Assessment 4 Flashcards
Classic endocrine glands
Pituitary
Adrenal
Thyroid
PTH glands
Atypical endocrine glands
GI
Adipose
Kidney, heart, liver,
Classes of hormones
Peptide/protein
Steroid
Amine
Steroid hormone precursor
Cholesterol
Amine hormone precursor
Tyrosine or Tryptophan
Hormone receptor types
Ion channel linked
Enzyme linked
Nuclear receptor
Regulation of hormone production
Biosynthesis regulation
Precursor processing
Regulation of hormone secretion
Feedback loops
Cyclical variation
Protein binding
Extends half life of hormone
Protect from degradation
Solubilize lipophilic compounds
Hormone clearance
Hepatic clearance/metabolism
Renal filtration
receptor mediated endocytosis
Target tissue hormone regulation
Receptor population
Upregulation vs downregulation of receptors
Only tissues with specific receptors will respond
Pituitary gland anatomical location
Inferior to hypothalamus
Enclosed in sella turcica
Parts of Pituitary gland
Anterior: Adenohypophysis
Posterior: Neurohypophysis
Connected to hypothalamus via pituitary stalk
Median eminence
Inferior border of hypothalamus
Posterior PG embryology
Arise from diencephalon
Anterior PG embryology
Arise from oral ectoderm
Envagination = rathke’s pouch
Normally loses connection to oral ectoderm
Rathke’s cysts
Usually benign
Craniopharyngioma
Benign and rare
Headache, vision issues, hormone deficiency
Surgery or radiation
Anterior PG blood supply
Parvocellular neurons from hypothalamus, end at median eminence
Hormones secreted into portal vessels which act on anterior PG
Posterior PG blood supply
Magnocellular neurons extend from hypothalamus into PPG
Synthesize and secrete ADH and Oxytocin and store in PPG
Hypothalamic pituitary GH axes
Hypothalamus (GHRH) –> APG (GH) –> Liver (IGF-1)
Hypothalamic pituitary Thyroid axes
Hypothalamus (TRH) –> APG (TSH) –> Thyroid (T3, T4)
Hypothalamic pituitary adrenal axes
Hypothalamus (CRH) –> APG (ACTH) –> Adrenal (Cortisol)
Hypothalamic pituitary gonadal axes
Hypothalamus (GnRH) –> APG (LH/FSH)
Prolactin
Promotes alveolargenesis during pregnancy
Post partum: Milk synthesis/secretion
Estrogen = (+)
Dopamine = (-)
Negative feedback on itself
Prolactinoma
Most common pituitary adenoma
Pharmacological intervention: Dopamine agonists
Sheehan syndrome
Complication of post partum hemorrhage
APG enlarged but blood supply same during pregnancy –> infarction from hypovolemic shock due to hemorrhage
Sheehan syndrom presentation
Acute: fail to lactate, hypotension, tachycardia
Chronic/Late: Amenorrhea, hypothyroidism
ADH
Vasopressin
Increase water permeability in kidneys: V2 receptor, aquaporin channel
Vascular smooth muscle contraction: V1 receptor
Oxytocin
Milk ejection
Uterine contraction
Stimulated by suckling, infant, orgasm
Action of growth hormone - Liver
Increase RNA, protein, glucose, IGF synthesis
Action of growth hormone -adipose
Lipolysis
Decrease glucose uptake
Action of growth hormone - muscle
Increase AA uptake and protein synthesis
IGF action
Increase organ size/function
Linear growth
Increase lean body mass
Categories of GH secretory factors
- Hormones
- Neural
- Metabolic
- Pharm
- Other
GH and metabolism
Fasting/starving or decreased glucose concentration = more GH
Increase glucose = low GH
Gonadotroph
Clinically non function pituitary adenoma, gonads
Thyrotrophs
Central hyperthyroidism or clinically non functioning
Lactotrophs
Hyperprolactinemia
Somatotrophs
Acromegaly
Corticotrophs
Cushings
Hyperprolactinemia clinical mainifestations
Decrease LH/FSH via GnRH inhibition
Infertility/galatctorrhea/amenorrhea
Impotence, decreased libido (men)
Gigantism vs acromegaly
GH excess
Acromegaly = epiphyseal closure Gigantism = no closure
Acromegaly diagnosis
IGF-1
Acromegaly treatment
Somatostatin analog (GH inhibitor)
GH receptor antagonist
Radiotherapy
Cushings syndrome vs disease
Syndrome: Symptoms caused by prolonged exposure to glucocorticoids
