Case Studies

These case studies contain detailed information on the diagnostic and treatment process for each individual animal.

Zorro

Case Background

Name: Zorro
Age: 7 years old
Sex: Male
Breed: Cocker Spaniel
Weight: 19.2kg
Reason for visit: Coughing, pre-dental evaluation

Attitude/demeanor: Normal demeanor, bright, alert and responsive
Coughing: Cough started 6-8 months ago, may be getting more frequent; no associated respiratory difficulty, worse with activity/excitement (especially after drinking water).
Abnormal respirations: Otherwise normal breathing, no distress/dyspnea.
Exercise intolerance: None, normal activity
Sleep patterns: Normal
Weight change (loss or gain): Static over the last 18 months
Appetite: Eats well (very well)
Usual diet: Canine Maintenance
Vomiting: None
Diarrhea: None
Syncope: None
Change in urinary habits: None, normal urinations
Change in drinking habits: None, normal drinking
Other symptoms or signs: None
Preventatives: Up to date on vaccines and flea, tick and heartworm prevention

Physical Exam - General

Please review Zorro’s physical exam results

Body condition: 6/9, slightly overweight
Attitude: Normal
Mobility | gait: Normal
Posture: Normal
Hydration: Normal
Arterial pulse – rate, regularity, intensity: Strong, slightly irregular but synchronous with heart beats
Mucous membranes – color & CRT: Pink, CRT<2
Abdominal palpation: No significant findings
Lymph nodes: Normal
Oral cavity: Grade 3 dental disease (moderate to severe dental calculus)

Physical Exam - Auscultation

Please review the results of Zorro’s auscultation.

Heart rate & respiratory rate: 84 bpm and 24 bpm
Heart rhythm: Slightly irregular
Heart sounds: Heart sounds are of normal intensity, grade 4/6 left apical systolic murmur
Extra sounds – clicks or gallops: No click/gallop
Precordial palpation: No thrill
Lung auscultation: Within normal limits

Physical Exam - Differential Diagnosis

The following are potential diagnosis for you to consider at this time. Based on the history and the physical examination, please indicate the likelihood of each as:

High (could explain most or all of the signs)
Possible (less likely to explain most of the signs)
Unlikely

MYXOMATOUS MITRAL VALVE DEGENERATION

High
correct
Possible
incorrect
Unlikely
incorrect

CONGESTIVE HEART FAILURE

High
incorrect
Possible
correct
Unlikely
incorrect

PRIMARY AIRWAY DISEASE

High
correct
Possible
incorrect
Unlikely
incorrect

The CEG considers the following differential diagnosis as most likely (and why):Given the presence of a moderately loud left apical systolic murmur in an older Cocker Spaniel, degenerative mitral valve disease is most likely. The cause of the cough could be related to primary heart disease, but congestive heart failure would be less likely based on a chronic cough with no associated respiratory distress. Primary airway disease (chronic bronchitis or collapsing trachea) must also be considered.

Diagnostic Test Selection

Blood Pressure

Systolic blood pressure: 130mmHg, #4 cuff
Diastolic blood pressure: Not available for this case
Mean blood pressure: Not available for this case
Consensus Statements of the American College of Veterinary Internal Medicine (ACVIM) provides the veterinary community with up-to-date information on the pathophysiology, diagnosis, and treatment of clinically important animal diseases. ACVIM published guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats in the the Journal of Veterinary Internal Medicine.

Click here to view and download a PDF of the updated ACVIM consensus statement, guidelines for the identification, evaluation, and management of systemic hypertension in dogs and cats.

Radiography

Please review Zorro’s radiographs.

Click here for Zorro’s’s radiography viewer (measure VHS and VLAS here)
View the right lateral radiograph View the ventral dorsal radiograph

Is this patient in congestive heart failure?

Yes; there is a severe alveolar infiltrate
incorrect Please select another answer. There is no infiltrate seen on these X-rays.
No; the heart is not enlarged
incorrect Please select another answer. The heart is enlarged, but the presence of heart enlargement alone does not satisfy the criteria for CHF.
No; there is no evidence for pulmonary edema
correct Despite the subtle increase in pulmonary opacity, these changes are not consistent with edema especially on the VD view.
Yes; the dog has a murmur and is coughing
incorrect Please select another answer. The presence of a murmur in this patient is suggestive for the presence of heart disease, but the diagnosis of CHF requires the presence of substantial cardiac enlargement in the setting of edema.

Could this dog be coughing from heart disease?

