Rebound hyperglycemia in presumed insulinoma dog

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Rebound hyperglycemia in presumed insulinoma dog

  • 10yr old FS Labrador Retriever with history of acute collapsing episodes for the past 3-4 weeks
  • Normal EKG and chest radiographs
  • Serial bloodwork showed consistent hypoglycemia in the 20-40mg/dl range;  All other chems were normal
  • Insulin level was 11 microunits/ml and insulin to glucose ratio was 75
  • Abdominal ultrasound was normal except for the right pancreas appeared slightly hypoechoic, and the patient is obese.  Ultrasound guided fna’s of the right pancreas were nondiagnostic.

    • 10yr old FS Labrador Retriever with history of acute collapsing episodes for the past 3-4 weeks
    • Normal EKG and chest radiographs
    • Serial bloodwork showed consistent hypoglycemia in the 20-40mg/dl range;  All other chems were normal
    • Insulin level was 11 microunits/ml and insulin to glucose ratio was 75
    • Abdominal ultrasound was normal except for the right pancreas appeared slightly hypoechoic, and the patient is obese.  Ultrasound guided fna’s of the right pancreas were nondiagnostic.
    • The owner declined CT and exploratory surgery. 
    • The referring DVM initiated prednisone therapy at 0.3mg/kg BID with resulting glucose levels of 100 or 150mg/dl.  Now they are up to the 400’s and 500’s.  Once the glucose level exceeded 200mg/dl, the patient was decreased to 0.15 mg/kg prednisone PO SID.  Glucose levels remain >200mg/dl.  The only other new treatment is the dog was placed on Royal Canine Diabetic Dog diet. 
    • Have any of you ever heard of a dog with an insulinoma having this kind of response to prednisone? My differentials for the hyperglycemia include prednisone sensitivity, prednisone induced hyperadrenocorticism, intermittent insulin secretion by the tumor (rebound hyperglycemia), and possible multiple endocine neoplastic syndrome (glucogonoma and insulinoma). 
    • Any other thoughts?

Comments

rlobetti
May 27, 2015 at 5:00 pm -

Very odd case. Not seen an

Very odd case. Not seen an insulinoma behave like this. Also a very low dose of preds to induce euglycemia to hyperglycemia. Any possiblity that the dog got hold of oral hypoglycemic drugs or was injected with insulin? Also possible that there is intermittent secretion by the tumor.

Electrocute
May 27, 2015 at 9:21 pm -

Thank you for your thoughts.

Thank you for your thoughts.  Unknown accidental drug ingestion is unlikely as the owner is a veterinary technician, but I will check this out.

rlobetti
May 27, 2015 at 5:00 pm -

Very odd case. Not seen an

Very odd case. Not seen an insulinoma behave like this. Also a very low dose of preds to induce euglycemia to hyperglycemia. Any possiblity that the dog got hold of oral hypoglycemic drugs or was injected with insulin? Also possible that there is intermittent secretion by the tumor.

Electrocute
May 27, 2015 at 9:21 pm -

Thank you for your thoughts.

Thank you for your thoughts.  Unknown accidental drug ingestion is unlikely as the owner is a veterinary technician, but I will check this out.

EL
May 27, 2015 at 8:00 pm -

He didn’t get ahold of some

He didn’t get ahold of some chewing gum or other Xylitol sources did he?? I don’t see insulinoma here but here are some cases of insulinoma and other hypoglycemia reported cases 

http://sonopath.com/members/case-studies/search?text=hypoglycemia&species=All

and attached is an insulinoma in a cat I did in Vancouver last month:) My first feline insulinoma… behaved just like a dogs with insulinoma and fna confirmed:)

EL
May 27, 2015 at 8:00 pm -

He didn’t get ahold of some

He didn’t get ahold of some chewing gum or other Xylitol sources did he?? I don’t see insulinoma here but here are some cases of insulinoma and other hypoglycemia reported cases 

http://sonopath.com/members/case-studies/search?text=hypoglycemia&species=All

and attached is an insulinoma in a cat I did in Vancouver last month:) My first feline insulinoma… behaved just like a dogs with insulinoma and fna confirmed:)

Electrocute
May 27, 2015 at 9:25 pm -

Interesting cat case.  Since

Interesting cat case.  Since the owner does not want to pursue surgery, my plan is to rescan the dog in a few weeks to see if anything grows.

