ABSTRACT Electrothermal injury is a significant cause of morbidity and mortality.  Documentation of injuries is important not only for the immediate resuscitation of  the   victims but also medicolegally.  Most of the  cases of electrical injuries   involve litigation   or  worker compensation..  Cutaneous  electro thermal injuries  in 22 cases  from the department of pathology, BMC&RI Bangalore was correlated with the various patterns based on morphology and also  to  estimate the changes in vital organs. The pattern of cutaneous injury appears to persist in all 22 cases with observation of changes in both skin and vital organs. This study shows  combined  pattern of morphology not compatible with single pattern .Thus, establishment of histomorphological patterns in skin & vital organs appear to be useful in monitoring tissue damage.The epidermal changes includes   denudation of epidermis, blister formation  and  streaming of  epidermal  nuclei. Dermal changes includes edema,    extravasation of RBC’s and coagulative necrosis .

KET WORDS: Cutaneous, Electro Thermal Injury, Histomorphological patterns  


The morphological hall marks of the injury caused by electric current are the ‘current mark’ and the electro thermal burn.1

Electro thermal injuries elicit physiologic and metabolic interaction involving all major organ systems.The exact patho physiology of electrical injury is not well understood because of the large number of variables that cannot  be measured or controlled when an electrical current pass through  tissue.2

Hence the severity of injury to the tissue is directly proportional to the amount of energy flowing through the tissue and the duration of exposure of these tissues. The resistance of a tissue to injury is based on the exposure of the tissue to voltage. The higher the resistance of a tissue to flow of current, the greater the potential for transformation of electrical energy to thermal current .2 Skin is the primary  resistor  to  the flow of current  into the body. Nerves, muscles, blood vessels have low resistance and are good conductors because of their high electrolyte and water content.2 Bone, tendon & fat have a very high resistance and tend to heat up and coagulate rather then transmit current due to large amount of inert matrix.2 This study evaluates the combined   histomorphological changes observed due to electro thermal injury in skin   and to estimate the changes in other vital   organs based on morphology.

Objectives of the study

The objectives of the  present  study is to estimate  reliable histomorphological variations that  incorporate  all  important  components of the skin & vital organs  and to review current  histomorphological changes with discussions .




Study design

A   retrospective study designed to establish a combined  histomorphological changes that  occur in the skin & vital organs after electro thermal injury.

Study population and sampling size  

343 autopsy cases were reported  out of which  22 patients died as a result of electro thermal injury. The study is carried out over a period of one and half years in the Department Of Pathology, BMC & RI, Bengaluru from June 2011 to December 2012.

Methods of sample collection

The study was perfomed on 22 cases of  victims who died due to electrothermal  in the department of pathology, BMCRI, bengaluru over a period of one and half years.. The organs were  received   in 10% formalin to the department of pathology for histopathological examination. Histopathological studies were done on formalin- fixed, paraffin-embedded tissue blocks and stained with hematoxylin & eosin .The findings were observed using light microscopy.


A total of 22 cases of electro thermal injury out of 343 autopsy cases were included in the study. The age ranged from 20 and 42 years. The majority of patients were males ( 21 cases) ,  while  1 was   female. The pattern of cutaneous injury appears to persist in all 22 cases with observation of changes in both skin and vital organs are shown in  (Table 1 &2).

Description of histomorphological cutaneous injury

The effect of injury on epidermis showed denudation of  lining  epithelium  in 8 cases &  blister formation  in 3cases. The epidermis also showed elongation of the nuclei , spindle shaped and are arranged in parallel sheets in  basal  layer and in  all epidermal  strata  in 14 cases (nuclear streaming) as shown in ( Fig 1,2).The effects of  injury on dermis   showed   dermal collagen edema in 10 cases ,  congested blood vessels  in 8 cases  & extravasated RBC’s in 3 cases. .  Coagulative  necrosis   was seen   adjacent to the blood vessels in subcutaneous   tissue   in  3 cases  and   blood vessel in the dermis showed elongation of the nuclei in 1 case  as depicted in  (Fig 3,4). The ducts of sweat or sebaceous glands did not show any changes.

Evaluation of the histomorphological appearance of the vital organs

The histomorphological   appearance of the   lungs, kidneys and heart  were  observed  using a light microscopy. The changes includes  hemorrhage, edema and  markedly congested blood vessels (Fig 5, 6).


