Endocrine #1 Flashcards
A somtatotroph adenoma, an anterior pituitary tumor, secretes ________ that leads to acromegaly in adults or gigantism in children.
Growth Hormone (GH)
Growth Hormone (GH) increases ________.
Increased GH also stimulates hepatic production of what other hormone?
GH increases glucose
Increased GH also increases insulin-like growth factor (IGF)
Symptoms of Acromegaly/Gigantism
-Diabetes Mellitus or glucose intolerance
-Enlargement of soft tissues, cartilage and bone (macrognathia, increased ring/shoe/hat size)
-Obstructive sleep apnea, carpal tunnel syndrome, increased space between teeth, deepened voice
-Headache, Bitemporal Hemianopsia, thick/moist/doughy skin
-Hypertension, kidney stones, colonic polyps
Screening test for Acromegaly/Somatotroph Adenoma
Confirmatory Test
What imaging study should be done?
-Screening: insulin-like growth factor
-Confirmatory: oral glucose suppression test. Increased GH levels (normal is suppression of GH)
MRI of the pituitary
Management of somatotroph adenoma (acromegaly)
-Transsphenoidal surgery
-Octreotide or Lanreotide (somatostatin inhibits GH release)
-Cabergoline or Bromocriptine (dopamine inhibits GH release)
-Pegvisomant (GH receptor antagonist that inhibits insulin like growth factor release)
______ is the MC type of pituitary adenoma
Prolactinoma
Prolactin is responsible for _______, suppression of pregnancy during lactation, and suppression of gonadotropin-releasing hormone, leading to decreased FSH and LH.
_______ Inhibits prolactin release
-Lactation
-Dopamine
Symptoms from a prolactinoma are due to ______
Women:
Men:
-Hypogonadism
-Women: amenorrhea, infertility, galactorrhea, headache/vision changes from local compression
-Men: ED, decreased libido, infertility, headache/vision changes
-Bitemporal hemianopsia (optic chiasm compression)
What lab studies are expected with a prolactinoma?
What imaging study should be done?
-Increased prolactin, decreased FSH and LH
MRI of the pituitary
What is the treatment for a prolactinoma (think of what inhibits it)?
-Dopamine agonists (Bromocriptine, Cabergoline)
-Transsphenoidal surgery if refractory medical treatment, or women who wish to become pregnant
A corticotroph adenoma, is a pituitary adenoma that secretes _________, that leads to _________ (Cushing’s Syndrome).
Symptoms of this condition
-Secretes ACTH that leads to hypercortisolism (Cushing’s Syndrome)
-Proximal muscle weakness, weight gain, headache, ED, polyuria, osteoporosis, mental disturbances
A corticotroph adenoma is AKA ________.
Explain what differentiating tests are done (labs) and what is shown to determine the cause of the hypercortisolism.
-Also known as Cushing’s Disease
-Increased baseline ACTH + suppression of cortisol on high-dose Dexamethasone suppression
What imaging study should be done for a corticotroph adenoma?
What is the management?
MRI of the pituitary
Transsphenoidal resection is the treatment of choice
Symptoms of Growth Hormone Deficiency
-Children
-Adults
-Children: Short stature, growth delays, dwarfism, fasting hypoglycemia
-Adults: central obesity, hypertension, dysplipidemia, muscle wasting, decreased cardiac output, impaired concentration
How do you diagnose growth hormone deficiency?
What is the treatment?
-Arginine and sleep stimulation test: no change in GH if hypopituitarism
-Recombinant human GH
Multiple Endocrine Neoplasia I (MENI) has three main manifestations. Think of the 3 P’s.
What are the screening labs that should be done?
-Parathyroid (Hyperparathyroidism)
-Pancreatic Tumors: Gastrinomas (ZES)
-Prolactinomas
PTH + Calcium, Gastrin, Prolactin
Multiple Endocrine Neoplasia II (MENII) has four main manifestations. Name them.
What screening labs should be done?
-Medullary thyroid carcinoma, Marfanoid habitus, Pheochromocytoma, Neuromas (lips, tongue, eyelids, conjunctiva, nasal, and laryngeal mucosa)
-Calcitonin, epinephrine, PTH, calcium
For metabolic syndrome, you need 3 of the 5 criteria to diagnose. What are the 5 criteria?
-Low HDL: < 40 in men, < 50 in women
-High BP: > 135 SBP, > 85 DBP
-High fasting TG: > 150
-High fasting blood sugar: > 100
-High abdominal circumference: > 40 inches in men, > 35 inches in women
Or on treatment for any of them
Metabolic Syndrome, also known as Syndrome X, has one main component, which is __________.
Explain how this works and causes the other symptoms
-Insulin resistance is the key
-Free fatty acids are released, which causes an increase in TGs and insulin production.
-High levels of insulin lead to sodium reabsorption, leading to hypertension.
Management for metabolic syndrome (initial)
What medications can be used for weight loss?
