endocrine, diabetes, metabolism Flashcards
what is the single most effective preventative measure in almost all patients, especially those with diabetes
smoking cesation
how will free and total T4 levels and TSH levels be altered in primary hypothyroidism
low free and total T4 and increased TSH
how will free and total T4 levels and TSH levels be altered in thyroid hormone resistance
high TSH and T4
how will free and total T4 levels and TSH levels be altered in central hypothyroidism
low TSH and T4
in transient hypothyroidism during pregnancy, how are free and total T4 levels and TSH levels affected
decreased free and total T4 and increased TSH
if a new born presents with elevated serum TSH and decreased T4, and a normal size and normally located thyroid, what is the likely diagnosis
thyroid gland resistance to TSH
TSH is normally produced where?
anterior pituitary gland
name the 3 layers of the cortex of the adrenal gland starting most outward to inward
zona glomerulosa
zona fasciculata
zona reticularis
what do the cells in the zona glomerulosa secrete
mineral corticoids, primarily aldosterone
what do cells in the zona fasciculata secrete
glucocorticoid hormones, primarily cortisol
what do cells in the zona reticularis secrete
androgens
the adrenal medulla is sharply demarcated from the cortex and is composed of _____ cells with a deeply basophilic cytoplasm
chromaffin
chromaffin cells are modified neuroendocrine cells derived from ____
neural crest
chromaffin cells are stimulated by ______
acetylcholine
chromaffin cells are stimulated by acetylcholine released by sympathetic preganglionic neurons and secrete _____
catecholamines (80% epinephrine, 20% norepinephrine)
the superior thyroid artery and vein and what nerve travel together in a neurovascular triad that originates superior to the thyroid gland and lateral to the thyroid cartilage
external branch of the superior laryngeal nerve
injury to the external branch of the superior laryngeal nerve during a thyroidectomy may result in what symptoms due to loss of function of what muscle
low, hoarse voice with limited range pitch
cricothyroid muscle
raloxifene MOA
selective estrogen receptor modulator
tamoxifen MOA
selective estrogen receptor modulator
what are adverse effects associated with selective estrogen receptor modulators
hot flashes
venous thromboembolism
endometrial hyperplasia and carcinoma (tamoxifen only)
where is epinephrine primarily produced
adrenal medulla
what is the rate limiting step in catecholamine synthesis
conversion of tyrosine to dihydroxyphenylalanine (DOPA) by tyrosine hydroxylase
in the adrenal medulla, norepinephrine is quickly converted to epinephrine via what enzyme
phenylethanolamine-N-methyltransferase (PNMT)
PNMT expression in the adrenal medulla is upregulated by what?
cortisol
following pituitary resection, the loss of ____ results in decreased synthesis of cortisol in the adrenal cortex which results in decreased ______ activity leading to low conversion of norepinephrine to epinephrine
ACTH
PNMT
medullary carcinoma, a primary thyroid carcinoma, is derived from what cell type
parafollicular calcitonin-secreting C cells
what is the most common type of primary thyroid carcinoma
papillary
_____ carcinoma cells are characteristically large with overlapping nuclei containing finely dispersed chromatin, giving them an empty or ground glass appearance (Orphan Annie eye nucleus). numerous intranuclear inclusions and grooves may be found. Psammoma bodies may be found within the tumor.
papillary
a majority of T4 is bound to ____
thyroxine binding globulin (TBG)
to patients with congenital thyroxine binding globulin deficiency require treatment
no
total T4 is low because decreased fraction of bound T4 but feedback on the thyroid still functions properly to keep free T4 levels constant
what presents as painful thyroid enlargement with transient hyperthyroid symptoms following the onset of a viral illness
subacute granulomatous thyroiditis
what are diagnostic tests with subacute granulomatous thyroiditis
elevated ESR & CRP
decreased radioiodine uptake
pathology of subacute granulomatous thyroiditis shows inflammatory infiltrate with ____ and ___ cells
macrophage
giant cells
what condition is an autoimmune condition that causes painless thyroid enlargement and presents with predominantly hypothyroid features
Hashimoto thyroiditis
pathology of Hashimoto thyroiditis shows lymphocytic infiltrate with well-developed _____ and ____ cells (eosinophilic epithelial cells)
germinal centers
Hurthle
what is the Whipple triad
symptoms consistent with hypoglycemia (tremor, diaphoresis, confusion)
low blood glucose level
relief of symptoms when glucose is administered
nocturnal back pain, spinal tenderness, and indurated prostate suggests what diagnosis
prostate adenocarcinoma with bony metastases
leuprolide MOA
GnRH analog ( treats prostate cancer)
what are androgen levels in a patient starting leuprolide
transiently elevated (GnRH analog) then decrease as it leads to downregulation of GnRH receptors
in a patient with an insulin deficiency, how can glucose be formed in the liver
triglycerides in adipose tissue is degraded and produces glycerol which can be converted to glucose in gluconeogenesis via glycerol kinase
How does testosterone use alter serum LH
Decreases serum LH
How does testosterone use alter serum estrogen
Increases
How does testosterone use aler spermatogenesis
Decreases spermatogenesis
Spermatogenesis is driven by what hormone
FSH
Testosterone is produced by ____ cells in the testes
Leydig cells
Excess testosterone is converted by aromatase to ____
Estradiol
The thyroid gland is formed from evagination of the ____
Pharyngeal epithelium
The thryoid gland descends to the lower neck. Failure of migration can cause the thyroid to reside anywhere along the _________’s usual path
Thyroglossal duct
The thyroglossal duct extends from the ____ on the dorsal surface of the tongue to the superior border of the thyroid isthmus
Foramen cecum
Primary adrenal insufficieny is also called what
Addison disease
In Addison disease, how is serum sodium and urine sodium altered
Decreases
Increased
(Decreased aldosterone –> renal salt wastin)
In Addison disease, how is serum and urine potassium effected?
