Radiation Injuries

1. THE OPERATIONAL PARADIGM

• The Paradigm Shift: A radiologic disaster shifts the emergency response from individual patient care to population-based triage under the Hospital Incident Command System (HICS). The response relies heavily on the integration of a Radiation Safety Officer to manage dosimetry, contamination perimeters, and specialized diagnostics.
• Irradiation vs. Contamination: This is the most critical operational distinction. Irradiated patients have been exposed to a beam of ionizing radiation (e.g., from a sealed industrial source or nuclear detonation); they are not radioactive, pose zero threat to ED personnel, and require no decontamination. Contaminated patients have radioactive dust, liquid, or shrapnel on their bodies or internalized; they actively emit radiation and require immediate, controlled decontamination to protect staff and prevent facility tracking.
• The "Dirty Bomb" Reality: A Radiologic Dispersal Device (RDD), or "dirty bomb," utilizes conventional explosives to scatter radioactive material. The operational priority must remain on the conventional blast effects, as the risk of lethal radiation injury from an RDD is extremely low, whereas the kinetic blast trauma is highly lethal.

2. THE TRIAGE & SEVERITY CRITERIA

• The Golden Rule of Radiologic Triage: Do not alter standard mass-casualty triage principles (e.g., START or JumpSTART) based solely on radiation exposure.
• Prioritization: Radiation exposure is never immediately life-threatening; therefore, severe physical trauma, thermal burns, or medical emergencies (e.g., acute myocardial infarction) strictly take precedence over radiologic surveying and decontamination.
• Combined Injury Syndrome: Patients suffering from radiation exposure combined with physical trauma or burns have exponentially higher morbidity and mortality than those with either injury alone.

3. THE IMMEDIATE THREAT PROTOCOL

• Step 1: Emergency Stabilization: If the patient has life-threatening traumatic or medical conditions, bypass decontamination and immediately stabilize the airway, breathing, and circulation (ABCDs) using standard precautions.
• Step 2: Departmental Control: Establish an ad hoc triage area and control perimeters to minimize the "tracking" (spread) of radioactive material through the ED. Issue dosimeters to all participating ED staff.
• Step 3: Rapid Decontamination: For contaminated, medically stable patients, begin decontamination by simply removing the patient's clothing and isolating it in impervious bags, which eliminates the vast majority of the radioactive burden.
• Step 4: Targeted Hydrotherapy: Wash the patient with warm water and soap, strictly following this priority sequence: (1) Wounds (cover with waterproof dressings once clean), (2) Body orifices, (3) Intact skin. Avoid aggressive scrubbing, which can cause epidermal abrasions and internalize the isotopes.

4. THE TOXICOLOGY / PATHOLOGY MATRIX

• Acute Radiation Syndrome (ARS): Occurs after significant whole-body irradiation and progresses through distinct phases:
• Prodromal Phase (0–3 days): Characterized by anorexia, nausea, vomiting, and fatigue.
• Latent Phase (3–20 days): A transient period of clinical improvement. The duration of this phase is inversely proportional to the radiation dose (it may be absent in massive exposures).
• Illness Phase (21–60 days): Manifests as bone marrow depression (infection, bleeding), GI sloughing (uncontrollable diarrhea), and at extreme doses (>20–30 Gy), Cardiovascular/CNS syndrome resulting in refractory hypotension, cerebral edema, and death within 24–72 hours.
• Critical Diagnostic Markers:
• Time to Emesis: The onset time of vomiting is the most crucial early clinical marker for biologic dosimetry; rapid onset correlates with a massive, highly lethal dose.
• Absolute Lymphocyte Count (ALC): Obtain a CBC every 6 hours for 24–48 hours. The rate of lymphocyte depletion is the best early laboratory predictor of the radiation dose.
• Amylase & CRP: Check daily for 3 days. The parotid glands are highly sensitive to radiation; serum amylase will rise if the patient was exposed to >0.5 Gy.
• Chromosomal Analysis: Blood drawn for dicentric chromosome analysis is the gold standard for exact dosimetric quantification.

5. THE ANTIDOTE & THERAPEUTIC GRID

• ARS Symptom Management: Treat prodromal nausea aggressively with 5-HT3 antagonists like ondansetron. Initiate fluoroquinolones for patients demonstrating the GI syndrome. Crucially, avoid NSAIDs for pain control if the exposure is suspected to be >5 to 6 Gy due to the profound risk of catastrophic GI bleeding.
• Internal Contamination Antidotes:
• Radioactive Iodine (I-131): Administer Potassium Iodide (KI) (130 mg PO for adults) to block radioactive uptake by the thyroid gland.
• Plutonium (Pu-239): Administer Ca-DTPA or Zn-DTPA (1 gram in 250 mL NS or D5W over 60 mins) to chelate the heavy metal.

6. THE DANGER ZONE

• The "Clean-Kill" Delay: A fatal operational error is delaying endotracheal intubation, hemorrhage control, or chest tube placement in a crashing patient out of fear of radiologic contamination. Standard PPE provides adequate protection; treat the life-threat first.
• The "Dirty Bomb" Distraction: Treating a victim of an improvised "dirty bomb" for radiation poisoning while missing lethal occult blast trauma (e.g., pulmonary barotrauma or hollow viscus perforation). The blast kills; the radiation does not.
• The NSAID Trap: Administering ibuprofen or ketorolac for radiation-induced headaches or burns. Radiation rapidly destroys platelets and the GI mucosa; NSAIDs will precipitate severe, uncontrollable gastrointestinal hemorrhage in high-dose exposures.

7. MCQ MASTERCLASS

• The "Time to Emesis" Buzzword: A board question asking for the best early clinical prognostic indicator of radiation exposure severity is testing "time to onset of vomiting".
• The Diagnostic Pairing: If a patient presents after a nuclear reactor incident, the most critical serial lab to order to estimate their exact radiation dose is the "Absolute Lymphocyte Count (drawn every 6 hours)".
• The Triage Distractor: A vignette presents two patients: one exposed to a lethal dose of radiation (LD50) but with normal vitals, and another unexposed patient with an acute STEMI. Distractors will suggest isolating or prioritizing the irradiated patient. The correct answer is to prioritize the STEMI patient, as pure radiation exposure does not cause immediate cardiovascular collapse, and irradiated patients pose no threat to staff.

8. THE COMMAND CENTER REPORT

"Incident Commander, this is the ED Casualty Care Unit Leader. We are operating under HICS for a localized radiologic dispersal device (dirty bomb) detonation. The facility is secured, and we have established controlled entry points and external decontamination zones to prevent facility tracking. We have processed 42 casualties: 8 Red, 14 Yellow, and 20 Green. All Red tags are being managed primarily for blast trauma and hemorrhage; we have not delayed life-saving interventions for radiologic surveying. The Radiation Safety Officer is on-site actively monitoring staff with dosimeters and guiding warm-zone hydrotherapy. Clothing removal has successfully eliminated the majority of external contamination. We are actively drawing serial CBCs every 6 hours and tracking time-to-emesis for biologic dosimetry. Requesting immediate logistical resupply of Potassium Iodide and DTPA from the regional stockpile for potential internal contamination, and mobilization of additional trauma surgical teams. End of briefing."