Wednesday, November 4, 2009

The complexities and conundrums of medicine...

So, a little case study for my pre-vet, veterinary student, and vet readers:

My technician brings in her 12 year old, 4 kilogram, male castrated Yorkie. Two days ago, he was normal, bright, and healthy. At that time, he became slightly lethargic. It progressed to vomiting and severe depression. He has no known history of medical problems (she has owned him for 2 years, and he was a rescue), does not receive any medications other than cyclosporine (Optimmune) for his dry eye (keratoconjunctivitis sicca/KCS). He is an indoor dog, up to date on his vaccines except for leptospirosis, and he didn't ingest anything he shouldn't have. He goes outside on walks with the owner and her daughter and sometimes plays in a dirty, algae-filled pond near the house.

My physical exam findings were as follows:

1) A very depressed dog
2) 10% dehydration (eyes sunken in, skin stays tented when pinched, gums dry, capillary refill time greater than 3.5 seconds)
3) A painful, doughy feeling abdomen
4) Sparse hair growth/alopecia over the middle of his back to his tail, fleas
5) Mucopurulent eye discharge OU consistent with history of KCS
6) Very slightly icteric (yellow), very pale gums

I started with bloodwork and urine specific gravity and found the following abnormalities:

PCV/TS 30/10.5

White blood cell count of 66,000 (normal 5,000-12,000)
Blood smear confirms that this is a neutrophilic leukocytosis with a significant left shift (14% bands noted)

Blood urea nitrogen (BUN) 188 (normal 7-20)
Creatinine 6.4 (normal 0.2-1.4)
Phosphorous 20.2 (normal 2-4)

ALT 1000 (normal 20-200)
ALP 550 (normal 50-220)
GGT 35 (normal 0-7)

Bilirubin 2.0 (normal 0.2-0.7)

Cholesterol 427 (normal 50-300)

prothrombin time (PT): 10 sec (normal 3-17)

activated partial thromboplastin time (aPTT): 110 sec (normal 74-103)

Urine specific gravity: 1015 (AFTER a bolus of 100mL NormR)

Systolic BP: 70

A slide agglutination test was negative for macro or micro agglutination. No agglutination was noted in the blood tube. No spherocytes were seen on smear. Very mild anisocytosis was noted. No polychromasia was seen.

What problems do we have? What differentials would be appropriate for this dog? What diagnostics would you have done next? What treatments would you institute? What other information could be useful?


Hermit Thrush said...

Multiorgan failure (kidney, liver), a high white blood cell count, and a "doughy abdomen." I would suspect a toxin, even a blue green algae, but the WBC is more consistent with infection or cancer. Anytime I see kidney failure I get concerned about leptospirosis (playing in a pond) but I don't know if the liver signs go with that or the doughy abdomen. (Also not up to date on leptospirosis vaccination concerns me with this clinical picture).
I'd run a test for lepto titers, start the dog on antibiotics (a pencillin/cephalosporin I think), keep diuresing the kidneys with an appropriate level of fluids and tell all my techs to wear gloves and treat the dog as potentially contagious since lepto is zoonotic.

If it came up negative for lepto I wouldn't know what to do next though. VIN, Cornell Veterinary Consultant and the veterinary library would be on my list to gather info for a more complete differential.

The Homeless Parrot said...

Elevated liver enzymes definitely go with leptospirosis. In many cases, ALP will be elevated more than ALT, but that is not always the case.

What do you think about the PCV/TS? Is there another important problem here that we're missing?

Hermit Thrush said...

Well, now that you mention it, yes. The PCV is low, especially given the level of dehydration, which one would expect to make it look artificially high. The PTT is normal, and the APTT is just slightly out of range, but I'd be concerned about internal bleeding. The liver failure could mean that there simply aren't enough clotting factors and that this patient might even be at risk for DIC (gasp). I'm not sure I'd transfuse though as I suspect at 30% the dog still has enough RBCs to perfuse vital organs adequately. I might order radiographs and do a quick ultrasound to see if there is fluid anywhere internally that there isn't supposed to be. And continue monitoring the PCV/TP during treatment as the PCV is likely to drop the dehydration is addressed, and to make sure it does not worsen substantially if there is ongoing bleeding.

Of course, this is all based on the 12 weeks of ANATOMY I've had. Meaning really anything I know clinically is stuff I've picked up from my years as an emergency technician, tech school and reading journals, which means it is disorganized knowledge with some big holes... Mainly what I've learned in my first semester is that I don't know much!

The Homeless Parrot said...
This comment has been removed by the author.
The Homeless Parrot said...

You're doing great! Yes, the PCV is low but also the TS is VERY high. That tells you that 1) dehydration is present and 2) the PCV is elevated falsely but still low! Remember packed cell volume is a %. This dog is very hemoconcentrated right now, so the PCV is higher than it would be when the dog is rehydrated. Since the PCV is 30 with dehydration, I estimated that this dog's actual PCV was somewhere around 18%. This would be getting into the range of transfusing him, although we would base this on his clinical picture, not on an arbitrary number.

Excellent next step for the plan. I've posted more informatio blow the original post (so as not to confuse those just joining us).