Disease: Pituitary corticotroph adenoma
Cushings disease
Hypersecretory Corticotroph adenoma causing excess adrenal secretion
Fat face/body
Excess ACTH
Cushings diagnosis
24hr urinary free cortisol
Late night salivary cortisol
Dexamethasone suppression test
Thyrotropin secreteing pituitary adenoma
Lab: High free T4 and T3, abnormally high TSH
Weight loss, diarrhea, tremors, palpitations/tachycardia
TSH deficiency signs/symptoms
Decrease in energy
Growth retardation
Constipation
Weight gain
Hypopituitarism treatment
Relief of mass effect
Replacement of hormones
Central diabetes insipidus
Excessive free water loss due to lack of ADH
21 alpha hydroxylase deficiency
Most common CAH (90-95% of cases)
- Decreased cortisol
- Increased androgens in utero (virilization of female fetus)
- Decreased aldosterone –> salt wasting. Decreased Na and increased K
11 beta hydroxylase deficiency
2nd most common CAH
- Decreased cortisol
- Increased mineralocorticoid activity (high 11-DOC)
- Increased androgens in utero
Either 1+2 or 1+2+3
Diagnose with increased 11 DOC in urine
Lipoid CAH
Rare CAH
Defect in P450scc or StAR
Buildup of cholesterol
Vasopressin hypofunction
Diabetes insipidus: cannot excrete concentrated urine
Neoplasm
Inflammation
Head trauma
Vasopressin hyperfunction
SIADH: Cannot excrete dilute urine –> hyponatremia and volume expansion
Ectopic secretion from tumors
Conn syndrome
Primary aldosteronism with hypertension and unprovoked hypokalemia
Suppression of renin
Most commonly due to aldo secreting adenoma
CAH
Congenital adrenal hyperplasia
Cortisol deficiency and ACTH increase
90% cases associated with 21 hydroxylase deficiency
Adrenal cortical carcinoma
Rare neoplasm
Necrosis and hemorrhage
Invasion of adjacent structures: IVC, adrenal vein
Adrenal gland hormones: medulla
Catecholamines
Adrenal gland hormones: cortex
Mineralocorticoids
Glucocorticoids
Androgens
Zona glomerulosa hormones
Mineralocorticoids
Zona fasciculata hormones
Glucocorticoids
Zona reticularis hormones
Androgens
Aldosterone function
Salt/water retention
K excretion
Primary aldosteronism
Aldosterone production is abnormally high
Primary aldosteronism physiological symptoms
HTN
Hypokalemia and mild hypernatremia
Mild metabolic alkalosis
Primary aldosteronism causes
Aldo producing adrenal adenoma (APA)
Adrenal hyperplasia (IHA, BAH, UAH)
Familial hyperaldosteronism
Screening test for primary aldosteronism
PAC/PRA > 20 = (+)
Primary aldosteronism confirmation tests
Oral sodium loading
IV NS load
Fludicortisone suppression
Check to see if aldo is suppressed
Primary aldosteronism subtype classification tests
CT: Can test cause (adenoma, hyperplasia, carcinoma) but not source
Adrenal vein sampling: Compare aldo from both sides, can find source
Right vs left adrenal vein
Right: Short and small. Directly enters IVC
Left: Tributary to real vein, easy to cannulate
Adrenal vein sampling results
Aldosterone concentration/Cortisol concentration
4:1 = unilateral
APA/IHA treatment
Surgery in good candidates
IHA/GRA treatment
Minrealocorticoid receptor blocker - Spironolactone
Secondary antihypertensive
Pheochromocytoma and Paraganlioma
Paraganglioma arise from autonomic ganglia, outside of adrenal glads
Excess production of epi and norepi
Pheochromocytoma and Paraganlioma incidence
90% adrenal
90% unilateral
90% benign
15-20% familial
Paraganglioma stats
Norepi excess
30% malignant
25% extra abdominal
Presentation of Pheochromocytoma
Pain Pressure (HTN) Perspiration Pallor Palpitations
Pheochromocytoma diagnosis
Metanephrine plasma level
24hr urinary metanephrine, fractioned catecholamines
Pheochromocytoma radiology
CT scan
MIBG: Compound that resembles Norepi, scan can detect tumors
Adrenal failure clinical presentation
Hyperpigmentation: Skin, buccal cavity, scars
Postural hypotension
Addisonian crisis
Nausea/vomiting
Hyperpigmentation w/ primary adrenal insufficiency?
