22.2 📚 國考版（醫師國考 / PGY OSCE）

M6 / PGY 國考衝刺。FUO 定義 + 病因 + workup 必考。

22.2.0.1 📌 一頁重點整理 (Cram Sheet)

22.2.0.1.1 🔥 高 yield 12 條
  1. Petersdorf 1961 定義：T ≥ 38.3°C + > 3 週 + 1 週住院/3 次門診/3 天住院 undiagnosed
  2. 4 types: Classic / Nosocomial / Neutropenic / HIV-associated
  3. 4 病因: Infection 30% / Malignancy 20% / NIID 25% / Misc + Undx 25%
  4. AOSD: spiking fever + salmon rash + arthritis + 極高 ferritin
  5. GCA in elderly FUO: ESR ↑ + jaw claudication
  6. IE in IVDU + new murmur
  7. Lymphoma B symptoms: fever + night sweats + weight loss
  8. PET-CT 22E 主流 for FUO
  9. Drug fever + Faget sign（relative bradycardia）
  10. 30% undiagnosed but self-limited
  11. Empiric antibiotic NOT routine for classic FUO
  12. Neutropenic FUO 與 classic 完全不同（< 1 hr antibiotic）
22.2.0.1.2 🔢 必背數字
項目 數字
Fever cutoff T ≥ 38.3°C (101°F)
Duration > 3 週
Outpatient evaluation 3 次
Inpatient evaluation 1 週（or 3 天）
Undiagnosed % ~30%
Infection % ~30%
Malignancy % ~20%
NIID % ~25%
AOSD ferritin > 1000（often > 10,000）
AOSD glycosylated ferritin < 20%
HIV CD4 < 200 PCP, MAC, TB, fungal, lymphoma
HIV CD4 < 50 CMV, cryptococcosis
22.2.0.1.3 ⚠️ 易錯陷阱
  • FUO 給 empiric broad antibiotic（錯）
  • 老人 FUO 不查 GCA（錯）
  • ANA - 排除 SLE（錯）
  • 不做 BC × 3（錯）
  • 把 nosocomial 當 classic（不同 timeline）

22.2.0.2 ⭐ 高 yield 摘要

22.2.0.2.1 Petersdorf Definition (Modified 1991)
條件 數值
Fever T ≥ 38.3°C (101°F) on multiple occasions
Duration ≥ 3 週
Workup not yielding 1 週 inpatient OR 3 outpatient visits OR 3 days hospital
22.2.0.2.2 4 Types of FUO
Type 定義 主要病因
Classic 傳統 community Infection / Malignancy / NIID
Nosocomial 入院 ≥ 24h + admission 無 fever Catheter, C. diff, drug, DVT/PE
Neutropenic ANC < 500 Bacterial / fungal sepsis
HIV-associated HIV+ + > 4 週 OI（依 CD4）、lymphoma
22.2.0.2.3 Classic FUO 4 大類病因
類別 % 代表
Infection ~30 TB extrapulmonary, IE, abscess, mycoses, Q fever
Malignancy ~20 Lymphoma, RCC, HCC, leukemia, atrial myxoma
NIID ~25 AOSD, GCA, SLE, vasculitis, IBD, sarcoid, FMF
Misc / Undx ~25 Drug fever, factitious, DVT, undiagnosed
22.2.0.2.4 Adult-Onset Still’s Disease (AOSD)

Yamaguchi Criteria (5/8, 含 ≥ 2 major)： - Major: - Fever ≥ 39°C ≥ 1 週 - Arthralgia ≥ 2 週 - Salmon-pink rash with fever spikes - WBC > 10,000 with > 80% neutrophils - Minor: - 喉嚨痛 - LAP / 脾大 - LFT ↑ - ANA + RF negative

輔助：ferritin 極高（often > 1000；> 10,000 highly suggestive）+ glycosylated ferritin < 20% = highly specific

處置：NSAID → steroid → IL-1 antagonist (anakinra) / IL-6 (tocilizumab)

