Acute Radiation Syndrome (Cont.)

•The signs and symptoms that develop in the ARS occur in four distinct phases: prodromal (initial), latent period, manifest illness stage and recovery or death.

•Prodromal phase. Depending on the dose of radiation, patients may experience a variety of symptoms including loss of appetite, nausea, vomiting, fatigue, and diarrhea. After extremely high radiation doses, additional symptoms such as prostration, fever, respiratory difficulties, and increased excitability may develop.

•Latent period. This is a transitional period in which many of the initial symptoms partially or completely resolve. It may last for a few hours or up to a few weeks depending on the radiation dose. The latent period shortens as the initial dose increases.

•Manifest Illness Stage. These three phases occur with increasing radiation exposure and are described on the following slides.

•The severity of the symptoms increases with dose, amount of the body exposed (whole body vs. partial body exposure), and the penetrating ability of the radiation. The severity is also affected by factors such as age, gender, genetics, medical conditions, etc.