Increased
Decreased
(In renal collecting duct principal cells, decreased aldosterone –> increased potassium absorption)
Low cortisol levels in Addison disease stimulates increased _____ which leads to water retention and hyponatremia
ADH
Paraneoplastic hypercortisolim, most commnly caused by small cell lung cancer, is due to ectopic ____ secretion
ACTH
What common feature of Cushing syndrome is uncommon in paraneoplastic hypercortisolism
Central obesity
Hyperthyroidism causes upregulation of ________ leadng to increased catecholamine effect
Beta adrenergic receptor expression
Beta blockers are used to blunt adrenergic manifesttions of hyperthyroidism as wll as reduce _______ activity in peripheral tissues
5’-monodeiodinase
Familial chylomicronemia syndrome(type I hyperlipoproteinemia) is due to a defect in what protein(s)
Lipoprotein lipase
ApoC-2
What lipoproteins are elevated in familial chylomicrnoemia syndrome (type I hyperlipoproteinemia)
Chylomicrons
What are the major manifestations offamilial chylomicronemia syndrome (type I hyperlipoproteinemia)
Acute pancreatitis
Lipemia retinalis
Eruptive xanthomas
What proteins are defected ini familial hypercholesterolemia (type II A hyperlipoproteinemia)
LDL receptor
ApoB-100
What lipoproteins are elevated in familial hypercholesterolemia (type II A hyperlipoproteinemia)
LDL
What are the major manifestations of familial hypercholesterolemia (type II A hyperlipoproteinemia)
Premature atherosclerosis
Tendon xanthomas
Xanthelasmas
What proteins are defected in familial dysbetalipoproteinemia (type III hyperlipoproteinemia)
ApoE
What lipoproteins are elevated in familial dysbetalipoproteinemia (type III hyperlipoproteinemia)
Chylomicron
VLDL remanants
What are the major manifestations of familial dysbetalipoproteinemia (type III hyperlipoproteinemia)
Premature aterosclerosis
Tuboeruptive and palmar xanthomas
What protein is defective in familial hypertriglyceridemia (type IV hyperlipoproteinemia)
Polygenic
What lipoproteins are elevated in familial hypertriglyceridemia (type IV hyperlipoproteinemia)
VLDL
What are the clinical manifestations of familial hypertriglyceridemia (type IV hyperlipoproteinemia)
Associated with coronary disease, pancreatitis, and diabetes
Where are ApoE3 and ApoE4 found
On chylomicrons and VLDLs
ApoE3 and ApoE4 function
Bind hepativ apolipoprotein receptors (allow liver to remove chylomicrons and VLDLs from circulation)
How is hyperprolactinemia treated (ex. Prolactinoma)
Dopamine agonist (cabergoline, bromocriptine)
Diabetes insipidus is due to impaired activity of what hormone
ADH
Injection of exogenous ADH can help distinguish between central and nephrogenic diabetes insipidus. Which will have an increase in urine osmolality
Central diabetes insipidus
_____ injury results in dath of magnocellular neurons, causing permanent central diabetes insipidus
Hypothalamic
Damage to ___ causes transient diabetes insipidus because the cell bodies of the magnocellular neurona remain intact
More distal portions of the hypothalamic hypophyseal tract (below the infundibulum)
what may present months after birth with an enlarged fontanelle, lethargy, poor feeding, protruding tongue, puffy face, umbilical hernia, and constipation
congenital hypothyroidism
ADH administration substantially increases urine osmolality in patients with ____ diabetes insipidus (central or nephrogenic)
Central
Permanant central DI is due to injury where? while transient central diabetes insipidus is due to damage where?
Permanent: hypothalamic injury –> death of magnocellular neurons
Transient: distal portions of hypothalamic-hypophyseal tract (below infundibulum) –> madocellular neurons remain intact
How does hyperthyroidism caus osteoporosis
T3 stimulates osteoclast differentiation –> increased bone resorption –> release of calcium
Insulin causes activation of PFK-1 or PFK-2
PFK-2
Insulin causes activation of PFK-2 leading to increased levels of ______ which ihibits gluconeogenesis
Fructose 2,6-bisphosphate
High levels of fructose 2,6-bisphosphate inhibit gluconeogenesis leading to decreased conversion of alanine and other substrates to ____
Glucose
What is the likely diagnosis of a patient with severe hypertension, headaches, and an adrenal mass
Pheochromocytoma
Pheochromocytoma is a catecholamine-secreting tumor of ___ cells in the adrenal ____
Chromaffin
Medulla
Multiple endocrine neoplasia (MEN) type 2 is associated with germ-line mutations in the ____ gene
RET
What are the characteristics of MEN type 2
Pheochromocytomas
Medulary thyroid cancer
Either parathyroid hyperplasia (MEN 2A) or mucosal neuromas and marfanoid habitus (MEN 2B)
The chromaffin cells of the adrenal medulla re derived from ____ tissue
Neural crest
The adrenal cortex is derived from _____
Mesoderm
Medullary thryoid cancer is a malignancy of ____ cells
Parafollicular C
What are the structures arising from neural crest cells
"SOME SALTS" Schwann cells Odontoblasts Melanocytes Enterochromaffin cells Spinal membranes (pia and arachnoid) Adrenal medulla/ganglia Laryngeal cartilage Tracheal cartilage
Progressive symptoms of hypothyroidism and diffuse goiter are consistent with what diagnosis
Lymphocytic (hoshimoto)thyroiditis)
Characteristic findings of hashimoto thyroiditis biopsy
Intense mononuclear infiltrate: lymphocytes and plasma cells
Germinal centers
Hurthle cells surounding residual follicles
What are the 3 reactions carried out by thyroid peroxidase
(Thyroid peroxidase = TPO)
Oxidation of iodide
Iodination of thyroglobulin
Coupling reaction between 2 iodized tyrosine residues
Antibodies against ____ are present in >90% of patients with chronic lymphocytic (hoshimoto) thyroiditis
TPO (thyroid peroxidase)
alkaptonuria is an autosomal recessive disorder of ____ metabolism
Tyrosine
Alkapotonuriais an auto recessive disorder of tyrosine metabolism that leads to the accumulation of ______
Homogentisic acid
The build up of homogentisic acid in alkaptonuria leads to what change in urine
Black color (homogentisic acid undergoes oxidation if sits around long enough and turns black)
What physical exam findings are seen in alkaptonuria
Ochronosis (blue-black pigmentation most evident in ears, nose, cheeks)
Ochronotic artropathy
Wha hormone influences development of internal male genitalia, spermatoenesis, male sexual differentiation at puberty
Testosterone
What hormone influences the development of external male genitalia, growth of prostate, male pattern hair growth
Dihydrotestosterone (DHT)
What hormone influnces endometrial proiferation, development of ovarian granuosa cells, and breast development
Estrogen
Deficiency in what enzyme resultls in deminished conversion of testosterone to DHT in the male urogenital tract
5 alpha reductase type 2
Male pseudohermaphroditism will have what clinical features
Genitalia at birth can range from small phallus with hypospadias to ambiguous or female-type genitalia (many are raised female util reaching puberty)
Where is 5 alpha reductase type 1 found
Postpubescent skin
Where is 5 alpa reductase type 2 found
Genitals
For a patient with male pseudohermaphroditism who have a deficiency in 5alpha reductase type 2, what changes happen at peuberty?
