Methimazole
MoA
Use
Tox
Inhibits Peroxidase
Hyperthyroidism
Tox: skin rash, agranulocytosis, aplastic anemia, teratogen
Key Terms
Methimazole
MoA
Use
Tox
Inhibits Peroxidase
Hyperthyroidism
Tox: skin rash, agranulocytosis, aplastic anemia, teratogen
Thyroid Hormone Regulation
Hypothalamus --> TRH --> Pituitary --> TSH --> Follicular cells of thyroid gland --> TH
Negative feedback by T3 to anterior pitui...
Wolff-Chaikoff Effect
Excess I temporarily inhibits thyroid peroxidase --> ↓ iodine organification --> ↓ T3/T4 production
Function of Follicular Cells in Thyroid Gland
Take up I- and oxidize it to I2 for excretion into lumen. In lumen TG and I2 form MIT and DIT.
Take up TG and proteolysis occurs to release T3/T...
Cushing's Syndrome
Primary Pathophysiology
Different kinds of causes
↑ cortisol
| Exogenous vs Endogenous causes
1 cause of Cushing's syndrome?
Exogenous steroids --> ↓ ACTH
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| Term | Definition |
|---|---|
Methimazole | Inhibits Peroxidase |
Thyroid Hormone Regulation | Hypothalamus --> TRH --> Pituitary --> TSH --> Follicular cells of thyroid gland --> TH |
Wolff-Chaikoff Effect | Excess I temporarily inhibits thyroid peroxidase --> ↓ iodine organification --> ↓ T3/T4 production |
Function of Follicular Cells in Thyroid Gland | Take up I- and oxidize it to I2 for excretion into lumen. In lumen TG and I2 form MIT and DIT. |
Cushing's Syndrome | ↑ cortisol | Exogenous vs Endogenous causes |
1 cause of Cushing's syndrome? | Exogenous steroids --> ↓ ACTH |
Endogenous causes of Cushing's Syndrome | Cushing's Disease (70%): ACTH secretion from pituitary adenoma |
Presentation of Cushing's Syndrome | HTN, Wt Gain, Moon facies, Truncal obesity, Buffalo hump, Hyperglycemia (insulin resistance), Skin changes (thinning, striae),peptic ulcers, osteoporosis, amenorrhea, immune suppression |
Dexamethasone Suppression Test on Cortisol Normal ACTH pituitary tumor Ectopic ACTH producing tumor Cortisol producing tumor | Low dose High Dose Suppressed Suppressed Remains ↑ Suppressed Remains ↑ Remains ↑ Remains ↑ Remains ↑ |
Primary Hyperaldosteronism Causes Presentation Distribution Treatment | Adrenal hyperplasia or aldosterone secreting adrenal adenoma (Conn's Syndrome) |
Secondary Hyperaldosteronism Pathophysiology Underlying Causes Associated with... Treatment | Renal perception of low intravascular volume --> overactive Rennin-Angiotensin system |
Addison's Disease What is it? Pathophysiology Presentation Diseases that can lead to it | "Adrenal Atrophy and Absence of hormones from All 3 cortical layers" |
Why is skin hyper-pigmented in Addison's disease? | MSH, a byproduct of ACTH production from POMC, is elevated |
How is Primary adrenal insufficiency different from Secondary adrenal insufficiency | Secondary is from ↓ pituitary ACTH. No skin hyper-pigmentation and no hyperK |
Waterhouse-Friderichsen Syndrome | Acute Primary adrenal insufficiency |
Pheochromocytoma Arise from Most tumors secrete Findings Associated with what other diseases? | Arise from chromaffin cells (neural crest cells) |
Treatment of Pheochromocytoma | Tumor surgically removed only after effective α and β blockade is achieved |
Symptoms of episodic HTN | Pressure (elevated BP) Pain (headache) Perspiration Palpitations (tachycardia) Pallor |
Rule of 10 with Pheochromocytoma | 10% malignant 10% bilateral 10% extra-adrenal 10% calcify 10% kids |
Path of DA, NE and Epi synthesis | Phenylalanine --> Tyrosine --> L DOPA --> DA --> NE --> Epi |
Product of DA metabolism | HVA |
Product of NE and Epi metabolism | VMA |
Neuroblastoma Frequency Location Findings Presentation Genetics | Most common tumor of adrenal medulla in children |
Hypothyroidism Temp Wt Activity GI Reflexes Myxedema Skin Hair Heart TSH TH | Cold intolerance Wt Gain with ↓ appetite Hypoactivity, lethargy, fatigue, weakness Constipation ↓ reflexes facial/periorbital myxedema Dry cool skin Coarse brittle hair Bradycardia, SOBE ↑ TSH ↓ free T4 |
