Trauma Listrik dan Petir

01Pathophysiology

The fundamental physics of electrical injury is governed by Joule's law, expressed as:

$$H=I^2\times R\times tH\; =\; I^2\; \backslash times\; R\; \backslash times\; t$$

where $HH$ is heat generated, $II$ is current, $RR$ is tissue resistance, and $tt$ is duration of contact. This equation tells you that heat production (and therefore tissue destruction) increases with current magnitude, tissue resistance, and contact time. The clinical implication is that visible skin burns may dramatically underestimate the extent of deep tissue injury, because current follows the path of least resistance through highly conductive internal tissues (nerves, blood vessels, muscle) while generating the most heat at points of highest resistance (bone-muscle junctions, skin contact points).

Kouwenhoven's factors describe the variables that determine injury severity: type of current (AC vs DC), amperage, voltage, resistance of tissues, pathway through the body, and duration of contact. Of these, the pathway through the body and current type are the most clinically relevant for exam purposes. A hand-to-hand pathway is especially dangerous because the current traverses the thorax and heart. A hand-to-foot pathway similarly crosses the myocardium. A foot-to-foot pathway, while still harmful, is less likely to cause cardiac arrest.

Alternating current (AC) at household frequencies (50-60 Hz) is more dangerous than direct current (DC) at comparable voltages. AC causes tetanic muscle contraction that prevents the victim from releasing the source, a phenomenon called the "can't let go" phenomenon. The let-go threshold for AC is approximately 15 mA (versus ~75 mA for DC). This sustained grip prolongs contact time and increases total energy delivery. AC is also more effective at inducing ventricular fibrillation because the cyclical nature of the current repeatedly stimulates the myocardium during the vulnerable repolarization period (the relative refractory period, analogous to the R-on-T phenomenon). In contrast, DC tends to cause a single, violent muscular contraction that throws the victim away from the source, often resulting in blunt trauma. High-voltage DC or lightning tends to cause asystole rather than ventricular fibrillation.

At the cellular level, electrical current causes injury through three mechanisms. Joule heating produces thermal coagulation necrosis of tissues along the current path. Electroporation creates permanent pores in cell membranes, disrupting cellular integrity and leading to delayed cell death even in areas that initially appear viable. Electrochemical injury denatures proteins and disrupts ion gradients. These mechanisms explain why electrical burns are often described as an "iceberg injury": the surface burn represents only the tip, while extensive deep muscle necrosis, vascular thrombosis, and nerve damage exist beneath seemingly intact skin.

Lightning behaves differently from industrial electrical injury. A lightning bolt delivers approximately 100 million to 2 billion volts but for an extremely short duration (0.001 to 0.003 seconds). This ultra-short exposure time means that much of the energy travels over the surface of the body rather than through it, a phenomenon called flashover. Flashover explains why many lightning victims survive with relatively minor burns, yet a direct strike to the head can cause respiratory center paralysis and cardiac arrest. The blast wave generated by the rapid heating and expansion of air surrounding the lightning bolt causes barotrauma, most notably tympanic membrane rupture (found in up to 50% of lightning victims).

02Classification and Clinical Manifestation

2A. Classification of Electrical Injury by Voltage

2B. AC versus DC: Clinical Differences

2C. Mechanisms of Lightning Injury

2D. Organ System Manifestations

03Diagnostic Workup

The best initial test in all electrical injury patients is the 12-lead ECG. It must be obtained immediately upon arrival. This is the single most important triage tool because it determines the need for cardiac monitoring and admission.

For low-voltage electrical injury (LVEI), a patient who is asymptomatic with a normal ECG on presentation can be safely discharged after a period of observation (typically 4-6 hours). No further cardiac monitoring is required if the patient remains asymptomatic and the initial ECG is normal. This is a frequently tested decision point.

For high-voltage electrical injury (HVEI), all patients require admission with continuous cardiac monitoring for at least 24 hours, regardless of whether the initial ECG is normal. The rationale is that delayed arrhythmias can occur after high-voltage exposure, and the internal tissue destruction may not be immediately apparent.

Creatine kinase (CK) is the cornerstone lab for assessing the degree of muscle injury and rhabdomyolysis. Serial CK measurements guide the aggressiveness of fluid resuscitation. A CK level greater than 5,000 U/L places the patient at significant risk for acute kidney injury from myoglobin-induced renal tubular obstruction.

The urinalysis finding that is most suggestive of myoglobinuria is urine that tests positive for blood on dipstick but negative for red blood cells on microscopy. This discrepancy occurs because the dipstick detects the peroxidase activity of both hemoglobin and myoglobin, but microscopy only identifies intact red blood cells.

For suspected compartment syndrome, clinical evaluation is the primary diagnostic method. The classic "5 Ps" (pain, pallor, paresthesia, pulselessness, paralysis) are unreliable in electrical injuries because of concurrent nerve damage and distracting burns. Pain out of proportion to exam and pain with passive stretch are the earliest and most sensitive clinical findings. Compartment pressure measurement confirms the diagnosis when clinical suspicion exists.

In lightning injury, the workup is similar but with added emphasis on: bilateral ear examination for TM rupture, ophthalmologic evaluation, and head CT if there is any loss of consciousness or direct head strike.

