385.4 📋 章末速蚘 Summary

385.4.1 🔑 䞀句話瞜結

Prion diseases (transmissible spongiform encephalopathies TSEs) = caused by misfolded prion protein (PrP) — PrPC normal cellular misfolds to PrPSc (scrapie-like) that templates further misfolding (self-propagating) + resistant to standard sterilization; human prion diseases classification — sporadic CJD (sCJD ~ 85%) + familial/genetic (~ 15%) — fCJD + Gerstmann-StrÀussler-Scheinker (GSS, ataxia + late dementia, P102L) + fatal familial insomnia (FFI, D178N + 129M, insomnia + autonomic + motor + thalamus prominent) + acquired (rare) — variant CJD vCJD from BSE “mad cow” + iatrogenic CJD (dural grafts + growth hormone historical + neurosurgery instruments + corneal transplants) + kuru (historic Papua New Guinea ritualistic cannibalism); sCJD presentation — mean onset 65 (40-90) + rapid progression median survival 4-7 months from onset + rapidly progressive dementia + myoclonus (startle myoclonus characteristic) + cerebellar ataxia + visual changes (Heidenhain variant — occipital) + behavioral changes + pyramidal/extrapyramidal signs + akinetic mutism terminal; vCJD features — BSE-related + younger (mean 28) + longer course ~ 14 months + psychiatric symptoms early + painful dysesthesia + pulvinar sign (bilateral thalamic) on MRI + tonsillar biopsy can detect PrPSc; diagnosis — MRI very useful: cortical ribboning on DWI (cortex bright) + basal ganglia hyperintensity on DWI/FLAIR + EEG: periodic sharp wave complexes (PSWCs) in sCJD (late, ~ 65% sensitive) + CSF: RT-QuIC (real-time quaking-induced conversion) most accurate > 95% sens/spec >> 14-3-3 protein sensitive but less specific + total tau ↑ + brain biopsy/autopsy gold standard with spongiform vacuolation + PrPSc immunostaining; no effective treatment — supportive only; anti-prion drugs (quinacrine, doxycycline) unsuccessful; investigational antisense (PRN100, BIIB104) limited efficacy so far; HIV-associated neurocognitive disorder (HAND) — Frascati criteria (ANI, MND, HAD); even on cART 20-50% have some HAND; subcortical pattern (psychomotor slowing + attention + executive + bradykinesia + gait + apathy + depression); treatment cART + supportive; neurosyphilis — tabes dorsalis + general paresis + meningovascular; VDRL CSF + treponemal serum + IV penicillin G 18-24 million units/d × 10-14 days; Whipple disease CNS = Tropheryma whipplei + oculomasticatory myorhythmia PATHOGNOMONIC + dementia + ataxia + ophthalmoplegia + often GI symptoms → PCR or biopsy → ceftriaxone → TMP-SMX or doxycycline + hydroxychloroquine; autoimmune encephalitis — subacute cognitive decline + psychiatric + seizures; anti-NMDA-R (young women, paraneoplastic ovarian teratoma + others, psychiatric → seizures → movement → autonomic) + anti-LGI1 (faciobrachial dystonic seizures + amnesia + hyponatremia) + anti-CASPR2 + anti-GAD65 + onconeural Hu/Ma2/CV2 (paraneoplastic); immunotherapy (IVIG, methylprednisolone, rituximab, cyclophosphamide); Hashimoto encephalopathy (SREAT — steroid-responsive encephalopathy associated with autoimmune thyroiditis) — anti-TPO high + subacute + steroid-responsive + mimics CJD (always check anti-TPO in rapidly progressive); reversible/treatable dementias must rule out — B12 deficiency + Wernicke-Korsakoff (thiamine) + heavy metals + hepatic/uremic encephalopathy + hypothyroidism (myxedema dementia) + hyperparathyroidism + Hashimoto encephalopathy + CO poisoning + alcohol-related + substance-induced + neurosyphilis + HIV + NPH + autoimmune + medication side effects + Wilson disease (always test in young < 40 with movement + cognitive + KF rings, low ceruloplasmin, high urine copper); rapidly progressive dementia mnemonic VITAMINS — Vascular + Infectious + Toxic + Autoimmune + Metabolic + Iatrogenic + Neoplastic + Seizure/Structural/sCJD; leukodystrophies + mitochondrial (MELAS, MERRF) + storage diseases also considered。

