Case Studies

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

Jazzy

Case Background

Name: Jazzy
Age: 13 years
Sex: Male, castrated
Breed: Miniature Schnauzer
Weight: 7.4 kg
Reason for visit: Coughing
Medications: Jazzy is currently receiving Heartgard® Plus and Frontline®. He is not on any other chronic medications.

Clinical History

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): Possibly, some mild weight loss.
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.

Physical Exam - General

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.

Physical Exam - Auscultation

Listen to Jazzy’s heart sounds. (Recommend high-end headphones)


What do you hear?

Listen to Jazzy’s thorax and lungs. (Recommend high-end headphones)

Do they sound normal or abnormal?
Direct HR: 142 bpm
Heart rhythm: Rhythm is regular. Rare premature beats were heard (not on sound file).
Intensity of sounds: Abnormal. The first sound is prominent.
Extra sounds – clicks or gallops: No
Precordial palpation: Precordial thrill (vibration) is evident.

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
Degenerative mitral valve disease (stage C)
Respiratory disease
Dilated cardiomyopathy (stage C)
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.

Diagnostic Test Selection

BLOOD PRESSURE

Non-invasive blood pressure

CLINICAL LABORATORY

CBC with platelet count
Coagulation profile
Serum biochemical profile (includes electrolytes)
Urinalysis
Serum thyroxine (T4)
Heartworm antigen test
Heartworm antibody test
Heartworm microfilaria test
NT-ProBNP
Cardiac troponin-I
Blood culture
Thoracocentesis or abdominocentesis for diagnosis or therapy

DIAGNOSTIC IMAGING (some may require a referral)

Thoracic radiographs
Abdominal radiographs
Echocardiogram with doppler studies
Abdominal ultrasound

ELECTRODIAGNOSTICS (some may require a referral)

ECG rhythm strip or 6 lead ECG
Ambulatory ECG - holter ECG or event monitor
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. Pulmonary ultrasound (noncardiac, thoracic imaging) is helpful in the point-of-care setting to identify intrapulmonary fluid (B-lines), especially in dogs with respiratory distress.
Abdominal imaging (radiography or ultrasound) is 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.

Blood Pressure

Systolic blood pressure: 117 mmHg
Diastolic blood pressure: Not available for this case
Mean blood pressure: Not available for this case

Radiography

Please review Jazzy’s thoracic radiographs

Click here for Jazzy’s radiograph viewer (measure VHS and VLAS here) View the right lateral radiograph

View the dorsal ventral radiograph Click here to see the CEG’s recommendation on evaluating heart size on radiographs
What is the vertebral heart size?
Is Jazzy's heart enlarged?
If Jazzy's heart is enlarged, which chambers are involved?
Is there evidence of congestive heart failure present (pleural effusion or pulmonary edema)?
Technical quality: Diagnostic but considerable rotation on the lateral projection and some on the VD.
Pulmonary venous congestion: There is prominent pulmonary vasculature. There is probable enlargement of the right caudal pulmonary vein on VD and cranial vein on left lateral.
Pulmonary infiltrates: There is an unstructured interstitial to alveolar density with a perihilar distribution.
Other findings: Hepatomegaly; some aerophagia (with food in stomach). Notes: It is very challenging to perform a VHS and VLAS for this dog. The rotation and pulmonary infiltrates make it challenging to see the vertebrae clearly. The infiltrates obscure (border efface or silhouette) the caudal vena cava so VLAS is difficult to determine.

Clinical Labs

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/dLHeatworm
Heartworm test results: NegativeUrinalysis
Urinalysis – USG: 1.024
Urinalysis – protein: Trace
Urinalysis – biochemical: All values within normal limits
Urinalysis – sediment evaluation: Occasional epithelial cells limitsCBC
White blood cells: All values within normal limits
Red blood cells: Hb – 13.4 G/L;  PCV – 40.1%
Platelets: 272,000

Echocardiography

Please review the results of Jazzy’s echo

Watch echo #1 Watch echo #2 Watch echo #3 Watch echo #4 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

The echo diagnosis is mitral and tricuspid regurgitation due to chronic degenerative valve disease with secondary left heart enlargement. There are selected images shown. The right parasternal long axis (#1) shows a prolapsing mitral valve with subjective enlargement of the left atrium and ventricle. The short-axis image (#2) shows a hyperdynamic and subjectively dilated left ventricle. The third image is an apical image centered on the left ventricle (top) and atrium (bottom). The mitral valve is thick and prolapses (anterior leaflet). The color Doppler echocardiogram (#4) is another apical view that shows an eccentric jet of mitral regurgitation (coded in green). The M-mode study showed left ventricular dilation for the size of the dog and a normal fractional shortening. The septal excursion is greater than free wall, typical of volume overload of the left ventricle. The mitral Doppler shows a holosystolic jet of regurgitation. The tricuspid Doppler shows a holosystolic jet of tricuspid regurgitation; the maximal velocity is <3 m/s indicating an absence of significant pulmonary hypertension.

ECG

Please review Jazzy’s ECG.

Click here for Jazzy's 6 - lead ECG

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

Diagnosis

You’re ready to form a diagnosis for Jazzy! Which of the following diagnoses are correct (you can select more than one)?

