Endocrine - Pathology Part 2 Flashcards
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?
Papillary carcinoma
Which thyroid cancer has the best prognosis?
Papillary carcinoma
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?
Calcitonin
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?
Older patients
What type of cancer is associated with Hashimotos thyroiditis?
Lymphoma of the thyroid
What risk factor is associated with papillary carcinoma of the thyroid?
Childhood irradiation
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
In what manner is pseudohypoparathyroidism inherited?
Autosomal dominant
A patient with hypocalcemia is of short stature and has shortened fourth/fifth digits. What genetic condition should be considered?
Pseudohypoparathyroidism, also known as Albright hereditary osteodystrophy
Would parathyroid hormone be increased or decreased in pseudohypoparathyroidism?
Increased; since the end-organ targets are resistant to the hormone, serum calcium levels will remain low, causing increased secretion of parathyroid hormone.
What is the most common type of pituitary adenoma?
Prolactinoma
A patient complains of amenorrhea, galactorrhea, and low libido. She has been trying to get pregnant for 3 years. What tumor should be considered?
Prolactinoma
What is the medical treatment for a prolactinoma?
Bromocriptine or cabergoline (dopamine agonists)
A 40-year-old patient presents with a headache and cannot see on the temporal sides of his visual fields; what should you look for?
Brain imaging may reveal a pituitary adenoma, which can impinge on the optic chiasm and cause bitemporal hemianopsia
Acromegaly is the result of an excess of what hormone?
Growth hormone
Excess growth hormone in children causes what disease?
Gigantism (increased linear bone growth)
A 50-year-old patient has a large tongue with deep furrows, a deep voice, large hands and feet, and coarse facial features; what is the likely diagnosis?
Acromegaly
What is the treatment of acromegaly?
Pituitary adenoma resection followed by octreotide administration
A patient has an elevated growth hormone level; what are three situations in which this increase in growth hormone production is normal?
Stress, exercise, and hypoglycemia
How is acromegaly diagnosed with lab tests?
Increased insulin-like growth factor-1 or failure to suppress serum growth hormone following oral glucose tolerance test
What causes Sheehans syndrome?
Postpartum infarction of the anterior pituitary gland following severe bleeding during delivery
Why are pregnant women more susceptible to pituitary infarction?
An increased number of lactotrophs without an increase in the blood supply to the anterior pituitary
A postpartum patient has fatigue, anorexia, difficulty lactating, and thin sparse pubic and axillary hair; what is the likely diagnosis?
Postpartum hypopituitarism, or Sheehans syndrome
A patients comes to the emergency room with intense thirst, polyuria, and very dilute urine; what endocrine disorder should be on your differential?
Diabetes insipidus
What is the primary defect in central diabetes insipidus?
Lack of antidiuretic hormone production
What is the primary defect in nephrogenic diabetes?
Lack of renal response to antidiuretic hormone
What are some causes of central diabetes insipidus?
Pituitary tumor, trauma, surgery, histocytosis X
What are some causes of nephrogenic diabetes insipidus?
Hereditary or secondary to hypercalcemia, lithium, demeclocycline
What test is used to diagnose diabetes insipidus?
Water deprivation test (urine osmolality does not increase even with low fluid intake)
How does the urine-specific gravity help diagnose patients with diabetes insipidus?
It is low, often below 1.006 g/mL
How does the serum osmolality help diagnose patients with diabetes insipidus?
It is high, often above 290 mOsm/L