-Weight reduction, exercise, activity, diet
-Phentermine
-Phentermine/Topiramate
-Lorcaserin: induces satiety
-Orlistat: inhibits fat absorption
SIADH is excess ADH from the __________ which leads to free water retention and hyponatremia due to kidney’s inability to dilute the urine to excrete excess water.
Pituitary gland or ectopic source
Etiologies of SIADH
-What is the MC
-Others
-CNS (MC): Subarachnoid hemorrhage, head trauma, stroke, hydrocephalus
-Small cell lung cancer, legionella PNA
-Anticonvulsants, Carbamazepine, Hydrochlorothiazide, Antidepressants, IV Cyclophosphamide, Ecstasy
Explain why hyponatremia occurs in SIADH
-Not enough water excreted, due to excess ADH
-This dilutes the blood, including sodium in the blood
-Leads to a low blood sodium level (hyponatremia)
Symptoms of SIADH
-Symptoms of hyponatremia and cerebral edema
–confusion, lethargy, disorientation, seizures, coma
Explain the labs of SIADH (dilutional labs)
-Increased ADH levels
-Normovolemic hypotonic hyponatremia (no signs of edema)
-Decreased serum osmolarity
-Increased urine osmolarity (concentrated urine), sodium urine > 20 mEq/L
Treatment for SIADH
-What can happen if corrected too fast?
-Treat underlying cause
-Rapid correction (>0.5 mEq/L/hour may lead to central pontine myelinolysis or osmotic demyelination)
-Mild: water restriction
-Moderate: ADH receptor antagonists (Conivaptan, Tolvaptan)
What is the treatment for severe SIADH (obtunded, seizures, coma)?
IV hypertonic saline + Furosemide
Chronic SIADH is treated with what medication?
Demeclocycline (inhibits ADH)
On the other hand, Diabetes Insipidus is the inability of the kidney’s to concentrate urine, leading to large amounts of dilute urine. There are two types. Name them.
Central: No production of ADH
Nephrogenic: kidney’s insensitivity to ADH
2 Types of Diabetes Insipidus
-Central: No production of ADH (MC type). Idiopathic MC, destruction of posterior pituitary, head trauma, CNS tumor
-Nephrogenic: renal insensitivity to ADH. Lithium, Hypokalemia, Hypercalcemia, hyperparathyroidism, ATN
Symptoms of DI
-Polyuria (20L daily) + polydipsia
-High volume nocturia
-Neurologic symptoms of hypernatremia (confusion, lethargy, seizures, coma)
-Dehydration, hypotension
Explain the labs of DI (dilutional labs)
-Hypernatremia
-Increased serum osmolarity
-Decreased urine osmolality and specific gravity
-Increased urine volume
What diagnostic establishes the diagnosis of DI?
-Fluid deprivation test
–Normal response: progressive urine concentration
–DI = continued production of large amounts of dilute urine
What diagnostic distinguishes central from nephrogenic DI?
-Desmopressin (ADH) stimulation test
–Central: reduction in urine output + increase in urine osmolality (response to ADH)
–Nephrogenic: continued production of dilute urine (no response to ADH)
Management of central DI
Management of Nephrogenic DI
-Central: Desmopressin (DDAVP)
-Nephrogenic: Sodium/Protein restriction, Hydrochlorothiazide, Indomethacin, Amiloride for symptoms
-Amiloride for Lithium induced
What is the MC type of thyroid cancer?
Papillary thyroid carcinoma
Risk Factors for Papillary Thyroid Cancer
Symptoms
Workup
Treatment
-RF: MC after radiation of head/neck, family history of thyroid cancer, smoking, women > men
-Painless thyroid nodule
-FNA, Thyroid tests normal
-Treatment: Thyroidectomy + postoperative Levothyroxine
Follicular Thyroid Carcinoma
-RF
-Mets
-Diagnostics (what is unique about this one)
-Management
-RF: Iodine deficiency***, less often due to radiation
-Mets: Distant METS MC (lung MC, liver, bone, brain)
-FNA with biopsy cannot distinguish between follicular adenoma vs carcinoma, so post surgical histology done
-Thyroidectomy with Levothyroxine post-operatively
Medullary Thyroid Carcinoma is derived from ___________, but is also associated with ____________.
What labs are positive with this type of cancer?
Management
What is used to monitor recurrence?
Derived from Calcitonin-synthesizing parafollicular C cells
-Also associated with MENIIa or IIb
-Calcitonin is increased
-Total thyroidectomy
Calcitonin levels used to monitor recurrence
The most aggressive type of thyroid cancer is _______.
What are some symptoms of this type?
Management?
-Anaplastic Thyroid Carcinoma
-Rapid growth, compressive symptoms, dyspnea, dysphagia, rock hard thyroid mass that may be fixed
Most not amenable to surgical resection. External beam radiation or chemotherapy. Palliative tracheostomy to maintain airway.
