Final_Endocrine Flashcards
· Anterior pituitary- what hormones are produced here?
Growth Hormone ACTH TSH FSH LH Prolactin
· Posterior pituitary- what hormones are stored here? Where are these hormones produced?
Stored: ADH (vasopressin) + Oxytocin
Produced in Hypothalamus
Cushing Syndrome: S&S
muscle wasting, weakness, Osteoporosis
○ Central obesity, abdominal striae, buffalo hump
○ Glucose intolerance
○ Menstrual irregularity
○ HTN
○ Mental status changes - emotional instability
Acromegaly & anesthetic considerations
Airway issues:
- face mask fit
- upper airway obstruction: large tongue; difficult intubation
- May want to do awake fiberoptic (20-30% = difficult intubations)
Nerve stimulator
- may not show true extent of block
- ↓NDMR dose
Skeletal changes may make regional technq difficult or impossible
-Stretching of RLN→ hoarseness or vocal cord paralysis
○ Subglottic narrowing
○ Peripheral nerve entrapment hypertension
○ Diabetes– glucose intolerance; insulin required
○ HTN, cardiac disease
○ Osteoarthritis, osteoporosis
○ Muscle weakness
anesthetic considerations for transsphenoidal approach of pituitary
Positioning- supine, arms at sides; beach chair
● General; ETT; muscle relaxants a necessity
● Careful attention to securing ETT- surgeon will work around/in mouth + nose. –consider RAE tube
● Type and X match.
● Special eye care- tape, ointment, pads
● Urinary output- DI is possible after resection (40% pts post op)
● OG tube- blood accumulates in stomach
● Arterial line, 2 large bore IVs, CVP
●PA cath if cardiac hx
● Precordial doppler – Venous air embolism
● If optic nerves involved– may use visual evoked-potential monitoring
● IV fluids- NS or LR to maintain normovolemia
○ NS-will↓brain fluid > LR
*Avoid glucose/hypotonic soltns→ ↑ free H2O→ cerebral edema
● Keep patient warm- bair hugger, fluid warmer, etc
● Prophylactic antiemetics
● Keep PaCO2 ↓
○ hypoventilation causes cerebral vasodilation
● Avoid N2O
●Antibiotics
● Steroid dose may be indicated
↓NDMR dose
DI- anesthetic management
● Continuous monitoring of U/O
● Hourly measurement of sodium + plasma osmolality
● Pts with complete DI require:
○ Pre-op trans-nasal desmopressin or IV bolus of 100 mU, followed by continuous infusion 100 – 200 mU/h
● Isotonic IVFs should be used for fluid resuscitation
● Close monitoring for myocardial ischemia
○ vasopressin causes vasoconstriction of arteriolar beds
Cushing Syndrome: anesthesia considerations
- May be volume overloaded & hypokalemic metabolic alkalosis (Correct this preop)
- Osteoporosis– At risk for fracture from positioning
- Glucose control- May be difficult
- If HTN exists, some measure of control should be attempted
- Stress induced release of cortisol from the adrenal cortex
SIADH management
Mild SIADH: fluid restriction
● If Na < 120 mEq/L – slow IV 3% saline infusion
● Correct deficit slowly to prevent permanent neuro damage (central pontine demyelination syndrome)
● Demeclocycline- (ABX) antagonizes the effects of vasopressin on the renal tubules. Used for chronic SIADH
● Stress/surgery may initiate an inappropriate release of ADH
● Volume status should be calculated preop
● Peri-op fluid management- restrict fluids- use isotonic solutions
● Careful attention to I & O, fluid status
● Frequent check intraop of Na level
● Prevent nausea– can cause ADH release
● Intra-op CVP to measure fluid volume status
● Monitor: urine osmolality, plasma osmolality, serum Na+
● Emergence considerations should follow the same for any neuro case: Smooth, no bucking, no HTN
● Check nerve stimulator to make sure patient is reversed
● Post op vent may be indicated if surgery took long, patient was a
difficult intubation, or other comorbidities exist
Thyroid regulation and hormones
Thyroid Regulation
● controlled by hypothalamus, pituitary, thyroid glands ● Exogenous iodine is necessary for hormone production
Thyroid hormone: ● ↑ myocardial contractility directly ● ↓ SVR ●↑ Intravascular volume ● Influences growth and maturation of tissues, Stimulates protein synthesis, enhances tissue function
Subtotal thyroidectomy - anesthesia implications
● Establish euthyroidism before surgery
● Pre-op: Anxiolytics & eval of upper airway (CT scan of neck?)
● Induction: No ketamine. Intubate? LMA?
● Maintenance: Any volatiles are safe. N20 and opioids are safe
● Muscle relax: Avoid pancuronium; use glycopyrrolate w/ reversal
● Treat hypotension with phenylepherine
Subtotal thyroidectomy - immediate post op concerns
Post-op Concerns
● Tracheal compression from expanding hematoma
● Rapid respiratory compromise
● Immed. hematoma evacuation- OR ideally, bedside if necessary
● Thyroid tray w/ tracheostomy set - remain w/ pt in post-op period
-Airway obstruction from tracheomalacia (post-extub)
Thyroid Storm
*Medical emergency
● Precipitated by trauma, infxn, medical illness, or surgery
● Thyroid storm + MH present similarly
● Extreme anxiety, fever, tachy/CV instability, alter LOC, shock
● D/t release of T4 & T3 into circulation
Thyroid Storm - management
● Cooled glucose-containing IV fluids, acetaminophen, cooling ● β-Blockers to maintain HR <90 BPM
● Potassium iodide to block release of T4 & T3
● Propylthiouracil (PTU) PO/NGT
● Mortality rate is high: 20%
Pheochromocytoma - most commonly found?