385.4.2 💊 治療粟芁

  • prion (sCJD, vCJD, GSS, FFI)no effective treatment — supportive only; investigational antisense (PRN100, BIIB104) limited efficacy
  • HANDcART optimization (some agents better CNS penetration — CHARTER score) + supportive
  • neurosyphilisIV penicillin G 18-24 million units/d × 10-14 days (continuous infusion or 3-4 million units q4h); aqueous procaine PCN alternative; probenecid 500 mg QID improves CSF levels
  • Whipple CNSceftriaxone 2 g IV daily × 14 days → TMP-SMX 160/800 mg BID PO × 1-2 years or doxycycline + hydroxychloroquine (controversial regimens)
  • autoimmune encephalitis1st line — IVIG 2 g/kg + methylprednisolone pulse 1 g × 5 days + plasmapheresis; 2nd line — rituximab + cyclophosphamide; treat underlying tumor if paraneoplastic; anti-NMDA-R search for ovarian teratoma
  • Hashimoto encephalopathy (SREAT)high-dose prednisone (1 mg/kg/d) or methylprednisolone pulse — often dramatic response; taper slowly
  • reversible dementias treat underlyingB12 supplementation (1000 ÎŒg IM weekly × 4 weeks then monthly) + thyroid replacement (levothyroxine) + heavy metal chelation + treat hepatic/uremic encephalopathy + thiamine for Wernicke + treat NPH (shunt) + medication discontinuation
  • Wilson diseasechelators (penicillamine 250-500 mg QID + pyridoxine to prevent deficiency, or trientine) + zinc (50 mg TID, blocks intestinal absorption) + low-copper diet + liver transplant for severe
  • CAA-related inflammation (CAA-ri)high-dose steroids (methylprednisolone pulse → oral taper) + immunosuppression for refractory

385.4.3 🎯 盧醫垫的考前提醒

  1. Prion diseases classification: sporadic CJD (sCJD ~ 85% most common) + familial (~ 15% — fCJD + GSS + FFI) + acquired (vCJD from BSE + iatrogenic from dural grafts/growth hormone historical + kuru)
  2. sCJD clinical: mean onset 65 + RAPID progression median 4-7 months survival + rapidly progressive dementia + myoclonus (startle myoclonus characteristic) + cerebellar ataxia + visual changes (Heidenhain variant) + behavioral changes
  3. CJD diagnosis (memorize): MRI cortical ribboning on DWI + basal ganglia hyperintensity + EEG periodic sharp wave complexes (PSWCs) late ~ 65% sensitive + CSF RT-QuIC most accurate > 95% sens/spec >> 14-3-3 protein (less specific) + total tau ↑
  4. vCJD distinguishing: BSE-related + younger (mean 28) + longer course + psychiatric symptoms early + painful dysesthesia + pulvinar sign (bilateral thalamic) on MRI
  5. No treatment for prion diseases — supportive only; anti-prion therapies (PRN100 mAb, BIIB104 antisense) investigational limited efficacy
  6. Reversible/treatable causes of dementia must rule out before declaring degenerative: B12 + Wernicke (thiamine) + hypothyroidism + Hashimoto encephalopathy (anti-TPO, steroid-responsive!) + neurosyphilis + HIV + NPH + autoimmune encephalitis + heavy metals + medication + Wilson (young < 40 + KF rings + ceruloplasmin) + paraneoplastic
  7. Hashimoto encephalopathy (SREAT): anti-TPO high + subacute + MIMICS CJD + STEROID-RESPONSIVE (high-dose prednisone often dramatic response) — always check anti-TPO in rapidly progressive
  8. Whipple disease CNS: oculomasticatory myorhythmia PATHOGNOMONIC + dementia + ataxia + ophthalmoplegia + GI symptoms → ceftriaxone + TMP-SMX or doxycycline + hydroxychloroquine
  9. Autoimmune encephalitis (always consider, treatable): anti-NMDA-R (young women, paraneoplastic ovarian teratoma) + anti-LGI1 (FBDS + amnesia + hyponatremia) + anti-CASPR2 + anti-GAD65 + onconeural paraneoplastic (Hu, Ma2, CV2) → IVIG + methylprednisolone + plasmapheresis + rituximab + cyclophosphamide + treat tumor
  10. VITAMINS mnemonic for rapidly progressive dementia: Vascular + Infectious (HIV, syphilis, Whipple) + Toxic + Autoimmune (encephalitis, Hashimoto) + Metabolic (B12, thyroid, hepatic, uremic) + Iatrogenic + Neoplastic (paraneoplastic, primary CNS lymphoma) + Seizure/Structural/sCJD — workup must include LP + MRI + EEG + autoimmune/paraneoplastic panels + B12 + thyroid + syphilis + HIV