Keraunoparalysis: Definition and Management
Keraunoparalysis is a transient, reversible paralysis of the extremities that occurs following a lightning strike, typically resolving within 24-48 hours without permanent sequelae. This benign neurological phenomenon can mimic serious spinal cord injury but requires only conservative management and close observation 1, 2.
What is Keraunoparalysis?
Keraunoparalysis represents a temporary neurological dysfunction caused by the massive electrical discharge from lightning affecting peripheral nerves and potentially causing vasospasm. The condition manifests as:
- Acute onset weakness or paralysis (can be hemiparesis, paraparesis, or affect single extremities)
- Associated sensory deficits (numbness, paresthesias, complete sensory loss)
- Vascular changes (affected limb may appear pale, cold, pulseless with absent capillary refill)
- Complete resolution typically within hours to days (most within 12-48 hours) 2, 3, 4
Critical distinction: This mimics arterial occlusion or spinal cord injury but is fundamentally different in prognosis and management 3.
Initial Evaluation and Management
Immediate Priorities (First Minutes to Hours)
Address life-threatening complications first - the primary cause of death in lightning strikes is cardiac arrest (VF or asystole) and respiratory arrest from thoracic muscle spasm and respiratory center suppression 5.
Airway and breathing take precedence:
- Assess for respiratory arrest - this may persist even after cardiac rhythm returns
- Early intubation if extensive burns to face, mouth, or anterior neck (rapid soft-tissue swelling complicates delayed intubation) 5
- Standard ACLS protocols apply without modification 5
Cervical spine precautions:
- Assume cervical spine injury until proven otherwise
- Logroll patient as a unit if repositioning needed 5
Specific Evaluation for Keraunoparalysis
Neurological examination must document:
- Pattern of weakness (hemiparesis, paraparesis, monoparesis)
- Sensory deficits
- Cranial nerve function
- Deep tendon reflexes
- Vascular status of affected limbs (pulses, temperature, color, capillary refill)
Imaging to exclude structural injury:
- Brain CT/MRI - rule out hemorrhage, edema, small-vessel injury 2, 6
- Spinal MRI - exclude spinal cord injury, hemorrhage, or edema 6, 7
- Cervical spine imaging - rule out traumatic injury 4
Laboratory evaluation:
- ECG - assess for QT prolongation, T-wave inversions, arrhythmias 5
- Cardiac enzymes - myocardial necrosis can occur 5
- Creatine kinase and myoglobin - assess for rhabdomyolysis 1
- Electrolytes - particularly potassium (hypokalemia common and dangerous) 1
- Renal function - monitor for acute kidney injury from myoglobin
Neurophysiological studies (if available and indicated):
- EMG/nerve conduction studies - may show peripheral nerve involvement 7
- Somatosensory evoked potentials - assess central pathway integrity 7
Management Strategy
Keraunoparalysis is a diagnosis of exclusion - only confirm after imaging rules out structural CNS injury 2, 6.
Conservative Management Protocol
Once structural injury excluded:
- Close observation for symptom progression (first 24-48 hours critical)
- Aggressive IV hydration - maintain diuresis to facilitate myoglobin excretion if rhabdomyolysis present 5, 1
- Correct electrolyte abnormalities - particularly hypokalemia 1
- Analgesics for pain control 2
- Physical therapy for affected limbs during recovery 4
- Avoid unnecessary interventions - no indication for anticoagulation, thrombolytics, or surgical intervention 3, 6
Critical Pitfall to Avoid
Do not mistake keraunoparalysis for arterial occlusion requiring vascular surgery or amputation 3. The pulseless, pale, cold extremity will recover spontaneously as vasospasm resolves. Premature surgical intervention is harmful and unnecessary.
Prognosis and Timeline
Excellent prognosis with conservative management:
- Symptoms typically begin improving within 12-24 hours 2
- Complete resolution usually within 48 hours to 1 week 2, 6, 4
- No permanent neurological sequelae expected 1, 6
- Mild paresthesias may persist for several days after motor recovery 4
Monitoring During Recovery
- Serial neurological examinations every 4-6 hours initially
- Continuous cardiac monitoring for first 24 hours
- Urine output monitoring if rhabdomyolysis present
- Repeat electrolytes every 6-12 hours until stable
Patients who do not suffer cardiac or respiratory arrest and respond to immediate treatment have an excellent chance of complete recovery 5. The key is recognizing keraunoparalysis as a benign, self-limited condition while systematically excluding life-threatening structural injuries that require different management.