What is the risk of the nodules in a toxic multinodular goiter becoming malignant?
None; the nodules in a toxic multinodular goiter are not malignant
What mutation is responsible for the activity of the follicles in a toxic multinodular goiter?
A mutation in the thyroid-stimulating hormone receptor makes these cells function independently of thyroid-stimulating hormone
What is the Jod-Basedow phenomenon?
Thyrotoxicosis when a patient with endemic goiter moves to an iodine-replete area
Which thyroid cancer is the most common?
Which thyroid cancer has the best prognosis?
What are the histological findings of papillary carcinoma of the thyroid?
Psammoma bodies, "ground-glass" nuclei (Orphan Annie), nuclear grooves
Place the following thyroid cancers in order from best to worst prognosis: follicular, undifferentiated/anaplastic, and papillary.
Papillary, follicular, and undifferentiated/anaplastic
Medullary carcinoma of the thyroid originates from which cells?
Parafollicular C cells
Medullary carcinoma of the thyroid produces what substance?
What are the histological findings of medullary carcinoma of the thyroid?
Sheets of cells in amyloid stroma
Medullary carcinoma of the thyroid is associated with what two genetic syndromes?
Multiple endocrine neoplasia types 2A and 2B
Undifferentiated/anaplastic carcinoma of the thyroid is most commonly found in what population?
What type of cancer is associated with Hashimotos thyroiditis?
Lymphoma of the thyroid
What risk factor is associated with papillary carcinoma of the thyroid?
What mnemonic illustrates the causes of hypercalcemia?
Calcium ingestion, Hyperparathyroidism, Hyperthyroidism, Iatrogenic (thiazides), Multiple myeloma, Pagets disease, Addisons disease, Neoplasms, Zollinger-Ellison syndrome, Excess vitamin D, Excess vitamin A, Sarcoidosis (remember: CHIMPANZEES)
What is the most common cause of primary hyperparathyroidism?
A parathyroid adenoma
What are the relative levels of parathyroid hormone, calcium, phosphate, and alkaline phosphatase in primary hyperparathyroidism?
Increased parathyroid hormone, calcium, and alkaline phosphatase and decreased phosphate
What is the classic triad of symptoms in primary hyperparathyroidism?
When present, symptoms include weakness, constipation, and renal stones (remember: stones, bones, and groans)
What is the mechanism by which a patient develops secondary hyperparathyroidism?
Decreased calcium absorption from the gut and increased levels of phosphate lead to secondary hyperplasia of the parathyroid gland
What is the most common cause of secondary hyperparathyroidism?
Chronic renal disease
What are the relative levels of parathyroid hormone, calcium, phosphate, and alkaline phosphatase in secondary hyperparathyroidism?
Increased parathyroid hormone, phosphate, and alkaline phosphatase, and decreased serum calcium
How does chronic renal disease contribute to secondary hyperparathyroidism?
Renal failure leads to decreased activation of vitamin D which, in turn, leads to decreased absorption of calcium from the gut
What is the bone pathology associated with osteitis fibrosa cystica?
Cystic bone spaces filled with brown fibrous tissue causing pain; due to elevated levels of parathyroid hormone
What bone pathology might you see in a dialysis patient?
Renal osteodystrophy, caused by secondarily elevated parathyroid hormone levels
What neuromuscular finding is common among patients with hypoparathyroidism?
Tetany, secondary to hypocalcemia
Following thyroid surgery, a patient presents with muscle spasms; what electrolyte abnormality is likely present?
Hypoparathyroidism and resultant hypocalcemia
List three causes of hypoparathyroidism.
Accidental surgical excision (thyroid surgery), autoimmune destruction and DiGeorges syndrome
Upon tapping the facial nerve, a patient has twitching in the ipisilateral facial muscles; what is the sign?
Chvosteks sign, indicating hypocalcemia
After occluding the brachial artery with a blood pressure cuff, your patient has spasms in the wrist; what is the name of the sign?
Trousseaus sign, indicating hypocalcemia
What is the name of the condition in which the kidneys are unresponsive to parathyroid hormone?
Pseudohypoparathyroidism, a genetic condition