Electrocute
May 27, 2015 at 9:25 pm -

Interesting cat case.  Since

Interesting cat case.  Since the owner does not want to pursue surgery, my plan is to rescan the dog in a few weeks to see if anything grows.

randyhermandvm
May 27, 2015 at 10:17 pm -

Dogs with insulinomas removed

Dogs with insulinomas removed surgically often show signs of hypoglycemia because there is atrophy of the other beta cells. I don’t know if this is playing a role in this problem or not. 

This was a good workup Electrocute – as always

randyhermandvm
May 27, 2015 at 10:17 pm -

Dogs with insulinomas removed

Dogs with insulinomas removed surgically often show signs of hypoglycemia because there is atrophy of the other beta cells. I don’t know if this is playing a role in this problem or not. 

This was a good workup Electrocute – as always

Electrocute
May 28, 2015 at 1:51 am -

Thanks Randy.  Did you mean

Thanks Randy.  Did you mean to say hyperglycemia?

Electrocute
May 28, 2015 at 1:51 am -

Thanks Randy.  Did you mean

Thanks Randy.  Did you mean to say hyperglycemia?

randyhermandvm
May 28, 2015 at 2:22 am -

Yep- typo

Yep- typo

randyhermandvm
May 28, 2015 at 2:22 am -

Yep- typo

Yep- typo

ultrasound4pets
May 29, 2015 at 9:09 pm -

I treated a dog (WHWT) last

I treated a dog (WHWT) last year with clinical signs, glucose and insulin all consistent with insulinoma.  Insulin >7 x top end of reference range at time of hypoglycaemia.  She has at least one discrete pancreatic mass (in a very heterogeneous pancreas) and a pancreatic lymphadenopathy.

Treated with prednisolone.  Stopped falling over.  About 3 months into prednisolone treatment became more PUPD, then anorexic.  Bloods hyperglycaemia plus ketosis.  Stopped prednisolone and instigated insulin after a bit of crisis control.  Has gone on to do well on conventional DM management with no further signs to suggest insulinoma to date.

I couldn’t find anything comparable in the literature.  Like you I’m down to speculating what the hell happened.  My no 1 theory was that maybe pancreatitis obliterated the insulinoma.  Pancreatic images attached.  I have an appointment with that pancreas if the opportunity arises.

Thanks for posting this case.  If you ever pin down what happened give me a shout and we can write them up somewhere maybe.

Roger 

ultrasound4pets
May 29, 2015 at 9:09 pm -

I treated a dog (WHWT) last

I treated a dog (WHWT) last year with clinical signs, glucose and insulin all consistent with insulinoma.  Insulin >7 x top end of reference range at time of hypoglycaemia.  She has at least one discrete pancreatic mass (in a very heterogeneous pancreas) and a pancreatic lymphadenopathy.

Treated with prednisolone.  Stopped falling over.  About 3 months into prednisolone treatment became more PUPD, then anorexic.  Bloods hyperglycaemia plus ketosis.  Stopped prednisolone and instigated insulin after a bit of crisis control.  Has gone on to do well on conventional DM management with no further signs to suggest insulinoma to date.

I couldn’t find anything comparable in the literature.  Like you I’m down to speculating what the hell happened.  My no 1 theory was that maybe pancreatitis obliterated the insulinoma.  Pancreatic images attached.  I have an appointment with that pancreas if the opportunity arises.

Thanks for posting this case.  If you ever pin down what happened give me a shout and we can write them up somewhere maybe.

Roger 

ultrasound4pets
May 29, 2015 at 9:24 pm -

….actually, after thinking

….actually, after thinking about it, I recall i decided that maybe an insulin-resistant state was a more likely mechanism.  Induced by the prednisolone initially.  Then I read some human medicine articles about insulin resistance and my head started hurting and i went to walk the dogs instead.

further details are that my case had episodic collapse for almost 1 year before diagnosis so almost certainly not an intoxication issue.

ultrasound4pets
May 29, 2015 at 9:24 pm -

….actually, after thinking

….actually, after thinking about it, I recall i decided that maybe an insulin-resistant state was a more likely mechanism.  Induced by the prednisolone initially.  Then I read some human medicine articles about insulin resistance and my head started hurting and i went to walk the dogs instead.

further details are that my case had episodic collapse for almost 1 year before diagnosis so almost certainly not an intoxication issue.

Electrocute
May 30, 2015 at 1:26 am -

Thanks Roger for sharing your

Thanks Roger for sharing your case with me.  I will post again if anything changes with this case.

Electrocute
May 30, 2015 at 1:26 am -

Thanks Roger for sharing your

Thanks Roger for sharing your case with me.  I will post again if anything changes with this case.

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