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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?

Electrocute

20 responses to “Rebound hyperglycemia in presumed insulinoma dog”

  1. 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.

    • 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.

  2. 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.

    • 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. Thanks Randy.  Did you mean

    Thanks Randy.  Did you mean to say hyperglycemia?

  10. Thanks Randy.  Did you mean

    Thanks Randy.  Did you mean to say hyperglycemia?

  13. 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 

  14. 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 

  15. ….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.

  16. ….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.

  17. Thanks Roger for sharing your

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

  18. 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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