In dieser Lektion befinden sich 88 Karteikarten
USMLE First Aid
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- Familial hypocalciuric hypercalcemia Autosomal dominantly inherited defective G-coupled Ca2+-sensing receptors (CaSR) in multiple tissues (eg, parathyroids, kidney).- Higher than normal Ca2+ levels required to suppress PTH. Excessive renal ...
- Primary hyperparathyroidism Usually due to parathyroid adenoma or hyperplasia. Hypercalcemia, hypercalciuria (renal "stones"), hypophosphatemia, ↑ PTH, ↑ ALP, ↑ cAMP in urine. - Most often asymptomatic. - May present ...
- Secondary hyperparathyroidism 2° hyperplasia due to ↓ Ca2+ absorption and/or ↑ PO43-, most often in chronic renal disease (causes hypovitaminosis D and hyperphosphatemia → ↓ Ca2+). Hypocalcemia, hyperphosphatemia in chronic ...
- Tertiary hyperparathyroidism Refractory (autonomous) hyperparathyroidism resulting from chronic renal disease. ↑↑ PTH, ↑ Ca2+.
- Nelson syndrome Enlargement of existing ACTH-secreting pituitary adenoma after bilateral adrenalectomy for refractory Cushing disease (due to removal of cortisol feedback mechanism). Presents with hyperpigmentation, ...
- Acromegaly Excess GH in adults. Typically caused by pituitary adenoma. Findings: Large tongue with deep furrows, deep voice, large hands and feet, coarsening of facial features with aging, frontal bossing, diaphoresis ...
- Laron syndrome (dwarfism) Defective growth hormone receptors → ↓ linear growth. ↑ GH, ↓ IGF-1. Clinical features: - Short height- Small head circumference- Characteristic facies with saddle nose and prominent forehead- ...
- Diabetes insipidus Characterized by intense thirst and polyuria with inability to concentrate urine due to lack of ADH (central) or failure of response to circulating ADH (nephrogenic). Central DI- Etiology: Pituitary tumor ...
- Syndrome of inappropriate antidiuretic hormone secretion ... Characterized by:- Excessive free water retention- Euvolemic hyponatremia with continued urinary Na+ excretion- Urine osmolality > serum osmolality Body responds to water retention with ↓ aldosterone ...
- Glucagonoma Tumor of α pancreatic cells → overproduction of glucagon. Presents with:- Dermatitis (necrolytic migratory erythema)- Diabetes (hyperglycemia)- Deep vein thrombosis- Declining weight- Depression ...
- Insulinoma Tumor of β pancreatic cells → overproduction of insulin → hypoglycemia May see Whipple triad:1. Low blood glucose2. Symptoms of hypoglycemia (eg, lethargy, syncope, diplopia)3. Resolution of symptoms ...
- Somatostatinoma Tumor of pancreatic δ cells → overproduction of somatostatin → ↓ secretion of secretin, cholecystokinin, glucagon, insulin, gastrin, gastric inhibitory peptide (GIP). May present with- Diabetes/glucose ...
- Carcinoid syndrome Rare syndrome caused by carcinoid tumors (neuroendocrine cells, prominent rosettes), especially metastatic small bowel tumors, which secrete high levels of serotonin (5-HT). Not seen if tumor is limited ...
- Multiple endocrine neoplasias All MEN syndromes have autosomal dominant inheritance. MEN 1:- Pituitary tumors (prolactin or GH)- Pancreatic endocrine tumors: Zollinger-Ellison syndrome, insulinomas, VIPomas, glucagonomas- Parathyroid ...
- Diabetic ketoacidosis Usually due to insulin noncompliance or ↑ insulin requirements from ↑ stress (eg, infection). Excess fat breakdown and ↑ ketogenesis from ↑ free fatty acids, which are then made into ketone ...
- Zollinger-Ellison syndrome Gastrin-secreting tumor (gastrinoma) of pancreas or duodenum. Acid hypersecretion causes recurrent ulcers in duodenum and jejunum. - Presents with abdominal pain (peptic ulcer disease, distal ulcers), ...
- Insulin regulation Glucose is the major regulator of insulin release. ↑ insulin response with oral vs IV glucose due to incretins (eg, glucagon-like peptide 1 [GLP-1], glucose-dependent insulinotropic polypeptide [GIP]), ...
- Prolactin Secreted mainly by anterior pituitary. Structurally homologous to growth hormone. Stimulates milk production in breast; inhibits ovulation in females and spermatogenesis in males by inhibiting GnRH synthesis ...
- Antidiuretic hormone (vasopressin) Synthesized in hypothalamus (supraoptic and paraventricular nuclei), stored and secreted by posterior pituitary. Function: Regulates serum osmolarity (V2-receptors) and blood pressure (V1-receptors). ...
