Lecture 15- Hypoglycemia And Thyroid Cancer Flashcards
At what level of blood glucose to normal healthy individuals typically experience sxs of hypoglycemia?
<55
What are the autonomic sxs of hypoglycemia?
Adrenergic
- tremor
- palpitations
- anxiety
Cholinergic
- diaphoresis
- hunger
- paresthesias
What are the neuroglycopenic sxs of hypoglycemia?
Sensation of warmth, weakness, fatigue Difficulty thinking, confusion Changes in affect, behavior Difficulty speaking Blurred vision Amnesia Seizures Coma Death
Whipple’s Triad
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
How does alcohol induce hypoglycemia?
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
What are the treatment options for notoxic multinodular goiter?
Observation
Thyroxine suppression (do NOT suppress if TSH is below normal)
Surgery
Radioactive iodine
If there is a solitary thyroid nodule, what is the first question you need to ask yourself?
Is TSH suppressed?
If yes? —> get thyroid scan
If no? —> get US
Who is more likely to get thyroid cancer?
Females
5 year survival rate is good
What are the prognostic risk factors for papillary thyroid cancer?
Age
Local invasion
Distant metastases
Tumor size
What is the treatment of differentiated thyroid cancer?
Thyroidectomy
Radioiodine (131I) ablation
Thyroxine replacement/suppression of TSH to a low level
What are the different types of thyroid cancer?
Papillary (MC)
Follicular (15%)
Anaplastic (1-2%)
Medullary Thyroid Cancer - derived from C cells
Neuroendocrine tumors clinical features
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
Calcitonin
Sensitive tumor marker for medullary thyroid cancer
What is the clinical presentation of medullary thyroid cancer?
Thyroid nodule
Water diarrhea
Flushing, pruitus
Carcinoid tumors
Arise from enterochomaffinc ells scattered throughout the body
Common locations are appendix and small bowel
What are the clinical features of carcinoid syndrome?
Flushing
Diarrhea
Less common
Cardiac lesions (d/t fibrosis from 5HT)
Bronchospasm
Skin lesions
What do you dx carcinoid syndrome?
Primary test: elevated urinary 5-HIAA (hydroxyindoleacetic acid)
Be aware that urinary 5-HIAA can be elevated by avocado, banana, walnuts
What is the treatment of carcinoid syndrome?
Hormonal therapy
Long acting somatostatin analogues (octreotide, lanreotide)
How do people get multiple endocrine neoplasia syndromes?
Autosomal dominant inheritance
MEN 1
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
MEN 1 vs MEN 2
MEN 1 is tumor suppressor menin mutation
MEN 2 is proto onco gene RETs mutation
MEN 2A
Pheochromoctyoma
medullary carcinoma of thyroid
parathyroid hyperplasia
MEN 2B
pheochromocytoma
medullary carcinoma of thyroid
marfanoid habitus with mucosal/visceral ganglioneurofibromas
RET proto onco gene mutation
mucosal neuroma is pathognomic for MEN 2b
What are the two most common iatrogenic causes of hypoglycemia?
insulin
sulfonylureas
5HIAA urine test
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
What causes flushing with carcinoid syndrome?
increase histamine release from the nueroendocrine cells
What hormones are being released from the neuroendocrine cells in carcinoid syndrome?
amines – 5HT + H2
polypeptides (Bradykinin)
Protaglandins
Are carcinoid tumors fast or slow growing?
slow
commonly seen in the GI tracts such as small bowel, appendix, pancreas, liver
