Chemical Burns and Radiation Injuries

Denise WattApril 18, 2002

Outline

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

Common Chemicals Burns

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

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

Injury Patterns

• Dermal burns• Ocular burns• Inhalation burns• Esophageal/gastric burns• Systemic effects

General Management Principles

• Decontaminate• Remove clothes, brush off (lime), irrigate/dilute

(*metals)• Neutralize• Debride ± graft• Analgesia• Topical Abx, Td• Treat systemic symptoms

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

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

HF: Pathophysiology

• Acts like alkali: liquefaction necrosis• F binds Ca & Mg poisons enzymes

release of K nerve stimulation• Penetrates deeply: bone destruction

HF: Presentation

• PAIN• Later: blanching, central blue-gray,

erythema, vesicles, coagulation• Systemic effects: hypocalcemia,

hypomagnesemia, hyperkalemia arrhythmias, seizures

HF: Presentation

Strength of HF Onset of symptoms

< 20% Pain.erythema delayed 24hr

20-50 % 1-8 hr

> 50% Immediate pain & tissue destruction

HF: Management

• Irrigate >15 min• ANTIDOTE!

• Ca or Mg (Ca better in some animal studies)• Topical• s/c injection• IV • Intra-arterial• Nebulized• Ophthalmic

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

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

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!

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 CGIngestion• Almost universally fatal

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?

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)

Physics for dummies

• Non-ionizing radiation• heat, UV, U/S, microwave

• Ionizing• Xrays, , , , H+

• Pass through cellsionize atomsfree radicalsscavenged OR DNA damage

• stem cellsCA, embryonic mutations• Non-stem cellscell death (mitotic cells)

• Background radiation: harmless!

Radiation Injuries

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: Local

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

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)

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

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

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

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

Decontamination:External

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

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

Chelators + Radioactive isotope(or, how to win Trivial Pursuit Geek Edition)

• 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

Staff Safety

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

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!!!