The most common site of contact with the source in the present study was hands and foot. In the study conducted by Ann cooper the most common sites of contact with the source included the hands & the skull with areas of ground were heels. 2

Progressive loss of epithelial & mesenchymal cutaneous elements as well as increased disorganization of collagen would be expected to result in greater disfigurement and functional impairment.5

Resnik etal  &  Christopher et al   revealed identical findings of skin with extravasation of red blood cells in their study . No epidermal changes characteristic of electro thermal injury were identified.3,4  In the current study histological changes in epidermis due to electrothermal injury were streaming of basal cell nuclei in 14 cases with denudation of epidermis in 8 cases and blister formation in 3 cases. Histological changes in dermis due to electrothermal injury include dermal collagen edema in 10 cases, coagulative necrosis in 3cases and extravasation of RBC’S in 3 cases.

The  current flow is the main cause of muscle damage .6 The histologic changes seen in muscle injury that results from direct contact with an electrical source is coagulation  necrosis with shortening of sarcomere . 7 In the present study only 3 cases showed coagulation necrosis.

Vascular damage also occurs similar to muscle damage when the current flows through the tissue. Vascular damage is greater   in tunica media. This can lead to delayed hemorrhage when the vessel eventually ruptures .8, 9, 10    The injury is severe in branches of small muscular arteries, where blood flow is slower. This damage to small muscular arteries combined with mixed muscle   viability that   is not visible to gross inspection, creates the illusion “progressive”  tissue necrosis. 2   In our study we observed predominantly vascular damage in all 22 cases.

  Histomorphological appearance in vital organs


Exposure to electro thermal injury may cause immediate death from asystole, ventricular fibrillation or respiratory paralysis depending on the voltage and pathway .2 In the current study there were no observable changes noted grossly except for extravasation of RBC’S microscopically in a single case. This suggests that injury to the heart is rare from electro thermal injury as it has least resistance to the flow of current.


Injury to the lungs may occur because of associated blunt trauma but is rare from electrical current, perhaps because air is a poor conductor. Pulmonary hemorrhage & contusion are reported with lightning injury. 11,12  In our study we observed pulmonary hemorrhage in 2 cases  & pulmonary edema in 14 cases attributing to vascular damage.


The laboratory evaluation of   live   patients sustaining an electrical injury depends on extent of injury. The laboratory tests include CBC, electrolyte levels, serum myoglobin,  blood urea nitrogen (BUN), serum creatinine & urine analysis. 2   In our study  only one case  showed  interstitial  hemorrhage  &  5 cases  showed  marked congestion  on histopathological examination.

Nervous System

Electrical injury affects both CNS & peripheral nervous system .2    Electricalcurrent flowing through the brain stem may cause death by inhibition of the respiratory centers and electricity flowing through the heart may cause death by central circulatory failure .13  In our study due to lack of history no CNS findings were observed.

Skeletal System

Fractures of most of the long bones caused by trauma associated with electrical injury are reported.14,15  Both posterior and anterior shoulder dislocations caused by tetanic spasm of the rotator cuff muscles are also reported .2   In the current study we did not observe fracture of long bones or shoulder dislocation. 



The current study is mainly focused on cutaneous changes resulting from electro thermal injury. It is also our interest to put forth combined   histomorphological changes that could be generalized to skin & vital organs resulting from electro thermal damage. We also observed whether histomorphological parameters correlate with the other author’s studies.

An accurate history is necessary to ensure that the injury is due to electrocution. Since most of the time the incident is unobserved the presence of positive findings from victims needs more careful examination to categorize the burn pattern.  Limitation being, lack of    history, the discussion of the study is based on circumstances.