Melanocyte stimulating hormone and ACTH on part of same protein
Adrenal failure lab findings
Hyperkalemia, hyponatremia, hypoglycemia
Lymphocytosis, eosinophilia
Adrenal autoantibodies if auto immune disease
Primary adrenal failure
Addisons
Decreased aldo and decreased cortisol, issue with adrenal gland
Hyperkalemia, hypotension
Increase ACTH
Secondary/tertiary adrenal insufficiency
Normal aldo, less prominent hypotension
Decreased ACTH, no hyperpigmentation
Primary adrenal insufficiency etiology
Autoimmune Infection Cancer Adrenal hemorrhage CAH
Secondary adrenal insufficiency etiology
Glucocorticoid withdrawal
Hypopituitarism via radiation, surgery, mass
Low cortisol + Low ACTH =
Secondary adrenal insufficiency
Low cortisol + High ACTH =
Primary adrenal insufficiency
Most common CAH enzyme deficiencies
21 hydroxylase
11B hydrolxylase
17a hydroxylase
21 a hydroxyalse deficiency symptoms
Virilizing + Salt wasting
Cortisol and metabolism
Gluconeogenesis and glucose storage, decrease glucose breakdown
Lipolysis but also increase appetite
ACTH independent vs dependent Cushings
Dependent: Cushings disease
Ectopic ACTH
Ectopic CRH
ACTH independent: Adrenal adenoma/carcinoma/hyperplasia
Exogenous steroids
Thyroid blood supply
Superior thyriod artery
Inferior thyroid artery
Lowest thyroid artery
- Branch of brachiocephalic trunk, present in 5-10%
Recurrent Laryngeal nerves
Innervate muscles of larynx, open/close vocal cords
T3 and T4 action
T3 is better ligand for receptor
T4 is negative feedback on hypothalamus
T3/4 synthesis
- Iodide uptake via NIS
2a. Thyroglobulin synthesis and exocytosis into follicle - not driven by TSH
2b. Free iodide transported into follicle by Pendrin
- Iodide oxidized by TPO to iodine
- Iodination of thyroglobulin = MIT and DIT
- TPO - TSH stimulated conjugation of iodinated tyrosines to make T3 and T4
- Endocytosis of iodinated thyroglobulins, lysoendosome formed
- Proteolysis in lysoendosome releases T3, T4, RT3. MIT/DIT recycled
- Secretion into circulation
DIT + DIT =
T4
MIT + DIT =
T3, most active
DIT + MIT =
reverse T3
Useless sack of shit
Thyroid transport proteins
Thyroxine binding globulin (TBG) - T3, T4
Trasnthyretin - Thyroxine
Calcium sensing receptor
Highly expressed on chief cells of parathyroid gland
Sense serum Ca concentration
Vit D
Diet or synthesized via cholesterol
Vit D and Ca
Vit D increases Ca transport proteins in duodenum
PTH synthesis
Prohormone, processed in golgi
PTH increases serum calcium
PTH and bone
Induces RANK ligand and M-CSF on osteoblasts
Activate osteoclast precursor cells which become osteoclasts –> eat up bone and release Ca
PTH and kidney
Ca reabsorption in DCT and CCD
PTH related protein
PTHrP
Binds PTH receptor, mobilize Ca to produce milk
Mediates osteolytic bone metastasis
Calcitonin
Less bone resorption and decreased Ca released
Mutations in CaSR
Inactive: Hypercalcemia/hypocalciuria
Active: Hypocalcemia
Leptin
Produced in fat
Circulating levels signal to brain how much fat is in system
Melanocortin system
alpha-MSH (agonist) and AgRP (antagonist)
AgRP = increased feeding/body weight
a-MSH = reduced feeding and body weight
Diet and melanocortins
Diet = aMSH down and AgRP up
Leptin deficiency and melanocortins
MSH down
AgRP up
High fat leptin pathway
Leptin activates POMC –> MC4 receptor –> decreased weight
Inhibits AgRP
Low fat leptin pathway
Low leptin does not stimulate POMC, less AgRP inhibition –> Activate Y1/Y5 –> Increase weight
AgRP also inhibits MC4 receptor
Leptin and thyroid function
Leptin is positive regulator of TRH
Increase Leptin = increase Thyroid
Leptin and gonads
Positive regulator
Increase leptin = increase LH/FSH
