INTERACTIVE CASE STUDIES

 
 

AthenaCase Background

 
Name Athena
Age 6 years
Sex Female
Breed Doberman
Weight 30 kg
Reason for Visit Decreased appetite, cough and labored breathing
Medications Amoxicillin 500mg: 1 capsule q 12hrs
     

Please review Athena's clinical history.

 
Attitude/Demeanor Lethargic
Coughing Coughing for two weeks
Respirations Increased respiratory effort over the last 2 days
Exercise Tolerance Refusing to go on normal walks
Sleep Patterns Prefers to lay in sternal recumbency which is atypical
Weight Change (loss or gain) None
Appetite Has become very particular about food over the last 2 weeks
Usual Diet Purina OM™, 4 cups per day
Vomiting None
Diarrhea None
Syncope None
Change in urinary habits None
Change in drinking habits None
Other symptoms or signs None
 

Please review the results of Athena's physical exam.

Body Condition Good
Attitude Quiet
Mobility | Gait Ambulating normally
Posture Standing or sternally recumbent
Hydration Adequate
Body Temperature 100.2 F
Arterial pulse - rate, regularity, intensity Weak, irregular pulses with a rate of 180/min with pulse deficits
Respiratory Effort Increased respiratory effort
Mucous Membranes - Color & CRT Mildly pale
Jugular Venous Pulse & Pressure No jugular distention
Abdominal Palpatation Normal
Lymph Nodes Normal
Oral Cavity Normal
Other abnormalities None
 

Let's auscult Athena's heart & lungs.

Listen to Athena's heart and lungs.

What do you hear?

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Heart rhythm is irregularly irregular. The intensity of the heart sounds are quiet. No clicks or gallops detected. Irregularly irregular precordial impulse.
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Listen to Athena's thorax and lungs. Do they sound normal or abnormal?

Athena's thorax and lungs sound abnormal. There are increased bronchial sounds and audible crackles.
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Direct HR: 210 bpm

 

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

Dilated Cardiomyopathy

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Degenerative Valve Disease

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Primary Respiratory Disease

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

The patient's signalment (age and breed), along with the complaint of cough, respiratory distress, and an arrhythmia makes dilated cardiomyopathy the leading differential in this case. The patient's decreased appetite, altered exercise tolerance, and lethargy would be common findings in cases of congestive heart failure compared to many more benign causes of cough. Degenerative valve disease is less likely given the signalment and the lack of a significant heart murmur, however arrhythmias may often reduce the intensity of heart murmurs so valvular disease can not be completely excluded. The presence of the arrhythmia also leads us away from a diagnosis of primary respiratory disease, however we can not completely exclude the possibility of primary respiratory disease with an unrelated arrhythmia.

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: 

        The highest priority diagnostic test to help determine the etiology for the clinical signs was thoracic radiographs. Benefits of thoracic radiographs in Athena's case include assessment of the pulmonary vasculature and pulmonary parenchyma, along with assessment of the heart size. Because dilated cardiomyopathy is often accompanied by cardiac dilation, thoracic radiographs are often useful to detect the eccentric hypertrophy in symptomatic dogs. NT-proBNP assessment may add information in cases in which the radiographic findings are ambiguous (click here for the circulation article "Use of NT-proBNP in the Dog"). The electrocardiogram is equally critical to document the presence of supraventricular arrhythmias, ventricular arrhythmias, or a combination of the two. The type of arrhythmia present alters management protocols and level of risk for sudden cardiac death. Blood pressure measurement was strongly recommended to assess the degree of hypotension present and establish a baseline blood pressure that may be followed to guide acute therapy. The chemistry profile and urinalysis are important to evaluate renal function as we suspect dilated cardiomyopathy and congestive heart failure account for the clinical signs. The presence of concurrent renal disease complicates management of congestive heart failure. The complete blood count, although not 100% specific, may provide insight into the presence of infectious or inflammatory pulmonary disease. Echocardiography is required for the confirmation of dilated cardiomyopathy.

        Systolic Blood Pressure: 105 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 Athena'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?

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        Is Athena's heart enlarged?

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        Athena's heart shows moderate cardiac enlargement.
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        If Athena’s heart is enlarged, which chambers are involved?

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        Athena's heart shows left-sided cardiomegaly with a tall upright heart consistent with left ventricular enlargement with a moderate to severe caudodorsal bulge consistent with left atrial enlargement.
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        Is there evidence of congestive heart failure present (pleural effusion or pulmonary edema)?

