236.2 📚 國考版

236.2.0.1 必背 — Schistosoma Species

Species Geography Disease Egg
S. mansoni Africa, S America Hepatic + intestinal Lateral spine
S. japonicum E Asia Hepatic + intestinal Round small knob
S. haematobium Africa, Mid East Urinary + bladder CA Terminal spine

236.2.0.2 必背 — Life Cycle

  • Snail intermediate host (specific per species)
  • Cercariae penetrate skin during freshwater contact
  • Adult worms in venous plexuses (mesenteric or vesical)

236.2.0.3 必背 — Clinical Stages

  1. Cercarial dermatitis (swimmer’s itch) — hours after exposure
  2. Katayama fever — 4-8 wk post-exposure, acute schistosomiasis, eosinophilia
  3. Chronic: hepatic (periportal fibrosis), intestinal (diarrhea), urinary (hematuria + bladder CA), neuroschistosomiasis

236.2.0.4 必背 — Hepatic Schistosomiasis

  • Symmers’ pipe-stem periportal fibrosis (S. mansoni, japonicum, mekongi)
  • Portal hypertension with variceal bleeding
  • LFTs preserved early (presinusoidal portal HTN)
  • Hepatosplenomegaly

236.2.0.5 必背 — Urinary Schistosomiasis

  • S. haematobium
  • Terminal hematuria + dysuria
  • Bladder squamous cell carcinoma (chronic inflammation)
  • Hydronephrosis + renal failure

236.2.0.6 必背 — Diagnosis

  • Stool O+P (S. mansoni, japonicum) — eggs with characteristic spines
  • Urine O+P (S. haematobium) — concentrated, terminal hematuria
  • Serology
  • Eosinophilia in acute
  • US (liver, bladder)

236.2.0.7 必背 — Treatment

  • Praziquantel 40 mg/kg PO single dose (S. mansoni, S. haematobium)
  • 60 mg/kg PO (S. japonicum, S. mekongi)
  • 85-95% cure rate

236.2.0.8 必背 — Acute Schistosomiasis Treatment

  • Praziquantel may be ineffective on immature worms
  • Delay treatment 1-2 months or repeat course
  • Steroid for severe acute symptoms

236.2.0.9 必背 — Other Trematodes Quick

Pathogen Source Disease Treatment
Fasciola hepatica Watercress Biliary + RUQ pain + eosinophilia Triclabendazole (single dose)
Clonorchis + Opisthorchis Undercooked freshwater fish (Asia) Biliary + cholangiocarcinoma Praziquantel
Paragonimus Freshwater crab/crayfish Lung (cough + hemoptysis) Praziquantel

236.2.0.10 必背 — Mass Drug Administration

  • Praziquantel annual in endemic communities
  • School-age children + at-risk adults
  • WHO STH + Schistosomiasis programs

236.2.0.11 必背 — Cholangiocarcinoma Risk

  • Opisthorchis viverrini + Clonorchis sinensis (Asian liver flukes)
  • WHO Group 1 carcinogen
  • Endemic regions (NE Thailand high)
  • Praziquantel + screening