Chemical Burns and Radiation Injuries

1. Chemical Burns and Radiation Injuries Denise Watt April 18, 2002

2. Outline • basics of chemical burns • hydrofluoric acid • “grab bag” • physics for dummies • approach to radiation injuries/exposure

3. Household lye phenols Sodium hypochlorite Sulfuric acid Methacrylic acid Industry Tannic acid Formic acid Sulfuric acid Acetic acid Hydrocloric acid Hydrofluoric acid NaOH, KOH, LiOH, BaOH, CaOH, NH4 White phosphorus Common Chemicals Burns

4. Principles of Chemical Burns • Tissue damage is a function of: • Concentration • pH • Type of contact • Quantity of agent • Duration of contact • Mechanism of action • Extent of penetration

5. Injury Patterns • Dermal burns • Ocular burns • Inhalation burns • Esophageal/gastric burns • Systemic effects

6. General Management Principles • Decontaminate • Remove clothes, brush off (lime), irrigate/dilute (*metals) • Neutralize • Debride ± graft • Analgesia • Topical Abx, Td • Treat systemic symptoms

7. Acids and Alkalis • Acids • coagulate protein, desiccate tissue • dry, hard eschar • Strong = pH <2 • Alkalis • liquefaction necrosis: dissolve & damage keratin, saponify fats • penetrate deeper, takes longer • soft, gelatinous eschars • Strong = pH > 11

8. HF • 35 yo man presents 8 hr after using rust remover. Notes pain in fingers starting 2 hr post, now worse. • No obvious burns/lesions

9. HF: Pathophysiology • Acts like alkali: liquefaction necrosis • F binds Ca & Mg  poisons enzymes release of K  nerve stimulation • Penetrates deeply: bone destruction

10. HF: Presentation • PAIN • Later: blanching, central blue-gray, erythema, vesicles, coagulation • Systemic effects: hypocalcemia, hypomagnesemia, hyperkalemia  arrhythmias, seizures

11. HF: Presentation

12. HF: Management • Irrigate >15 min • ANTIDOTE! • Ca or Mg (Ca better in some animal studies) • Topical • s/c injection • IV • Intra-arterial • Nebulized • Ophthalmic

13. Topical • Ca gluconate gel preferred • 2.5% • 3.5g Ca gluconate powder in 140g lubricant • 10% CG injection + KY jelly to conc of 2.5% • Other recipes for Mg • Jelly glove, or wrap area in cellophane

14. Ca Gluconate injections • s/c: • pain on injection, tissue irritation • Vascular compromise • Limited amount (0.5mL 10% CG: /digit) • Nail removal • IV: Bier block, anecdotal evidence • Intra-arterial • 10cc 10% CG in 40cc D5W over 2-4 hr

15. HF: Management Endpoints • Significant pain reduction (ie, 50%) • Pain at rest vs fingertip pain on palpation vs. fingernail pain • Reduce duration of treatment • Use pain scale • Normal skin blanching • Monitor ECG, Ca, Mg, lytes!

16. Other HF exposures Ocular • Immediate, copious irrigation until PH 7.5 • Controversy over 1% ophthalmic Ca gtts • One study showed same as saline Inhalation • Nebulized CG Ingestion • Almost universally fatal

17. Radiation Injuries • Patch call: 29 yo woman exposed to radioactive material from chem lab enroute. • What do you want to know? • Is there a danger to staff? How can I tell? • Does she need to be isolated? • What equipment do I need? • Do I call public health? • Her questions: • Will I get cancer? • Will my future children be affected?

18. Radiation Injuries: big picture • Very rare to have access to enough radiation to cause significant injuries • Most exposures are occupational; usually safety precautions taken • Experience with high doses limited to major disasters (WWII, Chernobyl)

19. Physics for dummies • Non-ionizing radiation • heat, UV, U/S, microwave • Ionizing • Xrays, , , , H+ • Pass through cellsionize atomsfree radicalsscavenged OR DNA damage • stem cellsCA, embryonic mutations • Non-stem cellscell death (mitotic cells) • Background radiation: harmless!

20. Stochastic random, no threshold dose e.g., carcinogenesis, gonadal/embryonic cell mutations unpredictable untreatable irreversible Non-stochastic threshold dose required tissue damage sec. to mitotic cell death e.g., RT side effects often treatable Radiation Injuries

21. Radiation Injuries: Local • Can tolerate much higher doses (1000 rads) • delayed presentation: days-weeks • hyperesthesia • erythema • itching • desquamation • necrosis

22. Radiation Injuries: Total Body • Low dose (<150 rads) • asymptomatic, N&V • risk of stochasitic effects • gonads: low risk (Nagasaki) • cancer: 10 rads = 0.08% lifetime mortality risk • embryonic: <10 rads = no damage, <100 = unlikely • High dose • 500 rads in short time = 100% lethal • Acute Radiation Syndrome (>50 rads)

23. Acute Radiation Syndrome • Prodrome • 1-2 hr post exposure, lasts <48 hr • anorexia, N/V/D • Latent phase • asymptomatic; 1-3 weeks • Main phase • Hematopoietic, GI, CNS effects

24. Acute Radiation Syndrome • Hematopoietic (200-600 rads) • bone marrow suppression • death from infection, hemorrhage • GI (600-1000 rads) • small intestinal cell damage • death from infection, dehydration, enterocolitis • CNS (>5000 rads) • no latent phase: disorientation, tetany, coma • fatal in 24-72 hr

25. Radioactive Contamination: Who is a risk? • NOT if irradiated by external source only • Risk is more for patient: future harm • External contamination • skin, clothes • use Geiger counter to detect; outside preferably • Internal contamination • inhaled, ingested, absorbed • risk only if contact with excreta

26. Approach to Pt in ED • ABCs, manage life-threatening injuries • Determine if actual exposure occurred • Determine if contaminated • Notify radiation safety officer (AEBC) • Decontaminate • Supportive Rx: fluids, analgesic, Abx • Baseline B/W: CBC (*lymphocytes), HLA

27. Decontamination:External • Decontamination room • Remove clothes, irrigate (don’t scrub) • Re-measure contamination • Don’t need to know radionuclide

28. Decontamination:Internal • Need to know radionuclide • Prevent absorption/ enhance elimination • AC, lavage, cathartics (?evidence) • Aluminum salts (Strontium) • BAL (if ++high dose inhaled) • Antidotes • Isotopic dilution: iodine, inorganic phosphorus • Chelators

29. Prussian blue Penicillamine Chlorthalidone Deimercaprol Deferoxamine Ca-EDTA Zn-DTPA Cesium Cu, Co, Ag, Pb, Hg Rubidium Polonium Iron Cd, Cr, Pb, Zn All the weird ones ± American names Chelators + Radioactive isotope(or, how to win Trivial Pursuit Geek Edition)

30. Staff Safety • Call CNSC • Universal precautions: mask, gown, gloves • Lead apron if contaminated • Wear dosimeters • Limit time & distance with patient • Keep pregnant staff away!

31. Summary • Radiation injuries are rare • Call Atomic Energy Board • Counsel patient on potential future risks and their likelihood • Contamination: use precautions, but don’t panic • Cover your gonads at all times!!!