No; the heart does not appear to be enlarged, and therefore heart disease is unlikely.
incorrect Please select another answer. The heart is enlarged both subjectively and by VHS (11)
Yes; the dog is likely in congestive heart failure based on these x-rays.
incorrect Please select another answer. Although there is cardiac enlargement seen, there is no evidence for pulmonary edema.
No; there is no evidence for congestive heart failure on these x-rays.
incorrect Please select another answer. While there is no edema, there are cardiac causes of cough other than heart failure.
Yes; although there is no obvious edema, the heart is enlarged making airway compression a possible cause.
correct CHF is not the only cardiac cause of coughing; some dogs with an enlarged heart can cough from airway compression.

Additional Radiograph Information: These chest X-rays identify a heart that is enlarged, with a VHS of approximately 11.1. The VLAS is 2.3 suggesting that the LA is not significantly enlarged. The degree of left atrial dilation is inconsistent between the lateral and VD views. In this case, the VD view is rotated, possibly obscuring left atrial enlargement. This makes an echocardiogram that much more important to fully evaluate the severity of disease. In addition, there is a mildly increased pulmonary opacity, consistent with peribronchial interstitial changes (so-called bronchointerstitial pattern).

Echocardiography

Please review the results of Zorro’s echocardiogram.

Watch Zorro's echo Click photos to enlarge

Subjective – lesions of valves, myocardium, pericardial space: These images identify a left atrium that is mildly enlarged, with a left ventricle that is also mildly enlarged. The left ventricular function is adequate. A mild to moderate amount of mitral regurgitation is identified. The mitral valve is slightly thickened. No cavitary effusions are noted.LV chamber size and thickness:Left atrial size: LAD (long axis LA dimension) – 4.47cm (upper limits of normal is 4.3cm) LA/Ao in 2D imaging – 1.42 in 2D imaging (normal limit by this measurement method is <1.6); 1.5 by M-mode imaging (normal in M-mode imaging is <1.3). These values are interpreted as being mildly increased (mild left atrial dilation).LVIDd & LVIDs: LVIDd – 4.48cm (upper limits of normal is 4.3cm). This is interpreted as mildly enlarged. LVIDdn – 1.8. This is considered mildly enlarged. LVIDs – 2.87cm (upper limits of normal is 2.9cm). This value is at the upper limits of normal.LV shortening fraction: The FS% is 36%, which is interpreted as adequate.RA, RV and Pulmonary Artery: All within normal limits.Effusions: None seen.Doppler results: Mild to moderate mitral regurgitation, no tricuspid regurgitation is identified (no pulmonary hypertension is documented); both the left and right ventricular outflow tract velocities are normal. No aortic or pulmonic insufficiency is seen.

ECG

Please review Zorro’s ECG and answer the following questions.

Click here for Zorro's ECG

What is the heart rate?

Approximately 70
correct
Approximately 140
incorrect
Approximately 200
incorrect
Approximately 30
incorrect

What is the rhythm diagnosis?

Sinus tachycardia
incorrect The rhythm is sinus, but the rate is actually at the lower limits of normal, not fast.
Sinus arrhythmia
correct The rhythm is sinus, with an irregularity that is physiologic in origin.
Atrial premature complexes
incorrect Even though there are some shorter R-R intervals, all QRS complexes are associated with upright P waves, indicating a probable sinus node origin.
Atrial fibrillation
incorrect There are clear P waves, with a ventricular rate that is normal to low. Atrial fibrillation does not have visible P waves and the ventricular response rate is usually rapid.

Diagnosis & Treatment

You’re ready to form a diagnosis and treatment plan for Zorro! Please select your answer to each question below.

What kind of heart disease does this dog have?

Dilated cardiomyopathy (DCM)
incorrect DCM is characterized by ventricular dilation and dysfunction. In this case, the degree of dilation is minimal, and the ventricular function is normal.
Mitral valve dysplasia
incorrect Mitral valve dysplasia is a congenital heart disease characterized by a primary developmental abnormality of the mitral valve. Given this patient’s age, acquired valve disease is much more likely than a congenital lesion.
Myxomatous mitral valve degeneration
correct Primary mitral valve disease is characterized by thickening of the mitral leaflets, with secondary mitral regurgitation. There can be a varying degree of chamber dilation, but the ventricular function is generally preserved until later stages of disease. In this case, the degree of chamber dilation is mild, with intact function and mild to moderate mitral regurgitation.
None of the above, this dog has no heart disease.
incorrect This patient does have heart disease, consistent with primary degenerative mitral valve disease.

