Unit 12 Flashcards
Posterior pituitary hormones
ADH- produced in supraoptic nuclei
Oxytocin- produced in paraventricular nuclei, positive feedback loop
Both are produced in thalamus
Anterior pituitary hormones
FLAT PiG Follicle stimulating hormone Luteinizing hormone Adrenocorticotropin Thyroid Stimulating hormone Prolactin- neural control, increased dopamine decreases prolactin release (Ignore) Growth hormone
Hormones stored and secreted by thyroid gland
Thyroxine=T4 (prohormone from tyrosine), high concentration in blood, more protein binding, less potent, 7 day half life
Triiodothyronine=T3 (Active), high concentration in target cell, less protein binding, more potent, 1 day half life, mostly converted from T4
Calcitonin
Goiter formation
Chronic high TSH
TSH stimulates follicles to make thyroglobulin colloid and iodine isn’t required
Thyroglobulin continued to be produced and causes gland to increase in size
Goiter=awake intubation
Next best = spontaneous ventilation
Beta blockers for hyperthyroid
Propranolol and esmolol
Also inhibit peripheral conversion of T4 to T3
Treating thyroid storm
4 B’s
Block synthesis (methimazole, PTU)
Block release (radioactive iodine, K iodide)
Block T4 to T3 conversion (PTU, propranolol)
Beta blocker (propranolol, esmolol)
RLN injury
Innervates all intrinsic laryngeal muscles
Unilateral- ipsilateral paralysis, hoarseness
Bilateral- both cords midline on inspiration=obstruction
Resection of parathyroid gland
Hypocalcemia at least 6-12 hours after surgery
Increased nerve and muscle irritability
Hypotension
Prolonged QT
Chvosteks- tapping angle of jaw=facial contraction on ipsilateral side
Trousseaus- upper extremity cuff inflated for 3 min, decreased BF=irritability and causes muscle spasm of hand/FA
IV Ca- Ca gluc is less Ca but lower risk of necrosis than Ca Cl
Mineralacorticoids
(Aldosterone) Zona glomerulosa (outer layer)- cortex Sodium retaining potency
Glucocorticoids
(Cortisol)
Zona fasciculata
Anti inflammatory potency
Androgens
(Dehydroepiandrosterone)
Zona reticularis- inner most layer
Adrenal medulla
(Middle)
Catecholamines (epi 80% and norepi 20%)
Adrenal context
GFR from outside to inside
Salt, sugar, and sex
Decreased ACTH
Minor influence on aldosterone release
Decreased does not cause hypoaldosteronism
Aldosterone
Regulates intravascular volume- NOT osmolality
Causes fluid retention and expansion of extracellular space- stimulates Na K ATPase in distal tubule and collecting duct
With reduction in serum K and metabolic alkalosis
Stimulated by- RAAS stimulation, increased K, decreased Na
1-2 hour delay before effect
ADH
Increases absorption of water and NOT Na
Diluted plasma sodium
Half life 5-15 min
Cortisol
Diffuses into cell to bind with intracellular receptors= slow onset of steroids
CRH from HT and stimulates anterior pituitary
ACTH from anterior pituitary and stimulates cortex
Cortisol production
15-30 mg/day
Serum cortisol level
12 mcg/dL
Up to 30-50 mcg/dL during and after surgery
Cortisol effects
Energy mobilization
Anti inflammatory- doesn’t decrease histamine release
Increases number and sensitivity of beta receptor in myocardium
Vasoconstrictive
Cortisol
Equal GC and MC
Cortisone
Equal GC and MC
Prednisone and prednisolone
4 GC: 0.8 MC
Methylprednisolone
5 GC: 0.5 MC
Dexamethasone and betamethasone
25 GC: 0 MC
Triamcinolone
5 GC: 0 MC
Given in epidural space
Incidence of muscle weakness
Causes sedation and anorexia
Conns syndrome
Hyperaldosteronism
Primary- normal renin, increased from adrenal gland
Secondary- increased renin activity
Long term Licorice- glycyrrhizic acid causes resembling syndrome
Htn
Decreased K
Metabolic alkalosis
Cushing’s syndrome
Excess cortisol from overproduction or exogenous
Causes GC, MC, and androgenic effects
Increase glucose
Htn
Low K
Metabolic alkalosis
Adrenal insufficiency
Primary (Addison’s)
Hotn Low gluc Low Na High K Metabolic acidosis
Treat with 15-30mg cortisol day
Stress dosing
Yes- greater than 20mg for greater than 3 weeks
