Endo Exam Flashcards
How do hormones cross the cell membrane?
Typically cannot cross via diffusion
GPCR, receptor tyrosine kinase, ligand gated ion channels
When can a hormone cross the cell membrane by diffusion?
Lipid soluble
What does the magnitude of response to a hormone depend on?
How many receptors are occupied at the target cell
What is the free hormone concentration affected by?
- Secretion of hormone
- Elimination of hormone
- Extent of hormone binding to plasma proteins
What cancer can produce ACTH?
SCLC
Clinical manifestations of Cushing’s d/t cortisol excess
Obesity, HTN, poor wound healing, hyperglycemia, hypokalemia, alkalosis
Clinical manifestations of Cushing’s d/t androgen excess
Hirsutism, menstrual problems, erectile dysfunction
Results of mineralocorticoid deficiency
Dehydration, decr Na, incr K, metabolic acidosis
Glucocorticoid deficiency
Weakness, weight loss, vomiting, hypoglycemia
Where is the pituitary located?
Sella turcica at the base of the skull
What structures is the pituitary located near?
Cavernous sinuses, nasal sinuses, carotid arteries, cranial nerves II, III, IV, VI (can all be compressed by tumors)
What causes the pituitary to double in size?
Pregnancy
What hormones are produced in the adenohypophysis?
GH, TSH, PRL, FSH, LH, ACTH
What is stored and released in the neurohypophysis?
ADH (vasopressin) and oxytocin
What are the stimulants for PRL?
TRH, DA antagonists
What inhibits PRL?
DA
What can cause hyposecretion of pituitary hormones?
Agenesis, atrophy, destruction
What causes hypersecretion of pituitary hormones?
Tumor, hyperplasia
What inhibits GH production?
Glucose
Which hormone is first effected by hypopituitarism?
GH
What inhibits PRL secretion?
DA
Where is DA produced?
Hypothalamus
What is the MC cause of Addison’s?
Autoimmune adrenalitis
What are the different categories of etiology for Addison’s?
A
What are the MAIN lab signs of primary adrenal insufficiency?
- Hyponatremia
2. Hyperkalemia
What is aldosterone escape?
A
What are the 3 confirmatory tests for primary aldosteronism?
- Aldosterone:renin
- Confirmatory testing
- CT scan —> (if want to go to surgery) Adrenal venous sampling to test aldosterone
What is cushingoid habitus?
- Central obesity
- Moon face
- Supraclavicular fat
- Dorsal fat pad
- Abdominal purple striae
- Easy bruising
Dichotomy of Cushing syndrome
ACTH dependent vs ACTH independent
Three tests for Cushing
- Low dose dexamethasone suppression test
- 24hr urine free cortisol (twice)
- Late night salivary cortisol swabs (twice)
Classic triad of pheo
- Episodic HA
- Sweating
- Tachycardia
What is hirsutism?
Unwanted male pattern hair growth in women
What is hyperthecosis
Full beard
Another name for 21-hydroxylase deficiency
Congenital adrenal hyperplasia
What is the rate limiting step when TSH is really high in a normal person?
Iodine
Why does one iodine make such a difference between T3 and T4?
A
Clinical presentation of hyperthyroidism
High metabolism = weight loss, nervousness, tachycardia, heat intolerance
Exophthalmus
MC cause of hyperthyroid
Grave’s Disease
What is Grave’s dz?
A
Clinical presentation of hypothyroidism
Low metabolism = weight gain, lethargy, bradycardia, cold intolerance, myxedema
What are 3 common causes of hypothyroidism?
Hashimoto’s, atrophy, surgery
What is the best imaging modality for the thyroid?
US
What bx method is used for sampling the thyroid?
FNA (cytology)
Subacute painful, rapid enlargement of the thyroid
De Quervain
What are the 2 main categories of thyroid neoplasms?
Follicular and C-cell
What are the types of follicular cell neoplasms?
Papillary carcinoma
Follicular adenoma
Follicular carcinoma
Poorly differentiated/anaplastic carcinoma
What are the types of C cell neoplasms?
Medullary carcinoma
What are the clinical manifestations of hyperprolactinemia?
Infertility, menstrual irregularity, galactorrhea
What are some things that trigger the HPA axis?
Cerebral cortex, environment, feedback from organs that it controls
What is the best thyroid function screening test?
TSH
How do you follow patients on thyroid hormone tx?
-Follow TSH (low: decr levo, high: incr levo)
If TSH is abnormal what is the next test to look at?
FT4 - determines thyroid hyperfunction or hypofunction
What does FT4 measure?
Free thyroxine levels
What does FT3 measure?
Serum triiodothyronine
If TSH is low and T4 is normal, what test do you look at next?
FT3
What is FTI?
Free thyroxine index (used when patient has protein abnormalities
What is RAIU?
Radioactive iodine test
What is cretinism?
Congenital hypothyroidism d/t maternal hypothyroidism or infant hypopituitarism
What are the clinical manifestations of cretinism?
Macroglossia, hoarse cry, coarse facial features, umbilical hernia, weight gain
How is cretinism treated?
Levo
What is a thyroid storm?
- Potentially fatal complication of untreated thyrotoxicosis (MC after a precipitating event)
- hypermetabolic state
What type of event can precipitate a thyrotoxicosis crisis?
Surgery, trauma, infection, pregnancy
How do steroids help in a thyroid storm?
Inhibits the peripheral conversion of T4 into T3 and impairs thyroid hormone production
What is levothyroxine?
Synthetic T4
Why is T4 given instead of T3?
A
How is BP altered by hypothyroidism?
DPB increased
How does hyperthyroidism affect the BP?
SBP increased
What can you do for sx relief in hyperthyroidism?
Beta-blocker to slow everything down
hormones produced by the hypothalamus
GNRH, GHIH, GnRH, PIF, TRH
hormones produced by the anterior pituitary
ACTH, FSH, LH, GH, PRL, TSH
hormones released from the posterior pituitary
ADH, oxytocin
hormones produced by the thyroid
T3 & T4
hormones produced by the adrenal cortex
aldosterone & cortisol
hormones produced by the adrenal medulla
epi & NE
action of cortisol
energy metabolism, permissive action for other hormones (presence enhances action of other hormones)
action of mineralocorticoids
regulate plasma volume via effects on serum electrolytes
action of thyroid hormone
controls basal metabolism in most tissues
