Chemical Burns

1. Chemical Burns Tintinalli Chapter 200 Ken Goodell

2. Chemical Burns 5-10% of all U.S. burn center admissions 100,000 nonoccupational exposures/yr face, eyes and extremities most common deaths are rare, usually from ingestion

3. Chemical vs Thermal Burns smaller lower mortality longer wound healing and LOS can produce systemic toxicity Many chemical burns can also cause thermal injury

4. Pathophysiology Burn Dermatitis Allergic reaction Thermal injury Systemic toxicity

5. Tissue damage determined by ... Strength/ concentration Manner of contact Quantity of agent Phase (liquid/solid) Duration of contact Mechanism of action Extent of penetration

6. Tissue damage determined by ... Strength/ concentration Manner of contact Quantity of agent Phase (liquid/solid) Duration of contact Mechanism of action Extent of penetration body site skin integrity nature of chemical occlusion

7. Acids Alkalis coagulation necrosis protein precipitation forming leathery eschar Eschar may prevent deeper penetration liquefaction necrosis saponification of lipids Results in deeper penetration Greater tissue damage/vol

8. Classification: Jelenko groups chemicals Oxidizing agents: chem is oxided, releases toxin Corrosives: protein denaturation, eschar Reducing agents: bind free electrons, denature Desiccants: cellular dehydration/ thermal injury Vesicants: local ischemia and anoxic damage Protoplasmic poisons: salt formation/ metabolic inhibition

9. Treatment: Chemical Burns Dilution aggressive hydrotherapy Debridement excision Neutralization

10. Treatment: Chemical Burns Aggressive Hydrotherapy Earlier irrigation = better prognosis If dry, brush off before irrigation Irrigate at a gentle flow If exothermic, use copious amount of irrigation Note: Na metals and related compounds Cover with mineral oil or excise (exothermic)

11. How Long Do I Irrigate? maybe for hours pH paper test more accurate if done 10-15 min after completion of irrigation Allows deeper chemicals to diffuse to surface

12. Treatment: Chemical Burns Irrigation Debridement of devitalized tissue / particles Topical antimicrobials Tetanus Td Aggressive IVF replacement Analgesics Allergic Rxn: antihistamines, steroids, epinepherine Surgical excision: if ongoing tissue destruction Grafts: full thickness Hyperbaric oxygen

13. Acids Coagulation necrosis Desiccating action on proteins Produces tough leathery eschar pH < 2 = strong corrosives Contact time most important factor that can be altered Respiratory/ mucus membrane irritants Skin absorption: may get systemic Sx

14. Acids: Acetic acid hair-wave neutralizer solutions (40% conc) scalp burns in women Tx: Irrigation Oral Abx if entire scalp involved

15. Acids: Carbolic Acid (Phenol) Widely used in industry and medicine white/ brown coagulum systemic exposure acrid odor � dec risk of airborn exposure Tx: Irrigation � may be ineffective Polyethylene glycol: 2:1 IMS or viscous glycerol Isopropyl alcohol

16. Acids: Chromic Acid hexavalent compound � powerful oxidizer chronic penetrating ulcerating lesion Local Sx: conjunctivitis, lacrimation, nasal septum ulceration Systemic Sx: liver/ renal failure, GI bleeding, coagulopathy, CNS disturbance 10%BSA � fatal; 1-2% BSA � significant Sx

17. Acids: Chromic Acid Tx copius irrigation observation for systemic SEs aggressive excision Topical agents: while waiting for excision 5% Thiosulfate Ascorbic acid

18. Acids: Formic Acid Acrylate-glue, cellulose formate, tanning Systemic Sx: decreased respiration AG metabolic acidosis Tx: Irrigation Debridement Skin graft if full thickness

19. Acids: Hydrochloric/ Sulfuric Acid Sulfuric Toilet bowl cleaners [80%] some drain cleaners [95-99%] munition, chemical, fertilizer manufacturers Hydrochloric Bleaches burns skin dark brown/ black well recognized, so early irrigation Tx: same as formic acid

20. Acids: Hydrofluoric Acid progressive tissue loss, bony destruction H+ ions � direct cellular damage Fluoride � immobilization of intracellular Ca, Mg poisoning of cellular enzymatic reactions inc K+ permeability � nerve depolarization � pain Systemic SEs: hypocalcemia, hypomagnesemia, hyperkalemia, myocardial irritability

21. Acids: Hydrofluoric Acid Tx: Immediate, copious irrigation Calcium gluconate 1cc 5% soln/cm2 burn area Topical gel: Iontopheresis Nebulized Ca gluconate for respiratory exposure IV, electrolytes, cardiac monitoring

22. Alkali deeper, longer skin penetration greater systemic absorption/ toxicity May appear superficial full thickness in 2-3d pH > 12 = strong alkali combines with proteins/ lipid - forms soluble complex Soft, gelatinous, friable, brownish eschar Allows hydroxyl ions to penetrate deep

23. Alkali: Lye NH3, Ba, Ca, Li, K, Na hydroxides drain & toilet cleaners, detergents, paint removers Ingestion upper airway occlusion rapid death Tx: voluminous & persistent irrigation

24. Alkali: Lime (calcium oxide) agricultural products, cement Lime + H2O = Ca Hydroxide (exothermic) Tx: Brush off excess strong stream of copious irrigation Portland cement sand, lime, metal oxides causes burns, contact dermatitis

25. Metals Na, Li, K, Mg, Al, Ca may ignite when exposed to air Tx: Water contraindicated � poss explosive exothermic rxn Mineral oil, wound debridement Class D extinguisher, smother in sand

26. Hydrocarbons Gasoline (MVC) resembles thermal scald or partial thickness fat-dissolving corrosive injury Tx: Decontamination; Tx as thermal injury Air bag burns 8% of air bag-related injury Na hydroxide, NO, ammonia, hydrocarbons cutaneous burns; chemical keratitis Tx: Irrigation

27. Potassium permanganate Oxidizer producing thick, brown-purple eschar Tx: copious irrigation Alkyl mercury compounds reducing agents dissinfectants, fungicides, wood preservatives erythematous burn, dermatitis, blistering Burn may deepen if blisters remain closed Tx: debride, drain, and irrigate blisters

28. Diquat dibromide herbicide; limited data Lacrimators Chloroacetophenone, chlorobenzylidenemalonitrile, dibenzoxazepine. Skin & mucosal irritation; contact dermatitis Tx: Irrigation Vesicants DMSO, cantharides, mustard gas ischemia & anoxic necrosis � edema, blistering Tx: Irrigation; absorbant powders (flour, talcum)

29. Occular burns true occular emergency ischemic conjunctiva, ant chamber clouding, corneal swelling, pupillary dilatation, corneal ulcer If substance unknown, use pH paper alkali � can penetrate cornea, AC, retina � globe perforation Tx: Irrigation, Pain control No neutralizing agents Severe corneal damage � collagenase inhibitor (cysteine) iridocyclitis, lens-iris adhesion, ectropion (lid deform)