Radiobiology > Deterministic Effects > Whole Body Irradiation Syndromes > Prodromal Syndrome

Whole Body Irradiation: The Prodromal Syndrome

The Prodromal Syndrome

  • Associated with exposures as low as 100 rads (1 Gy), nearly universal above 2 Gy
  • Radiation to the epigastric region most likely to elicit this syndrome
  • Has a latent period of 2-6 hours
  • Sx/Si: Sense of fatigue. Patient may appear withdrawn and uncooperative. Possible headache. Could be confused with depression. GI symptoms vary with dose (mild nausea to retching/vomiting; diarrhea is an ominous sign of higher dose exposure).
  • Recovery after 2-3 days (may be shorter for very mild cases)
  • Epidemiology: More common in women than men. Age <10 years or >60 years at higher risk.

The mechanism of the prodromal syndrome is likely increased tissue and cell permeability, allowing substances like serotonin and histamine to enter chemosensitive cells of the GI tract and activate neural pathways to the vomiting center in the medulla. 

Atropine and nicotine inhibit the response; acetylcholine enhances the severity of the response. Ondansteron or phenothiazine anti-emetics are effective.

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