Endocrine Flashcards
Test 4
The ______ is the primary source of glucose production. How is it created?
Liver
Glycogenolysis
Gluconeogenesis
What happens to glucose & insulin 2-4 hours after eating?
endogenous production of glucouse increases
endogenous insulin production decreases
This is to maintain normal BG levels
What hormones help regulate glucose levels?
Glucagon
Epi
Growth hormone
Cortisol
What are the roles of Glucagon?
Stimulates Glycogenolysis & Gluconeogenesis
Inhibits glycolysis
What is the most common endocrine disease?
DM
What causes DM?
inadequate supply of insulin and/or tissue resistance to insulin
Describe Type 1b DM?
Rare
Non-immune
Absolute insulin deficiency
Describe DM 1a
Autoimmune
-80-90% Destruction of pancreatic B-cells
-long period (9-13yrs) of B-cell antigen production before onset
-min/absent insulin production
-dx before 40yo
symptoms: fatigue, wt loss, polyuria, polydipsia, blurry vision, hypovolemia, ketoacidosis
Describe DM 2
90% of DM cases
Increasingly seen in younger pts now
-Under-Dx; normally present 4-7 yrs beforehand
Desensitized to insulin –> increased insulin secretion –> decreased pancreas function –> insulin levels inadequate
characterized by insulin resistance in skeletal muscle, adipose, & liver
Acquired & contributing factors: Obesity, sedentary life
Dx: A1c & fasting blood glucose
What are the 3 main abnormalities seen in DM2?
- impaired insulin secretion
- increased hepatic glucose release
- insufficient glucose uptake in peripheral tissues
What causes insulin resistance in DM2?
Abnormal insulin molecules
-Circulating insulin antagonists
-insulin receptor defects
What is the A1C Dx criteria?
<5.7% = Normal
5.7 - 6.5% = Pre DM
> 6.5 = DM
What is the Tx for DM2?
Diet
Exercise
wt loss
PO anti-DM meds:
-Metformin (biguanide - preferred)
-Sulfonylureas (not effective long term)
Insulin: Must have w/ DM1
-Rapid: Lispro, Aspart @ meals
-Short
-Interm: NPH, Lente
-Long: Glargine, Ultralente
What is the most dangerous complication of insulin? What exacerbates this? Tx?
Hypoglycemia
Exacerbated by: ETOH, metformin, sulfomylureas, ACE-I, MAOIs, BB
Tx: glucose
Describe DKA
Diabetic Ketoacidosis
Seen in DM1
-Trigger by illness/infection
Dx criteria:
glucose > 300
pH <7.3
HCO3- <18
serum osmo <320
++ urine ketones
Tx: IVF
-Insulin: Loading: 0.1u/kg + infusion: 0.1u/kg/hr
-bicard (correct acidosis)
-K+, phos, mag, sodium (electrolytes)
Describe HHS
Hyperglycemis Hyperosmolar Syndrome
occurs in DM2
Characterized by: severe hyperglycemia, hyperosmolarity (can lead to coma), dehydration
-Symptoms: polyuria, hypovolemia, hypotension, tachycardia
Slight acidosis
Tx: IVF, insulin bolus + infusion, electrolytes
Increased mortality
What are DM complications?
Microvascular: impaired blood flow
NEPHROpathy: –> ESRD
-Symptoms: HTN, proteinuria, periphery edema, decreased GFR
-tx: HD, PD, transplant
Peripheral neuropathy: Starts in toes/feet
-ulcers develop from unnoticed mechanical injuries/trauma –> infections
Retinopathy: dt microvascular damage
-includes color loss –> blindness
-BP/sugar control slows progression
Autonomic Neuropathy:
-CVS: abnormal CV dynamics, loss of HR variability, ortho hypotension, dysrhythmias
-GI: decreased GI secretions/motility, gastroparesis
—-Symptoms: N/V, decreased appetite, bloating, apigastric pain
—–Tx: control BG, small meals, prokinetics
When GFR <_____ your kidney can no longer clear _____
15-20
K+ (potassium)
What considerations should we have with DM?