Environmental causes of obesity
Genetics modified by environment
Obesogenic environment: Inactivity and readily available food supply (increased portions, energy dense)
Obesity guidelines: Waist circumference
Measure in pts with BMI of 25-34.9
> 35in (female)
40in (males)
Estimate of visceral fat
Obesity guidelines: Assess and treat CV risk factors and comorbidities
Weight loss vs maintenance
Weight loss: Overweight + 1 or more CV factor OR obese
Weight maintenance: Normal weight, overweight w/o comorb, overweight/obese but cant lose weight
Obesity guidelines: Recommend goals for weight loss
Initial goal: 10% weight loss in 6 months
Rate of weight loss:
.5-1 lb/week BMI (27-34.9)
1-2 lb/week (BMI>35)
Obesity guidelines: Recommend method for weight loss
Weight loss with both low carb and low fat diets
Diets should be tailored to individual patients
Obesity guidelines: Comprehensive lifestyle interventions
1200-1500kcal/day for females
1500-1800 kcal/day for men
500-700kcal/day energy deficit + increased activity
Acceptable macronutrient Distribution range
Carb: 45-65%
Protein: 10-35%
Fat: 20-35%
Thyroid hypofunction histology
Atrophic follicles
Mononuclear cell infiltration with germinal centers
Subacute thyroiditis
Granulomatous (painful)
Lymphocytic (painless)
Riedels thyroiditis
Rare, fibrotic
Acquired thyroid hypofunction
Post therapy for hyperthyroidism or thyroid neoplasms
Thyroid hyperfunction
Thyrotoxicosis
Increased production or increased release of pre formed hormone from damaged thyroid gland
Hyperthyroidism (increased production)
Autoantibody that mimics TSH (Graves)
Excess TSH or TRH (very rare)
Secretion by neoplasm
Thyroid storm
Life threatening
Fever, delirium, seizures, vomiting
Death from cardiac arrhythmia/failure
Treat by block T4–> T3 conversion
Nodular hyperplasia
Usually euthyroid
Dominant nodule may emerge, simulate neoplasm
Iodine deficiency
Dietary goitrogens
Thyroid anaplastic carcinoma
Aggressive tumor in elderly
Kills by direct invasion of airway
May have p53 loss
RAS point mutation cancer
Fillicular and anaplastic carcinoma
PTEN point mutation
Follicular and anaplastic carcinoma
BRAF point mutation
Papillary carcinoma
RET gene mutation
Papillary carcinoma
Medullary carcinoma
Hypoparathyroidism most common cause
Surgical excision of parathyroid gland
Hypoparathyroid causes
Surgery
Congenital agenesis/hypoplasia
Autoimmune
Mg deficiency
Hypoparathyroid biochemical features
Low PTH
Low Ca
High phosphorus
Hypoparathyroid clinical features
Increased neuromuscular excitability
Emotional disorders
Parkinson like syndrome
Basal ganglia calcification
Hyperparathyroidism causes
Adenoma (80%)
Hyperplasia (15%)
3% of all cases associated with MEN I or IIa
Secondary hyperparathyroidism causes
Chronic renal insufficiency
Vit D deficiency
Intestinal malabsorption
Secondary hyperparathyroidism and renal failure
Renal retention of phosphorus + loss of Ca
Reduced 1,25(OH) Vit D resulting in decreased Ca absorption
Advanced hyperparathyroidism
Severe kidney stones
Osteitis fibrosa
Malignancy associated hypercalcemia
80% due to direct invasion of bone by tumors
20% attributed to PTHrP: Blocks osteoprotegrin secretion by osteoblasts –> Promotes osteoclastogenesis
pH and Calcium serum concentration
Alkalosis = increase in albumin bound Ca but decrease in free Ca
Acidosis = Decrease in albumin bound Ca but increase in free Ca
Lower pH = Decreased albumin affinity for Ca
Hypercalcemia clinical presentation
Kidney Stones
Bones - osteitis fibrosa, fractures
Moans - lethargy, depression
Ab Groans - constipation, peptic ulcer
Osteitis fibrosa
Increased osteoclasts
increased bone resorption
