Case Studies In Small Animal

Cardiovascular Medicine

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Case 33

Eighteen weeks after first visit

Presenting Complaints

bulletRecheck heartworm disease

Pertinent History

bulletFisher was presented today to the Cardiology Service for a recheck of his heartworm disease. He was originally diagnosed with Class III heartworm infestation with severe pulmonary hypertension 18 weeks ago. At that time, eight worms were removed from the pulmonary arteries with Ishihara forceps under fluoroscopic guidance. He was later treated with Immiticide (melarsomine) on Feb 11, 2003 and March 13, 2003 according to the alternate dosing protocol.
bulletSince the last visit on March 13th, Fisher has been still coughing a little, but the owner feels that the coughing has significantly decreased. They are still restricting his activity.
bulletFisher is not currently on any medications. His vaccines are up to date, and he has been receiving Heartgard as a monthly heartworm preventative and Frontline for flea and ticks. His diet is Science Diet maintenance, 2-3 cups PO SID.
bulletFisher is primarily an indoor dog who lives with 3 other dogs, cats, chickens, and several other farm animals on a large fenced property. He currently goes on leash walks, but he has also been allowed to roam the property a couple of times at night.

Physical Examination

bulletGEN: BARH, T=101.1, P=100, R=panting, CRT < 2 sec.
bulletINTEG: Normal.
bulletEENT: Normal.
bulletMS: BCS=7/9, weight=40kg. Gait is normal, and body appears symmetrical with no abnormalities noted.
bulletCV: No arrhythmia or heart murmur ausculted.
bulletRESP: Normal.
bulletGI: Normal.
bulletLNs: Normal.
bulletNEURO: Full neuro examination not performed.


bulletHistorical Class III heartworm disease
bulletHistorical severe pulmonary hypertension
bulletHistorical proteinuria (glomerulonephritis)

Clinical Diagnoses

bulletHeartworm infection - resolved
bulletPulmonary hypertension - improved
bulletProteinuria (glomerulonephritis) - resolved


bulletRadiographs: Today's radiographs are compared to previous radiographs taken at the VMTH. Again, a diffuse interstitial pattern is appreciated along with severely enlarged, tortuous, and blunted pulmonary arteries. However, the right main pulmonary artery appears more prominent than previously noted.
bulletEcho: IVSd = 1.2 cm, EDD = 4.33 cm, LVFWd = 0.8 cm, IVSs = 1.4 cm, ESD = 2.8 cm, LVFWs = 1.2 cm, Ao = 2.1 cm, LA = 2.7 cm, FS = 37%, LA/Ao = 1.3. The previously noted septal flattening is no longer apparent. The pulmonary arteries are severely enlarged. No pulmonic insufficiency or tricuspid regurgitation is apparent. No heartworms are seen.
bulletDifil Test - negative. Synbiotics DiroCHEK heartworm antigen test: Negative
bulletURINALYSIS pertinent results:

Turbidity - clear; Color - yellow; Specific gravity - 1.037 Refractometer; pH 8.5; Protein 1+

bulletUrine Protein/Creatinine - 0.11
bulletConclusions: The echocardiographic findings today show that Fisher's severe pulmonary hypertension has improved. He is now heartworm antigen and Difil tests are negative and his glomerulonephritis has resolved with the treatment of his heartworm disease. Given the appearance of the right main pulmonary artery on his thoracic radiographs, Fisher could still have a male worm occupying this artery, causing an antigenic response and resulting in a negative antigen test. This is, however, of low likelihood. He is doing clinically well, and he will return yearly for rechecks. Fisher's owners were told that exercise restriction is no longer necessary, and Fisher should live a normal, healthy life now that his heartworm disease has been addressed and treated effectively.

Mark D. Kittleson, D.V.M., Ph.D. All rights reserved.