|Reason for visit||Presented two days ago to your colleague for a complaint of respiratory difficulty for one week. Now the owner, Mr. Brown, has brought him back to you because he has noticed a distended abdomen and is concerned because Riley is not eating well. During the initial visit a murmur was identified and Riley was tentatively diagnosed with CHF and started on Furosemide, enalapril and spironolactone.|
|Medications||Heartworm prevention: Heartgard® plus and Frontline®|
Please review Riley's clinical history.
|Attitude/Demeanor||Bright and alert|
|Respirations||Increased inspiratory effort with shallow breathing|
|Exercise Tolerance||Has generally been slowing, but is now more reluctant to exercise|
|Sleep Patterns||Sleeping well, but he prefers to sleep on his belly and not on his side|
|Weight Change (loss or gain)||Significant abdominal distension|
|Appetite||Not eating as well for the last 2 days|
|Usual Diet||Science Diet® maintenance dry|
|Change in urinary habits||Increase in urinating since meds started yesterday|
|Change in drinking habits||Increase in drinking since meds started yesterday|
|Other signs or symptoms||None reported|
Please review the results of Riley's physical exam.
|Body Condition||Good, BCS 6/9|
|Attitude||Alert, somewhat anxious|
|Mobility | Gait||Normal gait on inspection|
|Posture||Standing or sitting|
|Body Temperature||100.3 F|
|Arterial pulse - rate, regularity, intensity||132 beats/min, occasional premature beat, pulses fair|
|Respiratory Rate & Effort||40, mild inspiratory effort, breathing shallow|
|Mucous Membranes - Color & CRT||Pink, <2 seconds|
|Jugular Venous Pulse & Pressure||Jugular distension, no pulsation|
|Abdominal Palpatation||Severe abdominal distension, fluid wave suspected, internal organs difficult to palpate|
|Oral Cavity||Mild dental calculus|
Let's auscult Riley's heart & lungs.
|Heart Rhythm||Regular with occasional premature beats|
|Intensity of heart sounds||Heart sounds audible, but reduced|
|Extra sounds - clicks or gallops||None|
|Precordial palpation||No thrill detected|
The CEG considers the following differential diagnosis as most likely:
CHF secondary to chronic valvular disease (CVD) is the most likely underlying etiology of the clinical signs because Riley is a small (<20Kg) older dog with a loud heart murmur characteristic of mitral regurgitation (MR). Dilated cardiomyopathy (DCM) cannot be ruled out but would be very unlikely in a Shih Tzu. CHF secondary to heartworm (HW) disease should be considered in endemic areas especially if dogs are not on preventative. Pericardial effusion with tamponade is less likely because his heart sounds (murmur) are loud.
The CEG considers the following diagnostic tests as the highest priority:
Thoracic radiographs must be considered as the most important diagnostic test in a patient with respiratory signs suspected of having congestive heart failure.
An echocardiogram should be performed to confirm that there is enough underlying heart disease present to make the clinical signs likely to be attributable to heart failure. In addition, an echocardiogram is the definitive diagnostic test to document the presence of pericardial effusion, pulmonary hypertension and severe heartworm disease. Obtaining a serum chemistry is also important in this case, as the owner complained that Riley's appetite has suffered after starting the cardiac therapy. Impairment of renal function and resulting azotemia is an important cause of decreased appetite in patients receiving therapy for CHF. Similarly, a blood pressure evaluation is important to rule out systemic hypertension and to identify adverse effects of current therapy. This is especially important if additional therapy is contemplated. An ECG should be obtained in any patient where an arrhythmia is identified/suspected (Riley had premature beats detected on auscultation). NT-proBNP is less useful if significant heart disease has been identified by echo; however this may be a very useful test if an echocardiogram cannot be obtained. A heartworm test can also be considered in a patient presented with signs of heart disease and right-sided heart failure; while still appropriate in this case, it may be less important given the rest of the case history.
Evaluation of the abdomen (e.g. use of ultrasound, radiographs and/or fluid analysis) can also be considered, but would be most important if significant heart disease is not identified. In some cases, abdominal evaluation may be more important, especially if an acute abdomen (hemoabdomen, peritonitis, etc.) is suspected based on clinical findings. Similarly, a complete blood count can be considered a higher priority if infection/bleeding is a concern.
Please review Riley's thoracic radiographs
Technical Quality: Good
Pulmonary Venous Congestion: No pulmonary venous congestion seen
Pulmonary Infiltrate: No convincing interstitial changes are seen on the VD. Increased opacity is seen on the lateral, but may be due to the expiratory nature of the film.
