INTERACTIVE CASE STUDIES

 
 

JazzyCase Background

 
Name Jazzy
Age 13 years
Sex Male, castrated
Breed Miniature Schnauzer
Weight 7.4 kg
Reason for Visit Has been coughing daily for the past 2 to 3 weeks; cough seems dry but might occasionally be productive (retch at end of cough with swallowing).
Medications Jazzy is currently receiving Heartgard® Plus and Frontline®. He is not on any other chronic medications.
     

Please review Jazzy's clinical history.

 
Attitude/Demeanor Seemed normal until 24 hours ago.
Coughing Has been coughing daily for the past 2 to 3 weeks. Cough seems dry but might occasionally be productive (retch at end of cough with swallowing).
Abnormal Respirations Tachypnea and respiratory distress. Owner reports rapid breathing recently and "trouble breathing" over the past 24 hours which prompted the veterinary examination.
Exercise Tolerance Has been slowing down, but was still taking short walks.
Sleep Patterns Has seemed restless at night over the past week with some coughing.
Weight Change (loss or gain) None observed/known.
Appetite No change.
Usual Diet Purina One® with some table scraps and cold cut treats.
Vomiting None - occasional retch after cough but nothing produced.
Diarrhea No.
Syncope No.
Change in urinary habits No.
Change in drinking habits Been drinking more past few days.
Other symptoms or signs Occasionally scratches ears.
 

Please review the results of Jazzy's physical exam.

Body Condition Good, BCS 4/9.
Attitude Alert, somewhat anxious.
Mobility | Gait Normal gait upon inspection.
Posture Standing or sitting.
Hydration Suspect mild dehydration.
Body Temperature 100.3 F
Arterial Pulse - rate, regularity, intensity 142 beats/min, regular, normal strength.
Respiratory Rate & Effort 40, mild inspiratory effort.
Mucous Membranes - Color & CRT Pale to pink / 3 seconds.
Jugular Venous Pulse & Pressure Normal.
Abdominal Palpatation Liver is palpably enlarged; moderate-size bladder.
Lymph Nodes Normal.
Oral Cavity Mild dental calculus, no periodontal disease.
Other Abnormalities Slight odor from ears.
 

Listen to Jazzy's heart sounds.

What do you hear?

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Auscultation identifies a loud (Grade 4 to 5/6) systolic murmur. This murmur was loudest over the mitral area & left apex and radiated prominently to the right
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Listen to Jazzy's thorax and lungs.

Do they sound normal or abnormal?

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Jazzy's lung sounds are abnormal. There are prominent crackles bilaterally.
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Direct HR: 142 bpm

Heart Rhythm: Rhythm is regular. Possible infrequent premature beats.

Intensity of Sounds: Abnormal. The first sound is prominent.

Extra Sounds - Clicks or Gallops: No

Precordial Palpation: Precordial thrill (vibration) is evident.

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

Degenerative Mitral Valve Disease (Stage C)

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Respiratory Disease

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Dilated Cardiomyopathy (Stage C)

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The CEG considers the following differential diagnosis as most likely (and why):

The loud left apical systolic murmur is compatible with mitral regurgitation. In an older small breed dog, mitral regurgitation is likely due to myxomatous mitral valve disease, a degenerative disorder (also called valvular endocardiosis). The findings of cough and inspiratory crackles may indicate cardiogenic pulmonary edema and therefore left-sided congestive heart failure is a top differential diagnosis. Crackles may also be noted in conditions such as pneumonia, small airway disease, or pulmonary fibrosis and therefore a primary respiratory disease should be on the differential list for Jazzy's symptoms. In such cases, the mitral regurgitation may simply be a comorbid condition and not the cause of the respiratory distress. Dilated cardiomyopathy is certainly possible but is an uncommon to rare cause of congestive heart failure in small breed dogs.