Yes 5-20mg for greater than 3 weeks
No- less than 5 mg for less than 3 weeks
5mg prednisone=20mg hydrocortisone
Surgeries
Superficial-dental, biopsy
Minor- inguinal hernia, colonoscopy 25mg IV (hydrocortisone)
Moderate- colon resection, total joint, hysterectomy
50-75 mg, taper
Major- CV, thoracic, liver, whipple
100-150mg, taper
Glucagon
Alpha cells
Catabolic- promotes energy release from adipose and liver
Stimulate pancreas to release insulin
Glucose antagonist
Increases contractility, HR, and AV conduction- increases cAMP
Releases biliary sphincter in ERCP
N/V
Insulin
Beta cells Anabolic- promotes energy storage Stimulates Na/K ATPase to decrease serum K Glucose=primary stimulator of release Beta agonists=increased serum glucose
Somatostatin
Delta cells
Growth hormone inhibitions hormone
Inhibits insulin and glucagon
Inhibits splanchnic blood flow, gastric motility, and gall bladder contraction
Pancreatic polypeptide
PP cells
Inhibits pancreatic exocrine secretion, gallbladder contraction, gastric acid and motility
Insulin receptor
2 alpha and 2 beta subunits- insulin binds to beta
Activate tyrosine kinase and activate substrates
Turns on GLUT 4 transporter to increase glucose uptake into muscle and fat
Organs that dont need insulin for glucose uptake
Brain- needs steady glucose supply to function
Liver
Diabetes triad
Polyuria
Dehyrdation
Polydipsia
DKA
Cause=infection
Ketoacidosis, hyperosmolarity, dehydration
Hyperglycemia but cells starved for fuel
Metabolic acidosis= kussmaul respirations
Acetone= fruity breath
Tx= volume, inclusion, K after acidosis
HHS
Enough produced to prevent ketones, but not hyperglycemia (greater than 600)
Increases osmolarity
Dehydration and hypovolemia
Mild metabolic acidosis (no gap)
Tx= volume, insulin, correct electrolytes
prayer sign
Joint glycosylation
Increased risk of difficult intubation
Biguanides
Metformin MOA- inhibits gluconeogensis and glycogenolysis in liver, decreased peripheral insulin resistance NO hypoglycemia Lactic acidosis Vit B12 deficiency used in PCS Discontinue 48 hours before surgery
Sulfonylureas
Glyburide, glipizide, glimepiride, gliclazide, tolbutamide, chlorpromazine, acetohexamide MOA- stimulates insulin secretion CAN cause hypoglycemia Avoid in sulfa allergy Discontinue 24-48 hours before surgery
Meglitinides
Repaglinide, nateglinide
MOA- stimulates insulin secretion
CAN cause hypoglycemia
Thiazolidinediones
Rosiglitazone, pioglitazone
MOA- decrease insulin resistance, increase hepatic glucose utilization
NO hypoglycemia
Black block warning- increased risk of CHF
A Glucosidase inhibitors
Acarbose, miglitol
Slows digestion and absorption of carbs
NO hypoglycemia
Glucagon like peptide 1 receptor agonists
Exenatide, liraglutide
Increase insulin release, decrease glucagon release, prolong gastric emptying
Risk of hypoglycemia
Dipeptidyl peptidase 4 inhibitors
:liptin
Increase insulin release, decrease glucagon release
Risk of hypoglycemia
Myelin agonists
Pramlintide
Inhibit glucagon release, reduce gastric emptying
Risk of hypoglycemic with insulin
N/V
Goals of insulin therapy
HbA1c less than 7
Glucose 70-130 (before meal)
Glucose less than 180 (after meal)
Carcinoid syndrome
Secretion of vasoactive substances from enterochromaffin cels
Usually GI tumors
Cleared by liver- in liver dysfunction have mimicked symptoms
Flushing and diarrhea
Concurrent cardiac disease= pulmonic stenosis and tricuspid regurg
Carcinoid syndrome and drugs
Give- somatostatin, antihistamines, serotonin antagonis, steroids
Don’t give- histamine releasing, succ, exogenous catecholamine, sympathomimetic
When does glycosuria occur
Serum glucose greater than 180 mg/dL
Renal hormone production
Erythropoietin
Calcitrol
Prostaglandins
Calcitrol
Synthesize from Vit D
Converted to inactive rom in liver
Active form (1.25 Oh 2- Active Vit D3)
Stimulates absorption from Ca2 from food
Stimulates bone to store
Stimulates kidneys to reabsorb
Cardiac output to kidneys
20-25%
Blood filtered through glomerulus