04Management and Treatment

Reverse triage is a concept unique to lightning mass casualty incidents and is the highest-yield management pearl for this topic. In standard triage, patients who appear dead are triaged last (expectant). In lightning triage, the opposite applies: treat the apparently dead first. The rationale is that cardiac automaticity often returns spontaneously after a lightning-induced asystolic arrest, but the medullary respiratory center remains paralyzed for a longer period. If the victim receives ventilatory support during this window, the heart may resume function and the patient may survive. Without ventilation, the patient experiences a secondary cardiac arrest from prolonged hypoxia, which is then irreversible. Survivors of lightning arrest who are breathing on their own will generally survive; those in respiratory arrest need only ventilation to bridge them to recovery.

The Parkland formula ($4mL\times kg\times \mathrm{\%}TBSA4\backslash \; mL\; \backslash times\; kg\; \backslash times\; \backslash \%TBSA$) is the standard starting point for burn resuscitation but consistently underestimates fluid requirements in electrical burns. The reason is that the visible skin burn area does not reflect the true extent of internal tissue injury. Clinicians should use the formula as a starting point and then aggressively titrate based on urine output. For patients with clear urine, the target is 0.5-1 mL/kg/hr. For patients with pigmented (tea/cola-colored) urine indicating myoglobinuria, the target must be increased to 1-2 mL/kg/hr (some protocols recommend 100 mL/hr in adults) until the urine clears.

Keraunoparalysis is a transient condition following lightning injury where extremities (lower limbs more than upper limbs) become cold, mottled, blue, and pulseless due to autonomic nervous system overstimulation and vasospasm. This presentation mimics spinal cord injury or compartment syndrome, but it is benign and self-resolving, typically within hours to a day. The critical management point is to avoid performing fasciotomy for keraunoparalysis, as it will resolve spontaneously. Additionally, fixed and dilated pupils in a lightning victim should NOT be used to pronounce death or guide prognostication, as this finding can be a reversible effect of autonomic dysfunction.

For cardiac arrest in electrical or lightning injury, initiate prolonged resuscitation. Standard ACLS protocols apply, but the threshold for termination of resuscitation should be extended. Lightning victims in particular may have a favorable neurologic outcome even after prolonged arrest if ventilation is provided early. VF should be treated with defibrillation per standard protocol. Asystole (more common in DC/lightning) is managed with epinephrine and CPR.

Indonesian Regulatory Context

In Indonesia, electrical safety in the workplace is primarily governed by UU No. 1 Tahun 1970 on Workplace Safety and further regulated by Peraturan Menteri Ketenagakerjaan No. 12 Tahun 2015 on Occupational Safety and Health (K3) for Electrical Work in the Workplace. PP No. 50 Tahun 2012 requires companies with a certain level of risk to implement a formal occupational safety and health management system (SMK3), which includes electrical hazard identification, risk assessment, and control measures. Additional standards referenced include Permenaker No. 5 Tahun 2018 on K3 in the Electrical Sector and SNI 04-0293-1999 on procedures for the installation and use of electrical equipment. These regulations place the obligation on employers to ensure proper installation standards, provide competent safety officers (Ahli K3 Listrik), and maintain electrical installations in accordance with PUIL (Persyaratan Umum Instalasi Listrik). For exam purposes, it is worth knowing that Indonesia mandates these occupational protections, and that a workplace electrical injury may invoke both medical management and regulatory reporting obligations under the K3 framework.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most common way students lose points on electrical and lightning trauma questions is by underestimating the severity of electrical burns based on skin appearance. Electrical burns follow an "iceberg" pattern: the external skin injury may be minimal, but the deep tissue necrosis (muscle, nerve, vessels) can be devastating. The vignette will describe a patient with seemingly small entry and exit wounds who then develops rhabdomyolysis, compartment syndrome, and acute kidney injury. The tested competency here is recognizing that surface burns do not equal total injury burden, and that aggressive fluid resuscitation and serial CK monitoring are always warranted in high-voltage exposure.

The second major trap is applying standard triage rules to lightning mass casualty events. The exam will present a scenario with multiple lightning strike victims. The student's instinct will be to triage the breathing patients first (as in standard triage). The correct answer is reverse triage: prioritize the apparently dead, because respiratory arrest from medullary paralysis is the primary killer, and cardiac automaticity can recover if ventilatory support is provided. This is one of the very few scenarios in medicine where "treat the dead first" is the correct answer.

A third high-yield pearl involves the difference between AC and DC cardiac arrest. When a vignette describes a patient who "grabbed a wire and could not let go," the mechanism is AC, and the expected arrhythmia is ventricular fibrillation. When a vignette describes a patient who was "thrown from the source," the mechanism is DC, and the expected arrhythmia is asystole. Lightning also causes asystole as the primary arrest rhythm.

Students also commonly mistake keraunoparalysis for compartment syndrome and select fasciotomy as the answer. Keraunoparalysis resolves spontaneously and does not require surgery. The key clinical clue is that keraunoparalysis occurs bilaterally in the lower extremities after a lightning strike, while compartment syndrome from electrical injury is typically unilateral in the affected limb pathway.

Finally, remember that fixed and dilated pupils in a lightning victim are NOT grounds for terminating resuscitation. This autonomic finding can be reversible. Prolonged CPR is indicated, and lightning arrest victims can have favorable neurologic outcomes even after extended resuscitation.

For the Parkland formula, always remember that it underestimates fluid needs in electrical burns. When the question gives you tea-colored urine, the answer is to increase fluid rate targeting urine output of 1-2 mL/kg/hr and to alkalinize the urine with bicarbonate.