Hypercalcemia diagnosis
Check serum Ca
Check PTH level
Measure 24hr urinary Ca after repleting Vit D to rule out FHH
HyperPTH treatment
PTH surgery
Bisphosphonates: Anti resorptive agents (bone protection)
Cinacalcet: Decrease serum Ca level (symptomatic hypercalcemia)
Hypocalcemia pathogenesis
Deficiency Vt D supply/action
Deficient PTH synthesis/secretion
Normal Vit D level and required amount
> 30ng/mL
Need ~2000IU
Imparied PTH secretion causes
Antibody inhibition
CaSR activating mutation
Hyper/hypomagnesemia
PTH gene mutations
DiGeorge Syndrome clinical pres
Cardiac Abnormal fascies Thymic aplasia Cleft palate Hypocalcemia with 22q11 deletion
Hypocalcemia and neuromuscular
Lower threshold to nerve conduction = spasms, cramps, weakness
Chvosteks sign
Hypocalcemia
Press on cheek = twitch of face
Response = degree of hypocalcemia
Trousseau’s sign
Place BP cuff on upper arm –> carpopedal spasm
Treatment of hypocalcemia
Raise serum Ca to low-normal range
Avoid hypercalciuria
IV Ca, oral Calcitrol
Vit D, maybe Mg
Lobectomy/hemi thyroidectomy
Removal of one lobe
Diagnostic for suspicious nodules
Toxic adenoma
Total/near total thyroidectomy
Removal of entire thyroid - leave small remnant near nerve/PT
Cancer, graves
Thyroid surgery complications
Recurrent laryngeal nerve injury: Unilateral = hoarse, bilateral = airway obstruction
Superior laryngeal nerve injury: Loss of high pitch
Hypocalcemia/hypoPTH
Hemorrhage - cut open to prevent airway obstruction
Neck/Node dissection: Central
Level VI
Initial lymph drainage of thyroid
Elective or therapeutic: Positive or negative nodes
Neck/Node dissection: Lateral
Levels I-V
Secondary lymph drainage of thyroid - Jugular, transverse cervical
Therapeutic - positive for nodes
PTH surgery
Unilateral: sporadic primary hyperPTH
Bilateral: Both sides, non localized primary hyperPTH, hereditary (MEN1, MEN2a)
Secondary/tertiary hyperPTH
Indications for PT surgery
Bones
Stones
Muscle weakness
Parathyroid embryology: Inferior
3rd pharyngeal pouch
Descend with thymus
Anterior to recurrent laryngeal nerve
Parathyroid embryology: Superior
4th pharyngeal pouch
Posterior to recurrent laryngeal nerve
Primary HyperPTH MEN
MEN1: hyperplasia
MEN2a: multiple adenomas
Minimally invasive/unilateral parathyroidectomy benefits
Reduced risk
Positive preop localization
High cure rates
Intraoperative PTH assay
Helps in deciding when to stop procedure
Pre incision and pre removal level with post removal
80% reduction = specific
50% reduction = sensitive
Pancreatic islet cell types
Beta cells - Insulin
Alpha cells - Glucagon
Delta cells
Proinsulin –> insulin
Proinsulin cleaved to insulin (A+B) and C peptide
Incretin effect
GLP-1 and GIP - gut hormones
Dietary glucose –> GLP-1/GIP activation –> insulin secretion/glucagon inhibition
Insulin action
Insulin binds to receptor –> MAP kinase pathway –> Glucose transporter to membrane
Low glucose effect
Low glucose –> Decreased ATP/ADP –> KATP channel open –> weak Hyperpol –> Ca channel open –> Ca increase glucagon secretion
High glucose effect
High glucose –> ATP/ADP increase –> KATP channel close –> depol –> no glucagon release
Type I diabetes overview
Morbidity and mortality
Autoimmune destruction of islets
Absence of insulin
Genetic+environment
No cure
Type I Diabetes autoimmunity
Selective destruction of islet Beta cells
Circulating antibodies to islet cell antigens
Linkage with MHC genes
T cell mediated beta cell destruction
T cell mediated Type I DM
Infiltrating CD4+, CD8+ T cells
anti T cell therapies are effective
Genetic factors of T1D
MHC Class II locus
Defects in immunomodulation
Attack own cells
DCCT results