BLOOD PRESSURE

Non-invasive blood pressure

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CLINICAL LABORATORY

CBC with platelet count

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Coagulation profile

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Serum biochemical profile (includes electrolytes)

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Urinalysis

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Serum thyroxine (T4)

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Heartworm antigen test

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Heartworm antibody test

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Heartworm microfilaria test

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NT-proBNP

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Cardiac troponin-I

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Blood culture

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Thoracocentesis or abdominocentesis for diagnosis or therapy

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DIAGNOSTIC IMAGING (some may require a referral)

Thoracic radiographs

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Abdominal radiographs

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Echocardiogram Doppler studies

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Abdominal ultrasound

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ELECTRODIAGNOSTICS (some may require a referral)

ECG rhythm strip or 6 lead ECG

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Ambulatory ECG - Holter ECG or event monitor

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  • You considered the following to be higher priority
    • You considered the following to be lower priority
      • You considered the following to be not indicated

        The CEG considers the following diagnostic tests as the highest priority: 

        Jazzy fits the clinical picture of age-related mitral valve degeneration with development of heart failure. Blood pressure measurement is important in patients with mitral regurgitation because a high afterload may cause a greater volume of blood to regurgitate across the mitral valve. It is important to remember that heart disease does not cause high blood pressure, but high blood pressure can exacerbate heart disease. Common risk factors for hypertension include chronic kidney disease and Cushing's disease. If Jazzy's BP was elevated, therapy to control his BP would be important.


        Chest radiography (once the dog is stable) is mandatory to confirm the diagnosis and evaluate the severity of pulmonary edema. Echocardiography is advised to confirm the abnormalities present and evaluate cardiac size and function.


        Abdominal imaging (radiography or ultrasound) are not indicated at this time in our opinion based on a lack of abdominal signs or concerns about neoplasia; the hepatomegaly could simply relate to congestive heart failure. Alternatively, abdominal ultrasound might be useful if biochemical tests indicate hepatocellular injury or disease. This is mainly an issue of cost/resources at this point in terms of priority (as one can reasonably argue that hepatomegaly is an indication for abdominal imaging).


        Baseline bloodwork is advised in this geriatric patient to evaluate overall organ function and in particular kidney function and electrolyte status prior to diuretic therapy. Thus, a serum biochemical profile is high priority; a CBC and urinalysis would provide more complete "baseline" data, but are of lower priority. There are no overt signs of hypothyroidism and unless a thyroxine is part of the profile it would be considered low priority.


        A heartworm antigen test (with or without microfilaria test) can be done because respiratory signs could related to heartworm disease; however, the dog is taking preventative so this test is lower priority unless the dog resides in an "endemic" or macrolide-resistant region.


        Electrocardiography can be performed to document the suspected premature beats. If premature beats are infrequent, however, a short recorded ECG strip may be normal. However, at this time, a Holter ECG would be considered premature. Diagnostic centesis is not indicated in this patient; there is no evidence of ascites or of pleural effusion.


        An NT-proBNP or BNP may also be considered to support a cardiogenic cause for the respiratory distress (in particular, a low value would argue against CHF) and potentially to provide a baseline for therapeutic monitoring (though more data are needed before this can be routinely recommended). Natriuretic peptides are typically very high in dogs with CHF, but also can be elevated in advanced, compensated valvular disease without overt pulmonary edema. Thus diagnosis and any therapy should be based on a comprehensive evaluation of all findings, not a laboratory test. If clinical improvement with initial therapy is not observed or additional complications develop, referral to a cardiologist should be considered.

        Systolic Blood Pressure: 117 mmHg
        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. In 2007, 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 ACVIM Consensus Statement, Guidelines for the Identification, Evaluation, and Management of Systemic Hypertension in Dogs and Cats.  

        Please review Jazzy's thoracic radiographs

        Click here for the right lateral view
        Click here for the ventral dorsal view
        Click here to see the CEG's recommendation on Evaluating Heart Size on Radiographs

        What is the vertebral heart score?

        This is incorrect, although it is difficult to see cardiac borders due to edema
        Jazzy's VHS is 13.2
        This is incorrect, although it is difficult to see cardiac borders due to edema
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        Is Jazzy's heart enlarged?

        Jazzy's heart shows moderate to severe cardiac enlargement
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        If Jazzy's heart is enlarged, which chambers are involved?

        There is moderate to severe cardiac enlargement mainly involving the left atrium and left ventricle.
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        Is there evidence of congestive heart failure present (pleural effusion or pulmonary edema)?

        While there is no pleural effusion there are bilateral interstitial to alveolar densities with prominent localization in the perihilar region. Pulmonary veins are also prominent.
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        Technical Quality: Acceptable. Slight rotation on the lateral projection and VD.