5 alpha reductase type 1 is still functional –> male pattern muscle ass, voice deepening, penile and scrotal growth, testicular descent
Stress hyperglycemia is due to secretion of cortisol, catecholamines, glucagon, and proinflammatory cytokines increasing what metabolic processes
Glycogenolysis and gluconeogenesis in the liver
The release of proinflammatory cytokines is associated ith the increased expression of what GLUT transporter and therefore the decreased expression of what GLUT transporter
Increased GLUT1
Decreased GLUT4
Proinflammatory cytokines promote increased expression of GLUT1 and decreased expression of GLUT4 resulting in increeased glucose uptake where?
Brain
Immune cells
Ezetimibe MOA
Decrease intestinal absorption of cholesterol by inhibiting the Niemann-Pik C1-like 1 (NPC1L1) transporter
What physical exam findings can be seen in glucagonoma
Necrolytic migratory erythema
Erythematous papules/plaques on face, perineum, and extremities
Lesions enlarge and coalesce, leaving a central indurated area with peripheral blitering and scaling
Diabetes mellitus
GI symptoms
Glucagonoma arises from ____ cells
Alpha
Insulin increases or decreases pancreatic glucagon secretion?
Decreases
Insulin increases or decreases glycogen syntheis in the liver?
Increases
Insulin increases or decreases glycogenolysis in the liver?
Decreases
In diabetic keto acidosis describe the intracellular and extracellular potassium levels as either increased or decreased
Intracellular: decreased
Extracellular: normal or increased
A nonselective beta blocker will decrease neurogenic or neuroglycopenic symptoms of hypoglycemia?
Neurogenic
Neurogenic symptoms of hypoglycemia are mediated via _____ and ___ release
Norepinephrine/epinephrine
Acetylcholine
What are some neurogenic symptoms of hypoglycemia
Trmulousness Tachycardia Anxiety/arousal Sweating Hunger Paresthesias
Neuroglycopenic symptoms of hypoglycemia include what?
Behavioral changes, confusion, visual disturbances, stupor, seizure
Thiazolidinedione binds PPAR gamma to decrease insulin resistance by upregulating what 2 genes
GLUT4
Adiponectin
Fucntion of adiponectin
Increases number of insulin-responsive adipocytes
Stiulates fatty acid oxidation
(Cytokine secreted by fat tissue)
DiGeorge syndrome is due to a ______ microdeletion
22q11.2
In DiGeorge sydnrome, the neural crest fails to migrate into the derivatives of what 2 pharyngeal pouches
3 and 4
Why will patients with DiGeorge syndrome have hypocalcmia
Insuficienct parathyroid growth (arises from 3rd (inferior) and 4th (superior) pouches)
Describe Chvostek sign seen in patients with DiGeorge syndrome
Tapping on the facial nerve –> twitching of nose and lips
Describe Trousseau sign seen in patients with DiGeorge syndrome
Inflation of bloo pressure cuff –> carpal spasm
Sheehan syndrome presents with panhypopituitarism due to ______ of the pituitary gland
Ischeic necrosis
Why are women susceptible to ischemic necrosis of the pituitary gland peripartum
Estrogen levels during pregnancy –> enlargement of pituitary gland without proportional increase in blood supply (even higher risk if paeripartum hypotension occurs due to peripartym hemorrhage (low hemoglobin can indicate this))
Estrogen effects what part of the bone which results in ceasation of bone growth
Epiphyseal plate
Why might a patient with thyroid hormone resistance present with tachycardia and ADHD
Most cases are due to an inherited mutation in thyroid hormone receptor beta. Thyroid receptor alpha is found in higher level in the CNS and heart
Congenital adrenal cortical hyperplasia and elevated 17-hydroxyprogesterone and testosterone is most commonly due to a deficiency in what enzyme
21-hydroxylase
Why do girls present earlier (at birth) than boys (around age 2-4) with 21-hydroxylase deficiency
21-hydrozylase deficiency –> increased testosterone –> ambiguous genitalia for females at birth
Boys will have normal genitalia but begin early virilization (body odor, pubic hair)
Deficiency of 21-hydroxylase causes adrenal cortical hyperplasia due to excess stimulation of the adrenal cortex by _____
ACTH
Treatment of congenital adrenal hyperplasia due to 21-hydroxylase defiency can be treated by targeting the supression of what hormone in order to limit androgen over production?
Adrenocorticotropic hormone (ACTH) (Impaired cortisol synthesis --> increased ACTH release --> stimulate adrenal cortex and adrenal adrogen overproduction)
Thiomides (methimazole, propylthiouracil) MOA
Inhibit thyroid peroxidase
How can chronic adrenal insufficiency be fatal during a medical procedure?
Severe stress normally –> increased glucocorticoid
Adrenal insufficiency cannot produce more –> adrenal crisis (hypotension, shock)
In a patient with adrenal insuficiency why would skin hyperpigmentation be highly suggestive of primary adrenal insufficiency rather than secondary?
Primary adrenal insufficiency –> increased ACTH secretion
ACTH is derived from POMC (proopiomelanocortin) which is prohormone of melanocyte stimulating hormone as well, therefore increased ACTH secretion –> increased MSH secretion –> hyperpigmentation
What is the most common cause of primary adrenal insuficiency? Is it more often bilateral or unilateral?
Autoimmune adrenalitis
Bilateral
What is the main function of brown adipose tissue in humans
Heat production
Brown adipose cells contain more miochondria than white adipose cells and function to produce heat by uncoupling oxidative phosphorylation with the protein ______
Thermogenin
In a patient with hypertension, elevated triglyceride, and a an elevated fasting glucose, what is another physical characteristic that is most suggestive of increased insulin resistance?
Increased weight circumfrance (indicates high visceral fat)
This question was getting at metabolic syndrome
Glucocorticoids have what effect on hepatic gluconeogenesis? Glycogenosis?
Increase, increase
Liver enyzme expression with be increased as a result
Metformin inhibits glycerophosphate dehydrogenase and complex I in the mitochondria to reduce substrates for what metabolic process
Gluconeogenesis
Metformin upregulates AMPK in hepatocytes which inhibits what metabolic process
Lipogenesis
Gynecomastia is due to increased _____ to androgen ratio in males
Estrogen
Why can tamoxifen be useful in treating males with gynecomastia
Selective estrofen receptor modulator that acts as an estrgen antagonist in the breast
Leuprolide MOA
GnRH analog (used to suppress testosterone levels in tx of prostate cancer)
In what tissues are the glucose transporter proteins found that are upregulated in response to insulin?
Muscle cells
Adipocytes
A patient with type 1 diabetes is having overflow incontinence. What is the likely source of these symptoms?
Diabetic autonomic neuropathy affecting detrusor muscle innervation
(Initially infrequent urination bc unable to sense full bladder then incomplete emptying due to loss of inervation to detruser)
Which of the following is most likely to cause hypoglycemia in insulin-treated diabetes Infection Pain Sleep deprivation Intense exercise Mental stress
Intense exercise
(The rest cause hyperglycemia due to production of counterregulatory hormones such as catecholamines and cortisol which increase glyconolysis and gluconeogenensis)
What hormones are produced in cells with highly developed, smooth endoplasmic reticulum?
