(Nisha) Endocrinology p119-125 Flashcards
Anything that compresses the pituitary gland causes ?
Panhypopituitarism
What can damage the pituitary?
Tumors, trauma, and radiation.
Hemochromatosis, sarcoidosis, histiocytosis X, infection with fungi TB or parasites
Autoimmune and lymphocytic infiltration
Stroke
Panhypopituitarism is based on deficiency of specific hormones. Prolactin deficiency presents as ?
Prolactin deficiency inhibits lactation after childbirth.
Panhypopituitarism is based on deficiency of specific hormones. LH and FSH deficiency presents as ?
LH & FSH deficiency
women - amenorrhea
men - will not make testosterone or sperm, decreased libido, and decreased axillary, pubic, and body hair. erectile dysfunction and decreased muscle mass
Decreased FSH and LH from decreased GnRH + anosmia + renal agenesis in 50% of patients is seen in ________
Kallman syndrome
Panhypopituitarism is based on deficiency of specific hormones. Growth hormone deficiency presents as ?
children: short stature and dwarfism
adults: subtle findings - central obesity, increased LDL and cholesterol levels, reduced lean muscle mass
What imaging study is used to detect compressing mass lesions on the pituitary ?
MRI
How do you diagnose pituitary dysfunction via insulin stimulation test?
diagnosed via insulin stimulation. When insulin decreases glucose levels, GH should rise. if GH does not rise, it indicates PITUITARY INSUFFICIENCY
How do you diagnose pituitary dysfunction via metyrapone ?
Metyrapone inhibits 11 beta hydroxylase. decreases the output of the adrenal gland. Metyrapone should normally cause ACTH levels to rise because cortisol goes down.
Low TSH and low thyroxine. How to diagnose?
Decreased TSH response to TRH
Decreased ACTH and cortisol. How to diagnose?
Normal response to cosyntropin stimulation of the adrenal. Cortisol will release (adrenal is normal) in recent disease, but abnormal in chronic disease because of adrenal atrophy
No response (rise) in ACTH level with corticotropin releasing hormone (CRH)
An elevated baseline cortisol level excludes pituitary insufficiency
Decreased LH and FSH, decreased testosterone level. How to diagnose?
No confirmatory test
GH levels low, but this finding is not helpful since GH is pulsatile and maximum at night. How to diagnose?
No response to arginine infusion. No response to GHRH
Prolactin level low but not helpful. How to diagnose?
No response to TRH
Treatment for panhypopituitarism ?
Replace deficient hormones (cortisone, thyroxine, testosterone, recombinant human growth hormone)
always replace cortisone before starting thyroid
Posterior pituitary hormones?
ADH and oxytocin
Any deficiency disease for oxytocin?
NO
Deficiency of ADH causes ?
Central diabetes insipidus
Decrease in the amount of ADH from pituitary ( ______ ) or its effect on the kidney ( ________ )
Central DI or Nephrogenic DI
Any destruction of the brain from stroke, tumor, trauma, hypoxia, or infiltration of the gland from sarcoidosis or infection
Central DI
Kidney is damaged by kidney dz which inhibits the effect of ADH
Nephrogenic DI
Drug that causes Nephrogenic DI
Lithium
What electrolyte abnormalities inhibit ADH’s effect on the kidney?
Hypercalcemia and hypokalemia
Diabetes insipidus presentation ?
High volume urine and excessive thirst resulting in volume depletion and hypernatremia
Severe hypernatremia causes ?
Neurologic symptoms such as confusion, disorientation, lethargy and eventually seizures and coma
Excessive thirst
Urine - volume increases. osmolality decreases
Serum - volume decreases, osmolality increases, sodium increases (hypernatremia)
dx?
Vasopressin (desmopressin) stimulation test –> Diabetes insipidus
What is the vasopressin response in Central DI?
urine volume will decrease and urine osmolality will increase
What is the vasopressin response in Nephrogenic DI?
no effect of vasopressin use on urine volume or osmolality
Treatment for central DI
long term vasopressin (desmopressin) use
Treatment for nephrogenic DI
correct the underlying cause (hypokalemia or hypercalcemia). also responds to hydrochlorothiazide, amiloride, prostaglandin inhibitors (nsaids - indomethacin)
A 45-year-old female undergoes a transphenoidal approach for a pituitary prolactinoma. Surgery proceeded without complications and the entire mass was removed. The patient’s urine output is 4 L on post-operative day 1, and labs are significant for serum Na of 145 mEq/L (normal: 135-145). Urine osmolality is 185 mOsm/kg, and urine specific gravity is 1.004 (normal: 1.012 to 1.030). Which of the following choices is the next best step? Topic Review Topic
- Water restriction
- Loop diuretic
- CT scan of the brain
- 0.45% NaCl administered intravenously
- Desmopressin
- low urine osmolality (50-200 mOsm/kg) + increase sodium – DI –> must do desmopressin to determine if it is central or nephrogenic DI
Overproduction of growth hormone leading to soft tissue overgrowth throughout the body
Acromegaly
Acromegaly is almost always caused by a
pituitary adenoma
Increased hat, ring, and shoe size Carpal tunnel syndrome, OSA Body odor Coarsening facial features, teeth widening Deep voice, macroglossia Colonic polyps and skin tags Arthralgias HTN Cardiomegaly and CHF ED (increased prolactin)
Acromegaly
A 54 year old man presents to your office complaining of headache and blurred vision for the past several months. He also says that his family comments that his face looks different, his nose being bigger than it used to be. In addition, he says hi shoes feel tighter. On physical he has a coarse facial features with a prominent mandible and widely spaced incisors. MRI of the brain reveals a mass in the pituitary. This patient may be at increased risk of developping which of the following?
