/panting• Monitor and evaluate
• pneumonia• asthma• heart failure
• Should I hospitalize?• Should I discharge?
COUGHING CATSWhat tools do we have?
Plain Film Radiographs
There area at least 4 significant radiographic findingsThey are?
There area at least 4 significant radiographic findingsThey are?