Steroid hormones
Smooth ER involved in synthesis and processing of hydrophobic compounds
The initial step in the synthesis of steroid hormones is the conversion of ______ to pregnenolone in the mitochondria
Cholesterol
In a patient with cushing syndrome with normal-elevated ACTH levels, high-does dexamethasone supression test resulted in supression of ACTH and cortisol levels. What is causing the Cushing syndrome?
Pituitary adenoma
In a patient with Cushing syndrome and normal-elevated ACTH levels, a high-dose dexamethasone supression test does not change ACTH or cortisol levels. What is the cause of the patient’s cushing syndrome?
Ectopic ACTH production
In a patient with Cushing syndrome and supressed levels of ACTH, what are 3 possible causes of the cushing syndrome?
Adrenal adenoma
Adrenal malignancy
Exogenous glucocorticoid intake
Corticotropin-releasing hormone is released from the ___ to stimulate release of _____
Hypothalamus
ACTH
How will long term exogenous glucocorticoid use effect endogenous CRH, ATCH, and cortisol synthesis/release
Decrease all of them
How is insulin cleared
Hepatic and renal
Why might a patient with CKD who is being treated for type 1 diabetes suddenly begin having hypoglycemic episoides despite no change in treatment
CKD –> less renal clearance
Insulin causes an increase in glycolysis by activating _____ , the enzyme that produces fructos 2,6-bisphosphate
Phosphofructokines-2 (PFK2)
The most potent stimulator of phosphofructokinase-1 (PFK1) is _____
Fructose 2,6-bisphospate
Hypercortisolism causes hyper- or hypo-glycemia?
Hyperglycemia
What pathologic finding is preseent in the adrenal glads with ACTH dependent Cushing Syndrome
Bileteral hyperplasia involving the zona fasciculata and reticularis
ACTH is the major trophic hormone for which area(s) of the adrenal gland while angiotensin II is the major trophic hormone for which area(s)?
ACTH: zon fasciculata and reticularis
Angiotensin II: zona glomerulosa
Exopthalmos in Grave’s disease is treatd by what medication
Glucocorticoids
Binding of PCSK9 to _____ increases degradation –> decreased uptake of circulating LDL into hepatocytes
LDL receptor
Evolocumab MOA
PCSK9 inhibitor (decrease LDL-R degredation)
What is the peak for subcutaneously administered regular insulin
2-4 hours
What is the most sensitive test for primary hypothyroidism
TSH
how does TNF alpha affect the insulin receptor
TNF alpha activate serine kinases –> phosphorylate beta subunits on insulin receptor and insulin receptor substrate 1 –> inhibits tyrosine phosphorylation of insulin receptor substrate by the insulin receptr
what are 4 things that inhibit the insulin receptor by phosphorylation by serine kinase
TNF alpha
catecholamines
glucocorticoids
glucagon
what tyrosine panel levels will be abnormal in euthryoid sickness sydrome
low T3
aka low T3 syndrome
what causes low T3 levels in euthyroid sick syndrome
high cortisol, inflammatory cytokines and free fatty acids suppress 5’ deiodinase
multiple endocrine neoplasia type 1 classification (3)
primary hyperparathyroidism
pituitary tumors
pancreatic tumors
multiple endocrine neoplasia type 2A classifications (3)
medullary thyroid cancer
pheochromatoma
primary hyperparathyroidism
multiple endocrine neoplasia type 2B classifications (3)
medullary thryoid cancer
pheochromocytoma
mucosal neuromas/marfanoid habitus
estrogen is synthesized from androgens by _____
aromatase
expression of aromatase in ovarian tissue is dependent on _____
gonadotropin
anastrozole MOA
aromatase inhibitor
maple syrup urine disease, an autosomal recessive disorder characterized by the defective breakdown of _______
branched chain amino acids
what are the branched chain amino acids
leucine
isoleucine
valine
branched chain alpha ketoacid dehydrogenase complex requires what 5 cofactos
thiamine lipoate coenzyme A FAD NAD (tender loving care for nancy)
diet restriction and ___ supplementation can be used in managing patients with maple syrup urine disease
thiamine
methimazole is preferred for most patients due to what side effect of PTU
hepatotoxicity
what are the two potential diagnoses for a thyroid nodule that reveals neoplastic follicular cells and microfollicles
follicular adenoma (benign) follicular carcinoma (malignant)
how are folicullar adenomas and follicular thyroid carcinomas differentiated
follicular thyroid carcinomas invade the tumor capsule and/or surrounding blood vessels
what thyroid neoplasm tends to spread hematogenously
follicular thyroid carcinoma
11 beta hydroxylase leads to a build up of aldosterone and cortisol precursors which are then shunted toward adrenal ____ synthesis
androgen
what deficiency can cause ambiguous genitalia (virilization) in XX females
11 beta hydroxylase
11 beta hydroxylase deficiency leads to hypertension and hypokalemia how?
build up of 11-deoxycorticosterone which acts a mineralcorticoid
Hormone sensitive lipase is activated by what?
Stress hormones (catecholamines, glucagon, ACTH)
Hormone sensitive lipase is inhibitted by ____
Insulin
In Graves disease antibodies against ___ are present
Thyrotropin (TSH) receptor
In chornic lymphocytic (Hashimoto) thyroidits, ____ antibody is present
Thyroid peroxidase
What effect do the antibodies in Grave’s disease have?
TSH receptor antagonist (Gs)
What causes hypercalcemia in sarcoidosis
Excessive calitriol formation by activated macrophages
A hypothalamic mass such as neurosarcoidosis (sarcoidosis involvement of hypothalamus) could cause increase in which of the pituitary hormones
Prolactin
Multiple endocrine neoplasia type 2 is characterized by what 3 things?
