Endocrine Flashcards
Wolff-Chaikoff effect
Thyroid gland downregulation in response to increased iodide
Iodine uptake into thyroid
Secondary active transport as a co-transport with Na+
Benefit of potassium iodide (KI) supplement when radioactive exposure
Thyroid will preferentially take up the supplemental iodide instead of the radioactive iodide. Additionally, it will down-regulate the thyroid gland (Wolff-Chaikoff Effect)
Transsphenoidal surgical resection due to a pituitary adenoma affects what hormone production?
Those from AP: FSH, LH, ACTH, TSH, PRL, GH
Decrease in FSH and LH from AP will present in what way in women?
Amenorrhea
Treatment for osteoporosis and function
Bisphosphonates (end in -ronate or ronic acid); inhibit osteoclast activity
Prednisone’s effects on bones
Can induce osteoperosis or osteopenia due to osteoblast suppression
Fatigue, acne and hirsutism is indicative of increased/decreased levels of what
increased levels of sex hormones (androgens)
Partial glucocorticoid resistance causes (increase/decrease) in ACTH and cortisol production
Increase
Medullary thyroid carcinoma is derived from what cells? And what does it secrete?
Parafollicular C Cells; calcitonin
Parafollicular C cells of the thyroid gland are derived from what embryonically?
Neural crest cells
What physical symptoms do patients with medullary thyroid carcinoma present with?
Watery diarrhea and flushing (and symptoms of compression such as dysphagia and hoarseness)
Thyroid cancers show hot/cold nodules in imaging. What does that mean?
Cold; do not uptake iodine
Hurthle cells are what kind of cells? What disease are they seen in?
Follicular cells with eosinophilic cytoplasm; Hashimoto’s hypothyroiditis
Papillary thyroid carcinomas are derived from what cells?
Follicular epithelial cells
Follicular thyroid carcinomas are derived from what cells?
Follicular epithelial cells
How are calcium levels affected in medullary thyroid carcinoma?
Results in calcitonin secretion which can mildly bring down calcium levels, but no truly affected because of functioning PTH
Catecholamines are released from what extra-ganglionic structure? And in response to what hormone?
Chrmoffin cells of adrenal medulla; preganglionic sympathetic neurons release Ach
When someone presents with a pheochromocytoma, when MEN is that associated with? Pathology of what other organ should be considered?
MEN 2a and 2b;
Medullary thyroid carcinome
Why thyroid carcinoma presents with amyloid? What causes it?
Medullary thyroid cancer due to precipitated calcitonin
Apple-green birefringence is associated with what stain? And what does it reveal?
Congo Red; amyloid
Increase shoe size, large tongue, axillary skin tags in an adult are associated with (increase/decrease) of what hormone? What is the name of this condition?
Increase in growth hormone
What inhibits growth hormone?
Somatostatin
What is the analogue of somatostatin?
Octreotide
What diabetes medication are most patients started on? How does it work?
Metformin; downregulates gluconeogenesis in the liver.
Dysfunction of what organ serves as a contraindication for prescribing metformin?
Renal dysfunction
Sulfanylureas are contraindicated for patients with what organ dysfunction?
Liver
Angiofibromas and lipomas are associated with what MEN disorder? This MEN can affect which organs?
MEN I; Pituitary, Parathyroid, Pancreas
Increase PTH, increased Prolactin and involvement of pancreas are concerning for what condition?
Parathyroid, Pituitary, Pancreas- concerning for MEN1.
Prolactin can inhibit what hormones from the pituitary?
GnRH and FSH (this is also done during pregnancy)
The 3 levels involved in diabetic ketoacidosis are ______
Hyperglycemia, Increased ketones, acidity
What is Kussmaul breathing and where is it seen?
Deep, labored breathing seen in diabetic ketoacidosis. It is a way to expel more CO2 (and decrease serum H+ concentration)
In an androgen receptor defect, what are the levels of LH and testosterone?
Normally, they would turn of LH, but a defective receptor interrupts feedback and maintains high levels of LH and testosterone
micro vs macro pituitary adenoma
Micro tends to cause secretions whereas macro is non-functional. Macro also compresses the pituitary stalk
What thyroid disease presents with firm, hard, painless goiter? What does it look like on histology?