Assess hydration status
Avoid nephrotoxic drugs
preserve RBF
Increased aspiration risk dt gastroparesis
Hold PO diabetics drugs to avoid hypoglycemia
Describe Insulinoma
Insulin secreting pancreatic tumor
2x women > men
-50-60 yo
Dx: Based on Whipple triad:
1. Hypoglycemia w/ fasting
2. BG <50 w/ symptoms
3. symptom relief w/ glucose
high blood insulin during 48-72h fast
Tx: Meds: Diazoxide (Preop- inhibits insulin release)
-Verapamil, phenytoin, propranolol, glucorticoids, octreotide
Sx is curative
Hypoglycemia - intraop –> hyperglycemia once tumor removed
TIGHT MONITORING ON BG & TX REQUIRED
Thyroid gland is composed of ____ lobes joined by an _____
2 lobes
isthmus
What is the thyroid capillary network innervated by?
adrenergic & cholinergic NS
What is in close proximity of the thyroid?
-R laryngeal nerve
-External motor branch of the SLN (dont know what SLN is)
Thyroid hormone depends on availability of exogenous _______
iodine
Iodine binds to ________ and yields inactive __________ & ____________
thyroglobulin
monoiodotyrosine
diiodotyrosine
What is the T4/T3 ratio?
10:1
T/F: Thyroid hormones stimulate virtually all metabolic processes
T
The thyroid is regulated by _____ (3) describe each
- Hypothalamus: secretes thyrotropin, releasing hormone (TRH)
- pituitary: TRH –> signals anterior pituitary: releases, thyrotropin stimulating hormone (TSH)
- Thyroid glands: TSH –> binds to thyroid receptors: release T3/T4
TSH is influenced by plasma levels of T3/T4 – negative feedback loop
What is a normal TSH level?
0.4 - 5.0 millunits/L
What are the labs to test for thyroid functioning?(2)
TSH assay: best test of thyroid action at cellular level
TRH stimulation test: use to test pituitary function and TSH secretion
What are the three main pathology for hyperthyroidism? symptoms?
-Graves disease
-toxic goiter
-Toxic adenoma
symptoms: sweating, heat and tolerance, fatigue, insomnia
What does T3 have main effects on?
Myocardium
Peripheral vascular
Describe Graves disease
Leading cause of hyperthyroidism
Autoimmune
dt thyroid stimulating antibodies
Females> males 7:1
20-40yo
Symptoms: goiter, ophthalmopathy
Dx: +TSH antibodies
low TSH
high T3/T4
Tx: Methimazole or Propylthiouracil (PTU) 1st line
-iodine therapy (preop correction or thyroid storm only)
-BB (relieves symptoms)
Sx: subtotal thyroidectomy when meds failed
Sx complications: hypothyroidism, hemorrhage, hematoma, tracheal compression, RLN damage, parathyroid damage
What are preop Graves’ disease considerations?
Assessed levels preop
Elective cases may need to wait 6 to 8 weeks for anti-thyroid meds to take affect
Emergent cases: IV BB, glucocorticoids, PTU are needed
Evaluate upper airway
Describe thyroid storm
Life-threatening hyperthyroid
Triggered by: stress, trauma, infection, medical, illness, surgery
Labs: thyroid levels may not be much higher than regular hyper thyroidism
Tx: anti-thyroid meds
Supportive care
Mortality 20%!!!!!!
Describe hypothyroidism
Also called “Myxedema”
Decrease T3/T4 despite normal TSH
Causes: ablation of the gland by radioactive iodine or surgery
-idiopathic/autoimmune
Types: Hashimoto thyroiditis
-goiter
-affects middle-aged women
symptoms: slow, progressive, course, cold, intolerance, weight gain, non-pitting edema, SIADH, fluid overload, plural, effusion, dyspnea, slow GI (ileus)
Tx: L-thyroxine
What are hypothyroidism considerations?