Medullary thyroid cancer
Pheochromocytoma
Parathyroid hyperplasia (type 2A) or marganoid habitus and mucosal neuromas (type 2B)
Medullary thyroid cancer is a neuroendocrine tumor that arises from what cells
Parafollicular calcitonin-secreting C cells
What is seen microscopically in medullay thyroid cancer
Nests or sheets of polygonal or spindle shaped cells
Extracellular amyloid deposits
Amyloid deposits in medullary thyroid cancer is derived from ____ secreted by neoplastic C cells and stains with ____
Calcitonin
Congo red
Pulsatile secretion of GnRH from hypothalamus stimulates the release of ____ and ____
FSH
LH
FSH and LH are prouced by ____ cells in the anterior pituitary
Gonadotroph
LH stimulates _____ release from ___ cells
Testosterone
Leydig (in testes)
FSH stimulates the release of ____ from ____ cells
Inhibin B
Sertoli (testes)
Inhibin B suppresses _____ secretion
FSH
Why will patients with only one testicle have elevated FSH
Less sertoli cells –> less inhibin B to supress FSH release
What causes hyperpigmentation in a patient with Addison disease
Increased release of melanocyte stimulating hormone (decreased cortisol feedback on pituitary gland)
The most common cause of primary adrenal insufficiency is autoimmune adrenalitis which results from autoantibodies against _____ zones in the adrenal cortex
All 3
How does Addisons disease affect Na, K, Cl, and bicarb levels
Decreased aldosterone –> decreased Na and increased K and H
Low H excretion –> nonanion gap metabolic acidosis with low plasma bicarb –> Cl retention to maintain electrical neutrality of extracellular fluid
(Decreased Na and bicarb, increased K and Cl)
What is the most common cause of acromegaly
Pituitary somatotroph adenoma –> increased growth hormone release
How does excessive GH in acromegaly cause joint pain
Hyperplasia of articular chondrocytes and synovial hypertrophy –> degeneration of articular cartilage and periarticualr bone resembling osteoarthritis
If a patient presents with antidiabetic drug induced hypoglycemia and an increased C peptide level, what are the possible drugs that could cause this
Sulfonylureas
Meglitinides
Gastrin secreating tumors can occur in association with what?
Multiple endocrine neoplasia
What is Zollinger-Ellison syndrome?
A gastric secreting pancreatic tumor
Why would you ask a patient with Zollinger-Ellison syndrome if they have a family history of recurrent kidney stones
Zollinger-Ellison could be due to MEN1 which is also associated with hyperparathyroidism (can cause kidney stones)
Diabetic ketoacidosis most commonly affects patients with which type of diabetes?
Type 1
The destruction of beta cells in type I diabetes is primarily through _______
Cell mediated immunity (islet leukocytic infiltration)
Congenital goiter causing hypothyroidism with increased TSH and low free T4 can be caused by maternal medication with what drug?
Propulthiouracil or antithyroid medication
Congenital goiter that causes hyperthyroidism with decreased TSH and elevated free T4 can be due to transplacental _______ antibodies
TSH receptor-stimulating
Neonatal Graves disease
Patients with sheehan syndrome will have ______ (central or peripheral) _____(hyper or hypo) thyroidism
Central
Hypo
What is the purpose of treating patients with thyroid cancer with levothyroxine
Supress pituitary secretion of TSH which can promote growth f residual malgnant cells following thyroidectomy
Agranulocytosis due to propylthioruacil use most commonly present as _____
Oropharyngeal infection (fever, sore throat, oral ulcerations) (Sepsis can develop quickly after)0
Why can erythrocytes not use ketone bodies for energy
They lack mitochondria
Why can the liver not use ketone bodies for energy
Liver lacks succinyl CoA-acetoacetate CoA transferase
Required to convert acetoacetate to acetoactyl CoA
How does cortisol cause increased blood pressure
Stimualtion of mineralcorticoid receptors (sodium retention)
Increased angiotensinogen production (increased vasoconstriction)
Increased adrenergic sensitivity (vasoconstriction)
Primary hyperaldosteronism causes what changes in Na, K, and bicarb
Na: normal
K: low
Bicarb: high
How does hyperaldosteronism cause metabolic alkalosis
Increased H+ excretion by alpha intercalated cells –> bicarb production
Why are normal serum Na levels seen in hyperaldosteronism depsite increased Na reabsorption
Aldosterone escape
Incerased intravascular volume –> increased renal blood flow –> pressure natriuresis –> limits net sodium retention and prevents development of overt volume overloadand significant hypernatremia
After glucose enters the beta cell, it is metabilized to glucose-6-phosphate by what enzyme
Glucokinase
What is the role of glucokinase in beta cells
Functions as a glucose sensor
Its lower glucose affinity than other hexokinases allows it to limit the rate of glucose entry into the glyolytic pathway based on glucose levels
How does maturity onset diabetes of the young differ from type 2 diabetes mellitus
MODY: mild hyperglycemia that often woresns with pregnancy induced insulin resistance. Patients are typically younger and nonobese. Non progressive condition, even without treatment
Mutations in glucokinase gene lead to what effect on insulin secretion
Higher glucose levels are required to stimulate insulin secretion
What are incretins
Gastrointestinal hormones produced by gut mucosa
Stimulate insulin secretion in response to sugar containing meals
Incretins are secreted in response to what? Do blood glucose levels affect incretin release?
Oral consumption of glucose
No
Pituitary apoplexy usually occurs in a preexisting _____
Pituitary adenoma
Patients with pituitary apoplexy can develop cardiovascular colapse, how?
ACTH deficiency and subsequent adrenocortical insufficiency
Pituitary apoplexy is a medical emergency that requires urgen neurosurgical consultation and what pharmalogic treatment?
Glucocorticoids (to treat the adrenal isufficiency which can cause cardiovascular colapse)
Define macrosomia, a common finding in infants of diabetic mothers
Used to describe newborns who are much larger than average (more than 8 lbs 14 oz)
Poorly controld maternal glucose leads to excessive transplacental ____ transfer to the fetus
Glucose
What pancreatic changes occur in a fetus who is recieving excessive transplaental glucose from a mother who is poorly controling their glucose levels
Beta cell hyperplasia –> hyperinsulinism
_____ is a catecholamine secreting neoplasm arising from the chromaffin cells of the adrenal medulla
Pheochromocytoma
Why must patients with medullary thyroid cancer and RET mutation be screened for pheochromocytoma before surgery?
Induction of anesthesia –> catecholamine surge –> hypertensive crisis, flash pulmonary edema, and atrial fibrillation
How do SGLT2 inhibitors reduce hyperfiltration
They increase sodium delivery to macula densa –> decreased renin secretion (–> delayed progression of nephropathy)
How does diabetes stimulate RAAS in the kidneys?
Excessive filtered glucose –> sodium reabsorbed with glucose by SGLT2 –> less sodium delivered to macula densa –> renin secretion
Functional hypothalamic amenorrhea, seen in patients with anorexia nervosa, is caused by decreased serum ____ levels
Leptin
In funcitonal hypothalamic amenorrhea, decreased serum leptin has what effect on GnRH?
Decreased leptin levels –> inhibits pulsatile GnRH
How does functional hypothalamic amenorrhea affect LH and FSH secretion
Both are decreased
How are circulating estrogen levels effected in functional hypothalamic amnorrhea
Decreased
Prostate enlargement in BPH is driven primarily by what hormone
Dihydrotestosterone (DHT)
DHT is derivedfrom testosterone by ____ in peripheral tissues
5 alpha reductase
Finasteride MOA
5 alpha reductase inhibitor
What are the side effects associated with 5 alpha reductase inhibitors
Decrease libido, erectile dysfunction, decreased ejaculation volume (due to low DHT)
Gynecomastia (residual testosterone availible for conversion to estradiol)
In menopause, how is FSH effected?