What is the likely cause of the cough?

Pneumonia
incorrect There is no evidence for substantial pulmonary infiltration that would be consistent with pneumonia. While there is a subtle increase in interstitial opacity, neither the chest X-rays nor the clinical signs fits pneumonia.
Congestive heart failure
incorrect There is no evidence for pulmonary edema on the chest X-rays, and the degree of left atrial enlargement would make CHF very unlikely
Heartworm disease
incorrect The heartworm (HW) test is negative; while there are rare examples where HW positive dogs can test antigen negative, the lack of any pulmonary arterial distension, pulmonary hypertension, right sided enlargement or visible worms all but excluded heartworm disease.
Primary airway disease
correct Given the breed, the nonspecific pulmonary infiltrates, the nature of the cough (chronic with no associated respiratory distress) and the lack of substantial left atrial enlargement, the cough is less likely cardiac in origin and more likely related to a primary airway condition (bronchitis most likely, with airway collapse as a lesser consideration). Additional diagnostics (airway scope and wash) are available for a more thorough evaluation to confirm this suspicion.

More information: Fluoroscopy was recommended to rule out dynamic airway collapse as a cause of cough. The fluoroscopic study showed significant intrathoracic airway collapse during coughing. Dynamic tracheal collapse was diagnosed. Bronchoscopy can also be performed to diagnose airway collapse. Bronchoscopic examination can be combined with an airway wash for cytologic examination and culture. And lastly, empiric therapy may also be employed. Therapeutic options include a course of antibiotics or a should course of cortico steroids.
Click here to learn more about the stages of heart disease (ABCD Brochure)

What treatment(s) would you recommend for Zorro?

THE CEG RECOMMENDS:

The CEG recommends no cardiac therapy. Empiric therapy for primary airway disease can be considered, to include cough suppressants, bronchodilators, /- antibiotics, /- steroids.

ACTUAL TREATMENT

Initial therapy: Given the relatively mild left atrial dilation, no cardiac therapy will be recommended. In addition, the lack of more substantial chamber enlargement makes heart disease a less likely cause for the cough. Primary respiratory disease (especially airway disease) is considered much more likely. The relatively mild nature of the heart disease does not represent a significant increase in anesthetic risk; we would have no objection to anesthesia for the dentistry.
Lifestyle adjustments: No lifestyle adjustments recommended.

Follow Up

Follow-up: A repeat echo and chest X-rays would be warranted in another 6-12 months to monitor for evidence of heart disease progression. An earlier followup appointment would be recommended for followup of the dog’s primary respiratory cough after empiric therapy.

Post Test - CE

Please answer the following questions.

Which of the following represents the most compelling finding that heart disease is present?

The presence of coughing
incorrect
The slightly irregular rate
incorrect
The left apical systolic murmur
correct
Dental disease
incorrect
None of the above
incorrect

Which diagnostic test in this case was most important in excluding left sided congestive heart failure?

Chest x-rays
correct
Echocardiogram
incorrect
Blood pressure
incorrect
ECG
incorrect
None of the above
incorrect

Which finding in this case makes heart disease an unlikely cause for the cough?

Bronchointerstitial pattern on chest x-rays
incorrect
Normal blood pressure
incorrect
Negative HW test
incorrect
Lack of significant left atrial dilation
correct
Sinus arrhythmia on the ECG
incorrect

Under what circumstances/when should you perform a BNP in a case like this?

Once the echo results come back
incorrect
If you are uncertain about the chest x-rays, and the owners refuse an echo
correct
An asymptomatic patient needs anesthesia for a dentistry
incorrect
As a routine part of the annual evaluation
incorrect
In a coughing dog that is not on heartworm prophylaxis
incorrect

Are you ok doing anesthesia for a dental in this dog?

No, he has heart disease
incorrect
Yes, the ECG is normal
incorrect
No, he is coughing
incorrect
No, I do not have enough information
incorrect
Yes, his heart disease is early/mild
correct

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Case Studies

Zorro

Case Background

Case History

Please review Zorro’s clinical history.

Physical Exam - General

Please review Zorro’s physical exam results

Physical Exam - Auscultation

Please review the results of Zorro’s auscultation.

Physical Exam - Differential Diagnosis

Diagnostic Test Selection

BLOOD PRESSURE

CLINICAL LABORATORY

DIAGNOSTIC IMAGING (some may require a referral)

ELECTRODIAGNOSTICS (some may require a referral)

Blood Pressure