        Pulmonary Venous Congestion: There is prominent pulmonary vasculature. Pulmonary vessels are prominent but not definitely large. There is possible enlargement of the right caudal pulmonary vein on VD and cranial vein on left lateral.

        Pulmonary Infiltrate Distribute: Distribution is heavy unstructured interstitial to alveolar.

        Other Findings: Hepatomegaly; some aerophagia (with food in stomach).

        Please review Jazzy's lab results

        SERUM CHEMISTRIES
        BUN 38 mg/dL Normal: <30 mg/dL
        Creatinine 1.8 mg/dL Normal: 0.3 - 2.1 mg/dL
        Sodium 149 mEq/dL Normal:138 - 154 mEq/dL
        Potassium 3.7 mEq/dL Normal: 3.6 - 5.2 mEq/dL
        Chloride 112 mEq/dL Normal: 105 - 119 mEq/dL
        ALT 32 IU/dL Normal: <75 IU/dL
        ALP 56 IU/dl Normal: <100 U/dL
        Glucose 104 mg/dL Normal: 68 - 126 mg/dL
        HEARTWORM
        Heartworm Test Results Negative
        URINALYSIS
        Urinalysis - USG All values within normal limits
        Urinalysis - Protein All values within normal limits
        Urinalysis - Biochemical All values within normal limits
        Urinalysis - Sediment Evaluation All values within normal limits
        CBC
        White Blood Cells All values within normal limits
        Red Blood Cells All values within normal limits
        Platelets All values within normal limits

        Please review the results of Jazzy's echo

        Subjective - lesions of valves, myocardium, pericardial space No pericardial effusion; subjectively hyperdynamic left ventricle, thickened mitral leaflets with mitral valve prolapse.
         LV chamber size and thickness LV dilated. Normal thickness.
         Left atrial size Moderate dilation
         LVIDd & LVIDs Diastole (3.4 cm); systole (2.1 cm)
         LV shortening fraction 38% (within normal range)
         RA, RV and Pulmonary Artery Not remarkable (detailed images not shown)
         Effusions None.
         Doppler results Mitral and tricuspid regurgitation; eccentric jet of MR is typical of primary valve disease; velocity of MR predicts normal systemic pressures; increased velocity of TR (~3.6 m/s) predicts moderate pulmonary artery hypertension (~55 mm Hg).
        Watch echo #1  
        Watch echo #2  
        Watch echo #3  
        Watch echo #4  
        Watch echo #5  
        Click here to view M-mode echocardiogram at the left of the left ventricle
        Click here to view continuous wave Doppler recording across the mitral valve
        Click here to view continuous wave Doppler recording across the tricuspid valve

        Please review Jazzy's ECG results.

          Click here for Jazzy's ECG results  
         Technical quality, leads, paper  speed, calibrations Satisfactory recording; 6 frontal leads and lead 2 rhythm strip recorded; paper speed 50 mm/sec; calibration 5 mm/mV
         Artifacts None
         Heart Rate 180/min
         Rhythm - Regular or irregular |  Patterns Regular
         Heart Rhythm Disturbances Sinus tachycardia; although auscultated (see Auscultation), no premature complexes were detected during this recording
         P Wave Abnormalities -  morphology, amplitude, duration Slightly wided (0.55 sec) especially evident in lead III (P-mitrale); normal amplitude (appear smaller due to calibration factor)
         QRS Abnormalities - axis,  morphology, amplitude, duration Normal frontal axis, upper limit duration, increased voltages (deep Q-waves with 4.8 mV R-waves in lead II suggestive of eccentric LV  hypertrophy or dilatation)
         Abnormal Intervals - PR, QRS, QT Normal intervals
         Other Slurred ST segment
             

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

        What is your diagnosis for Jazzy?

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        The following support your diagnosis: older age; small breed; elevated resting heart rate; typical murmur of mitral regurgitation; and prominent left-sided cardiomegaly with evidence of pulmonary edema suggesting left sided CHF. Hepatomegaly could indicate biventricular failure. The cardiac diagnosis can be confirmed by echocardiography. However, the clinical diagnosis of CHF depends on history, physical exam and your interpretation of radiographs. Response to therapy can also be instructive.
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        Which stage of heart disease is Jazzy in?