Increased (lack of feeback from inhibin from follicles)
An elevated serum ____ level confirms diagnosis of menopause
FSH
What is the function of FSH in the sertoli cells
Induce androgen binding protein production which concentrates. Testosterone in teh seminiferous tubuls and facilitates spermatogenesis
What provides feedback regulation to FSH
Inhibin
How does a unilateral orchiectomy affect erectile function and sperm count
Sperm count: decreased
Erectile function: normal
A patient with 45, XO karyotype has what syndrome that may present with webbed neck, delayed growth, low set ears, arched palate and cubitus valgus.
Turner syndrome
What can be used to treat patients with Turner syndrome in order to normalize height
Growth hormone
Growth hormone receptor is what class of receptor
JAK STAT
_____ is secreted by intestinal L cells in response to food intake and regulaes glucose levels by slowing gastric emptying, suppressing glucagon secretion, and increasing glucose-dependent insulin release
GLP-1 (glucagon-like peptide-1)
GLP-1 is degraded by _____
DDP-4 (dipeptidyl peptidase 4)
What test should be run prior to starting a patient on SGLT2 inhibitors
Serum ceatinine to determine the GFR (the effectiveness of SGLT2 inhibitors is dependent on GFR)
What is the most common cause of death in patients with diabetes mellitus
Coronary heart disease
What is reverse T3
An inactive form of thyroid hormone that is generated almost entirely from peripheral conversion of T4
What is xanthelasma?
A type of xanthoma usually found on the medial eyelid
Yellowish macules/papules
What is xanthoma
Dermal accululations of benign apparing macrophages with abundant, finelyvacuolated (foamy)cytoplasm containing cholesterol, phospholipids, and triglycerides
What can cause xanthomas, including xanthlasmas
Hyperlipidemia and/or dyslipidemia
After an obese patient loses 15 pounds what are the likely changes to be seen in grhelin, leptin, and insulin
Ghrelin: increased
Leptin: decreased
Insulin: decreased
What receptor/second messanger system does glucagon use to exert its effects
Adenulate cyclase: Gs –> adenylate cyclase –> cAMP –> PKA
What 2 tests should be monitored when administering testosterone therapy
PSA (prostate specific antigen) indicates increased prostate volume which increases risk of prostate cancer
Hematocrit: should not be started on patients with hematocrit >50% because testosterone can induce erythrocytosis –> increased blood viscocity –> increased risk of thromboembolism
Parasympathetic stimulation of ____ receptors promotes insulin secretion and is induced by the smell and/or sight of food
M3
Stimulation of ___ adrenergic receptors stimulates insulin release and stimulation of ___ adrenergic receptors inhibits insulin release
Beta 2
Alpha 2
Which adrenergic receptor mediated response is predominant in beta cells
Alpha 2 (sympathetic stimulation leads to overall inhibition of insulin secretion)
What is the likely diagnosis of a 7 yr old boy with 4 cm multiloculated, cystic, supracella lesion with calcifications
Craniopharyngioma
Craniopharyngiomass are tumors arisingfrom remnants of ___
Rathkes pouch
How does glucagon restore blood glucose
Inducing glycogenolysis and gluconeogenesis in the liver
What are the most common hormonally active adenomas
Prolactinoma
How will male patients present with prolactinomas
Mass effect: headaches, bitemporal heminanopsia
Supression of GnRH: hypogonadism (impotence, decreased libido, infertility)
Hypertension and muscle weakness may be due to overactivity of what area in the adrenal gland
Zona glomerulosa
Overactivity of the adrenal zona glomerulosa will result in increased secretion of what
Mineralocorticoids (aldosterone)
What is the function of aldosterone
Sodium retention
Decreased potassium and H+ reabsorption
What crosses the placenta and allows newborns with hypohyroidism to appear asymptomatic
T4
What is vitilization
Occurs with very high andreogen levels
Characterized by clitoromegaly, increased muscularity, and voice deepending in addition to hirsutism
What is the most common cause of hirsutism
Polycystic ovary syndrome (PCOS)
Where is somatostatin released from
Pancreatic delta cells
Somatostatin decreases the release of what? (6)
Secretin Cholecystokinin Glucagon Insulin Gastrin Growth hormone
Gallbladder stones in a somatostatinoma is due to the inhibition of what?
Cholecystokinin (normally causes gallbladder contraction)
MOA glyburide
Sulfonylurea
How can hypothyroidism cause elevated prolactin levels
Increasedd TRH –> prolactin release
Diabetes insipidus leads to increased osmolarity and contracted volumes in ICF, ECF, or both?
Both
In diabetes insipidus, is the volume contraction isosmotic, hyposmotic, or hyperosmotic
Hyperosmotic (loss of free water with retention of electrolytes)
What causes amenorrhea in a female with low body weight
Low leptin –> inhibits pulsatile GnRH from hypothalamus -> low FSH and LH release –> low estrogen –> emenorrhea
What is Kallmann syndrome
Absence of GnRH secretory neurons in hypothalamus due to defective migration from the olfactory placode
Presentation: hypogonadism and anosmia that often present with delayed puberty
What is the primary source of ATP at the begining (first 10 sec) of exercise
Phosphocreatine shuttle
How does SGLT2 inhibitor cause decreased sodium levels
SGLT2 is a sodium/glucose symptor, when inhibitted it increases both Na and glucose secretion
Why would a patient with MEN type 2B have episodic headaches
Pheochromocytoma –> catecholamines -> paroxysmal hypertension and tachycardia –> increase in BP –> headache
What can cause paresthesias and muscle weakeness in patients with primary hyepraldosteronism
Excess urinary K and H secretion
Do patients with primary hyperaldosteronism have significant fluid volume expansion? Why?
