Acute radiation syndrome

"Radiation poisoning" redirects here. For other uses, see Radiation poisoning (disambiguation).

Acute radiation syndrome
[[File: Autophagosomes |250px|alt=|Radiation causes cellular degradation by autophagy.]]
Synonyms	Radiation poisoning, radiation sickness, radiation toxicity
Pronounce	N/A
Field	Critical care medicine
Symptoms	Nausea, vomiting, loss of appetite, fatigue, headache
Complications	N/A
Onset	Within minutes to days
Duration	Weeks to months
Types	Bone marrow syndrome, gastrointestinal syndrome, neurovascular syndrome
Causes	High-dose ionizing radiation over a short period
Risks	N/A
Diagnosis	History of exposure, clinical symptoms, CBC
Differential diagnosis	N/A
Prevention	N/A
Treatment	Supportive care, blood transfusion, antibiotics, colony-stimulating factors, stem cell transplant
Medication	N/A
Prognosis	Dose-dependent
Frequency	Rare
Deaths	N/A

Acute radiation syndrome (ARS), also known as radiation sickness or radiation poisoning, is a serious medical condition caused by exposure to a high dose of ionizing radiation over a short period of time. ARS affects rapidly dividing cells and can damage tissues in multiple organ systems. Symptoms may begin within minutes to hours and progress over several days to weeks.

Signs and Symptoms

Main article: Effects of nuclear explosions on human health

Manifestations of acute radiation syndrome

The clinical course of ARS is classically divided into stages:

• Prodromal stage: Initial symptoms including nausea, vomiting, anorexia, headache, and fatigue appear within hours.
• Latent stage: Apparent improvement or lack of symptoms lasting hours to weeks.
• Manifest illness stage: Depending on the dose and exposed tissues, characteristic syndromes develop.
• Recovery or death: Depending on severity and treatment, patients may recover or deteriorate.

ARS Subtypes

ARS is categorized into three primary syndromes based on the dose and tissues affected:

1. Hematopoietic syndrome (0.7–10 Gy): Damage to bone marrow causes aplastic anemia, increasing risk of infections, anemia, and bleeding.
2. Gastrointestinal syndrome (6–30 Gy): Damage to the intestinal epithelium leads to severe diarrhea, vomiting, and abdominal pain. Death is often due to infection and fluid loss.
3. Neurovascular syndrome (>30 Gy): High doses result in cerebral edema, ataxia, seizures, and coma. Symptoms appear rapidly and are invariably fatal.

Cause

Acute radiation syndrome results from exposure to external sources of high-dose ionizing radiation, typically above 0.7 Gy (70 rads), over minutes. Common causes include:

• Nuclear accidents
• Atomic bombings
• Radiation therapy accidents
• Improper handling of industrial or research isotopes

Damage occurs primarily in rapidly dividing cells, especially those in the bone marrow, gastrointestinal tract, and skin. DNA damage, oxidative stress, and cell death lead to multi-organ failure at higher doses.

Diagnosis

Diagnosis is based on:

• Documented or suspected exposure to ionizing radiation
• Onset of characteristic symptoms
• Repeated CBCs to monitor blood cell depletion
• Use of biological dosimetry or chromosomal aberration testing, such as dicentric chromosome assay

Fluoroscopy burn

Treatment

The cornerstone of ARS management is **supportive care**:

• **Fluid and electrolyte replacement**
• **Infection control** with antibiotics, antifungals, and antivirals
• **Blood transfusions** and platelet transfusions
• **Colony-stimulating factors** (e.g., filgrastim) to promote bone marrow recovery
• **Stem cell transplant** in cases of irreversible bone marrow failure

Decontamination

If radioactive material remains:

• External: remove clothing, wash skin
• Internal: treat with specific agents like potassium iodide (for radioiodine), prussian blue, or DTPA

Prognosis

Prognosis depends on:

• **Total absorbed dose** and **rate of exposure**
• **Partial vs. whole-body exposure**
• **Access to prompt supportive care**

Doses <1 Gy generally have good outcomes, while >10 Gy typically result in poor prognosis. Survivors of moderate exposure may develop leukemia, thyroid cancer, or other malignancies years later.

Epidemiology

ARS is rare but has been documented in mass radiation events. Key historical incidents:

• Atomic bombings of Hiroshima and Nagasaki
• Chernobyl disaster
• Goiania accident
• Tokaimura nuclear accident

Prevention

Occupational safety

Radiation workers must follow:

• ALARA principles (As Low As Reasonably Achievable)
• Use of personal protective equipment (PPE)
• Routine monitoring with dosimeters

Emergency preparedness

Governments and agencies maintain:

• Radiation emergency plans
• Distribution of potassium iodide
• Public education for nuclear fallout scenarios

Related conditions

• Chronic radiation syndrome
• Radiation burns
• Radiation-induced cancer
• Radiation therapy complications

See also

• Effects of nuclear explosions on human health
• Ionizing radiation
• Radiation safety
• Radiation protection
• Radiation hormesis
• Internal contamination

References

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