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Endocrine
Question | Answer |
---|---|
Pituitary Acidophils & Basophils | FLAT PiG: Fsh, Lh, Acth, Tsh (Basophils) ProlactIn, Gh (Acidophils) |
Alpha & Beta Subunits | - Alpha: Common to TSH, LH, FSH, hCG. Beta: Determines hormone specificity. - ACTH & MSH (and beta-endorphin) derived from POMC |
Endocrine Pancreas Cells | Alpha cells: Glucagon, peripheral. Beta Cells: Insulin, central. Delta Cells: Somatostatin, interspersed. |
TRH | -> TSH, Prolactin. Dopamine --| prolactin. Somatostatin --|TSH. |
CRH | -> ACTH |
Somatostatin (Octreotide) (physiologic & Therapeutic functions) | --| GH, TSH Octretoide treats gigantism, Acromegaly, Carcinoid, Gastrinoma, Glucagonoma (Necrolytic migratory erythema, stomatitis, chelosis) |
POMC Derivatives | Produces Beta endorphin, ACTH, MSH |
17alpha-Hydroxylase Deficiency | CAH. Aldosterone only, no Cortisol or Androgens. -> Hypertension & Hypokalemia. Phenotypic female w/o maturation. |
21-Hydroxylase Deficiency | #1 CAH. Androgens only. No cortisol or aldosterone. -> Masculinization/female pseudohermaphrodite, Hypotension & hyperkalemia, elevated renin. Hypovolemic shock in newborn. |
11beta-Hydroxylase Deficiency | CAH. Androgens & aldosterone pre-cursor (11-Deoxycorticosterone). No cortisol. -> Masculinization & HYPERtension. |
PTH Function | - Activates Ca absorption (renal, GI) & inhibits PO4 absorption(renal). - Active 1,25(OH)2D production. - Osteoclast/blast stimulation. |
Vit D Synthesis & Function | Sources: D2 (Plants) & D3(sun) –(liver)-> 25-(OH)D. Low PO4/Ca, High PTH: 25-(OH)D –(kidney)-> 1,25-(OH)2D. -> -> Ca & PO4 GI reabsorption & bone release. |
Etiology of AlkPhos Elevation | Pagets, Osteoblastic bone tumor, HyperPTH, Rickets/Osteomalacia. |
Glut4 | Insulin-Dependent glucose uptake. Skeletal muscle & fat. |
Glut1 | Insulin-Independent glucose uptake. Brain, RBCs |
cAMP-Mediated Hormones | hCG, Calcitonin, CRH, Glucagon, Straight-up “hormones” |
cGMP-Mediated Hormones | Vasodilators (ANP, NO/Endothelium Derived Relaxing Factor) |
IP3-Mediated Hormones | Hypothalamus-Derived Hormones (GhRH, TRH, GHRH, ADH, Oxytocin) |
Steroid Receptor-Mediated Hormones | Glucocorticoids, Vit D, T3/4 |
Tyrosine Kinase-Mediated Hormones | Insulin, Growth FACTORS (IGF-1, FGF) |
Cushings Syndrome Etiology | - Cushing Disease (Pituitary adenoma, only responds to high Dex suppression, others don’t respond) - Adrenal hyper/neoplasia - Small Cell Lung Cancer - Steroid use |
Adrenal Insufficiency Sx, Etiology | - Primary Adrenal Insufficiency (Addison’s). HypoTN, skin hyperpigmentation (high ACTH). Tx: Glucocorticoids. - Waterhouse-Freidrichsen Syndrome (n. meningitidis bacteremia-> infarct). - Secondary: Pituitary insufficiency (low ACTH). |
Pheochromocytomas Genetics & Characteristics | #1 adult adrenal tumor. VMA. MEN II, III (ret), neurofibromatosis. +/-Bilateral, malignant, ectopic, calcified, pediatric, inherited. |
Neuroblastoma | #1 pediatric adrenal tumor. HVA. N-myc. Local or sympathetic chain-ectopic. |
Sheehan’s Syndrome Cause & Sx | Postpartum hemorrhage/hypotn-> pituitary infarct. Poor lactation. |
MEN I Cancers & Sx | Kidney stones & gastric ulcers. - Pancreas (ZE, VIPoma, Insulinoma) - Pituitary (Prolactinoma) - Parathyroid |
MEN II Cancers | ret - Pheochromocytomas - (Para)Thyroid. |
MEN III Cancers | ret. - Pheochromocytoma - Medullary thyroid carcinoma (Amyloid) - Oral/GI mucosal neuromas |
Riedel’s Thyroiditis | Fibrosis of thyroid. HypoThyroid |
Hashimoto’s Thyroiditis Sx, Dx | - Hypothyroid w/Thyrotoxicosis - AI: Anti-Microsomal & Thyroglobulin Antibodies. Hurthle Cells. |
Subacute/de Quervain’s Thyroiditis Presentation & variants | Post-flulike illness. Jaw pain. - Granulomatous form is painful - Lymphocytic form is painless. |
Toxic Multinodular goiter | TSH-independent TH production. Not malignant |
Jod-Basedow Phenomenon | Thyrotoxicosis when endemic-goiter patient moves to Iodine non-deficient area. |
