Insulinomacase v1

1. Case 1: Fizz
Signalment: 10 year old FN Springer spaniel
History: 8 month history of intermittent ‘funny turns’.
During these episodes her head drops slightly, she develops a
staggering gait and occasionally her forelegs buckle. At times
her owner notices the muscles in her neck and legs jerking. It
appears that these episodes are worse with exercise. However,
she is reported to be mentally aware / conscious throughout.
Her last episode was three days prior to presentation. No
known access to any toxins.
Physical examination: heart rate 80 bpm, normal respiratory
rate and effort, good body condition (score 5/9), otherwise
unremarkable.
Neurological examination: unremarkable.
Step 1:
You perform some baseline
bloodwork due to lack of
obvious clinical findings.
See next slides for results.

2. Results
• Haematology

3. Results
• Biochemistry

4. Results
• Blood glucose concentration (Alpha-Trak): 1.02mmol/l (RI 4-7).
This was a repeatable finding.
Question 1: What are your differentials for hypoglycemia?
Which of these would you consider to be your top differential.
Answers on the next page…….

5. Question 1: Hypoglycaemia differentials
• Spurious
• Excessive glucose utilisation
• Hyperinsulinism (iatrogenic, insulinoma, IGF-1 secreting tumour, xylitol toxicity)
• Large neoplastic burden (erythrocytosis, leukaemia, solid tumour)
• Prolonged exercise: Hunting dog hypoglycemia
• Polycythemia
• Impaired hepatic glucose gluconeogenesis / glycogenolysis
• Portovascular anomaly, fibrosis, chronic hepatitis, glycogen storage disease
• Deficiency in counter-regulatory hormones
• Hypoadrenocorticism, glucagon deficiency, GH deficiency
• Inadequate dietary intake
• Neonatal/toy breed, pregnancy, malnutrition, starvation
• Sepsis / endotoxin/parvovirus/ethylene glycol mediated
Top differential given this signalment,
waxing and waning presentation,
which is worse at exercise (high
glucose demand) and relatively
normal screening blood-work.

6. • Question 2: You suspect an insulinoma as a cause of Fizz’s clinical
signs. How would you confirm the diagnosis?
Answers on the next page…….

7. • Question 2: I would confirm the diagnosis by concurrent measuring
concurrent blood glucose and insulin concentration. To confirm persistent
hypoglycaemia fructosamine concentration can also be measured and is
either low to low-normal.
Blood glucose concentration = 2.2mmol/l (RI 4-7)
Insulin concentration= 39.2 IU/ml (RI 5-40)
• Question 3: Is this consistent with a diagnosis of insulinoma?
Answers on the next page…….

8. • Question 3: Yes, it is consistent with a diagnosis of insulinoma. This is because
although the insulin concentration is within the reference interval it is
inappropriate in the face of hypoglycemia.
Insulin should be undetectable during hypoglycemia.
You initially advise appropriate medical management of frequent small feeds and
short walks.
• Question 4: What long-term treatment options are available and which is
reported to provide the best long-term prognosis?
Answers on the next page…….

9. • Question 4: Surgical and medical management options exist.
• Surgery – partial pancreatectomy
• Medical
• Diet
• 4-6 meals a day, high protein, complex carbohydrate source
• Exercise
• Restricted exercise for short periods
• Glucocorticoids
• Start at 0.5mg/kg a day and titrate up
• Adjunctive options
• Diazoxide
• Streptozocin
• Octreotide
• TKIs?
Surgery improves long-term prognosis even if a cure is not
achieved.

10. Outcome for Fizz
• Partial pancreatectomy was performed, insulinoma confirmed
on histopathology of pancreas
• Fizz experienced abdominal pain post-operatively and required
fentanyl and ketamine CRI initially
• Insulin therapy required for 2 months post-operatively for
diabetes mellitus
• Two months later hypoglycaemia recurred and hepatic nodules
identified on CT