Other findings: Loss of serosal detail is noted on the abdominal portion of the film.
Please review Riley's lab results
|BUN||29 mg/dL, Normal: 6 - 25 mg/dL|
|Creatinine||0.8 mg/dL, Normal: 0.5 - 1.6 mg/dL|
|Sodium||145 mmol/L, Normal:139 - 154 mmol/L|
|Potassium||4.5 mmol/L, Normal: 3.6 - 5.5 mmol/L|
|Chloride||4.5 mmol/L, Normal: 3.6 - 5.5 mmol/L|
|ALT||33 IU/L, Normal: 12 - 118 IU/L|
|ALP||185 IU/L, Normal: 5 - 131 IU/L|
|Heartworm Test Results||Negative within the last 6 months|
|Urinalysis - USG||Not performed|
|Urinalysis - Protein||Not performed|
|Urinalysis - Biochemical||Not performed|
|Urinalysis - Sediment Evaluation||Not performed|
|White Blood Cells||Not evaluated|
|Red Blood Cells||Not evaluated|
Please reivew the results of Riley's echo. The images and videos were obtained by a cardiologist.
|Subjective - lesions of valves, myocardium, pericardial space||No pericardial effusion; thickened mitral leaflets|
|LV chamber size and thickness||Mild left ventricular enlargement|
|Left atrial size||Moderate to severe dilation|
|LVIDd & LVIDs||Diastole (3.22 cm); Systole (1.41 cm)|
|LV shortening fraction||Normal to hyper dynamic ~ 56%|
|RA, RV and Pulmonary Artery||Moderate right atrial and ventricular enlargement, moderately dilated main pulmonary artery|
|Effusions||Moderate ascites seen|
|Doppler results||Mitral and tricuspid regurgitation; velocity of MR predicts normal systemic pressures; increased velocity of TR (~5.2 m/s) predicts severe pulmonary artery hypertension (~110 mmHg)|
You're ready to form a diagnosis and treatment plan for Riley! Please select your answer to each question below.
THE CEG RECOMMENDS:
The CEG recommends treatment with Lasix, pimobendan, ACEi +/- Spironolactone.
|Initial Therapy||Heartworm Prevention continued monthly preventative per referring veterinarian.
Furosemide - 12.5 mg, 1 tablet - every 12 hours Given the degree of fluid increased dosing from 2 to 3 times a day is warranted.
Enalapril - 2.5 mg, 1 tablet - every 12 hours. The dose was kept the same, as it is close to the 0.5 mg/kg dose.
Pimobendan - 1.25 mg, 1 tablet - every 12 hours This was added given its benefit in CHF, as well as its potential value in the management of pulmonary hypertension. Doses of 1.875 mg or even as high as 2.5 mg could be given to this dog depending on response to therapy.
Sildenafil - 20 mg, 1/2 tablet - every 8 hours. The use of sildenafil is recommended in the setting of severe pulmonary hypertension, as it is a particularly effective pulmonary arterial vasodilator. Reducing pulmonary pressures can often help ameliorate clinical signs of pulmonary hypertension such as syncope, shortness of breath or tachypnea, as well as minimize the severity of right heart failure that can accompany severe PH.
Spironolactone - 25 mg, 1/2 tablet - every 12 hours. Spironolactone has negligible diuretic effects; this drug is used to reduce the negative effects, but in used commonly in patients with right sided CHF to reduce retention due to chronic renin-antiotensin-aldosterone system activation. In addition, the drug is used to reduce pro-fibrotic effect of aldosterone on tissue such as cardiac muscle. The dose was increased to maximal value of 2 mg/kg twice daily.
|Diet||Avoid high sodium treats and foods - such as processed meats, hot dogs, cheese, some table scraps.|
Abdominocentesis was performed - 1.4 L removed
|Recommended Follow-up||A typical follow-up interval for a dog receiving treatment for CHF is 1 to 2 weeks for initial re-evaluation and 2 to 6 months thereafter. Specific follow-up intervals relate to the severity of disease and to the client's perception of current symptoms and the dog's quality of life.
Riley was represented for evaluation of episodes of syncope, especially with excitement or exercise. Thoracic radiographs again showed no significant fluid (pleural effusion or pulmonary edema), but repeat echo identified a significant increase in the severity of the pulmonary hypertension (tricuspid regurgitation systolic velocity now 6.2 m/s, systolic gradient=150mmHg). The next step suggested to Riley's owner involved increasing the sildenafil dose (to 12mg q 8hrs, attainable by reformulating 20 mg tablets into a liquid form).