The prodromal phase of Acute Radiation Syndrome is characterized by:

• A. Initial onset of symptoms followed by the subsiding of symptoms
• B. Subsiding of symptoms following the initial onset
• C. Returning of symptoms following the subsiding of symptoms
• D. Initial onset of symptoms followed by the complete recovery

Answer: (A)

The prodromal phase happens right after radiation exposure and centers on an early wave of symptoms that appear quickly and then fade as the next stage begins. After exposure you typically see nonspecific effects like nausea, vomiting, fatigue, and sometimes diarrhea within minutes to hours. The hallmark of this phase is that these initial symptoms rise and then subside, leading into a latent period where the person may feel relatively well even though cellular damage is ongoing. The severity and duration of the prodromal symptoms depend on the radiation dose—the higher the dose, the more pronounced the prodrome, but it generally precedes a latent phase rather than a full, immediate recovery. So, the prodromal phase is best described by the initial onset of symptoms followed by their subsidence.