No
Aldosterone escape
What 2 hormones are dependent on neurophysins
Oxytocin
Vasopressin
Niemann-pick disease is an autosomal recessive lysosomal storage disorder caused by a deficiency in ____
Sphingomyelinase
What are the key features of Niemann-Pick disease
Macular cherry red spot
Progressive neurodegeneration
Hepatosplenomegaly
How will radioactive iodine uptake change in subactute (de Qyervain) thyroiditis
Decrease ( decreased thyroid metabolic activity and organification of iodine due to loss of TSH)
What is the pathophysiology of postpardum thyroiditis
Autoimmune distrution of thyroid follicles and release of preformed thyroid horone
Lymphocytic infiltrates and sometimes germinal centers present
How does cystic fibrosis cause increased serum glucose during glucose tolerance testing
Thick, inspissated secretions blok the lumen of pancreatic ducts –> destruction of pancreatic islet cells –> decreased insulin production –> CF related diabetes
How does estrogen tratment effect thyroid hormone levels
Estrogen increases thyroglobulin –> increased bound T4 and transient decrease in fre T4 and T3 until TBG is saturated andT3 and T4 normalize –> increased total T4
What test should be done before begining metformin treatment
Serum creatinine measurement (contraindicated in renal dysfucntion due to increased risk of lactic acidosis)
What are tamoxifen’s effects in breast, bone and endometrial tissue
Breast: estrogen antagonist
Bone: estrogen agonist
Endometrium: estrogen agonist
What are raloxifene’s effects in the breast, bone, and endometrial ltissue
Breast: antagonist
Bone: agonist
Endometrium: antagonist
How does chronic glucocorticoid use accelerate osteoperosis
Inhibit proliferation and differentiations of osteoblast precursosrs
Increased expression of RANK and RANK-L
Supressed calcium absorption and reabsorption –> increased clacium release from bone
What type of receptor is the insulin receptor
Transmembrane tyrosine kinase receptor –> phosphorylation of insulin receptor substrate 1
Activation of what kinase inducs the metabolic functions of insulin
Phosphatidylinositol 3 kinase (PI3K)
Stimulates GLUT4 translocation, glycogen synthesis, fat synthesis
Insulin activates phosphatidylinositol-3-kinase which activates _____ which dephosphorylates glycogen synthase, leading to its activation and promoting glycogen synthesis
Protein phosphatase
What is the likely diagnosis of a patient presenting with a history of hypothyroidism, weight loss, hyperpigmentation, abdominal pain, vomiting, weakness, fever, severe hypotension and refractory shock
Adrenal crisis (with chronic primary adrenal insufficiency)
What is the treatment fo acute adrenal crisis
Agressive fluid resuscitation Glucocorticoid supplementation (hydrocortisone or dexamethasone)
In a non medical setting (without venous access), sever hypoglycemia, causing loss of consciousness can be treated how?
Emergency glucagon kit: intranasal or subcutaneous/intramuscular formulations
In an emergency setting, subcutaneous administration of glucagon corrects hypoglycemia how?
Increasing hepatic glycogenolysis
How does hypothyroidism cause elevated total cholesterol
Decreased expression of LDL receptor expression –> decreased clearance of LDL
(May also decrease LDL receptor activity and biliary excretion of cholesterol)
How can hypothyroidism cause hypertriglyceridemia?
Decreased expression of lipoprotein lipase
What causes hypoglycemia in neonates born from mothers with diabetes
Hyperfuctioning of pancreatic beta cells
Patients with long standing type 1 diabetes can have increased risk of hypoglycemia due to decreased ___ secretion
Glucagon (long standing diabetes patients frequently also have alpha cell failure)
21 hydroxylase is responsible for conversion of ____ to _____
Progesterone –> 11 deoxycorticosterone
And
17 hydroxyprogesterone –> 11 deoxycortisol
Deficiency of 21 hydroxylase deficieny causes a build up of 17 hydroxyprgesterone which is then shunted toward ____ production
Androgen
Labratory studies in all forms of 21 hydroxylase deficiency reveal elevated _____ and ____ levels
17 hydroxyprogesterone
Testosterone
FSH stimulates ____ release and ____ production from Sertoli cells in the seminiferous tubules
Inhibin B
Androgen binding protein
What is the most commno inborn error of methionin metabolism leading to ectopia lentis (dislocated lens), intellectual disability, and marfanoid habitus?
Homocystinuria
Homocystinuria is most frequently caused by an autosomal recessive deficiency of cystathionine beta synthase, an enzyme that requires _____ as a cofactor
Pyridoxine (vitamin B6)
(50% patients repsond to pyrdoxine supplementation_
Homocystinuria is most commonly caused by a deficiency of cystathionine beta synthase and can be treated by dietary restriction of _____
Methionine
Excessive vitamin D can cause symptomatic ______
Hypercalcemia
Presentation of hypercalcemia
(Due to impaired depolarization of neuromuscular membranes)
Weakness
Constipation
Confusion
(Impaired concentration of urine in distal tubule)
Polyuria
Polydipsia
How do granulomatous diseases such as sarcoidosis and tuberculosis caues hypercalcemia
They can have PTH independent conversion of 25 hydroxyvitamin D to 1,25 hydroxyvitamin D due to expresion of 1-alpha-hydroxylase in activated macrophages
How can hyperparathyrdism cause constipation
High PTH –> hypercalcemia –> inhibitted nerve depolarization –> impaired smooth muscle contraction and reduced colonic motility
____ is secreted by intestinal L cells in response to food intake and regulates glucose by slowing gastric emptying, supressing glucagon secretion, and increasing glucose-dependent insulin release
GLP-1 (glucagon-like peptide)
Deposits of ___ are universally seen in the pancreatic islets of patients with type 2 diabetes
Amylin
How do 5 alpha reductase inhibitos cause gynecomastia
By blocking the conversion of testosterone to DHT, te excess testosterone is availble for conversion to gynecomastia
A patient presenting with infertility, gynecomastia, and long lower extremeties is suggestive of what diagnosis
Klinefeler syndrome
What is klinefelter syndrome cause by
Chromosomal disorder: 47, XXY
Klinefelter syndrome is the most common cause of male hypogonadism. How does it cause male hypogonadism?
Progressive destruction and hyalinization of the sminiferous tubules, leading to small, firm testes
Sertoli cells are damaged –> decreased inhibin levels
Leydig cells damaged –> decreased testosterone
Loss of feeback inhibition –> increased FSH and LH
Cholestyramine MOA
Bile acid-binding resin
How do bile acid binding resins such as cholestyramine cause hypertriglyceridemia
Increase hepatic production of triglycerides and increase the release of triglyceride heavy VLDL particles into circulation
How does low cortisol contribute to hyponatremia
Cortisol usually inhibits ADH
Primary adrenal insufficiency affects what portions of the adrenal gland
All 3 layers of the cortex
Normal aging causes what changes to free testosterone, total testosterone, LH, and serum sex hormone-binding globulin
Free Testosterone: decreased
Total testosterone: decreased
LH: increased (due to decreased testosterone feedback)
Sex hormone binding globulin: increased
Niemann-Pick disease is characterized _______ deficiency
Sphingomyelinase
What fundoscopic finding is consistant with Niemann-Pick disease
Cherry-red macular spot
What are 3 clinical features of Niemann-Pick disease
Hepatosplenomegaly
Neurological regression
Cherry-red macular spot
What behavior often causes weight gain in patients who initiate insulin therapy for type 2 diabetes
Patients may eat more to supress feelings of hypoglycemia
Should inquire about paitents perspective on appetite, dietary patterns, and hypoglycemic symptoms
Pheochromocytoma is a tumor of ___ cells in the _____ characterized by increased production of ____
Chromaffin
Adrenl medulla
Catecholamines
Pheochromocytoma stains positive for what 3 stains?
