Thermal injuries: chemical, electric and Lightening burns.

Introduction:

Chemical burns:-

• Chemical burns are produced by corrosive acids and alkalis.
• Acids with a pH less than 2 precipitate proteins causing coagulation necrosis.
• Nitric acid gives a yellow-brown scab, sulphuric (vitriol) a black-brown scab,
• Hydrochloric acid (spirit of salt) a white to grey scab, and carbolic acid (phenol or Lysol) gives a light grey to light brown scab.
• Alkalis with a pH above 11.5 cause more tissue damage than acids because they induce liquefactive necrosis, which facilitates ever deeper penetration of the alkali.
• The caustic alkalis, such as sodium hydroxide (caustic soda or lye) and ammonium hydroxide, leave a grey-white mucoid burn.
• Vesicles  and blisters, Charring  (soot)  and  singeing  are absent, except  in  cases  of mineral  acids  where  they  are present.
• The most serious alkali burns of the eye are produced by: Strong liquid ammonia.

Electric burns:-

• High tension electrical burns from overhead electric lines can cause Myoglobinuria and Acute renal failure.
• Electric  burns  are  at  times,  also  referred  to  as joule  burns.
• Regarding high-voltage electrical burns to an extremity.  Evaluation for fracture of the other extremities and visceral injury is indicated.
• Ulceration  is  present, Coagulative necrosis  is  seen  at the  site of contact  except  for  hydrogen  fluoride  which chelate  calcium.
• Calcium  phosphate  of bones  may also  melt and  is  radiologically  seen  as  bone pearls  (wax  dripping), Muscles  show  Zenker’s  degeneration.
• commonest  cause  of  death in electric injury  is  ventricular  fibrillation.
• The skin may get coloured due to metallic pigment :- green (in brass electrode), black (in iron electrode), blue (in copper electrode) and grey (in aluminium electrode).
• In high-voltage (more than 1,000 volts) electrical burns the contact injury of exit often appears as a blow-out type of wound.
• Alternating current (AC) is more dangerous than direct current (DC).

Lightening  burns

• Lightening refers  to  discharge  of current  between  a negatively charged  cloud and  positively  charged  article  on  earth.
• Direct  effect  of high voltage  current.
• Heat,  i.e.  super  heated  air causing  burns.
• Expanded  and displaced  air, which acts as  a  blast wave
• Sledge  hammer  blow  by compressed  air pushed before.
• The  characteristic  finding  in  lightening  burns is  filigree  burns.

Don’t Forget to Solve all the previous Year Question asked on Thermal injuries: chemical, electric and Lightening burns.