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62 Cards in this Set
- Front
- Back
Insulinoma
-what is it |
-functional neoplasm originating from the pancreatic beta-cell in the islet of Langerhans
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Insulinoma
-effect on insulin levels |
-autonomously secretes excessive amounts of insulin (hyperinsulinemia)
-non-responsive to serum glucose fluctuations |
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Insulinoma
-signalment |
-common in ferrets
-uncommon in dogs (middle aged and older, medium to large breed) -rare in cats |
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Insulinoma
-severity in dogs |
-malignant
-usually metastasized by time of diagnosis -metastasize to lymph nodes, liver, lungs |
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Insulinoma
-principle metabolic abnormality |
-hypoglycemia (excessive insulin)
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Insulinoma
-therapy |
-supportive to correct hypoglycemia
-anti-tumor (surgery, chemo) |
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Insulinoma
-etiology |
-unknown
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Insulinoma
-requirement for definitive diagnosis |
-histiologic examination of tissue samples
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Insulinoma
-differential diagnoses |
Disorders that cause hypoglycemia
-glycogen storage disorders -puppy hypoglycemia -hunting dog hypoglycemia -hypoadrenocorticism -paraneoplastic hypoglycemia -hypopituitarism -metabolic immaturity -sepatic disorders (PSS, liver failure, etc.) -Sepsis -prolonged fasting/malnutrition -pregnancy -drugs/toxins |
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Hypoglycemia
-can be due to |
-production of insulin/insulin-like substance
-decreased glucose production -inc. glucose consumption |
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To differentiate insulinoma from other causes of hypoglycemia, what is important to do?
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Interpret in the context of all available patient information
-signalment -history -physical exam -minimal lab data base |
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Hypoglycemia
-severity and type of clinical signs related to: |
-rate of glucose decline
-absolute blood glucose conc. -duration of hypoglycemia |
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Hypoglycemia
-signs |
Adrenergic signs
-restlessness -PU/PD -diarrhea -anorexia -focal or diffuse muscle fasiculations Neuroglycopenic signs -hunger -fatigue -ataxia -blindness -weakness -collapse -seizure -coma |
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Adrenergic signs of hypoglycemia
-due to |
counter-regulatory response
-glucagon -epinephrine -cortisol |
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Hypoglycemia
-why do the neurological signs occur |
-the brain relies primarily on glucose for energy
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Insulinoma
-History/Clinical signs |
-Signs of hypoglycemia
Episodic/Intermittent signs -last seconds to minutes -compensatory counterregulatory mechanisms Weight gain |
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Insulinoma
-when may signs occur |
-during a fast
-several hrs after a meal -after exercise -excitement -stressful event |
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Insulinoma
-ways to diagnose |
-routine lab chemistry
-Whipples's Triad -Imaging -Histopathology |
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Insulinoma
-diagnosis with routine lab assessment |
-CBC and serum chem normal except for glucose
-fasting blood glucose well below normal -rule out artifact hypoglycemia (RBCs consuming glucose) |
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How to prevent artifact hypoglycemia
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-store blood in a grey top tube (Paralyze RBC metabolism)
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Whipple's triad
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-neurological signs present
-signs present when hypoglycemia is present -signs improve with the administration of dextrose |
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Insulinoma
-why are radiographs not helpful? |
-tumors are typically very small and do not cause a mass effect
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Insulinoma
-why is histopathology usually not to helpful in diagnosis? |
-usually done either after surgery or at necropsy
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Insulinoma
-definitive diagnosis depends on |
-insulin level being relatively high relative to the fasting glucose concentration
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Insulinoma
-methods of treatment |
-surgical
-medical management of hypoglycemia -chemotherapy |
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Insulinoma
-treatment of choice |
-surgery
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Insulinoma
-surgery goal |
-remove primary adenoma and any metastasis
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Insulinoma
-how to increase survival time |
-follow debulking with medical management
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Insulinoma
-Surgery Immediate complications |