Synaptophysin
Chromogranin
Neuron-specific enolase
Failure of serum 11-deoxycortisol and urinary 17-hydroxycorticosteroid levels to rise in response to metyrapone indicate what?
Either primary or secondary adrenal insufficiency
Metyrapone blocks ___ synthesis by inhibiting 11 beta hydroxylase
Cortisol
List the 3 characteristics of MEN type 1
Primary hyperparathyroidism
Pituitary tumors
Pancreatic tumors
In SIADH, what is the volume status and sodium status
Euvolemic
Hyponatremia
In congenital adrenal hyperplasia due to 21 hydroxylse deficiency, how will aldosterone, cortisol, and androgen production be affected
Decreased aldosterone and cortisol production
Increased androgen production
How does 21 hydroxylase deficiency present in male patients
1-2 weeks after birth with vomiting, hypotension, hyponatremia, hyperkalemia due to salt wasting, genitalia are normal
What cellular mechanism causes hypoglycemia in patients with type 2 diabetes
Increased transocation of GLUT4 induced by muscle contraction –> increased glucose uptake during exercise
What is the most common cause of secondary hyperthyroidism
TSH secreting pituitary adenoma
Hypertension, hypokalemia, and absent secondary sexual characteristics, and a blind puch vagina in a person with X,Y chromosome indicate a deficiency in what enzyme
17 alpha hydroxylase
Elevated TSH and low T4 in a newborn who has normal length and weight likely has what diagnosis
Thyroid dysgenesis
In the polyol pathway, glucose is converted into ____ by aldose reductase, which is trapped inside the cell until it is converted into ____ to facilitate excretion
Sorbitol
Fructose
Build up of ____ leads to cataracts in patients with diabetes
Sorbitol (and advanced glycosylation end products)
How does sorbitol lead to cell injury
Itt accumulates in certain cells and causes an influx of water –> osmotic cellular injury
Also aldose reductase (converts glucose to sorbitol) depletes NADPH which increases oxidative strewss
What are signs that Cushing syndrome is ACTH dependent
Hyperpigmentation (MSH is derived from POMC also)
Androgenization (ACTH stimualtes production of adrenal androgens –> increased DHEAS and hirtutism and menstrual abnormalities)
Why might a patient with lupus show signs of Cushing syndrome
Iatrogenic Cushing syndrome from chronic glucocorticoid use
Phentermine MOA
Stimulates the release and inhibits the reuptake of Norepinephrine
What mechanism is responsible for hyponatremia following a subarachnoid hemorrhage
Damage to hypothalamus –> excesive production of ADH
Beta thalassemia minor causes what hemoglobin changes
Decreased hemoglobin A
Inceased hemoglobin A2
Beta thalassemia major causes what hemoglobin changes
Hemoglobin A absent
Hemoglobin A2 increased
Hemoglobin F increased
How can hemolytic anemia give a misleadingly low hemoglobin A1C
Rapid erythrocyte turnover –> misleadingy low A1C
Diagnostic riteria for diabetes includes fasting plasma glucose _____, hemoglobin A1C ____, or random glucose _____ in a patient with symptoms of hyperglycemia, or oral glucose tolerance test ith plasma glucose _____
Fasting: > or equal to 126
A1C: > or equal to 6.5%
Random: > or equal to 200
Glucose tolerance: > or equal to 200 (2 hrs after glucose ingestion)
what is acanthosis nigricans and what does it indicate
hyperpigmentation is skin folds
insulin resistance
how do chronically elevated free fatty acids contribute to insulin resistance
they impair insulin dependent glucose uptake and increase hepatic gluconeogenensis
what amino acids should be restricted from the diet of a patient with maple syrup urine disease
leucine
isoleucine
valine
what enzyme is deficient in patients with maple syrup urine disease
branched chain alpha ketoacid dehydrogenase complex
In a patient presenting with hyperthyroid symptoms, low TSH, elevated T4 and low thyroglobulin indicates what diagnosis
thyrotoxicosis from exogenous source (ie. levothyroxine tablets)
thyrotropin receptor antibodies are present in what disease
Graves disease
thyroid dermopathy is caused by stimulation of ____ by TRAb and activated T cells, leading to excess production of ____ and adipogenesis
fibroblasts
glycosaminoglycans
what is a common adverse side effect of highly active antiretroviral therapy (HAART)
medication induced body fat redistribution (lipoatrophy or lipodystrophy)
advanced atherosclerosis at a young age seen in both a father and a son causing early onset MI is likely due to decreased expression of what receptor
LDL receptor in the liver (familial hypercholesterolemia)
fibrates MOA
activate peroxisome proliferator activated receptor alpha (PPAR alpha) –> increased synthesis of lipoprotein lipase
what are the most effective agents for the treatment of hypertriglyceridemia
fibrates (fenofibrate, gemfibrozil)
what is the most common cause of inadequate thyroid hormone level in infants with treated hypothyroidism
rapid growth (which increases the physiologic need for thyroid hormone) another common reason is decreased absorption
what can cause poor intestinal absorption of levothyroxine
co administration with various foods (soy products) and certain medications (iron, calcium, antacids)
Growth hormone’s growth promoting effects are primarily mediated by ____ which is released from the liver
IGF-1
besides rapid linear growth, what are other manifestations of gigantism in children
large hands and feet thickening of calvarium protrusion of jaw excessive sweating oily skin
if metoclopramide is not tolerated, what antibiotic can be used to treat gastroparesis
erythromycin
how is erythromycin prokinetic
it activates the motilin receptor in smooth muscle of the upper GI tract which results in persistaltic contractions
what changes in GnRH, LH, and testosterone are seen in a patient with a prolactinoma
GnRH, LH, and testosterone are all decreased
what vitamin D supplementation should be chosen for patients with hypoparathyroidism
calcitriol
calcidiol is dependent on PTH for conversion into calcitriol
high serum levels of _____ confirms diagnosis of infants with 21-hydroxylase deficiency
17-hydroxyprogesterone
21 hydroxylase is responsible for converting ____ into 11-deoxycorticosterone and 17-hydroxyprogesterone to _______
progesterone
11-deoxycortisol
what does a TSH level
their current dose is too high
what is the most common risk of thyrotoxicosis due to thyroid replacement therapy
cardiovascular complications due to increased beta adrenergic receptor expression (A fib, angina, high output heart failure)