  1. Hubert Fischer, CJ ames  Kirk patrick: Effects of electric current in : A Colour Atlas of Trauma Pathology, Published by Wolfe Publishing Ltd, 1991, ISB N0 723415668.Page No 72-74.
  2. Mary Ann Cooper, Timothy G Price: Electrical and Lightening Injuries, WWW.Uie .edu/labs/lightning injury/elector & ltn.pdf
  3. Resnik B, Wetli C, Lichtenberg Figures Am J Forensic Med Pathol, 1996;17(2):99-102
  4. Christropher O, Bibb, P.F.Mellen:Lichtenberg Lightning Strike Figures :Report of an Autopsy Case with Gross and Microscopic Findings. Anil Aggrawal’s Internet Journal of Forensic  Medicine and Toxicology(serial online), 2006 ;Vol 7, No.1(January- June 2006)
  5. Adam J. Singer,  Henry C,  Thode JR,   Steve A,   Mc Clain : Development  of a Histomorphologic Scale    to quantify  Cutaneous  scars after Burns;  Academic Emergency Medicine: October 2000, volume 7, Number 10
  6. ten Duis HJ:Acute electrical burns, Semin  Neurol 15:381, 1995.PUBMED Abstract
  7. Puschel K, ,Brinkman B,  Lieske K;  Ultrastructural  alteration  of skeletal  muscles  after  electrical  shock, Am J Forensic Med Pathol 6:246, 1985
  8. Kobernick M: Electrical injuries : pathophysiology and  emergency management, Ann Emerg Med 11:633,1982.PUBMED  : Abstract
  9. Jaffe RH : Electropathology  ; a review of the pathologic changes produced by electric currents, Arch Pathol 5; 839, 1928
  10. Bongard O, Fagrell B; Delayed arterial thrombosis following an apparently trivial low- voltage electrical injury, Vasa 18:162,1989.PUBMED Abstract
  11. Buechner H A, Rothbaum J C: Lightning stroke  injury : a report of multiple casualties from a single lightning bolt, Mil Med 126:775,1961
  12. Solterman B, Frutiger A, Kuhn M; Lightning injury with lung bleeding in a tracheotomized patient , Chest 99: 240, 1991.PUBMED Abstract
  13. Charles .S.Hirsch, Ross .E.Zumwatt : Chapter 5,  Forensic Pathology in: Anderson’s Pathology 10th  Edition ,Edited by Ivan Damjanov & James Linder, published   by mosby year book Inc.1996 .Page No 80-109
  14. Hooshmand H, Radfar F, Beckner E; The neurophysiologic aspects  of electrical injuries, Clin Electroencephalogr 20:111,1989, PUBMED Absract
  15. Varghese G,  Mani MM,  Redford JB: Spinal cord injuries following electrical accidents, Paraplegia 24:159,1986, PUBMED Abstract


Table 1:   Histological  changes in skin due to electrothermal injury.

Pattern of injury

No of  cases

1. Epidermis
 Denudation of epidermis


 Streaming of nuclei


 Blister formation


 Dermal edema


Coagulative necrosis


Extravasation of RBC’S


Congested blood vessels











 Table 2:   Histological changes in vital organs due to electrothermal injury.


No of cases

Pulmonary  edema


Intra alveolar  hemorrhage


Congested blood vessels




Congested blood vessels


Extravasated RBC’S







Figures(IN PDF)


Fig 1: Skin shows elevation of epidermis at the dermo epidermal junction. H&E stain x200


Fig 2: Skin. The cells of the basal layer show  marked nuclear elongation and palisading of the nuclei. H&E stain x 400


Fig 3:   Subcutaneous tissue . The picture shows  coagulative necrosis. H&E stain x400




Fig 4: Subcutaneous  tissue. The blood vessels show elongation of the nuclei. H&E stain x 200.






Fig 5: Lung . The picture shows filling of the alveolar space with protein-rich edema fluid  . No inflammatory  cell infiltration seen.  H&E stain x 400





Fig 6: Lung .  The lung shows an intra alveolar hemorrhage. H&E stain x200.



  1. 1.        Dr.Ashalatha.N . MBBS,  MD (PATHOLOGY)    Associate Professor, Department of pathology, Bangalore Medical College & Research Institute, Bangalore.1
  2. 2.        Dr. Dr.Kuruba Sreelakshmi. MBBS, MD (PATHOLOGY) Associate Professor  , Department of pathology, Bangalore Medical College & Research Institute, Bangalore.2
  3. 3.      Dr. A. R. Raghupathi. MBBS,MD (PATHOLOGY)  Professor  & Head of the Department  , Department of pathology, Bangalore Medical College & Research Institute, Bangalore.
  4. 4.      Disclaimers: Nil
  5. 5.      Address of the corresponding author:



Associate   Professor   of Pathology

Department of Pathology

Bangalore Medical College and Research Institute


Karnataka, India

Mobile: +919448910567

E-mail ID: drasha72@gmail.com


  1. 6.      Sources of support: Nil


  1. 7.      Conflicting Interest : Nil


  1. 8.      Total  no of  pages : 17


  1. 9.      Total  no of pictures :06


  1. 10.  Total  no of Tables: 02


  1. 11.  Total  no of  references : 15


  1. 12.  Word count of Abstract:169


  1. 13.  Word count of Text:2032










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