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        The correct answer is stage C as Jazzy is showing signs of heart failure due to heart disease.
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        Click here to learn more about the stages of heart disease (ABCD Brochure)

        What treatment(s) would you recommend for Jazzy?

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        THE CEG RECOMMENDS:

        The CEG recommends treatment with furosemide, pimobendan, ACEi +/- Spironolactone.

         ACTUAL TREATMENT
         Initial Therapy Jazzy was administered 2 mg/kg furosemide IV and allowed to rest in oxygen for 4 hours. Following diuresis he appeared comfortable out of oxygen and was released to his owners on the treatment plan below.

        Furosemide - 12.5 mg - one tablet - b.i.d

        This is a relatively conservative dosage, and if respiratory signs re-developed, it would be appropriate to increase the dose from the current 1.7 mg/kg to 2.5 mg/kg (i.e. one and one-half 12.5 mg veterinary furosemide tablet).

        Enalapril - 2.5 mg - 1.5 tablets - b.i.d

        Some cardiologists would use 50% of this dosage initially, especially in dogs with impaired renal function, and would then increase the dose to ~0.5 mg/kg b.i.d. at the first recheck examination. Other ACE inhibitors (benazepril, ramipril, quinipril, etc.) are also approved for treatment of CHF in dogs in a number of countries. There are no clinical trials comparing the relative effects of different ACE inhibitors in dogs with CHF.

        Pimobendan - 5.0 mg - 1/2 tablet - b.i.d

        This drug can be useful in both initial (hospital treatment) as well as chronic therapy of CHF in dogs.

        Spironolactone - 25 mg - 1/4 tablet - b.i.d

        Spironolactone has negligible diuretic effects; this drug is used to reduce the negative effects of aldosterone on tissues such as the pro-fibrotic effect of this hormone on cardiac muscle.

         Diet Avoid high sodium treats and foods such as processed meats, hot dogs, cheese. Typically commercial dry foods contain half the sodium of commercial canned foods.
         Other Points Amlodipine was not prescribed because of his normal blood pressure. Occasionally, amlodipine is used to achieve more afterload reduction, but this would be an advanced treatment reserved for Stage D. Atenolol, a beta-blocker, is contraindicated in treatment of active CHF, and the use of beta-blockers in dogs with chronic heart disease is still under study. The CEG does not recommend routine use of this class of drugs in chronic valvular disease.

         

        7 day follow up:  Jazzy was released after diagnostic tests and instituting oral therapy for CHF. He was re-examined 7 days later.   At that time he was doing well: good appetite, able to exercise, sleeping and breathing comfortably, interacting with the owners, and having only an occasional cough. The owners had been recording the resting respiratory rate and most measures were between 24 and 28 per minute. Owners indicated a near-perfect compliance with medications and were trying to prevent the family from giving Jazzy high-sodium treats.   Systolic blood pressure (non-invasive Doppler flow method) was normal at 126 mm Hg.   Thoracic radiographs, non-invasive blood pressure, and renal function tests and electrolytes were obtained at this visit.   Laboratory tests showed borderline azotemia (BUN 39 mg/dl; creatinine 2.0 mg/dl) with normal sodium and potassium (both enalapril and spironolactone are "potassium-sparing" for the body).   The serum chloride was reduced (103 mg/dl). Hypochloremia is very common with furosemide therapy, because furosemide acts by blocking the transporter of chloride in the kidney. While sometimes associated with mild metabolic alkalosis, minor changes in this electrolyte typically do not require therapeutic adjustments or direct therapy. Thoracic radiographs showed persistent cardiomegaly but resolution of pulmonary edema (see radiographs through links below). Notice the prominent left atrial and left auricular borders on the VD image. The lungs appear normal. The caudal vena cava is obvious on the lateral projections. Compare this to the lateral film where the pulmonary parenchyma is more difficult to assess owing to superimposition of both lung fields as well as soft tissue structures in the caudal mediastinum such as the esophagus.   Click here to view 7 day left lateral radiograph   Click here to view 7 day right lateral radiograph   Click here to view 7 day ventral dorsal radiograph
        4 Month Follow Up: Jazzy was re-examined 4 months later and has been doing well. Kidney function was stable at that examination.   Click here to view 4 month left lateral radiograph   Click here to view 4 month right lateral radiograph   Click here to view 4 month ventral dorsal radiograph