Case Studies In Small Animal

Cardiovascular Medicine

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Case 21


One Day After Presentation

Problem #1:II/VI heart murmur and gallop rhythm: S/O: Freckles is looking a little more depressed this morning than he was last night. He is knuckling on his front right leg and his right front paw is cool to the touch. He appears to be painful in that leg as well. A chemistry panel was submitted this evening because Freckles looks very depressed and we are concerned about his kidney function. Results show a mild azotemia with a creatinine of 2.5 mg/dl and a BUN of 49 mg/dl. His ALT and AST are elevated at 539 and 399 IU/L respectively. A: The spontaneous contrast in his left atrium/auricle is indicative of red blood cell aggregation secondary to decreased flow velocity in this dilated chamber. It can be interpreted as the beginning of clot formation. The clot on his left auricle (in the pericardial space) could be from a rupture of his left atrium. His mild azotemia could be pre-renal in origin owing to the fact that Freckles is mildly dehydrated but is most likely at least in part renal since he has lumpy kidneys on PE and he was isosthenuric prior to Lasix therapy. His elevated liver enzymes are most likely due to muscle necrosis. According to Dr. Kittleson, this type of elevation is commonly seen in cats with systemic thromboembolism and there never is any other evidence of hepatic damage. P: The plan is to continue to monitor Freckles in ICU since he apparently threw another clot to his right front leg. He will continue with physical therapy (passive range of motion) and his right front leg will included with his hind legs. He received Lasix this morning, but we will discontinue it this evening. He will also continue on heparin. Rename to hypertrophic cardiomyopathy.
Problem #2: saddle thromboembolus: S/O: see above. Freckles has femoral pulses in both hind legs. He also has voluntary movement of both his hind limbs and his tail and they are warmer. A: Freckles saddle thrombus is being broken down. He is perfusing his hind limbs now and is showing improvement. P: Plan is to continue passive range of motion and heparin therapy.
Problem #3: right subclavian thromboembolus: S/O: see above A: The knuckling and pain in the right front leg are consistent with a thromboembolus. Small clots will more often embolize to the right front leg because the brachiocephalic trunk is the first branch off the aorta and leads to the right subclavian which is where the embolus most likely lodged. P: The plan is to begin passive range of motion therapy on this leg and to continue with heparin therapy.

Two Days After Presentation

Problem #2 saddle thromboembolus: S/O Freckles is looking much better today. He is
eating and drinking and is walking much better. He has femoral pulses in both hind limbs and is walking normally on them. He spiked a temperature of 104 last night, but his temp this morning is 102.1. A: Freckles appears to have lysed the clot in his caudal aorta. He is perfusing his hind limbs and has full use of them. P: this problem has been resolved.
Problem #3 right subclavian thromboembolus: S/O see above. He is now walking normally on his right front leg. The limb feels warm to the touch and does not appear to be cyanotic. A: Freckles appears to have lysed the clot in his right leg. P: this problem has been resolved.
Problem #4 hypertrophic cardiomyopathy: S/O see above. Freckles is much more
alert today. Because of his improved status, he has been moved back to the wards. He is having some unusual arrhythmias on auscultation of his heart. An ECG showed that he is in atrial fibrillation and has PVCs. A repeat echo also showed a large amount of spontaneous contrast in his left atrium. A: Freckles appears to be clinically doing better. He is lysing his clots on his own, however he will most likely continue to produce more since the spontaneous contrast seen on his echo is so severe. At this point warfarin therapy seems indicated. P: Plan is to do an ECG and re-echo his heart later today. He is on 6.25mg Lasix PO BID and 1.25mg enalapril PO BID. We will begin warfarin therapy tonight at 1mg PO SID. We will continue with the heparin for the next 3 days at 1000 units SQ to try and cover the initial hypercoagulable phase of warfarin therapy. Freckles will start on atenolol at 1/4 of a 25mg tablet PO.

Three Days After Presentation

Problem #4 Hypertrophic cardiomyopathy: (S/O) Freckles is looking g bright and
alert this morning. He is eating well and is drinking quite a bit. He still appears to be walking normally. T=101.6, P=140, R=25. He still has an irregularly irregular rhythm on auscultation of his heart; however, the rate seems to have slowed some from yesterday. A: Freckles is still in atrial fibrillation. He does not appear to have thrown anymore large clots to his limbs at this point. P: The plan is to send Freckles home with the owner this afternoon. He will return on Monday to have his clotting times rechecked.

Discharge Instructions

1.Freckles presented to us in left heart failure and had a clot obstructing blood flow to his hind limbs. He has since lysed that clot, but has continued to produce more. He is diagnosed as having severe hypertrophic cardiomyopathy, systemic thromboembolism, and atrial fibrillation (an arrhythmia).
2.Freckles is being sent home on medications in an attempt to control his heart failure and prevent him from producing more clots. He is to receive 1/2 of a 12.5mg tablet of Lasix orally twice a day, 1/2 of a 2.5mg tablet of enalapril orally once a day, 1/4 of a 25mg tablet of atenolol orally twice a day, and 1/2 of a 1 mg tablet of warfarin orally once a day. He also is to receive 1000 units (1 ml) of heparin subcutaneously every 8 hours for the next 3 days.
3.We would like you to monitor Freckles for any respiratory difficulty, coughing, extreme pain, drastic changes in mentation or personality, or overt signs that he is bleeding. If any of these should occur, we will need to see Freckles.
4.The warfarin that Freckles is receiving puts him at risk for developing severe bleeding complications. This is an unfortunate side effect of the drug, but we feel the warfarin is our only chance at attempting to prevent him from producing more clots. Although we are doing our best to prevent clot formation, there is still a high probability that Freckles will continue to produce thrombi. We would like him to return Monday evening for a recheck of his clotting times 2 hrs after his warfarin dose.
5.Thank you for bringing Freckles to the VMTH. He has been a wonderful cat to work with and we wish him the best of luck.

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