Lecture 15- Hypoglycemia And Thyroid Cancer

Question 1

At what level of blood glucose to normal healthy individuals typically experience sxs of hypoglycemia?

Answer 1

<55

Question 2

What are the autonomic sxs of hypoglycemia?

Answer 2

Adrenergic

• tremor
• palpitations
• anxiety

Cholinergic

• diaphoresis
• hunger
• paresthesias

Question 3

What are the neuroglycopenic sxs of hypoglycemia?

Answer 3

Sensation of warmth, weakness, fatigue 
Difficulty thinking, confusion 
Changes in affect, behavior 
Difficulty speaking 
Blurred vision 
Amnesia 
Seizures 
Coma 
Death

Question 4

Whipple’s Triad

Answer 4

Seen with insulinoma (could be MEN1)

1) sxs consistent with hypoglycemia
2) documented low blood glucose in association with sxs
3) prompt relief of sxs when blood sugar is normalized

Question 5

How does alcohol induce hypoglycemia?

Answer 5

Inhibits hepatic glyconeogensis

Pts typically dont present until they have exhausted their glycogen stores

Usually hx is moderate to excessive EtOH consumption with little or no food during the previous 6 to 36 hours

Pts are typically comatose at presentation

Question 6

What are the treatment options for notoxic multinodular goiter?

Answer 6

Observation
Thyroxine suppression (do NOT suppress if TSH is below normal)
Surgery
Radioactive iodine

Question 7

If there is a solitary thyroid nodule, what is the first question you need to ask yourself?

Answer 7

Is TSH suppressed?

If yes? —> get thyroid scan

If no? —> get US

Question 8

Who is more likely to get thyroid cancer?

Answer 8

Females

5 year survival rate is good

Question 9

What are the prognostic risk factors for papillary thyroid cancer?

Answer 9

Age
Local invasion
Distant metastases
Tumor size

Question 10

What is the treatment of differentiated thyroid cancer?

Answer 10

Thyroidectomy
Radioiodine (131I) ablation
Thyroxine replacement/suppression of TSH to a low level

Question 11

What are the different types of thyroid cancer?

Answer 11

Papillary (MC)
Follicular (15%)
Anaplastic (1-2%)

Medullary Thyroid Cancer - derived from C cells

Question 12

Neuroendocrine tumors clinical features

Answer 12

May secrete one or more peptide hormones

May occur sporadically or as a part of MEN syndrome (multiple endocrine neoplasia)

Pituitary - almost always benign
Pancreatic islet - benign or malignant
Small cell lung - malignant

Slow growing

Question 13

Calcitonin

Answer 13

Sensitive tumor marker for medullary thyroid cancer

Question 14

What is the clinical presentation of medullary thyroid cancer?

Answer 14

Thyroid nodule
Water diarrhea
Flushing, pruitus

Question 15

Carcinoid tumors

Answer 15

Arise from enterochomaffinc ells scattered throughout the body

Common locations are appendix and small bowel

Question 16

What are the clinical features of carcinoid syndrome?

Answer 16

Flushing
Diarrhea

Less common
Cardiac lesions (d/t fibrosis from 5HT)
Bronchospasm
Skin lesions

Question 17

What do you dx carcinoid syndrome?

Answer 17

Primary test: elevated urinary 5-HIAA (hydroxyindoleacetic acid)

Be aware that urinary 5-HIAA can be elevated by avocado, banana, walnuts

Question 18

What is the treatment of carcinoid syndrome?

Answer 18

Hormonal therapy

Long acting somatostatin analogues (octreotide, lanreotide)

Question 19

How do people get multiple endocrine neoplasia syndromes?

Answer 19

Autosomal dominant inheritance

Question 20

MEN 1

Answer 20

3Ps
Parathyroid adenoma (hypercalcemia d/t hyperparathyroidism)
Pituitary adenoma
Pancreatic islet cell tumor (ex. insulinoma)

basically 1 or more overactive endocrine glands secondary to menin tumor suppressor gene mutation

Question 21

MEN 1 vs MEN 2

Answer 21

MEN 1 is tumor suppressor menin mutation

MEN 2 is proto onco gene RETs mutation

Question 22

MEN 2A

Answer 22

Pheochromoctyoma
medullary carcinoma of thyroid
parathyroid hyperplasia

Question 23

MEN 2B

Answer 23

pheochromocytoma
medullary carcinoma of thyroid
marfanoid habitus with mucosal/visceral ganglioneurofibromas

RET proto onco gene mutation

mucosal neuroma is pathognomic for MEN 2b

Question 24

What are the two most common iatrogenic causes of hypoglycemia?

Answer 24

insulin

sulfonylureas

Question 25

5HIAA urine test

Answer 25

used to dx carcinoid syndrome because one of the hormones that gets increased when the neuroendocrine cells mutate and become a tumor is seretonin gets released. Seretonin gets sent to the liver where half of it gets metabolized to 5HIAA and the rest remains circulating in the blood

Question 26

What causes flushing with carcinoid syndrome?

Answer 26

increase histamine release from the nueroendocrine cells

Question 27

What hormones are being released from the neuroendocrine cells in carcinoid syndrome?

Answer 27

amines – 5HT + H2

polypeptides (Bradykinin)

Protaglandins

Question 28

Are carcinoid tumors fast or slow growing?

Answer 28

slow

commonly seen in the GI tracts such as small bowel, appendix, pancreas, liver