Hyperthyroidism Temp Wt Activity GI Reflexes Myxedema Skin Hair Heart TSH TH | Heat intolerance Wt loss with ↑ appetite Hyperactivity Diarrhea ↑ reflexes Pretibial myxedema Warm moist skin Fine hair Chest pain, palpitations, arrhythmias, ↑ β adrenergic receptors ↓ TSH (if primary) ↑ Free or total T3 and T4 |
Hashimoto's Thyroiditis Kind of thyroidism Frequency Pathophysiology Genetics Risk Histology Physical exam Course of disease | Hypothyroidism |
Cretinism | Fetal Hypothyroidism |
Subacute Thyroiditis Name Kind of thyroidism Description Usually follows Histology Findings Course | de Quervain's Hypothyroidism Self limited Often following flu like illness Granulomatous inflammation ↑ ESR, Jaw pain, early inflammation, tender thyroid May be hyperthyroidism early in course |
Reidel's Thyroiditis | Hypothyroidism |
Toxic multinodular goiter | Hyperthyroidism |
Jod-Basedow Phenomenon | Thyrotoxicosis if a pt with iodine deficiency goiter is made iodine replete |
Graves' Disease Kind of thyroidism PathoPhys Presentation Often presents during | Hyperthyroidism |
Thyroid Storm Kind of thyroidism What is it? What does it cause? What causes it? Findings | Hyperthyroidism |
Papillary Thyroid Carcinoma Frequency Prognosis Histology Predisposing factors | Most common thyroid cancer |
Follicular Thyroid Carcinoma | Good prognosis | Uniform follicles |
Medullary Thyroid Carcinoma Source What molecules does it produce? Histology Associated with what other diseases | Parafollicular C cells |
Undifferentiated/anaplastic thyroid cancer | Older pt with very poor prognosis |
What is thyroid lymphoma associated with? | Hashimoto's Thyroiditis |
Primary Hyperparathyroidism | Usually an adenoma |
Osteitis Fibrosa Cystica | ↑ PTH --> Cystic bone spaces filled with brown fibrous tissue --> bone pain |
Secondary Hyperparathyroidism | ↓ Gut Ca absorption and ↑ Phosphate |
Renal Osteodystrophy | Bone lesion due to secondary or tertiary hyperparathyroidism due to renal disease |
Tertiary Hyperparathyroidism | Refractory (autonomous) hyperparathyroidism resulting from chronic renal disease. ↑↑PTH and ↑ Ca |
Hypoparathyroidism | Surgical excision, autoimmune, DiGeorge Syndrome | HypoCa, Tetany, Chvostek's Sign, Trousseau's Sign. |
Chvostek's Sign | Tapping of facial nerve --> contraction of facial muscles |
Trousseau's Sign in Hypoparathyroidism | Occlusion of brachial artery w/ BP cuff --> carpal spasm |
PseudoHypoparathyroidism Name Genetics PathoPhys Findings | Albright's Hereditary Osteodystrophy |
Low Ca, High PTH | Secondary Hyperparathyroidism |
Low Ca, Low PTH | Hypoparathyroidism |
High Ca, High PTH | Primary Hyperparathyroidism |
High Ca, Low PTH | PTH independent HyperCalcemia |
Most common pituitary adenoma | Prolactinoma |
Prolactinoma | Amenorrhea, Galactorrhea, Low Libido, Infertility DA agonist (bromocriptine or cabergoline) |
Common presentation of pituitary adenoma | Bitemporal hemianopia from impingement on optic chiasm |
Acromegaly | Excess GH in adults |
Acromegaly | ↑ serum IGF1; Failure to suppress serum GH following oral glucose tolerance test; Pituitary mass on MRI |
Diabetes Insipidus | Central: Lack of ADH (pituitary tumor, trauma, surgery, histiocytosis x) |
Diabetes Insipidus | Urine specific gravity < 1.006; Serum osmolality > 290 |
SIADH Characteristics Normal body response Dangerous complication Possible causes Treatment | Excess water retention, Low Na, Urine osmolarity > serum osmolarity |
Hypopituitarism | Nonsecreting pituitary adenoma, craniopharyngioma Sheehan's Syndrome Empty Sella Syndrome Brain injury, hemorrhage Radiation Treat with substitution therapy |
Sheehan's Syndrome | Postpartum ischemic infarct of pituitary. Usually presents with failure to lactate |
Empty Sella Syndrome | Atrophy or compression of the pituitary. Often idiopathic. Common in obese women |
Acute manifestations of Diabetes Mellitus | Polydipsia, Polyuria, Polyphagia, Wt loss, DKA (type1), HHS (type2), Unopposed secretion of GH and Epi (exacerbate hyperglycemia) |
Reason for coma and death in DM? | Dehydration and Acidosis |
