Case 33 — Six Weeks After First Visit

Presenting Complaint

  • Heartworm

Pertinent History

  • Fisher was presented to the Cardiology Service for his second round of melarsomine injections.
  • Fisher was diagnosed with stage III heartworm disease 6 weeks ago. Eight heartworms were removed (2 from the left pulmonary artery and 6 from the right pulmonary artery) using a flexible alligator forceps. He recovered well from that procedure and received his first injection of melarsomine 4 weeks ago.
  • The owner reports that Fisher has been doing well at home. He has a variable appetite but has a good attitude. He is still under exercise-restriction; he is only allowed to go on leash walks to urinate and defecate. Fisher occasionally still coughs, but the frequency has decreased.
  • The owners report no adverse side effects from the last injection. They gave Fisher prednisone for about 2 days afterward to decrease any inflammation. Fisher is not taking any medications currently. He is due for his heartworm preventative (Heartgard) in 2 days.

Physical Examination

  • Gen: BARH, BW=34 kg.
  • Integ: Full coat, shaved area over left epaxial muscles
  • EENT: Eyes — clear corneas, no ocular discharge OU; ears — clean; nose — no discharge; throat — mild dental calculi, no oral masses.
  • MS: BCS=5/9, symmetrical muscling, no gait abnormalities.
  • CVS: No murmur or arrhythmia, split S2; strong, synchronous femoral pulses bilaterally; MM=pink, CRT=1sec.
  • Resp: Quiet breath sounds bilaterally, eupneic, no cough on tracheal palpation.
  • GI: No masses palpated.
  • GU: No preputial discharge.
  • LNs: Mandibulars, prescapular and popliteal LNs are symmetrical and <1cm.

Problems

  • Stage III heartworm disease
  • Moderate pulmonary hypertension
  • Proteinuria

Medical/Surgical Procedures

  • First day: 86mg Immiticide (3.4ml) deep IM right epaxial muscles
  • Second day: 86mg Immiticide (3.4ml) deep IM left epaxial muscles
  • Heartworm Ag: weak positive
  • Urine protein to creatinine ratio: 1.64
  • Urinalysis (free-catch sample): SpGr 1.050, 4+ protein, 1+ bilirubin, 2+ hemoprotein, 10-20 RBC, rare hyaline and 0-3 granular casts
  • Echocardiogram: IVSd 9 mm, LVIDd 39 mm, LVIDs 25 mm, LVFWd 10 mm, LVFWs 13 mm, IVSs 12 mm, Ao 22 mm, LA 33mm, LA:Ao 1.5, FS 35%; overall decreased right heart size from last recheck; no septal flattening in systole or diastole; large main PA; trivial pulmonic insufficiency (max velocity 2.96m/s, pressure gradient 35mmHg); no tricuspid regurgitation; no heartworms were visualized

    Conclusions: The echocardiographic findings today showed that the pulmonary hypertension has decreased significantly. There is no longer any tricuspid regurgitation. Heartworm treatment appears to be effective at this time.

Clinical Diagnoses

  • Heartworm Disease

Plans and Progress Notes

  • First day: Problem 1 and 2 - Heartworm disease and pulmonary hypertension. S/O: There is a split second heart sound on auscultation. A repeat echocardiogram showed a decreased right heart size overall. In addition the septal flattening in systole and diastole noted at the first admission is no longer present and his tricuspid regurgitation is gone. Pressure in the pulmonary artery during diastole was estimated at 35mmHg from a small pulmonic insufficiency jet velocity. A heartworm antigen test was still weakly positive. Fisher received 86mg (2.5mg/kg) of melarsomine deep IM in the right epaxial muscles. A: Fisher currently has mild to moderate pulmonary hypertension, but it represents a significant improvement since the last recheck. The split S2 is likely due to the pulmonary hypertension. P: Monitor Fisher overnight for increased respiratory effort and rate. Feed, water and walk. Administer second dose of melarsomine tomorrow.
  • First day: Problem 3 - Proteinuria. S/O: A urinalysis showed 4+ protein, and UPC was measured at 1.64. A: The proteinuria is likely due to the glomerulonephritis secondary to heartworm disease but is only mild. P: No action at this time. Recheck U/A and UPC in 3 months.
  • Second day: Problem 1 and 2 - Heartworm disease and pulmonary hypertension. S/O: At 8am, T=101F, P=100bpm, R=36bpm. His lung sounds are quiet bilaterally, and he is eupneic. At 8pm, T=101F, P=92bpm, R=60bpm, he is eupneic. Fisher received his second melarsomine dose (86mg) deep IM in the left epaxial muscles. Fisher appeared painful after the second injection. Therefore 70mg ketoprofen was administered SC. A: Fisher received his last dose of melarsomine. P: Monitor Fisher overnight for increased respiratory effort and rate. Feed, water and walk.
  • Third day: Problem 1 and 2 - Heartworm disease and pulmonary hypertension. S/O: At 8am, T=101F, P=140bpm, R=40bpm, eupneic, pink MM, CRT=1sec, quiet breath sounds bilaterally. He appears less painful than yesterday. Ate well. A: No immediate adverse reactions from the melarsomine injections other than pain. P: Discharge today. Advise owners to exercise-restrict Fisher for another 4 weeks. Recheck radiographs, echo, heartworm antigen, u/a and UPC in 3 months.
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