Saturday, March 15, 2014

BToW: The Importance of Diagnostics

"What has been the most interesting case you have seen?"

 I'm actually going to talk about my own dog here. 1) Because I can tell you everything without running afoul of confidentiality stuff and 2) because her case nicely illustrates why your vet wants to spend more of your money on things like bloodwork. For all you vet students and/or pre-vets and/or armchair vets, here's your case!

So, meet Baby.
June 2012:
Signalment: 13 year old female spayed Valley Bulldog.
History: Presented for a geriatric pet wellness exam. Lives with an indoor/outdoor cat. No real complaints from owners. Eating, drinking, urinating and defecating normally. Eating a grain-free store bought dry diet, some table scraps. Vaccines not up to date, had her puppy series, but nothing since. Dewormed a few times a year. Dog aggressive, kept away from other dogs at all times, except for an occassional visit from with the owner's daughter (my sister) who has a 2 year old Chihuahua, who is up to date on vaccines.
Physical exam findings: Good condition, 18kg, not over or underweight, some dental calculus, some dandruff, heart and lung ascultation normal, TPR normal. Mild opacity in eye but doesn't seem to cause problems (probably normal age related change and not cataracts.) Slight pot-bellied appearance, but she's a bulldog.

Owner's daughter is a vet student (c'est moi, duh) and wants a geriatric blood panel done. Results below with normals in parantheses)

WBC: 8.68 x 10^9/l (6-17)
LYM: 1.46 x 10^9/l (1-4.8)
MON: 0.46 x 10^9/l (0.2-1.5)
NEU: 6.50 x 10^9/l (3-12)
EOS: 0.18 x 10^9/l (0-0.8)
BAS: 0.08 x 10^9/l (0-0.4)
LY%: 16.8% (12-30)
MO%: 5.3% (2-4)
NE%: 74.8% (62-87)
EO%: 2.1% (0-8)
BA%: 0.9% (0-2)

RBC: 5.98 x 10^12/l (5.5-8.5)
HGB: 15.5 g/dl (12-18)
HCT: 43.25% (37-55)
MCV: 72 fl (60-77)
MCH: 26 pg (19.5-24.5)
MCHC: 35.9 g/dl (31-34)

PLT: 406 x 10^9/l (200-500)

ALB: 48 g/l (25-44)
ALP: 964 U/l (20-150)
ALT: 154 U/l (10-118)
AMY: 793 U/l (200-1200)
BUN: 7.4 mmol/l (2.5-8.9)
CA: 3.15 mmol/l (2.15-2.95)
PHOS: 1.68 mmol/l (0.94-2.13)
CRE: 87 umol/l (27-124)
GLU: 5.4 mmol/l (3.3-6.1)
NA+: 144 mmol/l (138-160)
TP: 75 g/l (54-62)
GLOB: 27 g/l (23-52)

A few abnormalities. The big glaring one is the ALP. She's not on steroids or anti-convulsants, she's certainly not a young growing animal, so the other big differential is hyperadrenocorticism (Cushing's). It sort of fits with her bad skin and pot-belly and with the old female signalment, but she's not the classic polyuric/polydipsic Cushing's dog. The monocytosis could be due to that too, but with no lymphopenia, we can't call it a stress leukogram (most offten associated with stress, or with steroids whether exogenous or endogenous).One of the biggest causes of high calcium is humoral hypercalcemia of malignancy; basically some tumors have this weird ability to secrete something called parathyroid hormone related protein (peptide? something that starts with p). The parathyroid gland takes this as a signal that the body is low in calcium, even though it isn't. So it increases calcium by taking it from the bones. One of the most common types of tumor that does this is perianal gland adenocarcinomas. A rectal exam was done, with no masses found.

The rule is, if you don't have a strong suspicion of Cushing's don't test for it, due to the high rate of false positives and the cost of testing. Baby's owners are told to watch for signs and bring her back if they see other signs. Until then, she's put on an EFA supplement to manage her skin problems.

December 2013:
Baby comes back, this time with a presenting complaint of (you guessed it) polyuria and polydipsia. She'd happily drain the bathtub if you let her and her urine looks basically the same coming out as going in. Could be diabetes mellitus, could be a progression of her suspected Cushing's. Oh, and she's had a couple episodes of impacted anal glands. Vet knows that money is a concern and provided the bloodwork doesn't show anything else weird, he's willing to start her on trilostane or mitotane for the Cushing's without doing all the expensive hormonal testing, since vet student daughter is home on winter break and can be in contact with him every few days and monitor the dog closely.

The bloodwork shows no diabetes mellitus, but does show the calcium is high; higher than it was a year and a half ago. It's now at 3.5. Vet does a rectal exam and... there's a small mass.

Given her age, the owners opted for palliative care and treating her polyuria/polydipsia with furosemide to bring the calcium down. She got a few more good weeks, and was euthanized in early February 2014.

The moral: Do the diagnostics. They aren't just to run up the bill.

2 comments:

  1. What an interesting case! It goes to show how important it is to spend money on diagnostics, especially for geriatric patients. Thanks for sharing. And I'm very sorry for your loss of Baby!

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    1. Thank you very much for your thoughts. There's still a big bulldog shaped hole on the sofa. But she is an interesting case and even I admit that a small part of me wanted a post-mortem done to see what was really going on. Ultimately we didn't though. Sometimes it's hard to reconcile vet student curiousity with owner emotions.

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