56.2 📚 國考版醫垫國考 / PGY OSCE

56.2.0.1 📌 Cram Sheet

56.2.0.1.1 🔥 高 yield 12
  1. HypoNa workflow: osm → volume status
  2. SIADH = euvolemic hypoNa most common (urine osm > 100)
  3. HypoNa correct < 8-10 mEq/L/24h (防 ODS)
  4. HyperNa correct < 0.5 mEq/L/h (防 cerebral edema)
  5. DI: central (DDAVP) vs nephrogenic (thiazide)
  6. HyperK ECG: peaked T → QRS wide → sine → asystole
  7. HyperK 急救順序: Ca → insulin → β-agonist → bicarb → loop / lokelma → dialysis
  8. HypoK + hypoMg → Mg first
  9. Thyrotoxic periodic paralysis in Asian male
  10. 3% NaCl 100 mL bolus for severe symptomatic hypoNa
  11. Lokelma / patiromer > kayexalate (22E)
  12. Tolvaptan for SIADH refractory water restriction
56.2.0.1.2 🔢 必背
項目 æ•žå­—
Hyponatremia < 135
Severe < 120
HypoNa correct < 8-10/24h
ODS risk > 10-12/24h
Hypernatremia > 145
HyperNa correct < 10-12/24h
3% NaCl bolus 100 mL × 1-3
Hyperkalemia > 5.0
Calcium gluconate 1-2 g IV
Insulin + glucose 10 U + D50 25 g
Hypokalemia < 3.5
IV K peripheral < 10 mEq/h
IV K central < 20 mEq/h
56.2.0.1.3 易錯
  • HypoNa 倪快 → ODS
  • HyperK 䞍 Ca first
  • HypoK 䞍 Mg first
  • Insulin 沒 glucose
  • Kayexalate ileus
  • DI 䞍分 central/nephrogenic

56.2.0.2 ⭐ 高 yield 摘芁

56.2.0.2.1 Hyponatremia DDx

Hypotonic: - Hypovolemic: GI, diuretic, salt-losing - Euvolemic: SIADH, hypothyroid, glucocorticoid, beer potomania - Hypervolemic: HF, cirrhosis, nephrotic

Pseudohyponatremia: lipid, protein → normal/high osm Translocational: hyperglycemia (correct: + 2.4 per 100 mg/dL > 100)

56.2.0.2.2 SIADH Causes
  • Malignancy: SCLC, head/neck SCC
  • CNS: stroke, hemorrhage, infection, trauma
  • Pulmonary: PNA, TB
  • Drugs: SSRI, SNRI, carbamazepine, oxcarbazepine, MDMA
  • Postoperative
56.2.0.2.3 SIADH Treatment
  • Water restrict 1 L/d
  • Salt tablet
  • Urea
  • Loop diuretic
  • Vasopressin antagonist (tolvaptan, conivaptan) — caveat liver
56.2.0.2.4 Hypernatremia Causes
  • Pure water loss: insensible, fever
  • Hypotonic loss: osmotic diuresis, diuretic
  • DI: central (DDAVP) vs nephrogenic (Li, hyperCa, hypoK)
  • Salt gain (rare)
56.2.0.2.5 Water Deficit Calculation
  • Total body water (TBW) = 0.6 × kg (M) or 0.5 × kg (F)
  • Free water deficit = TBW × (Na/140 - 1)
  • Replace half in 24h, rest in 24-48h
56.2.0.2.6 Hyperkalemia

Causes: - Cell shift: acidosis (mineral), insulin def, β-blocker, succinylcholine, lysis (rhabdo, TLS) - ↓ excretion: AKI/CKD, ACEI/ARB, spiro, NSAID, RTA IV - Spurious: hemolysis, thrombocytosis

ECG progression: peaked T → QRS wide → PR long → sine → asystole

Treatment: 1. Ca gluconate 1-2 g IV (10% × 10 mL) 2. Insulin 10 U + D50 25 g 3. Albuterol nebulizer 4. NaHCO3 if acidotic 5. Loop diuretic 6. Patiromer / lokelma / kayexalate 7. Dialysis

56.2.0.2.7 Hypokalemia Causes
  • GI: diarrhea, vomiting, NG
  • Renal: diuretic, hyperaldosterone, RTA 1/2, hypoMag, Bartter, Gitelman
  • Cell shift: insulin (refeeding), β-agonist, alkalosis, hyperthyroid (TPP), hypothermia
56.2.0.2.8 Calcium Sensing & Gitelman / Bartter
  • Bartter: NKCC2 mutation (loop), normomag, hyperCa urine
  • Gitelman: NCC mutation (DCT), hypomag, hypoCa urine, like thiazide
56.2.0.2.9 Refeeding Syndrome
  • Severe malnutrition + 突然逵食 → insulin spike → cell uptake P, K, Mg
  • Hypophosphatemia, hypoK, hypoMg, thiamine def
  • 防先 thiamine + slow feeding + replete electrolytes

56.2.0.3 🎯 自我檢枬

  1. SIADH urine osm? → > 100
  2. HypoNa correct rate? → 8-10 mEq/L/24h
  3. ODS at? → > 10-12 mEq/L/24h
  4. HyperK first drug? → Calcium gluconate
  5. DI central treatment? → DDAVP
  6. DI nephrogenic causes? → Li, hyperCa, hypoK
  7. Hyperglycemia hypoNa correction? → + 2.4 per 100 mg/dL > 100
  8. Tolvaptan use? → SIADH (caveat liver)
  9. Refeeding syndrome electrolytes? → Low PO4, K, Mg
  10. Hypokalemia + Mg? → Replace Mg first

⚠ AI 草皿。