Control of blood glucose works with intensive treatment - But difficult therapy
Hypoglycemia
Rate limiting factor for T1D treatment
Severe hypoglycemia sees unawareness of symptoms
Causes of hypoglycemia
Absolute excess insulin: Before lunch/dinner, predawn, gastroparesis
Relative excess: Exercise and alcohol
Exercise and glucose
Increase exercise = glucose into tissues = hypoglycemia risk
T1D routine management
HA1c multiple times a year Foot exams/neuropathy testing Renal monitoring Retinal exams Lipids BP
LADA
Latent autoimmune diabetes of adulthood
In between DM1 and DM2
Variable auto immune function, metabolic syndrome, insulin resistance
Diabetic ketoacidosis
Hyperglycemia
Acidosis
Volume depletion
Electrolyte abnormalities
Diabetic ketoacidosis management
Volume replacement
Insulin
Electrolyte balance
Education
Diabetic ketoacidosis pathogenesis
Decrease in insulin: Increase glucose, decreased glucose uptake –> hyperglycemia = osmotic diuresis
Increased FFA release, increased ketogenesis = ketoacidosis
DKA symptoms and signs
Symptoms: Polyuria, weakness, weight loss, nausea, vomiting
Signs: Tachycardia, hypothermia, ileus, acetone breath, altered sensorium, Kussmaul (deep, frequent) breaths
Prognostic factors of DKA
Hypotension
Age over 65
Altered mental status
DKA management
Hydration IV insulin Monitor K Bicarb for extreme cases Prevent recurrence: Education
Primary hypothyroidism etiology
Autoimmune
Thyroidectomy
Iodide deficiency
Drugs
Secondary hypothyroidism etiology
Hypopituitarism
Hypothalamic damage
Clinical manifestations of hypothyroidism
Weakness Lethargy Slow speech Cold intolerance Constipation Weight gain Hair loss Edema Decreased perspiration - dry skin
FT4 normal
TSH normal
Euthyroid
FT4 low
TSH High
Primary hypothyroidism
FT4 low
TSH normal/low
Secondary hypothyroidism
Subclinical hypothyroidism
T4 normal
Slightly high TSH
Few or no symptoms
Hypothyroidism therapy
Treat with hormone replacement
LT4 pills = synthetic T4
Check TSH 6-10 weeks
Target is TSH level
Thyroxine dosage
Higher weight = higher dose
Old patients on lower dose
Ca, Fe, soy can block absorption
Malabsorption = higher doses
Estrogen, antidep, anti seizure = increase requirement
Hypothyroidism in pregnancy
Thyroxine is safe
Dosage increases during pregnancy
Baby cant make thyroid hormone during first trimester
Important to keep regulated during pregnancy
Thyroid autoimmunity
Most common cause of hypothyroidism
Graves disease
Anti TPO antibodies (Hashimoto)
TRAB and TSI (Graves)
Thyrotoxicosis etiology
Graves
Toxic Adenoma
Subacute/silent thyroiditis
TSH secreting adenoma
Factitious/Iatrogenic (taking thyroid hormone)
Graves disease
Autoimmune hyperthyroidism
Female predominance
Associated opthalmopathy
Clinical manifestations of Graves
Nervous Fatigue Weakness Heat intolerance Tremor Hyperactivity Palpitations Increase appetite Weight loss
Lid lag
Hyperadrenergic effect of thyrotoxicosis
Graves opthalmopathy
Eyes bulge forward, eyelid retraction
Autoimmune response against orbital auto antigen shared by thyroid
Toxic multinodular goiter
2nd most common cause of hyperthyroidism, most common in elderly
Dysphagia, hoarseness, shortness of breath
Thyroiditis: Subacute and Silent
Acutre destruction of thyroid tissue, leakage of hormone
Subacute: painful, viral illness
Silent: post partum, painless, pre existing autoimmune
TSH secreting pituitary adenoma
Rare
Macroadenoma
Elevated T4
Inappropriately normal TSH
Factitious thyrotoxicosis
Due to ingestion of thyroid hormone
Serum thyrogolubulin used for diagnosis
Exogenous thyrotoxicosis: low thyroglobulin
Destructive thyroiditis: high thyroglobulin
Increased radio iodine uptake = ?