Papillary Thyroid Carcinoma | #1, good prognosis. - Orphan annie nuclei, Psamomma bodies. - Increased risk w/childhood radiation |
Follicular Thyroid Carcinoma | Good prognosis - uniform follicles. |
Medullary Thyroid Carcinoma | Parafollicular C cells->calcitonin. - MEN II, III - Amyloid forming |
Undifferentiated/Anaplastic Thyroid Cancer | Older patients, very poor prognosis |
Thyroid Lymphoma | Hashimoto’s-associated |
Acromegaly/Gigantism Dx, Tx | Dx’d w/ Poor glucose tolerance test. Octreotide tx Gigantism. |
Primary HyperPTH Etiology, associations, labs. | - PTH Adenoma: elevated urine cAMP, calcuria, constipation, Alk Phos - Assoc. w/Osteitis Fibrosa Cystica (Bone cysts w/ brown fibrous tissue) |
HypoPTH Etiology, PE | - DiGeorge - AI - Surgical - Chvostek + (facial nerve), Trousseau + (BP cuff-> carpal spasm) - PseudoHypoPTH: Kidney insensitivity to PTH. Short & small digits 4 & 5. |
HyperCalcemia Etiology | CHIMPANZEES: - Calcium intake - HyperPTH, HyperThyroid - Iatrogenic (thiazides) - Multiple myeloma - Paget’s - Addison’s - Neoplasms - Z-E - Excess vit D, A - Sarcoid |
DM1 | Insulin dependent (profound hypoinsulinism). DKA common. Viral-triggered AI attack on beta cells. Weak gene association (hla-DR3,4) |
DM2 | Insulin Independent. Strong genetic association |
DKA (Sx, Tx) | - Kussmaul respiration, N/V, abdominal pain - Anion gap metabolic acidosis. Intercellular hypoK (Arrhythmias), Mucormycosis, Rhizopus Infx, heart failure. - Rx: Fluid, insulin, K. |
Diabetes Insipidus (Etiology, Dx) | - Pituitary tumor - trauma/surgery - Histiocytosis X - Secondary HyperCa [renal] - Lithium, Demeclocycloine - Dx: Water deprivation. Desmopressin (ADH analog) distinguishes central & nephrogenic. - Urine <1.006, blood >290 mOsm/L. |
Diabetes Insipidus Tx | Central: Desmopressin. Nephrogenic: HCTZ, Amiloride, Indomethacin. |
SIADH Etiology, Labs, Tx | - Small cell Lung Ca & Pulm Dz - CNS trauma - Cyclophosphamide - Labs: HypoNa, Urine > Serum osmolarity. - Tx: slowly w/ demeclocycline, Lithium (SE’s), H20 Restriction. |
Carcinoid Syndrome Labs, Sx, Morphology, Tx | Elevated urine 5-HIAA. - GI enterochromaffin cell tumor (serotonin) outside GI. Sx: Flushing, Diarrhea, wheezing, peripheral edema. #1 appendix tumor, R Endocardial Fibrosis. MULTIPLE (metastatic, addt’l malignancy, multiple). - Tx: Octreotide |
Insulin | Time: Lispro & Aspart < NPH < Lente < Ultralente. Tx DM1, HyperK |
1st Gen Sulfonylureas | Tolbutamide, Chlorpropramide. SE: Disulfram-like effects. |
2nd Gen Sulfonylureas | Glyburide, Gilmepiride, Glipizide. |
Sulfonylurea mech | Close Beta cell K channel -> depolarization -> Ca influx -> Insulin release. Only DM2 |
Biguanides | Metformin Mech: Reduce gluconeogenesis, increase glycolysis, lowers serum glucose SE: Lactic Acidosis. CI:Renal, Liver Failure/Alcoholics, CHF, Sepsis |
Glitazones | Pio/Rosi-glitazone Mech: Increase sensitivity to insulin via PPAR gamma. SE: Wt gain, edema, hepato & cardio toxic |
Alpha Glucosidase Inhibitors | Acarbose & Miglitol Mech: inhibits brush border glucosidase -> slows glucose absorption SE: GI disturbances DM2 only |
Methimazole, Propylthiouracil | Inhibits TH synthesis via -|thyroid peroxidase PTU also inhibits T4->T3. SE: Rash, Agranulocytosis & Aplastic Anemia |
GH Therapy | GH Deficiency, Turner’s Syndrome |
Desmopressin Therapy | Central DI |
Glucocorticoid Use | Addison’s. |
Secondary HyperPTH Labs, Associations | Renal failure: Low Ca, high PO4 & Alk Phs Assoc w/Renal osteodystrophy (bone lesions b/c high PTH) |
Cortisol Physiology | Stimulates Gluconeogenesis, Glycolysis, Epinephrine synthesis, Proteolysis, Lipolysis, Neutrophil Demargination. Suppresses Insulin, non-neutrophil lymphocyte counts. |
Neurophysin | Transports ADH & Oxytocin from Hypothalamus to Neurohypophysis |
Acute Hyperthyroid Tx | Beta blockers |
Kallmans Syndrome | GnRH migration failure-> primary hypoandrogenism. + Anosmia |
Conn's Syndrome | Primary Aldosteronism: Adrenal Hyperplasia/Adenoma |