Acute Radiation Syndrome (ARS) involves three main areas as dose increases. Which trio is correct?

Acute Radiation Syndrome (ARS) involves three main areas as dose increases. Which trio is correct?

• A. Lungs, liver, kidneys
• B. Hematopoietic organs; GI tract; CNS
• C. Skin, muscles, nerves
• D. Heart, spleen, pancreas

Answer: (B)

In acute radiation syndrome, the body shows a progression of injury that tracks radiosensitivity of tissues: first the hematopoietic (bone marrow) system, then the gastrointestinal tract, and finally the central nervous system. The hematopoietic organs are among the most radiosensitive, so whole-body exposure first suppresses blood cell production, leading to fatigue, infection risk, and bleeding. As the dose increases, the rapidly dividing cells lining the GI tract become severely damaged, causing vomiting, diarrhea, dehydration, and electrolyte imbalance, with high risk of sepsis from bacterial translocation. At still higher doses, the CNS and cerebrovascular system are affected, producing severe neurologic symptoms and rapid progression to death in the absence of treatment. This sequence—hematopoietic organs; GI tract; CNS—fits the three main ARS syndromes as dose increases. Other organ groups can be affected, but they do not define the classic ARS progression.

In acute radiation syndrome, the body shows a progression of injury that tracks radiosensitivity of tissues: first the hematopoietic (bone marrow) system, then the gastrointestinal tract, and finally the central nervous system. The hematopoietic organs are among the most radiosensitive, so whole-body exposure first suppresses blood cell production, leading to fatigue, infection risk, and bleeding. As the dose increases, the rapidly dividing cells lining the GI tract become severely damaged, causing vomiting, diarrhea, dehydration, and electrolyte imbalance, with high risk of sepsis from bacterial translocation. At still higher doses, the CNS and cerebrovascular system are affected, producing severe neurologic symptoms and rapid progression to death in the absence of treatment. This sequence—hematopoietic organs; GI tract; CNS—fits the three main ARS syndromes as dose increases. Other organ groups can be affected, but they do not define the classic ARS progression.