To the Editor: The potential for permanent hearing loss dueto prolonged use of personal stereo equipment, such as portablecompact-disk or MP3 players, at high decibel levels has beenwell described in the literature.1 We have recently become awareof an additional, albeit uncommon, hazard associated with theuse of such devices.
A 37-year-old man was brought to the emergency department atour hospital. He had been jogging in a thunderstorm, listeningto his iPod, when an adjacent tree was struck by lightning.Witnesses reported that he was thrown approximately 8 ft (2.4m) from the tree.
The patient had second-degree burns on his chest and left leg.In addition, two linear burns extended along his anterior chestand neck to the sides of his face, terminating in substantialburns in the external auditory meatus bilaterally, correspondingto the positions of his earphones at the time of the lightningstrike. Both of his tympanic membranes were ruptured, and hehad a severe conductive hearing deficit. He also had a mandibularfracture. Computed tomography of the mandible (Figure 1A) andof the temporal bones showed bilateral dislocation of the incudomalleolarjoints (Figure 1B and 1C). Internal fixation of the mandibularfractures was performed and the perforations of the tympanicmembranes were managed with the use of perichondrial grafting.
Figure 1. Computed Tomographic Scan of the Mandible and Temporal Bones in the Patient.
A coronal image of the mandible (Panel A) shows bilateral fractures and dislocations of the condylar necks (arrows). A transverse image of the right middle ear (Panel B) shows dislocation of the incudomalleolar joint, with the head of the malleus (arrow) lying lateral to its expected articulation with the body of the incus (arrowhead); normally, these ossicles have an "ice-cream cone" appearance on transverse images. Similar ossicular dislocation is shown in the left middle ear (Panel C); in addition, abnormal soft tissue in the epitympanic recess (arrow) indicates the presence of hemorrhage.
Although people may be struck directly by lightning, it is morecommon for the lightning to jump to a person from a nearby object,such as a tree — a phenomenon known as a side flash.2Opisthotonic muscle contraction may project the victim somedistance, leading to further injury from blunt trauma. Becauseof the high resistance of skin, the lightning is often conductedover the outside of the body (an effect known as a flashover);however, sweat and metallic objects in contact with the skincan disrupt the flashover, leading to the internal flow of current.Although the use of a device such as an iPod may not increasethe chances of being struck by lightning,3 in this case, thecombination of sweat and metal earphones directed the currentto, and through, the patient's head. The mandibular fractureswere probably caused by muscle contraction, since there wereno external signs of injury to the face. The perforations ofthe tympanic membranes occurred as a result of the sudden heatingand expansion of air around the current, leading to pressurewaves. Perforations are commonly seen in patients who have beenstruck by lightning,4 although ossicular injuries appear tobe rare.5
Eric J. Heffernan, M.B. Peter L. Munk, M.D. Luck J. Louis, M.D. Vancouver General Hospital Vancouver, BC V5Z 1M9, Canada ejheffernan{at}eircom.net
References
Fligor BJ, Cox LC. Output levels of commercially available portable compact disc players and the potential risk to hearing. Ear Hear 2004;25:513-527. [CrossRef][ISI][Medline]
Mason AD, Crockett RK. When lightning strikes: a case report and review of the literature. Int Paediatr 2000;15:173-8.
Farragher RM. Injury from lightning strike while using mobile phone: statistics and physics do not suggest a link. BMJ 2006;333:96-96. [Free Full Text]
Glunci I, Roje Z, Glunci V, Poljak K. Ear injuries caused by lightning: report of 18 cases. J Laryngol Otol 2001;115:4-8. [CrossRef][ISI][Medline]
Meriot P, Veillon F, Garcia JF, et al. CT appearances of ossicular injuries. Radiographics 1997;17:1445-1454. [Abstract]
More on Thunderstorms and iPods
Andrews C., Cooper M. A., Mick P. T., Lee P. K., Longridge N., Heffernan E. J., Munk P. L., Louis L. J.
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N Engl J Med 2007;
357:1447-1448, Oct 4, 2007.
Correspondence
Andrews, C., Cooper, M. A., Mick, P. T., Lee, P. K., Longridge, N., Heffernan, E. J., Munk, P. L., Louis, L. J.
(2007). More on Thunderstorms and iPods. NEJM
357: 1447-1448
[Full Text]
Heffernan, E. J., Munk, P. L., Louis, L. J.
(2007). Thunderstorms and iPods -- Two Reports of the Same Case. NEJM
357: 723-723
[Full Text]
I, Roje Z, Glunci
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