-intraoperative hypoglycemia (lead to brain injury if not monitored)
-post-operative pancreatitis, DKA, sepsis -12% post-op mortality |
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Insulinoma
-Surgery late complications |
-diabetes mellitus (pancreas removal)
-recurrent hypoglycemia (most common due to the tumor returning) -Exocrine insufficiency |
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Insulinoma
-emergency therapy for hypoglycemia |
-Corn syrup (oral mm)
-IV dextrose bolus -IV glucagon CRI |
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Insulinoma
-problem with administration of IV dextrose bolus |
-rebound hypoglycemia can occur with stimulation of the insulinoma
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Insulinoma
-IV glucagon CRI function |
-facilitate glucose produced by the liver
-possible insulin inhibition |
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Insulinoma
-chronic medical management |
-glucocorticoids
-diet -environment |
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Insulinoma
-primary medical therapy in dogs |
-glucocorticoids
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Insulinoma
-goal for glucocorticoid treatment |
-antagonize the effects of insulin
-induce insulin resistance in target tissues also enhances hepatic gluconeogenesis and glycogenolysis |
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Insulinoma
-goal for treatment via altered diet |
-minimize rapid increase in blood glucose concentration
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Insulinoma
-diet changes for management |
-frequent feedings
-high fat, protein, complex carbs -limited simple sugars |
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Insulinoma
-environment changes for treatment |
-minimize exposure to stress/excitatory events
-limit exercise |
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Infrequently used drugs for hypoglycemia
-why |
-Diazoxide
-Octreotide -expensive |
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Diazoxide
-function |
-inhibits insulin release at the cellular level
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Octreotide
-function |
-direct inhibition of insulin release by binding to somatostatin receptors
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Most dogs receiving medical management for insulinoma are managed how?
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-diet
-prednisone |
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Insulinoma
-chemotherapy agent |
-Streptozotocin
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Streptozotocin
-function |
-direct toxic effects on pancreatic beta cells
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Streptozotocin
-side effects |
-nephrotoxic
-inc. liver enzymes -thrombocytopenia -renal failure -relapse usually occurs |
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Insulinoma
-prognosis |
Short term---> good
Median survival times -Medical therapy alone (shorter) -metastatic dz (middle) -all visible disease removed (longest) Obvious metastatic disease ---> poor long term |
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Puppy hypoglycemia
-signalment |
-toy/miniature breeds
- <6 mo |
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Puppy hypoglycemia
-possible causes |
-high energy requirements
-inadequate protein reserves for glucose production -poorly developed gluconeogenic enzymes -precipitated by other illnesses |
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Puppy hypoglycemia
-R/Os |
-PSS
-sepsis -genetics (glycogen storage dz) |
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Puppy hypoglycemia
-diagnosis |
-signalment
-clinical signs -hypoglycemia |
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Puppy hypoglycemia
-treatment |
Acute
-IV dextrose supplement Chronic -frequent feeding -L-carnitine |
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Hunting dog hypoglycemia
-history |
-hunting dog during strenuous exercise
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Hunting dog hypoglycemia
-possible cause |
-muscle/hepatic glycogen depletion
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Hunting dog hypoglycemia
-diagnosis |
-signalment
-history -BG |
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Hunting dog hypoglycemia
-treatment |
-owner education
-altered feeding schedule -change in training/hunting activity |
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Glycogen storage disease
-signalment |
-young dogs and cats
-GSP, Maltese -Norwegian forest cat |
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Glycogen Storage Disease
-cause |
-genetic mutation prevents normal glycogenolysis
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Glycogen storage disease
-clinical signs |
-failure to thrive
-hepatomegaly -hypoglycemia |
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Glycogen storage disease
-diagnosis |
-liver biopsy
-genetic analysis |
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Paraneoplastic hypoglycemia
-mechanisms |
-deranged glucose metabolism in neoplastic cells
-inc. glucose use by large tumors -tumor secretion of insulin-like factor -decreased hepatic function |
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Paraneoplastic hypoglycemia
-treatment |
-correct hypoglycemia
-therapy for neoplasia |