        There is pulmonary edema present
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        Technical Quality: Good Pulmonary Venous Congestion: Yes Pulmonary Infiltrate Distribute: Predominently perihilar and caudodorsal interstitial

        Please review Athena's lab results

        SERUM CHEMISTRIES
        BUN 24 mg/dL, Normal: 5 - 29 mg/dL
        Creatinine 1.7 mg/dL, Normal: 2.1 mg/dL
        Sodium 140 mmol/L, Normal:138 - 154 mmol/L
        Potassium 3.8 mEq/dL, Normal: 3.6 - 5.2 mEq/dL
        Chloride 115 mEq/dL, Normal: 105- 119 mEq/dL
        ALT 98 IU/dL, Normal: <75 IU/dL
        ALP 58 IU/dL, Normal: <100 IU/dL
        Glucose 140 IU/dL, Normal: 68 - 126 mg/dL
        HEARTWORM
        Heartworm Test Results Negative
        URINALYSIS
        Urinalysis - USG 1.020
        Urinalysis - Protein Negative
        Urinalysis - Biochemical Negative
        Urinalysis - Sediment Evaluation Negative
        CBC
        White Blood Cells 12,000/ul
        Red Blood Cells 41%
        Platelets 240,000/ul

        Please reivew the results of Athena's echo.

         Subjective - lesions of valves,  myocardium, pericardial space No valvular degeneration was seen. The left ventricular systolic function is subjectively reduced.
         LV chamber size and thickness There is severe left venticular eccentric dilation.
         Left atrial size The left atrium is moderately to severely enlarged.
         LVIDd & LVIDs Diastole (3.22 cm); Systole (1.41 cm).
         LV shortening fraction Left ventricular contractility is significantly reduced with a low fractional shortening of 11%.
         RA, RV and Pulmonary Artery Normal.
         Effusions No pleural or pericardial effusion.
         Doppler results There is moderate mitral valve regurgitation associated with geometric ventricular changes (dilation of the mitral valve annulus). Trivial tricuspid regurgitation.
          Watch echo #1
        Watch echo #2
        Watch echo #3  

        Please review Athena's ECG

        Click to enlarge

        Rhythm diagnosis is?

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         Technical quality, leads, paper  speed, calibrations  Leads I, II, III, aVR, aVL, 50mm/sec, 10mm/mV
         Artifacts  None
         Heart Rate  Average = 240/min
         Rhythm - Regular or irregular |  Patterns  Irregularly irregular R-R intervals
         Heart Rhythm Disturbances  Atrial fibrillation
         P Wave Abnormalities -  morphology, amplitude, duration  Absent P waves
         QRS Abnormalities - axis,  morphology, amplitude, duration  Normal axis with upright QRS complex in Lead II
         Abnormal Intervals - PR, QRS, QT QRS is slightly wide (0.06 sec) consistent with left ventricular enlargement
             

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

        What is your diagnosis for Athena?

        The following support your diagnosis: middle aged; at risk breed (Doberman) with prominent left-sided cardiomegaly and reduced systolic function on echocardiography. However, the history, physical examination findings and radiographic evidence of pulmonary edema suggest that left-sided CHF is present.
        The following support your diagnosis: Class C dog. Dilated cardiomyopathy is a common form of heart disease that we see in large breed dogs. Reduced systolic function of the ventricular muscle results in volume overload and congestive heart failure. Arrhythmias are a common finding with dilated cardiomyopathy, and include ventricular tachyarrhythmias, and atrial fibrillation.
        The following support your diagnosis: middle aged dog, with compatible history and prominent left-sided cardiomegaly with evidence of pulmonary edema suggesting left-sided CHF. However, although degenerative valve disease can be seen in any breed, it typically occurs in small breeds of dogs and when present, usually causes audible heart murmurs over the affected valve(s). In this case, although some mitral regurgitation was noted, the small amount of regurgitation without prominent visible valvular abnormalities as well as decreased systolic function are suggestive of dilated cardiomyopathy as a cause of the small regurgitant jet.
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        Which stage of heart disease is Athena in?

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        Athena 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 Riley?

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        THE CEG RECOMMENDS:

        The CEG recommends treatment with a combination of Furosemide, ACEi, Pimobendan(Vetmedin), Digoxin + Diltiazem.