What are your clinical diagnoses?

Click here to learn more about the stages of heart disease (ABCD Brochure)

Initial Therapy

The following are typical treatments for severe left-sided CHF:

What initial therapy would you provide for the acute left-sided CHF? Select all that apply.
The following are typical treatments for severe left-sided CHF:
  1. Oxygen administration to increase arterial oxygenation associated with ventilation perfusion inequality in the edematous lungs.
  2. Sedation for anxiety associated with respiratory distress – butorphanol 0.1 to 0.2 mg/kg IV or IM initially).
  3. Furosemide to reduce pulmonary venous and capillary pressures – initially boluses (2 mg/kg IV repeated in 30 minutes if an initial diuresis does not occur); this might be followed by less frequent boluses or IM or SQ administration, with dosing tailored to the patient response. If the initial therapy seems unsuccessful, a constant rate infusion of furosemide could be considered, although its merits over IV boluses have not yet been confirmed in clinical trials of dogs with CHF.
  4. Pimobendan (Vetmedin®) as the inodilator effects are beneficial in acute as well as chronic CHF – Label dose of 0.25 to 0.3 mg/kg PO; this can be repeated q12h or as an extralabel q8h treatment during hospital therapy. Intravenous Vetmedin® is available in some countries.
  5. Nitrates are venodilators administered topically and mixed arterio-venous dilators when given intravenously. These can potentially be considered for unloading the left ventricle in life-threatening pulmonary edema. However, such therapy is empirical and usually based on poor response to other treatments or a clinician’s assessment of the severity of pulmonary edema (“white-out lung”, expectoration of froth). Nitrates include topical nitroglycerine ointment (2%) and more potent injectable nitrates (sodium nitroprusside and intravenous nitroglycerine).
The referring veterinarian promptly identified CHF in this dog and initiated life-saving treatments prior to referral with injectable furosemide, butorphanol, and oxygen. The treatments reduced the pulmonary edema, reduced patient activity and anxiety, and improved oxygenation. Pimobendan was added shortly thereafter.

Treatment - Long Term Therapy

You’re ready to form a treatment plan for Jazzy!

 
Select all that apply
What chronic (home) therapy would you prescribe for Jazzy?
 
1.     Heartworm prevention Continued monthly preventative per referring veterinarian
2.     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 or one 20 mg generic “human” furosemide tablet).Oral torsemide (2.5 mg PO) once daily would be an alternative oral loop diuretic.
3.     Pimobendan 5.0 mg 1/2 tablet b.i.d. Pimobendan (Vetmedin®) is a standard of care for CHF due to myxomatous valve disease.
4.     Enalapril 2.5 mg 1.5 tablets b.i.d. Whether an ACE-inhibitor should be initiated immediately or the time of the first recheck depends on the cardiologist and the patient’s renal function at the time of hospital release.  One approach is to prescribe 0.4 to 0.5 mg/kg of enalapril or benazepril once daily initially and increase (double) the daily dosage if recheck renal function is relatively normal. Recent work suggests that both enalapril and benazepril should be administered twice daily in dogs. The CEG acknowledges the controversy related to ACE-inhibitors in treatment of CHF due to mitral valve disease but believe there is sufficient evidence of incremental value of RAAS inhibition in dogs receiving a loop diuretic. An optimal study combining enalapril (or benazepril) and spironolactone to background therapy with pimobendan and a loop diuretic is still needed. Cost of therapy is an issue in some countries were generics are unavailable. In the US there is a combination propriety pill containing benazepril with spironolactone (Cardalis®) and also generic equivalents of the individual drugs.
5.     Spironolactone 25 mg 1/2 tablet qd Spironolactone has negligible diuretic effects but is administered to diminish the negative effects of aldosterone on tissues including the pro-fibrotic effect of this hormone on cardiac muscle and renal tissues (in chronic kidney disease).
6.     Diet The main advice is to provide good quality protein, modest sodium restriction and a palatable diet. Some of the commercially available cardiac diets (Purina®, Royal canin®, Hill® fulfill these goals). Additionally, avoid high sodium treats and foods including most processed meats, many cheeses, hot dogs, and certain table scraps.

Follow Up

Thoracic radiographs were repeated before release from the hospital. 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. Click here to view next day right lateral radiograph Click here to view next day ventral dorsal radiograph 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. Radiographs were similar to the post-treatment images and showed stable heart disease (radiographs not shown). Laboratory tests showed mild 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). Due to the mild azotemia, the dose of enalapril was not increased. This degree of mild kidney dysfunction is usually acceptable in a heart failure paitent. 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.
5 Month follow up: Jazzy was re-examined 5 months later and has been doing well. Kidney function was stable at that examination. Repeated thoracic radiographs showed progressive cardiomegaly, but relatively clear lung fields. Click here to view 5 month left lateral radiograph Click here to view 5 month right lateral radiograph Click here to view 5 month ventral dorsal radiograph

    The CEG is funded through an educational grant from Boehringer Ingelheim Vetmedica, Inc., IDEXX Laboratories, Inc. and Nestle Purina PetCare.

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