Section 5: Prolactinoma, Acromegaly and Hormones of Reproduction Flashcards
Most accurate diagnostic test for prolactinoma
MRI of the brain
Best initial therapy for prolactinoma
Dopamine agonists: Bromocriptine Cabergoline
Why is DM common among those with acromegaly?
Because growth hormone acts as an anti-insulin
Best initial test for acromegaly
Insulin-like growth factor (IGF)
Why is GH not the best initial test for acromegaly?
Growth hormone (GH) level is not done first, because GH has its maximum secretion in the middle of the night during deep sleep. GH also has a short half-life.
Most acurate test to diagnose acromegaly
Suppression of GH by giving glucose excludes acromegaly.
What is the place of MRI in the diagnosis of acromegaly?
To locate the lesion
Outline the Rx of acromegaly
- Surgical resection with transphenoidal removal cures 70 percent of cases
- Octreotide: Somatostatin has some effect in preventing the release of growth hormone
- Cabergoline or bromocriptine: Dopamine agonists inhibit growth hormone release
- Pegvisomant: This is a growth hormone receptor antagonist.
Clinical features of Turner’s syndrome
- Short stature
- Webbed neck
- Wide-spaced nipples
- Scant pubic and axillary hair
- The XO karyotype prevents menstruation
Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Locations 3488-3490). . Kindle Edition.
What is the etiopathogenesis of testicular feminization syndrome?
The absence of testosterone receptors results in no penis, prostate, or scrotum.
Fischer, Conrad (2012-09-22). Master the Boards: USMLE Step 3 (Kindle Location 3492). . Kindle Edition.
Name two causes of primary amenorrhea
- Turner’s syndrome
- Testicular feminization syndrome
Enumerate the causes of secondary amenorrhea
- Pregnancy
- Exercise
- Extreme weight loss
- Hyperprolactinemia
- Polycystic ovary syndrome
Best initial tests for pheochromocytoma
- High plasma and urinary catecholamine levels
- Plasma-free metanephrine and VMA levels
Most accurate test for pheochromocytoma
CT or MRI of the adrenal glands
Rx outline for pheochromocytoma
- Phenoxybenzamine (alpha blockade) first to control blood pressure. Without alpha blockade, patients’ blood pressure can significantly drop intraoperatively
- Propranolol is used after an alpha blocker like phenoxybenzamine
- Surgical or laparoscopic resection
What is the strongest indication for screening for DM
HTN
Name the characteristics of MEN syndrome type 1 (Wermer’s syndrome)
- Parathyroid hyperplasia
- Pancreatic islet cell tumor
- Pituitary adenoma
Remember with 3 Ps (W looks like 3 rotated 90 degress anticlockwise)
Name the characteristics of MEN syndrome type 2A (Sipple’s syndrome)
- Parathyroid hyperplasia
- Thyroid medullary cancer
- Pheochromocytoma
Name the characteristics of MEN syndrome type 2B
- Thyroid medullary cancer
- Pheochromocytoma
- Mucocutaneous neuromas
- Ganglioneuromatosis of the colon
- Marfan-like habitus
Name the anterior pituitary hormones and the hypothalmic hormones that control their release
- ACTH controlled by CRH
- GH controlled by GHRH
- TSH controlled by TRH
- LH controlled by GnRH
- FSH controlled by GnRH
- PRL controlled by Dopamine (inhibits)
ACTH = AdrenoCortiTropic Hormone
CRH = Corticotropin Releasing Hormone
FSH = Folicle Stimulating Hormone
GnRH = Gonadotropin Releasing Hormone
GH = Growth Hormone
GHRH = Growth Hormone Releasing Hormone
LH = Leutinizing Hormone
PRL = Prolactin
Diagnosis:
HTN + Low renin + Low potassium
Hyperaldosteronism
Confirmatory diagnostic test for hyperaldosteronism
CT scan of the adrenals
Risk factors for osteoporosis
- Menopause
- Low BMI
- Family hx of osteoporosis
- Early ovarian failure
- Low calcium intake
- Smoking
- Nulliparity
- Alcohol
- High caffeine intake
(Source: S95)
What are implications of prebreakfast, prelunch, predinner and bedtime glucose levels?
- Prebreakfast glucose level: Reflects predinner NPH dose
- Prelunch glucose level: Reflects prebreakfast regular insulin dose
- Predinner glucose level: Reflects prebreakfast NPH dose
- Bedtime glucose level: Reflects predinner regular insulin dose
What are the time of onset, peak effect and duration of regular insulin
- Onset: 30-60 minutes
- Peak effect: 2-4 hours
- Duration: 5-8 hours
What are the time of onset, peak effect and duration of lispro
- Onset: 5-10 minutes
- Peak effect: 0.5-1.5 hours
- Duration: 6-8 hours
What are the time of onset, peak effect and duration of aspart
- Onset: 10-20 minutes
- Peak effect: 1-3 hours
- Duration: 3-5 hours
What are the time of onset, peak effect and duration of glulisine?
- Onset: 5-15 minutes
- Peak effect: 1.0-1.5 hours
- Duration: 1.0-2.5 hours
What are the time of onset, peak effect and duration of NPH (Neutral Protamine Hagedorn)?
- Onset: 2-4 hours
- Peak effect: 6-10 hours
- Duration: 18-28 hours
What are the time of onset, peak effect and duration of detemir?
- Onset: 2 hours
- Peak effect: No discernible peak
- Duration: 20 hours
What are the time of onset, peak effect and duration of glargine?
- Onset: 1-4 hours
- Peak effect: No discernible peak hour
- Duration: 20-24 hours
Possible diagnoses:
- TSH - low
- T4 - high
- RAIU - decrease
Subacute thyroiditis (hyperthyroid stage)
Hashimoto thyroiditis (hyperthyroid stage)
Exogenous T3/T4: levothyroxine
Postpartum thyroiditis
Possible diagnoses:
- TSH - low
- T4 - high
- RAIU - increase
- Graves’ disease
- Toxic adenoma
- Multinodular goiter
Possible diagnoses:
- TSH - low
- T4 - decrease
- Pituitary hypothyroidism
- Hypothalamic hypothyroidism
What are the predominant estrogens in reproductive years and during menopause?
Under the stimulation of the leutinizing hormone (LH), the theca cells of the post-menopausal ovary produce androstenedione and testosterone. Estrone, a product of androstenedione conversion in adipose tissue, is the predominant estrogen in menopause.
Estradiol is the most prevalent estrogen in the reproductive years, and estriol is made by the placenta during pregnancy.
Estrane is a minor estrogen
What is hungry bone syndrome?
Hypocalcemia following surgical correction of hyperparathyroidism in patients with severe, prolonged disease, as calcium is rapidly taken from the circulation and deposited into the bone.
