Electrical Injuries in Emergencies. Pathophysiology, Clinical manifistations, Investigations & treatment.

1. Electrical Injuries
Ahmed Mo’ness

2. Epidemiology (USA)
• 3000 annual hospital admissions
• 20% children(mainly children <6 yr)
• 40% die

3. Types of electric currents
• AC (Alternating Current)
• DC (Direct Current)
• Lightening
• High Volt.
• Low Volt.

4. Pathophysiology of injury
• Direct effect of electricity
• Thermal tissue damage
• Sever muscle contractions
• Fall after shock

5. Tissues either Transmit or Resist
• Highest resistance = Skin, Bone, Fat
• Lowest resistance = BVs, Nerves, muscles
Higher Resistance
=
Higher Heat production

6. Affected Systems/Organs
1) Skin
2) Bones
3) Muscles
4) CNS
5) Heart & BVs
6) Renal
7) Respiratory
8) GIT
9) Eye
10) Ear

7. Skin
• Superficial to full-thickness burn
• Findings underestimate the internal thermal
damage !
• characteristic kissing burn - at flexor creases
or others eg. Blisters

8. Bone
• Bone has highest resistance = highest heat
production.
• Destruction of bone matrix (necrosis) + deep
tissues and organs surrounding long bones
• Bone fractures d.t. Fall / Repeated sever muscles
contraction
– Mainly in UL long bones & Vertebrae
• X-ray cervical spine to exclude fractures
especially in comatose patients is MANDATORY

9. Muscles
• Rhabdomyolysis + AKI
• Acute Compartment Syndrome
– Limb swelling + sever pain not related to degree of physical
findings
– Loss of pulsation is a late non-reliable sign for the early
detection of ACS

10. Neuro
• Central & Peripheral
• Include: Loss consciousness, weakness,
paralysis, resp. depression , sensory,
autonomic & memory disturbance
• Usually Transient
• May present after months of electric shock !
(usually as Spinal Cord injury with LMNL
presentation)

11. Cardiac
• Arrhythmias (15%)
– Mostly present shortly after the shock with :
• Asystole (DC / Lightning)
• VF (AC) (most common fatal cause)
– Other arrhythmias : Atrial arrhythmias, BBB, 1st &
2nd degree HB
– Delayed VF may occur d.t prolonged Resp.
Paralysis & hypoxia
– Delayed arrhythmias is generally not common

12. Cardiac
• Myocardial affection
– Generaly not common
– Contusion
– Infarction (rare)
– Due to direct electric injury or Coronary spasm

13. Cardiac
• ** Arrhythmias
= with horizontal currents (hand to hand)
• ** Myocardial damage
= with vertical currents (head to foot)

14. Blood Vessels
• Vascular injury following compartment
syndrome
• Electrical coagulation & necrosis
• Delayed arterial thrombosis, aneurysm ,
rupture

15. Renal
• Heme pigment-induced AKI
(due to Rhabdomyolysis)
• Prerenal Failure (Fluid extravasation)

16. Respiratory
• Respiratory Arrest
Due to Central Affection
or
Respiratory Muscle Tetany after exposure to
electric shock

17. GIT
• Not commonly affected
• May present with P. Ileus / Vascular injury &
Ischemia
• Stress ulcer is common = need prophylactic
therapy

18. Eye
• Dilated fixed or asymmetric pupils (autonomic
dysfunction)
• Catarct (delayed days up to two years after
the electric shock)
• Haemorrhage : Hyphema (anterior) , Vitreous
Haemorrhage (posterior)
• Optic nerve affection

19. Ear
• Ruptured tympanic membrane
• SNHL , vertigo, tinnitus may occur

20. SUMMARY
• Skin : burn
• Bone : Fracture / necrosis
• Muscles : ACS / Rhabdomyolisis (+AKI)
• CNS : LOC / Paralysis / Sense / Autonomic / Memory
• Heart : Arrhythmias / Myocardial affection
• BVs : Injury / Thrombosis / Aneurysm
• Renal : Heme pigment-induced AKI / Prerenal Failure
• Respiratory : Arrest (central/peripheral)
• GIT : Ileus / Ischemia / Ulcer
• Eye : Cataract / Hemorrhage / Optic n. affection
• Ear : Tympanic membrane / SNHL / Tinnitus / Vertigo

21. Management

22. Emergency Measures
• ABC
• CPR
– Prolonged CPR = good outcome even in asystole &
dialted fixed pupil !
– Manage arrhythmia if present
• Cervical immobilization

23. Investigations
• Routine labs + electrolytes + ABG
• RFTs & LFTs
• ECG (mandatory in all patients)
• CK (Rhabdomyolysis + AKI)
• Imaging studies
– Brain imaging
– Cervical spine x-ray
– Peripheral limbs x-ray
– Chest & Pelvic radiographs (especially in previously
unconscious patients)

24. Investigations
• Cardiac
– ECG (mandatory)
– Monitoring (arrhythmia / autonomic dysfunction /
Haemodynamic instability)
– ECG & CK-MB = poor diagnostic in myocardial
affection
– Troponin-I & ECHO = better diagnostic
– Cardiologist consultation is always necessary

25. Treatment
• Fluid resuscitation
– Aggressive replacement if soft tissue injury
– Prevent Heme pigment-induced AKI
– Administer fluids till
• Normal blood pressure
• UOP ( 0.5 - 1 mL/kg/h if +ve Myoglobin // 1-2 mL/kg/h if -ve Myoglobin)
• CK < 5000 U/L
• negative urine for hematuria
– Not estimated from skin injury degree (Parkland formula)
– Normal Saline = best solution
– Monitor K level (released from damaged muscles)
– Over correction may lead to Abdominal Compartment Syndrome

26. • Foley's catheter
= mandatory to assess UOP & level of
hydration
Treatment

27. Treatment
• Mannitol
– Osmotic Diuresis to maintain UOP & prevent heme pigment deposition
– 1gm/kg/day
– Contraindicated if Oliguria is present
– Stopped if target UOP not reached with rising plasma osmolarity (may
complicate with hyper-osmolarity / Hyperkalemia)
• Bicarbonate
– Urine alkalization induced diuresis
– Prevent heme deposition
– Give only if :
• PH < 7.5
• HCO3 < 30
• No sever hypocalcemia
– Stopped after 4-6 hours if urine PH not rising above 6.5 or if
hyperCalcemia is present

28. Treatment
• Both Mannitol & Bicarb have questionable effect
– May be used together if CK > 30,000
• Loop Diuretics
– May worsen the case (Calcinuria + Ca deposition)
• Once AKI established
– No specific ttt
– Only stabilization
– Dialysis may be indicated

29. Treatment
• Surgical : Fasciotomy
– in Compartment syndrome = diagnostic &
therapeutic role

30. Treatment
• Limb amputation
– If severely affected with persistent myoglobinuria

31. Thanks

32. Refrences
• Uptodate
– “Environmental and weapon-related electrical injuries”
• Reviewed Sep. 2015
• Medscape
– “Electrical Injuries”