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Acute radiation syndrome
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								(Redirected from Radiation syndrome)
												
				Contents
Background
- Also called radiation poisoning, radiation toxicity, or radiation sickness.
 - Acute illness caused by exposure to high doses (at least 1 Gy)[1] of ionizing radiation over a short period of time.
- 1 Gray (Gy) = 100 rads
 
 - Generally requires exposure of whole body (or most of the body)
 - Fast-replicating cell lines most affected - GI, lymphohematopoietic, spermatocytes
 - Healthcare providers should use isolation precautions and decontamination procedures
- Geiger counters may be useful in identifying contamination
 
 
Clinical Features
Clinical Syndromes[1][2]
Bone Marrow Syndrome
- Clinical syndrome seen at doses >100-200 rad (1-2 Gy)
- Smaller doses cause clinically insignificant pancytopenia)
 
 - Lymphocytes depleted first, then granulocytes, platelets, and RBCs
- Lymphocyte depletion is predictable based on dose
 
 - Death usually secondary to infection or hemorrhage and poor healing
- Doses >350 rad fatal within several months if untreated
 
 
Gastrointestinal (GI) Syndrome
- Syndrome occurs at 600-1000 rad (6-10 Gy)
 - Characterized by abdominal pain, nausea, vomiting, diarrhea, ileus
 - Death occurs within weeks secondary to multiorgan failure and sepsis if untreated
 
Cardiovascular (CV)/Central Nervous System (CNS) Syndrome
- Syndrome occurs at >1000-2000 rad (10-20 Gy)
- At this dose, vomiting is suppressed
 - Characterized by ALOC, dizziness, papilledema, ↓ DTRs, ataxia, coma
 
 - Doses >3500 rad (35 Gy) damage large blood vessels → cardiovascular failure, cerebral edema
 - Doses >5000 rad (50 Gy) cause death within 48 hours
 
Clinical Course[1][2]
- Each ARS syndrome typically progresses through 4 stages of disease
 
Prodromal Stage
- Characterized by nausea and vomiting
- Other symptoms include: malaise, fever, conjunctivitis
 - Doses over 1000 rad (10 Gy), vomiting is not seen in early symptoms
 
 - Occurs within 48h-6d of exposure (at higher doses, can begin within minutes)
 - Lasts up to 2 days
 
Latent Stage
- Short period of symptom improvement
 - Lasts several days to 1 month
 
Manifest Illness Stage
- Manifestation of symptoms of clinical syndromes
 - Severity based on, among other things:
- Overall dose
 - Irradiated body volume
 - Comorbidities and overall health status
 - Age
 
 - Characterized by significant immunosuppression
 - Lasts for days to months
 
Recovery or Death
- If patient survives manifest illness stage, recovery is slow (weeks to years)
 - If lethal dose received, death can occur within days (very high, rapid doses) or may be delayed up to several months
 - Doses over 1000 rad (10 Gy) are uniformly fatal
 
Differential Diagnosis
Mass casualty incident
- Radiation exposure (disaster)
 - Dirty bomb
 - Bioterrorism
 - Chemical weapons
 - Natural Disaster (e.g. Hurricane, Earthquake, Tornado, Tsunami, etc)
 - Unintentional large-scale incident (e.g. building collapse, train derailment, etc)
 - Major pandemic
 - Explosions
 
Nausea and vomiting
Critical
Emergent
- Acute radiation syndrome
 - Acute gastric dilation
 - Acetaminophen toxicity
 - Adrenal insufficiency
 - Appendicitis
 - Aspirin toxicity
 - Bowel obstruction/ileus
 - Carbon monoxide poisoning
 - Cholecystitis
 - CNS tumor
 - Digoxin toxicity
 - Electrolyte abnormalities
 - Elevated ICP
 - Gastric outlet obstruction
 - Hyperemesis gravidarum
 - Pancreatitis
 - Peritonitis
 - Ruptured viscus
 - Testicular torsion/ovarian torsion
 - Theophyline toxicity
 
Nonemergent
- Biliary colic
 - Cannabinoid hyperemesis syndrome
 - Chemotherapy
 - Disulfiram effect
 - Erythromycin
 - ETOH
 - Gastritis
 - Gastroenteritis
 - Gastroparesis
 - Hepatitis
 - Ibuprofen
 - Labyrinthitis
 - Migraine
 - Motion sickness
 - Narcotic withdrawal
 - Thyroid
 - Pregnancy
 - Peptic ulcer disease
 - Renal colic
 - UTI
 
Evaluation
- Clinical diagnosis, based on history and physical
 - Absolute lymphocyte count is the best prognosticator at 48hrs post-exposure[3] (<1500 is abnormal and indicates a significant exposure)
 
Management
- Aggressive supportive care is hallmark of ED management
 - Potassium iodide as thyroid protectant, at 130mg qd for adults, until radiation exposure ceases[4]
 
Disposition
- Admit
 
See Also
References
- ↑ 1.0 1.1 1.2 Waselenko JK, MacVittie TJ, Blakely WF, et al. Medical management of the acute radiation syndrome: recommendations of the Strategic National Stockpile Radiation Working Group. Ann Intern Med. 2004 Jun 15;140(12):1037-51.
 - ↑ 2.0 2.1 Donnelly EH1, Nemhauser JB, Smith JM, et al. Acute radiation syndrome: assessment and management. South Med J. 2010 Jun;103(6):541-6.
 - ↑ Colwell CB: Radiation injuries, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2013, (Ch) 146: pp 1945-1951.
 - ↑ New York State Potassium Iodide (KI) and Radiation Emergencies: Fact Sheet. https://www.health.ny.gov/environmental/radiological/potassium_iodide/fact_sheet.htm.
 
