Endocrine Flashcards
17-alpha hydroxylase deficiency
- Boys - ambiguous genitalia (phenotypically female), undescended testes
- Girls - lacks secondary sexual development
- High: MINERALOCORTICOIDS, blood pressure
- Low: cortisol, sex hormones, [K+]
- Labs: low androstenedione
21-hydroxylase deficiency
- Boys: salt wasting in infancy, precocious puberty in childhood
- Girls: virilization (clitoromegaly)
Most common CAH
Needed for MC and GC production (instead ACTH is shunted to sex hormones)
- High: sex hormones, [K+]
- Low: cortisol, mineralocorticoids, BP
- Labs: increased renin activity, increased 17-hydroxy-progesterone
11-beta-hydroxylase deficiency
- Boys: ?
- Girls: virilization
Low aldosterone, but high 11-deoxycorticosterone –> elevated BP
- High: sex hormones, BP
- Low: cortisol, [K+]
- Labs: decreased renin activity
Cortisol upregulates what R?
Alpha1 on arterioles –> increased sensitivity to NE and Epi –> elevated BP
Thyroid hormones up-regulate what R?
Beta1 on heart –> increased CO, HR, SV, and contractility
- Also increase Na+/K+ ATPase –> increased O2 consumption, RR, body temp –> increased basal metabolic rate
5’-deiodinase
Converts T3 to T4 in peripheral tissue
- Inhibited by PTU but NOT methimazole
Thyroid Peroxidase
- Oxidation and organification of iodide
- Couples monoiodotyrosine to di-iodotyrosine
- Inhibited by PTU and methimazole
Metyrapone Stimulation
- Adrenal insufficiency
Blocks 11-deoxycortisol –> cortisol (last step of cortisol synthesis)
- Normal: decreased cortisol, compensatory increase in ACTH and 11-deoxycortisol
- Primary adrenal insufficiency: ACTH increases, but 11-deoxycortisol remains decreased after test
- Secondary adrenal insufficiency: both ACTH and 11-deoxycortisol remain decreased after test
Waterhouse-Friderichsen Syndrome
- Septicemia, DIC, endotoxic shock
- Primary adrenal insufficiency due to adrenal hemorrhage
- NEISSERIA MENINGITIDIS
Conn Syndrome
- HTN, metabolic alkalosis, no edema
- Adrenal adenoma –> primary hyperaldosteronism
- Increased aldosterone, decreased renin (negative feedback)
How can fibromuscular dysplasia and atherosclerosis cause hyperaldosteronism?
- Activate JGA –> increased renin –> increased aldosterone
Neuroblastoma
- Kids - abdominal distension, firm/irregular mass that can cross the midline (vs. Wilms tumor)
- Opsoclonus-myoclonus syndrome (“dancing eyes-dancing feet”)
- Most common tumor of adrenal medulla in children
- Originates from neural crest cells
- Increased HVA and VMA in urine
- Homer Wright rosettes
- Bombesin and NSE +
- N-myc oncogene overexpressed
- APUD tumor
Hashimoto Thyroiditis
- Hypothyroidism
- Ab: antithyroid peroxidase (antimicrosomal), antithryoglobulin
- HLA-DR5
- Increased risk of non-hodgkin lymphoma
- Histo: Hurthle cells, lymphoid aggregates w/ germinal centers
Congenital Hypothyroidism (Cretinism) - Neonates/infants
Pot-bellied, pale, puffy-faced child with protruding umbilicus, protuberant tongue, and poor-brain development
- Short stature and skeletal abnormalities due to decreased growth hormone
Subacute Granulomatous Thyroiditis (de Quervain)
- Hypothyroid
- Follows viral infection
- Histo: granulomatous inflammation (macs and giant cell)
TENDER THYROID
Riedel Thyroiditis
- Hypothyroid
- Thryoid replaced w/ fibrous tissue w/ inflammatory infiltrate
- Mimics anaplastic carcinoma
- IgG4-related systemic disease
- Hard, rock-like painless goiter
Graves Disease
- Hyperthyroid
Ab: thyroid-stimulating Ig (IgG, type II HSN)
- Dermal fibroblasts –> pretibial myxedema
- T cells –> increase CKs (TNF-alpha, IFN-gamma) –> increased fibroblast secretion of hydrophilic GAGs –> exophthalmos
- Histo: tall, crowded follicular epi cells, SCALLOPED COLLOID
- Rx: beta blockers, thiomide (blocks peroxidase), radioiodine ablation, prednisone for severe opthalmopathy
Treatment of thyroid storm
Beta blockers (propanolol), PTU, corticosteroids (prednisolone), potassium iodide
Wolff-Chaikoff Effect
Excess iodine temporarily inhibits thyroid peroxidase –> decreased iodine organification –> decreased thyroid hormone
Jod-Basedow Phenomenon
Patient w/ iodine deficiency and partially autonomous thyroid tissue is given iodine –> thyrotoxicosis
- Opposite of Wolff-Chaikoff effect
What nerve runs with inferior thyroid artery?
Recurrent laryngeal nerve
- Risk of injury during thyroidectomy –> hoarseness
What nerve runs with superior artery?