         ACTUAL TREATMENT
         Initial Therapy

        Acute Therapy

        Athena was administered furosemide IV as a 150mg bolus, and 30mg 2 hours later. 15mg of oral pimobendan was administered along with oxygen therapy. After 6 hours, the respiratory rate declined and respiratory effort normalized.

        Furosemide - 40 mg tablets

        1.5 tablets every 8 hours for 3 days, then decrease to every 12 hours.  After the onset of congestive heart failure, furosemide is indicated as a chronic therapy to prevent symptoms of respiratory distress and cough.  Twice a day dosing prevents a rebound fluid retention in between doses.  High ceiling drug with a dose dependent response.

        Enalapril - 10 mg tablets

        1.5 tablets every 12 hours. ACE inhibitors are indicated to reduce sodium and water retention, moderate blood pressure and limit the negative remodeling effects of angiotensin II and aldosterone.

        Pimobendan - 5mg tablets

        3 tablets ever 12 hours. This inodilator has been shown to outperform ACE inhibitors when used with furosemide in prolonging survival in Doberman pinschers with dilated cardiomyopathy and CHF. Pimobendan is indicated at the onset of congestive heart failure and is administered chronically.

        Digoxin - 0.125 mg tablets

        1 tablet every 12 hours. Digoxin is prescribed to reduce the ventricular response rate to the atrial fibrillation, and to provide mild inotropic support.  Dose:  0.003 to 0.004 mg/kg twice daily.  Rrough serum digoxin concentration can be measured every 3 months to assure therapeutic drug concentration.

        Diltiazem - 30 mg tablets

        1 1/2 tablets every 8 hours. This is being used to reduce the ventricular response rate to the atrial fibrillation.

         Diet Avoid high sodium treats and foods such as processed meats, hot dogs, cheese and some table scraps. Typically commercial dry foods contain half the sodium of commercial canned foods.

         

         Other Points

        None

         LIST CURRENT MEDICATIONS TABLET SIZE  LIQUID CONCENTRATE DOSE
          Furosemide IV    50 mg/ml   3 ml(150 mg) intial bolus
          Furosemide IV    50 mg/ml   0.6ml (30 mg)
        Pimobendan  5 mg   3 tablets
               
         ORAL MEDICATIONS TO GO HOME      
         Furosemide 40 mg    1.5 tablets
         Enalapril  10 mg   1.5 tablets
         Pimobendan  5 mg    
         Digoxin 0.125 mg    
         Diltiazem  30 mg   1.5 tablets
         Heartworm Preventions  Continue    

        Recommended Follow-up: A renal blood panel,  an 8-hour post-till serum digoxin concentration, ECG and thoracic radiographs should be performed in 5-7 days . The repeat radiographs are performed to ensure resolution of the pulmonary edema. An ECG is repeated to determine the need for additional rate control medication. The ventricular response rate goal would be an average of 135 bpm on Holter monitor, or less than 160 on an in-house ECG in a calm patient. Thoracic radiographs, ECG, blood pressure and serum biochemistries should be repeated in 3-4 months to check for progression of congestive heart failure and additional rhythm disturbances, if no clinical signs have been noticed earlier.
        7 Day Follow-up: Athena was released after diagnostic tests and instituting oral therapy for CHF. She was re-examined 7 days later. The owners have not noticed any coughing or labored breathing since discharge from the hospital. The appetite was reduced for the first 3 days, and is near normal today. Athena ws assessed with a renal panel, 8-hour post-pill serum digoxin concentration, ECG and thoracic radiographs. Renal panel: BUN=37mg/dl; creatinine 1.8mg/dl; phosphorus and electrolytes are within normal limits. Serum digoxin concentration: 0.9ng/dl (sample was drawn 6-8 hours post-pill into a red top tube without a serum separator. Eight-hour post-pill (trough) concentrations between 0.8 and 1.3 ng/dl are ideal to help with rate control and prevent toxicity signs. ECG: Rhythm is still atrial fibrillation, but the rate has been effectively reduced to an average of 150 bpm on the in-house rhythm strip. Thoracic radiographs: Left-sided cardiomegaly with a tall, upright heart consistent with left ventricular enlargement with a moderate to severe caudodorsal bulge consistent with left atrial enlargement. However, the caudodorsal interstitial pattern noted previously is absent on today’s films, and there has been improvement in the pulmonary venous distention. An increase in the furosemide dose is not warranted.