279.3 🏥 內科專科考前版

279.3.1 Mechanistic Deep Dive

279.3.1.1 Cerebral Autoregulation

  • Normal: maintains CBF over MAP 60-150
  • HTN patients: shifted right to 80-180
  • Acute drop below threshold → hypoperfusion
  • Hence gradual lowering (25% in 1h, then 23h)

279.3.1.2 PRES (Posterior Reversible Encephalopathy Syndrome)

  • Vasogenic edema in posterior circulation
  • Causes: HTN, eclampsia, immunosuppressants (calcineurin inh, chemotherapy), uremia
  • Symptoms: HA, vision change, seizures, AMS
  • MRI: T2/FLAIR hyperintensity, occipital + parietal
  • Treatment: BP control, address cause, anti-seizure if needed
  • Usually reversible in days-weeks

279.3.2 Recent Trials & Updates

279.3.2.1 INTERACT-2 (2013) + ATACH-II (2016)

  • ICH BP target < 140 within 1-6h
  • INTERACT-2: ↓ disability (mRS shift), no mortality benefit
  • ATACH-II: no benefit < 140 vs < 180; ↑ renal complications in more intense
  • Current: < 140 reasonable, individualized

279.3.2.2 ENCHANTED-2 / MT (2022-2023)

  • BP after mechanical thrombectomy
  • Lower BP (< 140) target may be harmful in successful recanalization
  • Trade-off: ↓ hemorrhage vs ↓ ischemic stroke
  • Current: < 180 if successful TICI 2c-3; < 140 if hemorrhagic transformation

279.3.2.3 Post-Thrombolysis BP Targets

  • < 180/105 for 24h
  • IV labetalol or nicardipine
  • AHA 2024 update

279.3.3 High-Yield Specialist Points

279.3.3.1 Aortic Dissection Management

  • Type A (ascending): EMERGENCY cardiac surgery
  • Type B (descending): medical first; TEVAR for complicated (rupture, malperfusion, refractory pain)
  • IRAD registry: ~ 30% in-hospital mortality Type A
  • HR control critical (esmolol, propranolol, labetalol)
  • BP < 120 within minutes
  • Vasodilator only AFTER β-blocker on board (avoid reflex tachy)

279.3.3.2 Spinal Cord Autonomic Dysreflexia

  • Spinal injury T6 or above
  • Stimulus below injury → unopposed sympathetic
  • Severe HTN + bradycardia + sweating above injury
  • Treatment: identify stimulus (bladder, bowel), nitrates, nifedipine, sit upright

279.3.3.3 Drug-Induced Crisis Management

  • MAOI + tyramine: phentolamine, nicardipine; AVOID β-blocker
  • Cocaine: BZD first, nitroglycerin, nicardipine
  • Amphetamines: similar to cocaine
  • Decongestants (pseudoephedrine): supportive, fluids

279.3.3.4 Differential of “Severe HTN” Presentation

  • True hypertensive crisis (above)
  • Adrenal mass / pheo
  • TTP/HUS
  • Scleroderma renal crisis (ACEi response)
  • Postoperative
  • Pain / anxiety / volume overload

279.3.3.5 Pediatric Hypertensive Crisis (Brief)

  • Causes: renal parenchymal, coarctation, secondary
  • Agents: labetalol, nicardipine, esmolol, hydralazine
  • Avoid abrupt reduction
  • Refer pediatric nephrology

279.3.3.6 Pregnancy-Specific Pearls

  • BP > 160/110 = severe → treat within 15-30 min
  • IV labetalol 20 mg → 40 → 80 → 80 (max 220 cumulative)
  • IV hydralazine 5-10 mg (slower onset)
  • Oral nifedipine 10 mg
  • Magnesium for eclampsia prophylaxis + treatment
  • Delivery definitive

279.3.3.7 Long-Term Post-Crisis

  • Identify and treat cause (secondary HTN, adherence, drugs)
  • Optimize regimen with SPC
  • F/U weekly initially, then monthly
  • Recurrent crisis rate: 25% in 12 months if not addressed
  • Cardiac and renal protection

279.3.4 Pearls

  • Emergency = end-organ damage; urgency = no damage
  • NO sublingual nifedipine for urgency
  • IV vs oral: based on emergency (IV) vs urgency (oral)
  • Aortic dissection = HR control FIRST (esmolol), then BP
  • ICH = < 140 within 1-6h (INTERACT-2)
  • AIS = permissive ≀ 220/120 unless thrombolysis (< 185/110)
  • Pregnancy / eclampsia = labetalol/hydralazine/nifedipine + magnesium; NO ACEi/ARB
  • Cocaine / pheo = phentolamine + nicardipine; NO β-blocker alone
  • Cyanide toxicity = limit nitroprusside duration / dose