22.2.0.2.5 Lymphoma B Symptoms
  • Fever > 38°C
  • Drenching night sweats
  • Weight loss > 10% in 6 months
    • LAP / HSM 必查
22.2.0.2.6 IE Diagnosis (Modified Duke Criteria)
  • Major:
    • Positive BC（typical organism × 2 sets）
    • Echo evidence of vegetation / abscess / new dehiscence
  • Minor:
    • Predisposing condition
    • Fever ≥ 38°C
    • Vascular phenomena (Janeway, septic emboli)
    • Immunologic phenomena (Osler, Roth, GN)
    • Microbiology not meeting major
22.2.0.2.7 Faget Sign（Relative Bradycardia）
  • 每升 1°C 心跳應 ↑ 10 bpm
  • Drug fever, typhoid, brucellosis, Legionella, leptospirosis, Q fever
22.2.0.2.8 PET-CT in FUO（22E 強調）
  • Increasingly first-line imaging
  • Sensitive for inflammation + malignancy
  • Higher diagnostic yield than CT
  • 健保限制部分 indication
22.2.0.2.9 HIV CD4 vs OI
CD4 OI
< 500 TB, candidiasis, HZ
< 200 PCP, toxoplasmosis
< 100 Cryptococcosis, MAC, CMV
< 50 Severe CMV (CNS, retinal), MAC disseminated

22.2.0.3 🏆 易混淆對照

22.2.0.3.1 AOSD vs Lymphoma
  • AOSD: salmon rash + arthritis + ferritin 極高 + ANA/RF -
  • Lymphoma: B symptoms + LAP > size > 2 cm + biopsy
22.2.0.3.2 TB vs Lymphoma（皆可 night sweats + weight loss）
  • TB: 旅遊/暴露/HIV、AFB、CXR
  • Lymphoma: lymphadenopathy + biopsy → diagnostic
22.2.0.3.3 GCA vs Polymyalgia Rheumatica
  • GCA: cranial symptoms + jaw claudication + ESR > 50 + biopsy
  • PMR: 雙肩/雙髖 morning stiffness + ESR > 40
  • 50% co-occur
22.2.0.3.4 Drug Fever Features
  • 多 7-14 天 after drug start
  • Faget sign
  • Eosinophilia
  • 停藥 24-72 hr 退燒

22.2.0.4 📝 過去考題類型

22.2.0.4.1 必考
  • FUO Petersdorf definition
  • 4 types FUO 區分
  • 4 病因類別分布
  • AOSD Yamaguchi
  • GCA in elderly FUO
  • IE Duke criteria
  • Drug fever Faget sign
  • PET-CT 用處
22.2.0.4.2 OSCE
  • FUO history（涵蓋 travel, animal, drug, occupation, family）
  • BC × 3 採血
  • Stepwise workup discussion
22.2.0.4.3 陷阱題
  • FUO 給 empiric antibiotic
  • 老人 FUO 不查 GCA
  • 把 nosocomial 當 classic

22.2.0.5 🎯 自我檢測

  1. Q：Petersdorf classic FUO 3 條件？ A：T ≥ 38.3°C + > 3 週 + 1 週住院/3 門診/3 天住院 undiagnosed

  2. Q：4 types FUO？ A：Classic / Nosocomial / Neutropenic / HIV-associated

  3. Q：Classic FUO 4 大病因 + 比例？ A：Infection 30% / Malignancy 20% / NIID 25% / Misc + Undx 25%

  4. Q：AOSD 4 個 major Yamaguchi criteria？ A：Fever ≥ 39 ≥ 1 週、Arthralgia ≥ 2 週、Salmon rash、WBC > 10k 80% neutrophil

  5. Q：AOSD 重要 lab？ A：Ferritin 極高（often > 10,000）+ glycosylated < 20%

  6. Q：> 50yo FUO 必查？ A：GCA（ESR + temporal a. US/biopsy）

  7. Q：Faget sign 表示什麼？6 病？ A：Relative bradycardia；Drug fever, typhoid, brucellosis, Legionella, leptospirosis, Q fever

  8. Q：HIV CD4 < 200 OI 4 個？ A：PCP, toxoplasmosis, TB, lymphoma

  9. Q：FUO 是否 routine empiric antibiotic？ A：No（除非 neutropenic、suspected IE）

  10. Q：22E 強調什麼影像 first-line FUO？ A：PET-CT

22.2.0.6 📚 想深入請看

⚠️ AI 草稿，未經盧醫師驗證。