Old collie with syncope

RE: Old collie with syncope

nikki — Sun, 21 Feb 2016 12:23:42 GMT

Thanks - that's really useful. The wall of the RV did look thickened (I did take measurements but can't remember off the top of my head) In the RPSA mushroom view the IVS did look like it was a bit flattened. He does have an elevated resting respiratory rate with some increase in effort too. I could have a go at an arterial blood gas - we have an EPOC. I've not done an arterial sample before but could give it a go.

RE: Old collie with syncope

Amy Lam — Sun, 21 Feb 2016 12:19:09 GMT

Those measurements and the enlargement of the RA / RV are consistent with PH> is there interventricular septal deviation, or any myocardial hypertrophy (other supportive indicators). Regardless the treatment with sildenafil sounds indicated to me, as a phosphodiesterase inhibitor it will contribute to pulmonary arteriovenous dilation. Pimobendin may also be useful in additional treatment if finances allowed.

The pathophysiological categories which I use for PH are:

1. Pulmonary Arterial Hypertension - heartworm, Systemic - pulmonary shunting (ASD, VSD, PDA, Idiopathic, vasculitis)

2. Pulmonary Hypertension with Left Heart Disease (increased pulmonary venous pressure) - Mitral valve disease, myocardial disease, misc left sided diseases.

3. Pulmonary Hypertension with Pulmonary Disease or Hypoxia - Chronic obstructive pulmonary disease, interstitial pulmonary fibrosis, neoplasia, altitude, reactive pulmonary arterial constriction to hypoxia.

4. Pulmonary Hypertension owing to Thrombotic and/or Embolic Disease - PTE (from underlying immune mediated disease, neoplasia, pancreatitis, PLN, PLE, HAC, Heartworm

5. Miscellaneous: Extramural disease compressing the pulmonary artery i.e. granulomas / neoplasia - rare in dogs and cats

These categories just help me to think and assess for potential etiologies. From the sounds of your echo, you've ruled out left sided heart disease and from the radiographs there are no obvious pulmonary lesions. PTE and pulmonary intersitital diseases can be very difficult to detect on radiographs - so they can't be excluded. Is the dogs respiratory rate elevated at rest? Is it possible to do an arterial blood gas? These may be helpful in assessing the perfusion / diffusion capacity.

I think the sildenafil will improve the dogs quality of life, but there may be something lurking as the underlying cause.

Hope this helps!

Amy

RE: Old collie with syncope

grumpyoldman — Sun, 21 Feb 2016 11:04:01 GMT

Seen a few odd syncopal geriatrics with intermittent hypertension from Cushings , not always having big ALKP if they are atypical and only show up on 17-OHProg tests. Possibly worth looking at the retinal vessels when the BP is high, sausage string vessels . We also had a syncopal phaecochromocytoma a few years ago. Insulinomas usually twitch first ,but you can just catch them with a BG in the 4-8 range if its not a fasted sample. It will be something weird.