- VIPoma Rare neuroendocrine tumor that secretes vasoactive intestinal pepide (VIP). - Most commonly arises in pancreas. - Associated with MEN-1. Primary symptom is secretory diarrhea. Associated with WDHA syndrome:- ...
- Hypothyroidism vs hyperthyroidism Hypothyroidism:- Metabolic: Cold intolerance, ↓ sweating, weight gain, (↓ basal metabolic rate → ↓ calorigenesis), hyponatremia (↓ free water clearance)- Skin/hair: Dry, cool skin (due to ↓ ...
- Postpartum thyroiditis Self-limiting thyroiditis arising up to 1 year after delivery. Presents as transient hyperthyroidism, hypothyroidism, or hyperthyroidism followed by hypothyroidism.- Majority of women are euthyroid following ...
- Papillary carcinoma Most common, excellent prognosis. Histology: - Empty-appearing, ground-glass nuclei with central clearing ("Orphan Annie" eyes)- Psammoma bodies- Nuclear grooves.Characteristically large cells with ...
- Follicular carcinoma Good prognosis. Invades thyroid capsule and vasculature (unlike follicular adenoma), uniform follicles. Hematogenous spread is common. Associated with RAS mutation and PAX8-PPAR-γ translocations.
- Medullary carcinoma From parafollicular "C cells"; produces calcitonin. Sheets of cells in amyloid stroma (stains with Congo red). Associated with MEN 2A and 2B (RET mutations).
- Undifferentiated/anaplastic carcinoma Older patients, invades local structures. Very poor prognosis. DD: Riedel thyroiditis
- Diabetes mellitus Polydipsia, polyuria, weight loss, DKA (type 1), hyperosmolar hyperglycemic state (type 2).Rarely, can be caused by unopposed secretion of GH and epinephrine. Also seen in patients on glucocorticoid therapy. ...
- Type 1 vs type 2 diabetes mellitus Type 1:- Autoimmune destruction of β cells (eg, due to glutamic acid decarboxylase antibodies)- Insulin necessary in treatment- Age <30 years- Weak genetic predisposition (50% concordance in identical ...
- Hyperosmolar hyperglycemic state State of profound hyperglycemia-induced dehydration and ↑ serum osmolality, classically seen in elderly type 2 diabetes with limited ability to drink. Hyperglycemia → excessive osmotic diuresis → ...
- PI3K/Akt/mTOR pathway The PI3K/Akt/mTOR pathway is an intracellular signaling pathway that is important for cellular proliferation. - The proliferation is typically activated when a growth factor binds to its receptor tyrosine ...
- MAP-kinase pathway - Receptor-linked tyrosine kinases (eg, EGFR) are activated by ligands (eg, EGF).- The EGRF becomes phosphorylated on tyrosine residues.- Docking proteins such as GRB2 contain a SH2 domain that binds ...
- Glucagon Made by α cells of pancreas. Function: - Promotes glycogenolysis (↑ glycogen phosphorylase)- Gluconeogenesis (↓ PFK-2 → ↓ PFK-1, ↑ phosphoenolpyruvate carboxykinase, glucose-6-phosphatase)- ...
- Hypothyroidism - Hashimoto thyroiditis- Postpartum thyroiditis- Congenital hypothyroidism (cretinism)- Subacute granulomatous thyroiditis (de Quervain)- Riedel thyroiditis- Iodine deficiency- Goitrogens (eg, amiodarone, ...
- Hyperthyroidism - Graves disease- Toxic multinodular goiter- Thyroid storm- Jod-Basedow phenomenon
- Diagnosing parathyroid disease ↑ PTH, ↑ Ca2+ → 1° hyperparathyroidism (eg, hyperplasia, adenoma, carcinoma) ↑ PTH, ↓ Ca2+ → 2° hyperparathyroidism (eg, chronic renal failure, vitamin D deficiency, ↓ Ca2+ intake) ...
- Glucose uptake Glucose is taken up by peripheral tissues by facilitated diffusion. Require insulin for effective uptake of glucose:- Skeletal muscle- Adipose tissue- Liver because of glucokinase stimulation Not affected ...
- Adiponectin Produced in adipose tissue and increases insulin sensitivity and tissue fat oxidation.- Low levels in type 2 diabetics Dysregulation of adiponectin may play a role in obesity, insulin resistance, anc ...
- Estrogen Conserves bone integrity. - Induces synthesis of osteoprotegerin (binds RANK-L, thereby preventing it from binding onto precursor or osteoclast cells) - Reduces the secretion of cytokines by T-lymphoctes → ...