20% of kidneys blood
amount of ultrafiltrate reabsorbed
99%
Amount of urine produced daily
1-1.5L/day
Renal blood flow
(MAP - renal venous pressure)/ renal vascular pressure
Renal autoregulation
50-180 mmHg
Conditions that increase renin release
Decreased renal perfusion pressure
SNS activation (B1)
TGF- decreased Na and CL in distal tubule
Renin
From JG cells in kidney
ACE
From lung
Serum osmolarity
2 Na + (glucose/18) + (BUN/28)
Na=primary determinant
Normal serum osmolarity
280-290 mOsm/L
Stimulation of ADH
Increased osmolarity of ECF
Decreased blood volume- baroreceptors in carotid bodies, transverse aortic arch, great veins, and RA
Anesthetic considerations that increase ADH
PEEP
Positive pressure ventilation
Decreased BP
Hemorrhage
Da 1
Increases cAMp
Vasodilation, increased RBF and GFR
Da 2
Decreased cAMP
Decreased NE release
GFR
125 mL/min
180 mL/day
Filtration fraction
20%
Net filtration
Glomerular hydrostatic pressure- Bowman’s capsule hydrostatic pressure- glomerular oncotic pressure
urinary excretion rate
Filtration-reabsorption+ secretion
Carbonic anhydrase inhibitors
Acetazolamide
Noncompetitively inhibit Ca in proximate tubule
Leads to reabsorption HCO3, Na, and H2O
Alkaline urine and hyperchloremic metabolic acidosis
Decreases K
Osmotic diuretics
Mannitol, glycerin, isosorbide
Sugars that get filtered and not reabsorbed- inhibit water reabsorption in proximal tubule and LOH
CHF, pulm edema, enters brain in disrupted BBB
Loop diuretics
Furosemide, bumetanide, ethacrynic acid
Disturbs Na K 2 CL transporter in thick ascending LOH
Large vol of dilute urine- with K, Ca, Cl
Decreased K, hypochloremic metabolic alkalosis
Ototoxicity
Decreased lithium clearance
Thiazides diuretics
Hydrochlorothiazide, chorthalidone, metolazone, indapamide
Inhibit NaCl cotrasnporter in distal tubule
Activates NaCa antiporter in distal tubule=increased Ca
Increase glucose
Increased Uric acid
Decreased K, hypochloremic metabolic alkalosis
Potassium sparing diuretics
Amiloride, traimterine- inhibit K secretion and Na reabsorption in collecting duct
Spironolactone- aldosterone antagonist at MC receptor in collecting duct
Metabolic acidosis
Libido changes and gynecomastia
BUN
10-20 mg/dL
<8= overhydration or decreased production 20-40= dehydration, increased protein, decreased GFR, catabolism >50= decreased GFR
Serum creatinine
0.7-1.5 mg/dL By product of creatine breakdown Proportional to muscle mass Filtered by NOT reabsorbed 100% increased= 50% GFR decrease
BUN: creatine ratio
10:1
> 20:1 suggest prerenal azotemia
Creatine clearance
110-150 mL/min
Most useful indicator of GFR
GFR calculation
((140-age) x weight in kg))/(72 x serum creat)
Multiply by 0.85 in women
Fractional excretion of sodium
1-3%
Relationship of Na clearance to creatinine clearance
<1%- increased Na conserved compared to creatinine cleared= prerenal azotemia
>3%- increased Na excreted compared to creatinine cleared= impaired tubular function
Urinary sodium
130-260 mEq/day
Failing kidneys waste Na
Urine protein
Large amount indicates glomerular injury
> 750 mg per day
+3 on urinalysis
Specific gravity
1.003-1.030
Weight of urine compared to sterile O2
Increase= more concentrated urine
Urine osmolality
65-1400 mOsm/L
Better test of tubular function than specific gravity
Risk factors for AKI
Prexisitng kidney condition Prolonged decreased perfusion CHF Increased age Sepsis Jaundice High risk surgery (cross clamp or liver transplant)
Hyperventilation and PaCO2 impact on K
10 mmHg decreased in PaCO2 leads to 0.5 mEq/L K decrease
Increases production of Comp A
High concentration of sevo
Decreased FGF
Increased temp of absorbent
Increased CO2
TURP fluid
Distilled water- increased TURP risk
Glycine- post op visual problems
Sorbitol- osmotic diuresis, increased sugar, lactic acidosis
Mannitol- osmotic diuresis, transient plasma volume increase
Na Cl 0.9%- fire risk with mono polar cautery
TURP syndrome
Htn
Bradycardia
Mental status change
Decreased serum sodium