Superior laryngeal nerve –> cricothyroid muscle
Papillary Carcinoma (Thyroid) - Most common, excellent prognosis
- Orphan Annie nuclei, psammoma bodies, nuclear grooves
- Increased risk with RET and BRAF mutations and childhood irradiation
Follicular Carcinoma (Thryoid) - Good prognosis
- Invades thyroid capsule and vasculature (vs. follicular adenoma)
- Uniform follicles
- Hematogenous spread
- RAS mutation
Medullary Carcinoma (Thyroid)
- Parafollicular “C” cells
- Neuroendocrine
- Produces calcitonin –> diarrhea, flushing
- Sheets of cells in AMYLOID STROMA (Congo red)
- Associated with MEN2A and MEN2B (RET)
Anaplastic Carcinoma (Thyroid) - Very poor prognosis, older patients
- invades local structures –> dysphagia, respiratory compromise
Thyroid Lymphoma
Associated with Hash thyroiditis
Chvostek and Trousseau sign?
- HYPOPARATHYROIDISM
- Hypocalcemia
- Chvostek –> facial nerve
- Trousseau –> BP cuff
Pseudohypoparathyroidism Type 1A (Albright hereditary osteodystrophy)
- Shortened 4th/5th digit, short stature
- Unresponsiveness of kidney to PTH –> hypocalcemia despite increased PTH levels
- AD –> defective Gs protein alpha subunit –> end-organ resistance to PTH
- Must be inherited from mother (imprinting)
Pseudopseduohypoparathyroidism
- Findings of Albright hereditary osteodystrophy but without end-organ PTH resistance
- Defective Gs protein alpha subunit is inherited from father
Familial Hypocalciuric Hypercalcemia
Defective Ca2+ sensing receptor in multiple tissues
- Excessive renal Ca2+ reuptake –> mild hypercalcemia with hypocalciuria with normal/elevated PTH levels
Sheehan Syndrome
- Postpartum failure to lactate, absent menstruation, cold intolerance, loss of pubic hair
- Ischemic infarct of pituitary following postpartum bleeding (pituitary is much larger during pregnancy but there is no increase in blood flow –> increased susceptibility to hypoperfusion)
Empty Sella Syndrome
- Idiopathic, obese women
Atrophy or compression of pituitary
Pituitary Apoplexy
- Sudden onset severe HA, visual impairment (bitemporal hemianopia, diplopia due to CN III palsy), features of hypopituitarism
- Sudden hemorrhage of pituitary gland –> compresses normal tissue
- Often in presence of existing pituitary adenoma
Type 1 DM Antibodies
Glutamic acid decarboxylase antibodies
Most common cause of death in DM
MI
Nodules seen in diabetic nephron
Kimmelstiel-Wilson Nodules
Type 1 DM HLA
HLA-DR3 and DR4
Histology of T1DM vs. T2DM
T1DM: islet leukocytic infiltrate
T2DM: islet amyloid polypeptide deposits
Deadly infection in DKA?
Mucormycosis (Thizopus)
Treatment for DKA?
- IV fluids –> sugar in urine is diuretic (dehydrated)
- IV insulin
- K+ –> lost lots of K+ in urine (even though labs show hyper K+, plus insulin drives K+ into cells)
- Glucose if necessary
Hyperosmolar Hyperglycemia Nonketotic Syndrome
- Thirst, polyuria, lethargy, focal neuro defects (seizures), can progress to coma and death
- elderly T2 diabetic w/ limited ability to drink
- Profound hyperglycemia-induced dehydration (osmotic diuresis)
- Labs: hyperglycemia, increased serum osmolarity, no acidosis, no ketones
- Rx: aggressive IV fluids, insulin therapy
Presentation of glucagonoma?
- Dermatitis (necrolytic migratory erythema)
- Diabetes (hyperglycemia)
- DVT
- Declining weight
- Depression
Rx: octreotide, surgery
Presentation of insulinoma?
- Whipple triad: hypoglycemia, sx of hypoglycemia (lethargy, syncope, diplopia), and resolution of sx after normalization of glucose levels
- Labs: decreased blood glucose, increased C-peptide
- MEN1 syndrome
Presentation of somatostatinoma?
- Diabetes/glucose intolerance, steatorrhea, gallstones due to decreased secretion of secretin, CCK, glucagon, insulin, gastrin
Presentation of carcinoid syndrome?
- Recurrent diarrhea, cutaneous flushing, asthmatic wheezing, R-sided valvular heart DZ, pellagra (niacin deficiency), 5-HIAA in urine
- Only seen if tumor has spread out of GI tract
- ROSETTES
- Serotonin
Presentation of gastrinoma?
Abdominal pain (PUD), diarrhea (malabsorption)
- Gastrin levels remain elevated after administration of secretin
- MEN1
Presentation of VIPoma?
Watery diarrhea, hypokalemia, achlorhydria
MEN1
Pituitary adenoma, pancreatic endocrine tumor, parathyroid adenoma
- MEN1 (menin) - tumor suppressor, Chr 11
MEN2A
- MEDULLARY THYROID CARCINOMA (amyloid on bx, prophylactic thyroidectomy), pheochromocytoma, parathyroid hyperplasia (hypercalcemia)
- RET (RTK in cells of neural crest origin)
MEN2B
Medullary thyroid cancer, pheochromocytoma, MUCOSAL NEUROMAS, MARFINOID HABITUS
- RET (oncogene)
