Thyroid Disease
High-Yield One-Liner: Disorders of thyroid hormone production causing metabolic slowing (hypothyroid) or hypermetabolism (hyperthyroid).
Physiology / labs
- TRH → TSH → T3/T4; negative feedback.
- T3 is most active; T4 is reservoir/prohormone.
- Primary hypothyroid: ↓ T4, ↑ TSH.
- Hyperthyroid: ↑ T3/T4, ↓ TSH.
Dr. K style: what matters in OR
- Hyperthyroid: prevent sympathetic stimulation and thyroid storm.
- Hypothyroid: sensitive to anesthetics, opioids, benzodiazepines.
- Direct-acting vasopressors preferred over ephedrine in hyperthyroid patients.
- Eye protection matters with Graves/proptosis.
Thyroid storm
- Life-threatening hyperthyroid crisis; often postop 6–18 hr.
- Fever, tachycardia, dysrhythmia, HTN, agitation/confusion, CHF.
- Differentiate from MH, pheo, light anesthesia.
- Treat clinically; don’t wait for labs.
Myxedema coma
- Severe hypothyroidism: coma/stupor, hypoventilation, hypotension, hypothermia, hyponatremia.
- Mortality can be >50%.
- Only lifesaving emergency surgery should proceed.
Treatment / anesthesia
- Hyperthyroid: PTU/methimazole, beta blocker, iodine after thionamide, steroids/supportive care if storm.
- Avoid ketamine, pancuronium, atropine/glycopyrrolate when not needed.
- Ensure euthyroid before elective surgery.
- Hypothyroid: continue levothyroxine; monitor temp, ventilation, myocardial function.
- Myxedema: intubate if needed, IV levothyroxine, hydrocortisone, fluids/electrolytes, cautious warming.
Flashcards
Cushing’s / Addison’s Disease
High-Yield One-Liner: Cushing = cortisol excess; Addison/adrenal insufficiency = cortisol deficiency, with opposite perioperative problems: hyperglycemia/HTN versus shock/hypoglycemia.
Adrenal cortex zones
GFR = Salt, Sugar, Sex
- Zona glomerulosa → aldosterone.
- Zona fasciculata → cortisol.
- Zona reticularis → androgens.
Cushing syndrome
- Excess cortisol: central obesity, moon face, buffalo hump.
- HTN, hyperglycemia, hypokalemia, poor wound healing, infection risk.
- Fragile skin/bones; difficult positioning/IV access.
Addison / adrenal insufficiency
- Deficient cortisol ± aldosterone.
- Hypotension, hypovolemia, hyponatremia, hyperkalemia, hypoglycemia.
- Primary may have hyperpigmentation from ↑ ACTH.
Adrenal crisis
- Think refractory hypotension/shock.
- Treat: hydrocortisone 100 mg IV, aggressive fluids, glucose/electrolyte correction, vasopressors if needed.
Stress-dose steroid memory
- Minor surgery: hydrocortisone 25 mg IV before induction.
- Moderate surgery: 50–75 mg IV before induction, taper.
- Major surgery: 100–150 mg IV before induction, taper by condition.
Flashcards
Conn’s Disease
High-Yield One-Liner: Excess aldosterone production leading to hypertension, hypokalemia, and metabolic alkalosis.
Patho
- Primary hyperaldosteronism, usually adrenal adenoma.
- ↑ sodium/water retention → HTN.
- ↑ potassium wasting → hypokalemia.
- Metabolic alkalosis.
Anesthesia implications
- Correct K+ before surgery.
- Monitor glucose, acid/base status, fluid balance.
- Avoid hyperventilation because alkalosis can worsen hypokalemia.
- Hypokalemia may prolong neuromuscular blockade and promote dysrhythmias.
Flashcards
Diabetes
High-Yield One-Liner: Disorder of insulin production or insulin resistance resulting in impaired glucose regulation.
Core patho
- Type 1: autoimmune beta-cell destruction → absolute insulin deficiency → DKA risk.
- Type 2: insulin resistance + relative beta-cell insufficiency.
- Stress hormones increase glucose: glucagon, cortisol, epinephrine, GH.
Periop targets / concerns
- Common inpatient goal: 140–180 mg/dL.
- Autonomic neuropathy: silent ischemia, gastroparesis, labile BP.
- Renal disease, infection risk, poor wound healing.
- Hypoglycemia is masked under anesthesia.
DKA
- Hyperglycemia + ketones + metabolic acidosis + dehydration.
- K+ may look high initially despite total body depletion.
- Treat: fluids first, insulin, potassium, trigger.
HHS
- Extreme hyperglycemia, hyperosmolarity, severe dehydration.
