2. Pituitary Stalk Damage, Sheehan’s Syndrome & Prolactinomas | USMLE Step 1 Physiology скачать в хорошем качестве

2. Pituitary Stalk Damage, Sheehan’s Syndrome & Prolactinomas | USMLE Step 1 Physiology

𝐒𝐮𝐛𝐬𝐜𝐫𝐢𝐛𝐞 𝗙𝐨𝐫 𝗠𝐨𝐫𝐞 𝗜𝐧𝐟𝐨𝐫𝐦𝐚𝐭𝐢𝐨𝐧 𝐨𝐧 𝗛𝐞𝐚𝐥𝐭𝐡 👩‍⚕‍ 𝐚𝐧𝐝 𝗠𝐞𝐝𝐢𝐜𝐢𝐧𝐞💉🩺💊 📌𝗜𝗻𝘀𝘁𝗮𝗴𝗿𝗮𝗺 :   / clinical.learning   Pituitary Stalk Damage, Sheehan’s Syndrome & Prolactinomas | USMLE Step 1 Physiology This high-yield USMLE Step 1 lecture covers three essential disorders involving the pituitary gland — pituitary stalk damage, Sheehan’s syndrome, and prolactinomas — each illustrating a different mechanism of hypopituitarism or hormone excess. These conditions are frequently tested in Step 1 clinical vignettes involving amenorrhea, lactation failure, hypotension, or visual changes, and mastering their pathophysiology and presentations is vital for real-world diagnosis and exam success. 🧠🩺 We begin with pituitary stalk damage, which disrupts the portal blood flow between the hypothalamus and anterior pituitary, impairing the delivery of releasing hormones like TRH, CRH, GHRH, and GnRH. This results in deficiencies of TSH, ACTH, GH, LH/FSH, while prolactin levels paradoxically rise due to loss of dopaminergic inhibition. Patients may present with central hypothyroidism, adrenal insufficiency, infertility, and galactorrhea. Causes include trauma, tumors, or surgery near the suprasellar region. 🧬 Next, we discuss Sheehan’s syndrome, a classic postpartum complication resulting from ischemic infarction of the anterior pituitary following severe obstetric hemorrhage. Due to the pituitary’s high metabolic demand during pregnancy and its limited blood supply, significant hypotension can cause necrosis. Women present post-delivery with inability to lactate (prolactin deficiency), amenorrhea (low LH/FSH), fatigue, hypotension, and cold intolerance due to panhypopituitarism. Early recognition and hormone replacement are life-saving. 🤱⚠️ Lastly, we cover prolactinomas, the most common functioning pituitary adenomas. These benign tumors of lactotroph cells secrete excess prolactin, leading to hypogonadism, infertility, galactorrhea, and amenorrhea in women, and erectile dysfunction and gynecomastia in men. High prolactin suppresses GnRH, resulting in low LH/FSH. Diagnosis is confirmed by elevated serum prolactin and MRI of the pituitary. First-line treatment is dopamine agonists like cabergoline or bromocriptine. Surgery is reserved for large tumors causing visual field defects. 🎯💊 This lecture prepares you to differentiate these conditions using clinical features, hormone levels, and imaging, and to select the right management approach in Step 1 scenarios involving pituitary pathology. #PituitaryStalkDamage #SheehansSyndrome #Prolactinoma #Hyperprolactinemia #Hypopituitarism #Panhypopituitarism #USMLEStep2CK #DopamineAgonists #EndocrinologyReview #Amenorrhea #Galactorrhea #Cabergoline #Bromocriptine #PituitaryAdenoma #Step2Prep #WhiteboardMedicine #DrGBhanuPrakash #MedicalEducationUSA #Prolactin #GnRH #MRIpituitary #PostpartumComplications #USMLEBuzzwords #USMLE2025