Airway compromise
Aspiration risk – slower GI
Cardiovascular hypodynamic
Compromise respiratory function
Hypothermia
Electrolyte and balances
Elective cases: Thyroid therapy should be initiated 10 days prior
-Emergent: IV thyroid & steroids ASAP
Describe Myxedema Coma
Rare, Severe form of hypothyroidism
Medical emergency
Mortality 50%
elderly women>
Trigger by: infection, cold, CNS depressants
Hallmark symtpom: Hypothermia dt impaired thermoregulation
-Symptoms: delirium, hypoventilation, hypothermia, bradycardia, hypotension, delusional, hyponatremia
Tx: IV L-thyroxine
L-triiodothyronine
-IVF w/ glucose, temp regulation, electrolyte correction, supportive care
Mechanical vent sometimes required
What causes goiters? Tx?
Lack of iodine
Ingestion of goitrogen
Hormonal defect
Tx: L-thyroxine
Sx: only indicated if medical treatment is ineffective and goiter compromises airway or is cosmetically unacceptable
What are complications of thyroid surgery?
RLN injury (unilateral, bilateral, temporary, permanent)
-unilateral: vocal hoarseness – resolves in 3 - 6 months
-bilateral: cause airway obstruction and warrant tracheostomy
Hypothyroidism
Hematoma
Keep a trach set bedside!!!!!
Each adrenal gland consist of a _______ (2)
Cortex
Medulla
What does the cortex in the adrenal gland synthesis?
Glucocorticoids
Mineralocorticoids (aldosterone)
Androgens
The hypothalamus sends _______ to the anterior pituitary, which stimulates release of _________
Corticotropin releasing hormone (CRH)
Corticotropin (ACTH)
Corticotropin (ACTH) stimulates the ________ to produce ________. What does this do?
Adrenal cortex
Cortisol
Cortisol helps convert NE to Epi
Describe Pheochromocytoma
Originates in Chromaffin cells
Location: 80%: adrenal medulla
18%: organ of Zuckerkandle
2%: neck/thorax
Can cause malignant HTN, CVA, MI
Secretes NE:Epi 85:15 inverse of normal
Can be spontaneous or triggered by: injury, stress, meds
Symptoms: HA, pallor, sweating, palpitations, HTN, orthostatic hypotension, coronary vasoconstriction, cardiomyopathy, CHF, EKG changes
Dx: 24 hour urine collection
CT, MRI
Preop: Alpha blocker
-Phenoxybenzamine
-Prazosin, Doxazosin
-BB (never give non selective - that works on B2)
-CCB
Describe hypercortisolism (Cushings)
2 types:
ACTH dependent: high plasma, ACTH stimulates adrenal cortex to produce excess cortisol
ACTH independent: excessive cortisol production by abnormal Edino cortical tissue that is not regulated by CRH/ACTH (these levels are suppressed)
-causes: adrenocortical tumors
Symptoms: weight gain, moon face, ecchymoses, HTN, glucose into intolerance, muscle, wasting, depression, insomnia
Dx, 24 hour urine cortisol
CT, MRI, US – determine tumor location
Preop: treat BP, electrolyte, imbalances, BG
Tx: Transsphenodial microadenomectomy (if resectable)
-subtotal resection of anterior pituitary
-pituitary radiation
-adrenalectomy
Describe hyperaldosteronism
Primary: excess secretion of Aldo dt tumor
-women>men
-associated w/ pheochromocytoma, hyperparathyroid, acromegaly
-renin supressed
Secondary: dt elevated renin
Hallmark symptom: spontaneous HTN w/ hypokalemia
Licorice can cause symptoms
Tx: Spironolactone
K+
Antihypertensive
Diuretics
Tumor removal
adrenalectomy
Describe Hypoaldosteronism
Hallmark symptom: hyperkalemia w/o renal insufficiency
symptoms: HB, orthostatic hypotension, hyponatremia
causes: congenital, ACE-I, Indomethacin-induced prostaglandin deficiency (reversible)
Tx: increase sodium intake
fludrocortisone daily
Describe adrenal insufficiency
2 types:
Primary (Addisons): autoimmune adrenal gland suppression
-90% of glands must be involved before signs appear
Secondary: hypothalamic-pituitary suppression leading to a lack of CRH or ACTH production
-only glucocorticoid deficiency
Causes: iatrogenic: synthetic glucocorticoids, pituitary surgery, radiation
These pts lack hyper pigmentation
Dx: baseline cortisol < 20 ug/dL even after ACTH stimulation
Tx: Steroids
There are ___ parathyroid glands located behind the ____ & _____ poles of the ______
4
Upper
Lower
Thyroid
Parathyroid hormone depends on ______. How?
