Insulinoma / Pheochromocytoma Flashcards
1
Q
What is an Insulinoma?
A
- Neuroendocrine tumor arising from pancreatic beta cells
- Malignant
2
Q
Where doe insulinomas commonly metastasize?
A
liver, mesentery
3
Q
What hormone is produced in an insulinoma
A
Insulin - autonomous (not regulated by blood glucose)
4
Q
What are the common clinical findings of Insulinoma?
A
- Intermittent/continuous hypoglycemia (mild to severe)
- Signs of hypoglycemia:
- lethargy, weakness, ataxia, acute collapse, seizure, coma
- Insulin excess produces weight gain in some patients
5
Q
How is an Insulinoma diagnosed
A
- Measure serum or plasma insulin when hypoglycemia is present
- Insulin should be low when hypoglycemia is present
- elevated insulin in the presence of hypoglycemia is a diagnostic of a hyperinsulinemia condition
6
Q
How is an Insulinoma diagnosed
A
- Measure serum or plasma insulin when hypoglycemia is present
- Insulin should be low when hypoglycemia is present
- elevated insulin in the presence of hypoglycemia is a diagnostic of a hyperinsulinemia condition
7
Q
What are the treatment options for an insulinoma?
A
- Surgical excision of the mass - TOC
- Medical management
8
Q
What are the drawbacks of surgical excision of insulinomas?
A
- may not be possible if the tumor is not located near the periphery of a pancreatic limb
- may be unsuccessful if metastases are present
9
Q
What medications can be used for medical management of insulinomas? How do they work??
A
- Used pre-op or as primary treatment (when sx is not an option/fails)
- Prednisone - ⇑ blood glucose by inducing insulin resistance
-
Tocerinib (Palladia®) - Tyrosine-kinase inhibitor (TKI) with anti-tumor action
- has shown promise for treating canine insulinoma
-
Diazoxide - directly inhibits insulin secretion by tumor cells
- expense may limit its use
-
Streptozotocin - chemotherapeutic agent with specific beta cell toxicity
- renal tox is a concern when using this drug
10
Q
What is the prognosis for insulinomas?
A
-
Guarded to Poor
- microscopic metastasis is common at the time of surgery
- Failure to control hypoglycemia carries a poor prognosis
11
Q
What is a Pheochromocytoma?
A
- Paraganglioma of the adrenal medulla
- Malignant - often invades nearby vascular structures
12
Q
What hormone does a Pheochromocytoma produce?
A
- Catecholamines
- Epinephrine and norepinephrine
13
Q
What are the common clinical findings of a Pheochromocytoma?
A
- Signs of catecholamine excess:
- restlessness, panting, weakness, acute collapse
- Severe systemic hypertension
- Retroperitoneal hemorrhage (vascular invasion)
14
Q
How is a Pheochromocytoma diagnosed?
A
- Measure catecholamines nd metabolites in plasma and/or urine
- epinephrine, norepinephrine and metanephrines
15
Q
How is a Pheochromocytoma treated?
A
- Surgical excision
