Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++Figure 25-1.Graphic Jump LocationView Full Size|Favorite Figure|Download Slide (.ppt)Pituitary gland. (Reproduced with permission from Longo DL, Fauci AS, Kasper, DL, et al. (eds). Harrison's Principles of Internal Medicine, 18th ed. New York: McGraw-Hill, 2012: Fig 339–1.) ++ Pathophysiology: underactive pituitary gland, 2/2 complete/partial loss of lobe functionSigns/symptoms: features of specific hormone deficiency: ↓ GH → fatigue; ↓ FSH/LH → ↓ libido, impotence, ↓ menstruation, ↓ pubic hair, Δ in sexual function, ↓ ACTH (different from Addison's disease—no ↓ K, salt cravings, or hyperpigmentation) if present with hypothyroidism treat adrenal insufficiency 1st to avoid adrenal crisis; ↓ TSH → similar to central hypothyroidism, usually no goiter; ↓ prolactin → ↓ lactation (uncommon); ↓ ADH (common in 2° disorder) → polyuria, polydipsia, ↑ NaDiagnosis: pituitary MRI & hormone studies; rule out anorexia, chronic liver disease, myotonia dystrophica, & polyglandular autoimmune diseaseTreatment: resolve underlying cause & replace deficient hormones; doses based on individual needs ++Table Graphic Jump LocationFavorite Table | Download (.pdf) | PrintClinical Pearl 25-1GFLAT P → order that anterior pituitary hormones are depleted → GH, FSH/LH, ACTH, TSH, prolactin ++Table Graphic Jump LocationTable 25-1 Causes of Primary & Secondary PanhypopituitarismView Table|Favorite Table|Download (.pdf)Table 25-1 Causes of Primary & Secondary PanhypopituitarismPrimary Disorder (directly affects pituitary)Secondary Disorder (indirectly affects pituitary)Pituitary tumors↓ supply of blood to pituitaryInfection & inflammatory diseasesRadiationSurgical removal of pituitary tissueAutoimmune disordersThrombosisTraumaSheehan's syndromeHypothalamic tumorsHead injuries/traumaInfectionRadiationSurgical damage to blood vessels connecting pituitary to hypothalamus ++ Pathophysiology: hypofunction of the anterior pituitary resulting in ↓ GH; GH regulated by growth hormone releasing hormone (GHRH stimulation) & somatostatin (inhibition) +++ Diagnosis & Evaluation ++ Signs/symptoms: adults—↑ LDL, ↑ central adiposity, ↓ exercise tolerance, ↓ bone mineral density, ↓ cardiac output, depressed mood, ↓ QOL; pediatrics—abnormally slow growth & short stature with normal proportions; >2.5 SD below mean height for ageDiagnosis: GH release pulsatile ∴ ↓ [GH] not diagnostic; use GH stimulation tests → failure to ↑ GH after stimulation suggests GH deficiency → insulin tolerance test (<3mcg/L); glucagon test (<3mcg/L); GHRH-arginine test (<9mcg/L; cut-off levels may vary by lab) obesity may cause false + +++ Treatment & Follow-Up ++ Treatment: GH → cannot mimic endogenous pulsatile secretion; suppressed postprandially; elevated postabsorptive → administer HS to avoid postprandial GH elevations → weight based (varies by product) or initial 0.2mg/d → low-dose replacement <3mcg/kg/d may have benefits on glucose metabolism & insulin resistance vs higher doses (Diabetologia 2010;53:1304); 3–6mo required to establish benefit; titrate Q2–4wkMonitor: lipids Q6mo, glucose Q3mo, T4 may ↓, T3 remains stable → patients using exogenous thyroid hormone may need dose ↑; adverse effects: edema, arthralgias, pancreatitis, insulin resistance ++Table Graphic Jump Location... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessPharmacy 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessPharmacy Full Site: One-Year Individual Subscription $595 USD Buy Now View All Subscription Options