Graves
Toxic MNG
Toxic adenoma
Decreased radio iodine uptake = ?
Thyroiditis
Exogenous thyroid hormone
Iodinated contrast
Thionamides
Treatment for hyperthyroidism
Methimazole and PTU block thyroid hormone formation - Block TPO
PTU decreases T4–>T3 conversion
Radioiodine treatment
Preferred treatment
NOT in pregnancy
Eventual hypothyroid
Sick Euthyroid Syndrome
Decrease in T3/T4/TSH but increase in rT3
Decreased 5 deiodinase
Decreased TBG
Plasma inhibitors to binding
Increased TBG
Decrease uptake of thyroid hormones
Pheochromocytoma treatment
Adrenalectomy - high risk, need to prepare
Cushings disease clinical presentation
Thin skin, acne, bruising, hirtuism
Hypertension
Depression
Moonface, buffalo hump, truncal obesity, thin limbs
Hyperglycemia, osteoporosis, hypokalemia
Cushings treatment
Transsphenoidal surgery – Pituitary irradiation –> Total bilateral adrenalectomy
Adrenal tumor disease treatment
Surgical resection –> Mitotane therapy –> Surgery of recurrent tumor –> Enzyme inhibitors
Ectopic ACTH syndrome treatment
Surgical resection –> Adrenal enzyme inhibitor –> Medical/surgical adrenalectomy
Epidemiological determinants of T2DM
Genetic risk factors
Demographics
Behavioral/lifestyle
MEtabolic determinants
Intermediate risk categories: insulin resistance, glu inteolerance
Diagnostic testing for diabetes
Fasting blood glucose: Normal 200
Random plasma glucose: >200
HbA1C: Normal 6.5%
HbA1C
Measure of glucose binding to Hb in blood
Accurate representation of 3 months glu level
T2DM organ pathophysiology: Liver, Muscle, Adipose, Pancreatic islet
Liver: Increased hepatic Glu production
Muscle: Decreased Glu uptake
Adipose: High lipolysis even with increased insulin
Islet: Glucagon high after meal, insulin doesn’t increase as much
Ominous octet
- Increased hepatic production of glucose
- Decreased incretin effect
- Increased lipolysis
- Increased kidney Glu reabsorption
- Decreased Glu uptake by muscle
- Neurotransmitter dysfunction
- Increased glucagon secretion
- Impaired insulin secretion
Natural history of Type 2 diabetes and Beta cell function
Insulin resistance increases
Genetic Beta cell dysfunction increases over time and eventually reaches failure
Mechanisms of insulin resistance
Elevated FFA Increase muscle TG Abnormal mitochondrial function Hyperinsulinemia Inflammation and TNFa Hyperglycemia Lipodystrophy
Lack of insulin and lipids
Adipose metabolism without insulin inhibition = elevated TG, reduced HDL, small dense LDL particles
Atherogenic
Treatment of diabetes goals
HbA1C target less than 7%
Diet/lifestyle modification
Medication
Manage CV risks
Diet recommendations for T2DM
Caloric restriction for obesity
Limit CHO to 45-60g
Limited saturated fat
Increase dietary fiber
Gestational diabetes
Glucose intolerance during pregnancy
7-10% pregnancy
Progressive insulin resistance
Failure of beta cell compensation
Gestational DM diagnosis
Screening: Glucose challenge
100g OGTT if over threshold of glucose challenge
SGLT2 Inhibitor
Blocks reabsorption of glucose in kidney
Dapaglifozin
Thiazolidinidiones