- Minimal ketones/acidosis.
- Altered mental status is common.
Medication traps
- Metformin: lactic acidosis concern with renal dysfunction/contrast/hypoperfusion.
- Sulfonylureas: hypoglycemia risk.
- SGLT2 inhibitors: euglycemic DKA risk; hold several days preop.
- GLP-1 agonists: delayed gastric emptying/aspiration concern.
- Basal insulin often continued at reduced dose.
- Short-acting insulin adjusted/held based on NPO and glucose.
- Check glucose frequently; treat trends, not vibes.
Flashcards
Pheochromocytoma
High-Yield One-Liner: Catecholamine-secreting tumor causing episodic hypertension, tachycardia, headaches, sweating, and dangerous perioperative hemodynamic swings.
DO NOT beta block first:
- Alpha blockade must come before beta blockade.
- Beta blockers before alpha blockade can leave unopposed alpha-1 vasoconstriction.
- This can cause severe hypertension, myocardial ischemia, pulmonary edema, and possible cardiovascular collapse.
- Typical prep: phenoxybenzamine or selective alpha-1 blockade first, volume expansion, then beta blocker only if tachycardia persists.
Patho
- Catecholamine-secreting tumor, usually adrenal medulla.
- Classic triad: headache, sweating, palpitations/tachycardia.
- HTN may be sustained or paroxysmal.
- Can cause hyperglycemia, cardiomyopathy, dysrhythmias.
Golden rule
Alpha before beta. Always.
- Phenoxybenzamine/doxazosin first.
- Beta blocker only after adequate alpha blockade.
- Volume expansion before OR.
OR plan
- A-line before induction, large bore IVs, vasoactive drugs drawn up.
- Blunt laryngoscopy response.
- Avoid fear, pain, hypoxia, hypercarbia, shivering.
- Avoid ketamine, pancuronium, atropine, morphine/atracurium if possible.
Hemodynamic swing
- Tumor manipulation → severe HTN.
- After venous ligation/removal → severe hypotension.
- HTN: nitroprusside, nicardipine, phentolamine, magnesium, esmolol as needed.
- Hypotension: fluids + vasopressors.
Flashcards
Pituitary: DI, SIADH, Acromegaly
Hormones
- Anterior: ACTH, TSH, GH, FSH, LH, prolactin.
- Posterior: ADH/vasopressin, oxytocin.
Acromegaly
- Excess GH in adults.
- Large tongue, prognathism, OSA, difficult mask/intubation.
- HTN, cardiomyopathy, diabetes.
DI
- ADH deficiency/resistance.
- Polyuria, dilute urine, hypernatremia, dehydration.
- Treat: desmopressin + replace free water/volume.
SIADH
- Excess ADH → water retention.
- Hyponatremia, low serum osm, confusion/seizures.
- Treat: fluid restriction; hypertonic saline if severe/symptomatic.
Flashcards
Calcium / Parathyroid
High-Yield One-Liner: Disorders of calcium regulation affect neuromuscular excitability, cardiac conduction, coagulation, and hemodynamic stability.
Albumin Correction = Testable:
- Total calcium is partly albumin-bound, so low albumin can make total calcium look falsely low.
- Corrected calcium formula: corrected Ca = measured Ca + 0.8 × (4.0 − albumin).
- Ionized calcium is the physiologically active calcium and is more useful when albumin or pH is abnormal.
- Acidosis increases ionized calcium because less calcium binds albumin.
- Alkalosis decreases ionized calcium because more calcium binds albumin — hyperventilation can worsen symptoms of hypocalcemia.
Normal + binding
- Total Ca: ~8.5–10.5 mg/dL.
- Ionized Ca is the active form.
- Low albumin lowers total Ca, not necessarily ionized Ca.
- Acidosis ↑ ionized Ca; alkalosis ↓ ionized Ca.
Hypocalcemia
- Tetany, Chvostek, Trousseau, paresthesias.
- Prolonged QT, seizures, laryngospasm/stridor.
- Treat with IV calcium gluconate or calcium chloride.
Hypercalcemia
- Shortened QT, dysrhythmias, weakness, dehydration.
- Stones, bones, groans, psychiatric overtones.
- Treat: IV fluids, calcitonin, bisphosphonates, dialysis if severe.
Thyroidectomy PACU trap
- Postop hypoparathyroid/hypocalcemia may occur 24–48 hr after thyroid surgery.
- Stridor can progress to laryngospasm.
- Neck hematoma = open wound/evacuate if airway compromise.
Flashcards
Mixed Dr. K-Style SATA Drill
These are intentionally picky: multiple distractors are “kinda true” but not best for the stem.