Adrenal Medulla
Pheochromocytoma - S/S
Episodic Tachycardia, diaphoresis, HA, HTN (most common), hyperglycemia, hypovolemia, tremulous, palpitations, wt loss
Conn Syndrome
Adrenal Cortex disorder - Primary aldosteronism
● cause- usually an adenoma
○ ↑ aldosterone levels; hypokalemic metabolic alkalosis
○ HTN, hypernatremia
○ H/A, muscle weakness
Tx: spironolactone or surgical removal of adenoma-adrenalectomy
Addison’s Disease
Adrenal gland: destroyed
TB = common cause
-also autoimmune dysfxn (Hashimotos, DM I, HIV, sarcoidosis, adrenal hemorrhage, trauma)
Secondary insufficiency
- caused by ACTH deficiency from HPA suppression after steroid therapy or pituitary gland dysfunction
Addisons: Rx
● replacement of both mineralocorticoids + glucocorticoids
● PO prednisone
●PO fludrocortisone
** avoid etomidate– Causes suppression of adrenals
Diabetes: diagnostics
● Hemoglobin A1C ≥ 6.5%
● Fasting plasma glucose ≥ 126 mg/dL
● 2-hour plasma glucose ≥ 200 mg/dL during oral glucose tolerance
test
● Random plasma glucose ≥ 200 mg/dL in a pt with symptoms of
hyperglycemia
Diabetes: complications
● Hyperglycemia +/- ketoacidosis
● Hypoglycemia: Activation of SNS (diaphoresis, tremulousness,
and tachycardia) + insufficient delivery of 02 to brain
(confusion, seizures, and unconsciousness)
● Retinopathy ●Nephropathy
● Peripheral neuropathy ●Stiff joint syndrome
● ANS dysfunction (diabetic autonomic dysfunction)
○ Orthostatic HOTN
○Resting tachycardia
○ Exercise intolerance ○Hypoglycemic unawareness
○ Gastroparesis (20% - 30%)
Tx of hyperglycemia
● Administration of large amounts of 0.9% NS
● Effective doses of insulin
○ Loading dose: Regular insulin 0.1 unit/kg IV
○ Infusion: Regular insulin 0.1 unit/kg/hr
○ Decrease insulin gtt when hyperglycemia is controlled,
blood pH is >7.3, and bicarbonate level is >18 meq/L
● Electrolyte supplementation → KCl, K2PO4, Mg
● Caution: Correction of hyperglycemia must be coupled w/ correction of serum sodium
Tx of hypoglycemia
● Discontinue insulin gtt ● Give D50W IV ○ Unconscious patient: 50 mL (1 amp) ○ Conscious patient: 25 mL (1⁄2 amp) ○ Repeat glucose checks q 20 mins ○ Repeat 1⁄2 amp of D50 if BS <60 mg/dL ○ Restart insulin gtt once BS >70 mg/dL after 2 consecutive checks ● IVFs: D5W or D51⁄2NS at 100–200 mL/h
Stress & cortisol
Stress induced cortisol release can result in:
○ Systemic HTN
○ Skeletal muscle weakness
○ ↓ wound healing
○ Hyperglycemia ○Obesity ○Susceptible to infxn
Surgical stimulation can cause this–any effort to control with anesthetic Rx may be futile
Diabetes: Racial disparity
- 7% american indian/alaska natives
- 5% hispanics
- 7% non-hispanic blacks
- 2% asian americans
- 5% non-hispanic whites
DM - anesthesia management preop
● Careful eval of CV, renal, neurologic, & musculoskeletal systems
● Renal system and hydration status
○ D5 1⁄2 NS with 20 mEq KCl/L at 100 cc/hr
● Autonomic neuropathy ↑risk: periop dysrhythmias, intraop HOTN
● Evaluation of musculoskeletal system (AO joint)
● Prior hospitalizations for glycemic instability?
○ H/o DKA, hypoglycemia
○ Non-diabetic meds affecting glucose control (steroids)
● Medications
○ D/C all oral hypoglycemics 24 – 48 hrs pre-op
● Integumentary system (breakdown on feet)
● Should we cancel the case? → No guidelines
○ If emergency surgery is needed
■ Correct hypoglycemia or hyperglycemia
■ Monitor blood glucose frequently
■ Attempt to correct fluid/EL imbalances
● Should we proceed?
○ If proceed: treat blood glucose values above 250 mg/dL
DM - anesthesia management intraop
● Avoid hypoglycemia or hyperglycemia
○ Intra-op glycemic control: 120 – 180 mg/dL
○ 1U Reg insulin lowers glucose by 25 – 30 mg/dL
○ Calculate hourly insulin dose
■ 0.02 unit/kg/hr
■ ↑ insulin requirements for open heart surgery
● Maintain fluid and EL status
○ Insulin drip
○ D51⁄2NS with 20mEq KCl/L 100–150mL/hr
DM - anesthesia management postop
● Optimal peri-operative blood glucose level not established
● ADA recommends postop BG 140 – 180 mg/dL in critically ill
● Hyperglycemia is assoc’ed with poor outcomes
● Aggressive insulin therapy with tight glucose control (80 – 110mg/dL) is associated with better outcomes