Reidel’s Thyroiditis; fibrosis and inflammation of the thyroid gland
Nephrogenic DI vs Central DI
Central DI: unable to secrete ADH and Nephrogenic DI: ADH unable to act in its receptor
Desmopressin administration in Central DI vs Nephrogenic DI
Central DI lacks ADH so administering it would resorb more water and increase urine osmolality. No change in nephrogenic because it cannot act on receptor
Genotype DR od Diabetes TI
DR3 and DR4
Layers of adrenal cortex and secretions
Glomerulosa: aldosterone Fasciculata: cortisol and reticularis: andorgens; medulla secretes catecholamines
Function of aldosterone
Na resorption, K+ secretion, H+ secretion
What is happening when there is increased thyroid production during early stages of pregnancy? What is it called?
The TSH-r is being activated by hCG because it looks similar to TSH. Familial gestations hyperthyroidism.
Presence of high insulin with undetectable C-peptide
Factitious hypoglycemia; psychological disordere from surreptitious self-injections of insulin
How does subacute granulomatous thyroiditis present? What is seen on labs?
Very tender, enlarged thyroid gland preceded by viral illness. Self-resolving. aka de Quervain; transient hyperthyroidism and inc ESR
What side effects should be considered in methimazole?
Agranulocytosis
If a patient with hyperthyroidism takes ______ and later presents with low-grade fever and sore throat, what should be considered?
Methimazole; agranulocytosis
Plasma fractionated metanephrine can be used to diagnose ______
pheochromocytoma (neuroendocrine tumor of adrenal medulla secreting catecholamines)
Headachesm palpitations, hypertension and anxiety may be caused by a tumor secreting ______
catecholamines (pheochromocytoma)
Pheochromocytoma is seen in what MEN conditions?
MEN 2a and 2b
Hashimoto’s Thyroiditis carries an increased risk for what cancer?
Non-Hodgkin B cell lymphoma
On histology, Hashimoto’s thyroiditis shows what?
Lymphocytic infiltrate with germinal centers; Hurthle cells (eosinophilic cytoplasm)
What enzyme deficiency prevents cortisol and androgen synthesis?
17 alpha hydroxylase
What enzyme deficiency prevents cortisol and aldosterone synthesis?
21 beta hydroxylase
How does GH secretion affect glucose and insulin levels?
Increased GH causes more insulin resistance and glucose intolerance. This increases blood glucose levels and produces a compensatory increase in insulin levels
Glucose tolerance test in relation to acromegaly
Acromegaly is caused by increased GH secretion. Normally, administering oral glucose will decrease the production of GH; however in when patients have acromegaly, GH levels do not drop
Acute vs chronic hypomagnesium and effects on PTH
Acute hypoMg increases PTH secretion, but chronic hypoMg decreases PTH secretion
Trousseau’s sign is ______ and indicates ______
Twitching of the hands when a blood pressure cuff is put on the patient and pressure goes above systolic. Hypocalcemia
Alcoholism and magnesium
Chronic alcoholism leads to hypomagnesemia
Cancer of what organ can commonly cause metastases to adrenals?
Lung
Conn Syndrome
Adrenal tumor causes primary hyperaldosteronism
What hormone will not be affected by hypopituitarism? Why?
Aldosterone; regulated primarily by RAAS
Prolactinoma has what effect on other hormones? Presents how?
Suppresses normal GnRH; amenorrhea, galactorrhea, infertility in women and loss of libido in med
Amorphous proteinaceous material in thyroid is suggestive of what carcinoma? And what is it?
Medullary thyroid; amyloid from calcitonin
Iodine deficiency is can cause (primary/secondary) hypothyroidism
Primary (need iodine to make T3 and T4)
How can chronic kidney disease lead to bone pain and fractures (osteopenia)
CKD means decreased phosphate excretion resulting in hyperphosphatemia. This can bind and deplete Ca++. The ability to make calcitriol is also damaged in CKD further adding to decrease in calcium.
Long standing effects of secondary hyperparathyroidism
Osteitis fibrosa cystics - increased osteoclastic resorption of calcified bone to try to normalize calcium in plasma
Increasing sensitivity of calcium-sensing receptor has what consequence
Decreased PTH secretion. The CaSR works by inhibiting PTH secretion so by increasing its sensitivity, it can become active under low calcium levels and inhibit PTH.
Drugs that increase calcium-sensing receptor sensitivity are ______ and function to ______
Calcimimetics (cinacalcet); decrease PTH secretion
In early stage of diabetes, what can be said about insulin levels and glucose levels?
Both are elevated. Insulin resistance results in hyperglycemia and increased serum osmolality
