Endocrine Flashcards
Causes of decreased Mg
Diarrhea, Aminoglycosides, Diuretics, Alcohol abuse
Control of blood flow to parathyroids?
Cervical sympathetic ganglia control blood flow to parathyroids
How does PTH activate osteoclasts?
PTH binds osteoblasts and causes increased production of macrophage colony stimulating factor and RANK-L –> RANK-L binds RANK receptor on osteoclasts to stimulate them and increase Ca
Where are parafollicular cells derived from?
Neural crest
Which endocrine hormones signal through cAMP?
FLATChAMP
FSH, LH, ACTH, TSH, CRH, hCG, ADH (V2), MSH, PTH, Calcitonin, GHRH, Glucagon
Which endocrine hormones signal through cGMP?
Vasodilators
ANP, BNP, NO (EDRF)
Which endocrine hormones signal through IP3?
GOAT HAG
GnRH, Oxytocin, ADH (V1), TRH, Histamine (H1), Angiotensin II, Gastrin
Which endocrine hormones signal through intracellular receptors? VETTT CAP
Vitamin D, Estrogen, Testosterone, T3/T4, Cortisol, Aldosterone, Progesterone
Which endocrine hormones signal though intrinsic tyrosine kinase?
Insulin, IGF-1, FGF, PDFG, EGF (think growth factors)
Which endocrine hormones signal through receptor-associated tyrosine kinase?
PIGG(L)ET
Prolactin, Immunomodulators (IL-2, IL-6, IFN), GH, G-CSF, Erythropoietin, Thrombopoietin
Functions of T3 hormone (4 B’s)
Brain maturation
Bone growth (synergism with GH)
B-adrenergic effects (increased B1 receptors in heart = CO, HR, SV, contractility)
Basal metabolic rate increases (via increased Na/K ATPase activity –> increases O2 consumption, RR, body temp)
Mechanism of Propylthiouracil
Mechanism of Methimazole
Propylthiouracil inhibits peroxidase (oxidation and organification of iodide, coupling of MIT and DIT) and 5-deiodinase (converts T3 to T4)
Methimazole inhibits peroxidase only
What is the Wolff-Chaikoff effect?
Excess iodine temporarily inhibits thyroid peroxidase –> decreases iodine organification and T3/T4 production
-The reason Iodine can be used to treat hyperthyroidism
What is metyrapone stimulation used for?
Metyrapone blocks the last step of cortisol synthesis (11 deoxycortisol –> cortisol)
Normal response is a decrease in cortisol and compensatory increase in ACTH but in adrenal insufficiency ACTH remains decreased after test
What do you see in urine of patient with neuroblastoma?
Homovanillic acid (HVA) - breakdown product of dopamine Vainllylmandelic acid (VMA) - breakdown product of NE
Stains for neuroblastoma
Bombesin and neuron-specific enolase positive
EPO secreting tumors
Renal cell carcinoma
Hepatocellular carcinoma
Pheochromocytoma
Hemangioblastoma
Rule of 10s for pheochromocytoma
10% malignant 10% bilateral 10% extra-renal (bladder wall) 10% calcify 10% kids
Associations of pheochromocytoma
Neurofibromatosis type 1
Von Hippel Lindau
MEN 2A and 2B
Urine of patient with Pheochromocytoma
Increased catecholamines and metanephrines in urine and plasma (vanillylmandelic acid)
Treatment for pheochromocytoma
IRREVERSIBLE alpha antagonist - Phenoxybenzamine followed by beta blocker prior to tumor resection
Increased CK from myopathy (w/o myoedema)
Hypothyroidism
Lab findings in hypothyroidism
Increased TSH
Decreased free T3 and T4
Hypercholesterolemia (from decreased LDL receptor expression)
Granulomatous inflammation of thyroid
Subacute thyroiditis (de Quervain)
Tender thyroid
Subacute thyroiditis (de Quervain)
Thyroid replaced by fibrous tissue
Riedel thyroiditis
IgG4 related systemic disease manifestations
Autoimmune pancreatitis
Retroperitoneal fibrosis
Non-infectious atrocities
Riedel thyroiditis
Rock like painless goiter
Riedel thyroiditis
Treatment for Thyroid storm
Propranolol
Propylthiouracil
Prednisolone
Ovarian tumor that presents as hyperthyroidism
Struma ovarii teratoma
How do beta blockers treat thyrotoxicosis?
Decreased peripheral conversion of T4 –> T3 by inhibiting iodithyronine deiodinase and block beta adrenergic receptors –> decrease HR and agitation
Complications of thyroid surgery
Hoarseness (recurrent laryngeal nerve damaged)
Hypocalcemia (removal of parathyroid glands)
Transection of recurrent and superior laryngeal nerves (during ligation of inferior thyroid artery and superior laryngeal artery)
Large cells with overlapping nuclei containing finely dispersed chromatin (empty nuclei with central clearing)
Orphan annie nuclei
Orphan annie nuclei and psammoma bodies
Papillary carcinoma of thyroid
Difference between follicular adenoma and follicular carcinoma
Carcinoma invades thyroid capsule
FNA can’t distinguish
Tumor that produces Calcitonin
Medullary carcinoma of thyroid
How does medullary carcinoma of thyroid spread?
