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E18 Endocrinology
Pituitary Gland Toronto Notes 2019
• enlargementofhandsandfeet,coarseningoffacialfeatures,thickeningofcalvarium,prognathism, thickening of skin, increased sebum production, sweating, acne, sebaceous cysts, fibromata mollusca, acanthosis nigricans, arthralgia, carpal tunnel syndrome, degenerative osteoarthritis, barrel chest, thyromegaly, renal calculi, HTN, cardiomyopathy, obstructive sleep apnea, colonic polyps, erectile dysfunction, menstrual irregularities, 2-3x increased cancer risk (particularly GI), and DM
Investigations
• elevatedseruminsulin-likegrowthfactor-1(IGF-1)isusuallythefirstlinediagnostictest
• glucosesuppressiontestisthemostspecifictest(75gofglucosePOsuppressesGHlevelsinhealthy
individuals but not in patients with acromegaly)
• CT,MRI,orskullx-raysmayshowcorticalthickening,enlargementofthefrontalsinuses,and
enlargement and erosion of the sella turcica
• MRIofthesellaturcicaisneededtolookforatumour
Treatment
• surgery,octreotide(somatostatinanalogue),dopamineagonist(bromocriptine/cabergoline),GH receptor antagonist (pegvisomant), radiation
Prolactin
HYPERPROLACTINEMIA
Etiology
• prolactinoma:mostcommonpituitaryadenoma(prolactin-secretingtumoursmaybeinducedby estrogens and grow during pregnancy)
• pituitarymasseswithpituitarystalkcompressioncausingreduceddopamineinhibitionofprolactin release
• primaryhypothyroidism(increasedTRH)
• decreasedclearanceduetochronicrenalfailureorsevereliverdisease(prolactinismetabolizedbyboth
the kidney and liver)
• medications with anti-dopaminergic properties are a common cause of high prolactin levels:
antipsychotics (common), antidepressants, antihypertensives, anti-migraine agents (triptans/
ergotamines), bowel motility agents (metoclopramide/domperidone), H2-blockers (ranitidine)
• macroprolactinemia(highmolecularweightprolactinalsoknownasbigbigprolactin)thathasno
action
Clinical Features
• galactorrhea(secretionofbreastmilkinwomenand,inrarecases,men),infertility,hypogonadism, amenorrhea, erectile dysfunction
Investigations
• serumPRL,TSH,liverenzymetests,creatinine,macroprolactinlevelinselectcases • MRIofthesellaturcicainselectcases
Treatment
• firstline:long-actingdopamineagonist:bromocriptine,cabergoline,orquinagolide
• surgery±radiation(rare)
• prolactin-secretingtumoursareoftenslow-growingandsometimesrequirenotreatment
• ifmedication-induced,considerstoppingmedicationifpossible
• incertaincasesifmicroprolactinomaandnotplanningonbecomingpregnant,mayconsiderOCP
Thyroid Stimulating Hormone
• seeThyroid,E21
Adrenocorticotropic Hormone
• seeAdrenalCortex,E30
Luteinizing Hormone and Follicle
Stimulating Hormone
HYPOGONADOTROPIC HYPOGONADISM
Etiology
• primary/congenital:Kallmannsyndrome,CHARGEsyndrome,GnRHinsensitivity
• secondary:CNSorpituitarytumours,pituitaryapoplexy,brain/pituitaryradiation,drugs(GnRHagonists/
antagonists, glucocorticoids, narcotics, chemotherapy, drugs causing hyperprolactinemia), functional deficiency due to another cause (hyperprolactinemia, chronic systemic illnesses, eating disorders, hypothyroidism, DM, Cushing’s disease), systemic diseases (hemochromatosis, sarcoidosis, histiocytosis)
Approach to Nipple Discharge
• Differentiate between galactorrhea (fat droplets present) versus breast discharge (usually unilateral, may be bloody or serous)
• If galactorrhea, determine if physiologic (e.g. pregnancy, lactation, stress) versus pathologic
• If abnormal breast discharge, must rule out a breast malignancy