Activate PPAR-gamma
Decrease FFA, increase insulin sensitivity
CHF issues
Weight gain
Secretagogues
SUR-1 activator: Block KATP channel –> insulin release
Sulfonylureas - Glipizide. Cheaper/lower dose
Meglitinide - Nateglinide
Weight gain, hypoglycemia
Biguanides
Metformin
Activate AMPK = increase glucose uptake by muscle/decrease hepatic gluconeogenesis
Lactic acidosis, GI issues
DPP4 inhibitor
Slow degradation of GLP-1/GIP
Sitagliptin, Linagliptin
Well tolerated, high cost
Alpha glucosidase inhibitor
Block CHO digestion (final step)
Acarbose
Diarrhea/flatulence
GLP-1 agonist
Increase GLP-1
Dulaglutide
Weight loss, GI, Injection
High cost
Amylin mimetics
Activate amylin receptor: Decrease glucagon, decrease gastric emptying, increase satiety
Weight loss
Decrease post prandial glucose
High cost
Pramlintide
Bile acid sequestrants
Bind bile acid
Decrease hepatic glucose production
High cost
Colesevelam
Dopamine-2 agonists
Modulate hypothalamic control of metabolism
Increase insulin sensitivity
High cost
Bromocriptine
Hyperglycemic damage to tissue (4)
- Increased accumulation of AGE’s
- PKC activation
- Aldose Reductase pathway acceleration
- Hexosamine pathway increase
Accumulation of AGE
Advanced glycosylated end products
Can diffuse out of cell and damage ECM and alter albumin
Results in pro inflammatory cytokines and growth factor
PKC activation
Induces PKC pathway
Increase blood vessel constriction
Blood vessel leakiness/angiogenesis
Clot formation and slowing of anti coagulation
Proinflammatory gene expression
Aldose Reductase acceleration
High glucose is converted to sorbitol by aldose reductase
Enzyme can’t be used to generate glutathione
Low glutathione = increased oxidative stress
Hexosamine pathway
Glu –> Fru –> F6P –> N acetyl glucosamine
N acetyl glucosamine can alter gene expression and result in pathology of damaging blood vessels
Unifying mechanism for hyperglycemia and tissue damage
Glucose –> ROS –> PARP –> Decrease GAPDH –> 4 pathways of tissue damage
Macrovascular damage mechanism
Increased FFA –> ROS –> PARP –> etc etc
Diabetic microangiopathy
Diffuse thickening of Basement Membrane
Distortion, abnormal permeability, eventual occlusion of capillaries
Diabetic retinopathy (2 types)
Background (Non proliferative) Retinopathy
Proliferative Retinopathy
Non proliferative Diabetic retinopathy
Mild – Moderate – Severe
Microaneurysms, hemorrhages, exudates
Macular edema
Proliferative Diabetic retinopathy
Neovascularization
Pre retinal hemorrhages
Fibrovascular tissue proliferation
Macular edema
Diabetic Nephropathy
Damage to vessels in renal system
Glomerulosclerosis, thickening of BM, nodular glomerulosclerosis
Nephrotic
5 Stages of Diabetic Nephropathy
- Hyperfunction/hypertrophy
- Silent stage - BM thickened
- Incipient stage - microalbuminuria
- Overt Diabetic nephropathy - macroalbuminuria
- Uremic - ESRD
Diabetic peripheral neuropathy
Nerve damage/destruction
Pain and sensory loss
5 Major factors of Diabetic foot
- Neuropathy
- Peripheral artery disease
- Ulceration
- Infection
- Impaired wound healing