A. Colon cancer B. Pancreatic adenocarcinoma C. Hepatocellular carcinoma D. Lung cancer E. Malignant brain tumor
A
Best initial test for acromegaly?
IGF-1
Most accurate test for acromegaly?
Glucose suppression test. Normally glucose should suppress GH levels
What imaging study can be done after laboratory identification of acromegaly?
MRI
Treatment for acromegaly?
Surgery (transphenoidal resection) in 70% of cases Medications Radiotherapy (radiation for those who don't respond to surgery or medications)
GH has cosecretion of what other hormone
prolactin
A 48-year-old man comes to your office complaining of wrist pain and numbness of the thumbs and index and middle fingers of both of his hands, which has been worsening over the last 6 months. His only chronic medical condition is “slight hypertension,” for which he is being treated with hydrochlorothiazide. On further questioning the patient states that he has noted progressive coarsening of his facial features, as well as an increase in his shoe size, all of which has continuously worsened. His blood pressure is 145/95 mm Hg, pulse is 95/min, respiration rate is 15/min, and he is afebrile. He has a deep, hollow-sounding voice, and you notice slight prognathism. He is alert and oriented to person, place, and time. Chest auscultation is normal, as is heart examination. The rest of his physical exam is unremarkable. Monitoring with which of the following will help prevent one of the major complications of this condition?
A. Bone density B. Colonoscopy C. Prolactin levels D. Prostate-specific antigen E. Thyroid-stimulating hormone
The correct answer is B. Patients with acromegaly are more prone to developing colon cancer than the rest of the population, so monitoring with regular colonoscopies is advised in patients diagnosed with acromegaly.
Acromegaly medications: Somastatin inhibits GH release. What medication?
Octreotide or lanreotide
Acromegaly medications: Dopamine will inhibit GH release. What medication?
Cabergoline
Acromegaly medications: GH receptor antagonist, it inhibits IGF release from the liver. What medication?
Pegvisomant
A patient with amenorrhea, and bilateral white discharge from the breasts; TSH is high, and free T4 is low. On imaging, there is diffuse enlargement of pituitary. What is the treatment option?
A. Bromocriptine B. Cabergoline C. Trans-spenoidal surgery D. Thyroxine E. Radiotherapy
D
The patient has hyperprolactinemia, amenorrhea, galactorrhea and primary hypothyroidism. MRI of the pituitary shows diffuse enlargement. the correct diagnosis is primary hypothyroidism. Primary hypothyroidism is one the functional causes hyperprolactinemic states. hyperprolactinemia occurs in about 25% of patients with hypothyroidism. There will be thyrotrope-cell hypertrophy and hyperplasia and increase of TRH due to the lack of negative feedback by thyroid hormones. TRH causes a diffuse pitutary enlargement with increased synthesis and secretion of prolactin. Thyroid hormone replacement will restore normoprolactinoma and cause repression of the pituitary enlargement
Prolactin can be increased due to ?
Cosecretion with GH. Hypothyroidism leads to hyperprolactinemia because high TRH levels will stimulate prolactin secretion.
Drugs that cause hyperprolactinemia?
Antipsychotic medications, methyldopa, metoclopromide, opoids, TCA, and verapamil (only calcium channel blocker to increase prolactin)
Women presents to clinic with galactorrhea, amenorrhea, infertility.
Hyperprolactinemia
Men presents to clinic complaining of erectile dysfunction and decreased libido. He also has gynecomastia
Hyperprolactinemia
Diagnostic test for hyperprolactinemia ?
Once prolactin level is high, perform
Thyroid function tests
Pregnancy test
BUN/creatinine (kidney dz elevates prolactin)
Liver function tests (cirrhosis elevates prolactin)
Once high prolactin is confirmed and secondary causes like meds are excluded + patient is not pregnancy, you should order an ?
MRI
Treatment for hyperprolactinemia ?
Dopamine agonists (cabergoline better tolerated than bromocriptine, transphenoidal surgery (for those who dont respond to medications), radiation is rarely needed
A 32-year-old woman comes to the physician because of amenorrhea. She had menarche at age 13 and has had normal periods since then. However, her last menstrual period was 8 months ago. She also complains of an occasional milky nipple discharge. She has no medical problems and takes no medications. She is particularly concerned because she would like to become pregnant as soon as possible. Examination shows a whitish nipple discharge bilaterally, but the rest of the examination is unremarkable. Urine human chorionic gonadotropin (hCG) is negative. Thyroid stimulating hormone (TSH) is normal. Prolactin is elevated. Head MRI scan is unremarkable. Which of the following is the most appropriate pharmacotherapy?
A. Bromocriptine B. Dicloxacillin C. Magnesium sulfate D. Oral contraceptive pill (OCP) E. Thyroxine
A