Hematogenous spread
Cancer associated with Hashimoto thyroiditis
Lymphoma (rapidly enlarging neck mass)
Albright hereditary osteodystrophy
Pseudohypoparathyroidism = unresponsiveness of kidney to PTH
Hypocalcemia, shortened 4th/5th digits, short stature
PTH levels are high
Familial hypocalciuric hypercalcemia
Defective Ca sensing receptor on parathyroid cells
PTH cannot be suppressed by increased Ca level –> mild hypercalcemia with normal to increased PTH levels
Calcium levels in acute pancreatitis
Hypocalcemia - Ca precipitates out of abdomen
Lab findings in primary hyperparathyroidism
Increased PTH Hypercalcemia Hypercalciuria Hypophosphatemia Increased ALP (sign of osteoblast activity) Increased cAMP in urine
Chronic renal failure labs
Hypocalcemia
Hyperphosphatemia (can’t excrete it)
Increased PTH
Lamellar bone structure resembling mosaic pattern
Pagets
Osteoid matrix accumulation around trabeculae
Vit D deficiency
Spongiosa filling medullary canals with no mature trabeculae
Osteopetrosis
Trabecular thinning with few connections
Osteoporosis
Treatment for prolactinoma
(Dopamine agonists)
Bromocriptine
Cabergoline
GH effects on glucose
GH decreases glucose uptake
Can cause secondary diabetes
Most common cause of death in Acromegaly
Heart failure
Treatment for Acromegaly
Removal of pituitary adenoma
Octreotide (somatostatin analog)
Pegvisomant (growth hormone receptor antagonist)
Diagnosis of Diabetes Insipidus
Urine specific gravity 290 mOsm/kg
Hyperosomotic volume contraction
Treatment of Central DI
Intranasal desmopressin acetate
Hydration
Treatment of Nephrogenic DI
HCTZ, Indomethacin, Amiloride
Hydration
How does body respond to water retention in SIADH?
Body responds with decreased aldosterone (hyponatremia) to maintain near-normal volume status
Causes of SIADH
Trauma to head/CNS disorders
Ectopic ADH (small cell lung cancer)
Pulmonary disease
Drugs (Cyclophosphamide)
Treatment of SIADH
Fluid restriction IV hypertonic saline Conivaptan - ADH antagonist Tolvaptan - ADH antagonist Demeclocycline - ADH antagonist
What is pituitary apoplexy?
Sudden hemorrhage of pituitary gland - often in presence of existing pituitary adenoma
Secondary diabetes
Due to unopposed secretion of GH and epinephrine
Complications of diabetes mellitus
- Nonenzymatic glycation: a. small vessel disease causes retinopathy, glaucoma, neuropathy, nephropathy and b. large vessel disease atherosclerosis, CAD, peripheral vascular occlusive disease, gangrene
- Osmotic damage: sorbitol accumulation in organs with aldose reductase and absent orbital dehydrogenase –> neuropathy and cataracts
What is Kussmaul breathing?
The body’s way of compensation for metabolic acidosis; trying to breathe off CO2 - happens in Diabetic ketoacidosis; rapid deep breathing
Why is there hyperkalemia in DKA?
H+/K+ exchanger is trying to pull H+ into cells because of metabolic acidosis –> then Kidney compensates and gets rid of K+ so total body K+ will be low
Why does hyperosmolar coma happen in type 2 DM instead of DKA?
There is some insulin in Type 2 so the insulin prevent lipolysis, B oxidation and ketone production
a. Histology of Type 1 DM
b. Histology of Type 2 DM
a. Islet leukocytic infiltrate
b. Islet amyloid polypeptide (IAPP) deposits
Precipitating factors of DKA
Increased insulin requirements due to stress (infection)
Complications of DKA
Mucormycosis
Cerebral edema
Cardiac arrhythmias
Heart failure
Dermatitis, Diabetes, DVT, Depression and Anemia
Glucagonoma
Treatment of hypoglycemia
In medical setting - IV glucose
In emergency non-medical setting - IM glucagon
Necrolytic Migratory Erythema
Seen in Glucagonoma
Erythematous papules, plaques on face/perineum/extremities
Lesions enlarge and coalesce leaving a bronze colored, central indurated area with blistering/scaling
5-Hydroxyindoleacetic acid (5-HIAA) in urine
Carcinoid syndrome
MEN 1
Parathyroid tumors (100%) Pituitary tumors (prolactin or GH) Pancreatic endocrine tumors (ZE, insulinoma, VIPomas, glucagonomas)
MEN 2A
Parathyroid hyperplasia (20%)
Pheochromocytoma (45%)
Medullary thyroid carcinoma (secretes calcitonin)
Associated with marfanoid habitus (mutation in RET gene)
MEN 2B
Pheochromocytoma
Medullary thyroid carcinoma
Oral/intestinal ganglioneuromatosis (Mucosal neuromas)
Associated with Marfanoid habits (mutation in RET gene)
Septicemia, DIC, adrenal hemorrhage, petechial rash
Waterhouse-Friderichsen syndrome from N. meningitidis
Derivatives of neural crest cells
Chromatin cells Parafollicular cells of thyroid Schwann cells Autonomic nervous system Dorsal root and celiac ganglia Melanocytes Cranial nerves Pia and arachnoid Odontoblasts Skull bones Aorticopulmonary septum
N-myc oncogene overexpression and homer-wright rosettes
Neuroblastoma
Drugs that cause hypothyroidism
Lithium - inhibits uptake and organification of iodine by thyroid gland and inhibits peripheral conversion of T4 to T3
Amiodarone
Plasma antimicrosomal (antiperoxidase) antibodies and lymphocytic infiltrate
Hashimoto’s thyroiditis
Gestational diabetes predisposes newborns to what?
Macrosomia
Hypoglycemia
Respiratory distress syndrome (Insulin inhibits surfactant synthesis)
What is Whipple’s triad?
Hypoglycemia
Symptoms that are attributed to hypoglycemia
Resolution of symptoms with eating