Calcium
decreased Ca = increased PTH release
increased Ca = decreased/supressed PTH release
What does parathyroid hormone (PTH) do?
Maintains normal plasma Ca by promoting the movement of calcium across the GI tract, renal tubules, and bone
Describe hyperparathyroidism
Classified as primary, secondary, ectopic
Primary:
Causes: benign parathyroid adenoma 90%
-carcinoma 5%
-parathyroid hyperplasia 5%
-symptoms: lethargy, weakness, N/V, polyuria, renal stones, PUD, cardiac disturbances
-Dx: plasma Ca, 24h urinary Ca
-Tx: Sx removal of abnormal portions gland
Secondary: compensatory response of the parathyroid gland to counteract a separate disease process involving hypocalcemia
Tx: treat underlying disease, normalize phosphate levels
Describe hypoparathyroidism
Causes: Iatrogenic: inadvertent removal of parathyroid gland during thyroidectomy
Dx labs: decrease PTH, decrease Ca, increase phos
Symptoms: Chronic: fatigue, cramps, prolonged QT, cataracts, SQ calcifications, Neuro deficits
Acute hypocalcemia after accidental parathyroid removal may cause inspiratory strider or laryngospasm
Tx: Ca replacement, Vit D
What is pseudohypoparathyroidism?
PTH is adequate, but the kidneys are unable to respond to it
The anterior pituitary gland secretes ____ hormones under the control of the ________. What are they?
6
Hypothalamus
GH
ACTH
TSH
FSH
LH
Prolactin
the posterior pituitary stores _________ (2) after being synthesized in the _________
Vasopressin
Oxytocin
Hypothalamus
Describe Acromegaly
Excessive growth hormone
seen with anterior pituitary adenoma
Dx labs: insulin-like growth factor 1 (ILGF-1) elevated
Overgrowth of soft tissues = upper airway obstructions
Hoarseness and abnormal movement of vocal cords or RLN paralysis dt overgrowth of surrounding cartilage
Tx: removal of pituitary adenoma
-LA somatostatin analogues (if sx not feasible)
What are anesthesia considerations for Acromegaly?
Distorted face anatomy – interfere with mask placement
Enlarged the tongue and epiglottis – interferes with visualization of vocal cords
Increase distance between the lips and the vocal cords
Epiglottis opening may be narrowed dt vocal cord enlargement – Smaller ETT, VL, awake fibrotic intubation
describe diabetes insipidus (DI)
Vasopressin (ADH) deficiency
Causes:
Central/Neurogenic: dysfunction of the posterior pituitary
Nephrogenic: failure of kidneys to respond to ADH
Symptoms: polydipsia, excessive/dilute urine despite increase serum osmo
Tx: IV electrolytes to offset polyuria
Neurogenic/Central: DDVAP
Nephrogenic: low salt, low protein, thiazide diuretics, NSAIDs
Considerations: monitor UO & electrolytes
Describe syndrome of inappropriate ADH (SIADH)
Causes: intracranial tumors, hypothyroidism, porphyria, lung cancer
Dx: hyponatremia, decreased serum Osmo, increased urine Na, increased urine osmo
Tx: fluid restrictions, Na tabs, Luke diuretics, Demeclocycline (ADH antagonist), hypertonic saline (severe hyponatremia)