Chronic manifestations of DM? | Nonenzymatic glycosylation and Osmotic damage |
Nonenzymatic Glycosylation in DM | Small Vessels: diffuse thickening of basement membrane --> retinopathy (hemorrhage, exudates, microaneurysm, vessel proliferation), glaucoma, nephropathy (nodular sclerosis, progressive proteinuria, chronic renal failure, arteriosclerosis leading to HTN, Kimmelstiel Wilson nodules) |
Osmotic Damage in DM | Sorbitol accumulation in organs with aldose reductase |
Tests for DM | Fasting serum glucose |
DM1 Defect Insulin in treatment Age Obesity Genetics HLA Glucose intolerance Insulin sensitivity Ketoacidosis β cell # Serum insulin level Classic symptoms Histology | Autoimmune destruction of β cells Insulin always used Pt <30 Not obese Weak genetic connection HLA DR3 and DR4 Severe glucose intolerance High insulin sensitivity Ketoacidosis common β cell # ↓ Serum insulin ↓ Classic symptoms common Islet leukocytic infiltration |
DM2 Defect Insulin in treatment Age Obesity Genetics HLA Glucose intolerance Insulin sensitivity Ketoacidosis β cell # Serum insulin level Classic symptoms Histology | Insulin resistance with progressive β cell failure Insulin sometimes used Pt >40 Obese Strong genetic connections No HLA Mild to moderate glucose intolerance Low insulin sensitivity Rare ketoacidosis β cell # variable w/ amyloid deposits Variable insulin levels Classic symptoms occur sometimes Islet amyloid deposits |
Diabetic Ketoacidosis | DM1 |
DKA | Kussmaul Respirations, nausea, vomiting, abdominal pain psychosis/delirium, dehydration, fruity breath odor (acetone) |
DKA | Mucormycosis, Rhizopus infection, cerebral edema, cardiac arrhythmias, heart failure |
Carcinoid Syndrome | Appendix |
MEN1 | Wermer's Syndrome |
MEN2A | Sipple's Syndrome |
MEN2B | "Triangle" |
Genetics of MEN syndromes | Autosomal dominant | 2A and 2B associated with ret gene mutation |
Treatment for DM1 | Low sugar diet + insulin replacement |
Treatment for DM2 | dietary modification, exercise for wt loss, oral hypoglycemics, insulin replacement |
Insulin Replacement Drugs | Lispro (rapid) Aspart (rapid) Glulisine (rapid) Regular (short) NPH (intermediate) Glargine (long) Detemir (long) |
Uses of insulin replacement drugs | DM1 and DM2, gestational diabetes, hyperK, stress-induced hyperglycemia |
Toxicity of insulin replacement drugs? | Hypoglycemia, Hypersensitivity rxn |
Biguanides Names MoA Uses Tox Contraindications | Metformin ↓ gluconeogensis, ↑ glycolysis, ↑ peripheral glucose uptake (insulin sensitivity) First line DM2. Can be used in pts without islet function GI upset, lactic acidosis Contraindicated in renal failure |
First generation sulfonylureas | Tolbutamide, Chlorpropamide |
Second generation sulfonylureas | Glyburide, Glimepiride, Glipizide |
Sulfonylureas | Close K channels in β cells --> insulin release |
Glitazones/Thiazolidinediones Names MoA Use Tox | Pioglitazone, Rosiglitazone |
α glucosidase inhibitors Names MoA Use Tox | α glucosidase inhibitors Names MoA Use Tox |
Amylin analogs Names MoA Use Tox | Pramlintide ↓ glucagon DM 1 and 2 Hypoglycemia, nausea, diarrhea |
Pramlintide | Exenatide, Liraglutide |
DPP4 inhibitors Names MoA Use Tox | Linagliptin, Saxagliptin, Sitagliptin |
Levothyroxine, Triiodothyronine | Thyroxine replacement |
Use of GH as a medicine | GH deficiency and Turners Syndrome |
Uses of octreotide | Acromegaly, Carcinoid, Gastrinoma, Glucagonoma, Esophageal varices |
Uses of Oxytocin | Stimulates labor, uterine contraction, milk let-down. Controls uterine hemorrhage |
Uses of Desmopressin | Central DI |
Demeclocycline Class of drugs MoA Use Tox | Tetracycline ADH antagonist SIADH Nephrogenic DI, Photosensitivity, abnormalities or bone and teeth |
Glucocorticoids Names MoA Use Tox | Hydrocortisone, Prednisone, Triamcinolone, Dexamethasone, Beclomethasone ↓ production of leukotrienes and prostaglandins by inhibiting PLA2 and expression of COX2 Addison's disease, Inflammation, Immune suppression, Asthma Cushing's syndrome, Peptic ulcers, Adrenocortical atrophy. Adrenal insufficiency if stopped abruptly |