Mountain medical mystery. Unwitnessed death of a healthy young man, caused by lightning

A healthy 20-year-old man failed to return home after a jog in the Colorado mountains. His lifeless body was found the next day on an exposed mountain slope. The differential diagnosis in such mysterious, unwitnessed mountain deaths includes cardiac arrhythmia, cerebral hemorrhage, pulmonary embolism, seizures, trauma, high-altitude sickness, and hypothermia. The cause of death in this case was established on postmortem examination. The findings of ruptured tympanic membranes and a melted shoe established this as a case of lightning strike fatality. The National Lightning Detection Network can be a valuable resource to investigators by providing information on the location and date of lightning strikes in the vicinity of the victim.

[Analysis on characters of 220 cases of tympani membrane perforated]

220 cases of tympani membrane perforated were summarized retrospectively. The tympani membrane perforated of injury was different from otitis media's because they had marked or extreme marked difference in sex, age, ear distinction, shape, position, size, degree of hearing damaged, time of healing, cause of perforating and adhesive substance. This difference was relative to mechanism of tympani membrane perforated. The distinction gist of two sorts of tympani membrane perforated was expounded through comparison and analysis. It would be of great value to clinical forensic medical examination.

Rupture pressures of membranes in the ear

The rupture pressures of the tympanic membrane, Reissner's membrane, the round window membrane, and the annular ligament have all been measured in cadaver ears from Norwegian cattle. For the tympanic membrane, a static overpressure was applied to the ear canal; for Reissner's membrane, to the endolymph; and for the round window membrane, to the perilymph. The rupture pressure of the annular ligament equals the rupture force to the footplate divided by the area of the oval window. The mean rupture pressures are 0.39 atm for the tympanic membrane, 0.047 atm for Reissner's membrane, greater than 2 atm for the round window membrane, and 29.4 atm for the annular ligament. This last pressure corresponds to 0.68 kilogram force applied to the footplate. The ruptures of the tympanic membrane appeared without exception as small tears in the pars flaccida. The rupture pressure of the tympanic membrane was also measured in a few ears from foxes.

Medical consequences of terrorism. The conventional weapon threat

As long as gunpowder and explosives are used to solve disagreements between nations, ethnic groups, and individuals, victims of blast injury continue to arrive occasionally at trauma centers around the world. Bombs planted in crowded urban locations or suicide bombings continue to stress civilian EMS and urban medical systems. Although the clinical presentation depends on whether the blast occurs in open or confined quarters, open air, or water, the pattern of injury inflicted on the body is relatively consistent. The proximity to the detonating device is probably much more important than the size of the bomb. If not injured by secondary, tertiary, or other miscellaneous mechanisms of most conventional bombs with 1 to 20 kg of TNT, people at distances exceeding 6 m will probably not experience substantial blast-induced injury. Three systems are prone to injury. The first is the auditory system, with damage to the eardrum in milder cases and inner-ear injury in more severe cases. The alimentary tract with contusions, hematoma, and occasional perforation of a hollow viscus is the second system involved. Solid organs are rarely damaged in survivors of blast injury. Close proximity to the blast can impose traumatic amputation of limbs (i.e., arms and legs) and ear lobes. Most of these victims succumb to their injuries in the immediate post-injury phase, but the hallmark of blast injury is the involvement of the respiratory system. With expeditious evacuation performed by efficiently coordinated and highly skilled EMS personnel, more patients with blast injuries arrive with signs of life to the medical facility. At the medical facility, the staff need to triage many victims into urgent and nonurgent groups. Only lifesaving procedures should be performed during the initial phase. Later, medical care is directed at patients moved to ICUs. Prompt evacuation after necessary lifesaving procedures in the field; proper triage and distribution; prudent hospital triage and surgical care; and, last but not least, expert critical care provide the best possible outcome in such circumstances.

Scintigraphic evaluation of the Eustachian tube functions

Eustachian tube (ET) dysfunction is one of the most important factors in the etiology of middle ear disease. There are several methods to assess the functions of ET which show the anatomic patency of the tube. However, functional patency of ET should be evaluated as well. For this reason, we used a scintigraphic method at 42 patients who had otitis media with effusion (study group) and traumatic perforation of the ear drum (control group) at 32 and 10 of them, respectively. After instillation of 100 microCi (100 microliters) Technetium 99m-macro-aggregated albumin (Tc99m-MAA) into the middle ear, 60 images were taken at 15 second intervals. Both groups were investigated as to whether there was radioactivity passage through ET and, the arrival time of the radioactivity to ET and to nasopharynx were calculated if the passage occurred. Radioactivity passage rates in the study and control groups were 5 (16%) and 10 (100%), respectively. The difference between both groups was statistically very significant (Chi-square, p < 0.001). Scintigraphy is a feasible tool for the assessment of ET functions. Scintigraphic methods should be improved and be used as a tubal function test in the future.

[Application of the myringoscope and myringophotography in forensice medical identification]

In analysis of tympanitio membrane injury, we have compared conventional otoscope with myringoscope and found that the myringoscope has an advantage over the conventional otoscope. The myringoscope can show the whole tympanitic membrane, the positions, shapes and characteristics of tympanitic membrane injuries more clearly. The pictures of myringophotography could be preserved and offered to court as an important forensic medical evidence.

Effect of healed tympanic membrane perforations on umbo velocity in the rat

Heterodyne laser interferometry was used to measure tympanic membrane (TM) velocity at the umbo during acoustic stimulation in 2 groups of rats. The control group had a normal TM, while in the other group the TM was perforated and then allowed to heal for at least 28 days. Umbo velocity functions for constant sound pressure level stimuli were obtained for test tones between 0.3 and 40.0 kHz in each animal. The results revealed that velocity was the same in the control and healed TMs below 3.0 kHz. Above 5.0 kHz, the velocity response in the healed ear was between 3 and 12 dB smaller than in the control ears. Histologic evaluation of the healed perforation revealed a thick fibrous reaction between the epidermal and lamina propria layers. The results indicated that the added mass of the scar tissue changed the middle- and high-frequency TM responses.

Post-traumatic guitar-shaped deformity of the tympanic membrane

We report a unique case of post-traumatic guitar-shaped deformity of the tympanic membrane in an 8-year-old boy. After a traffic accident, he exhibited bleeding from the ear, incomplete facial palsy and a conductive hearing loss on the left side. Although his symptoms gradually improved, the deformity of the tympanic membrane and external auditory canal persisted. The tympanic membrane appeared to be duplicated. Careful examination using an otoscope was required for accurate diagnosis. Without knowledge of the deformity, the physician could easily misinterpret the appearance of the tympanic membrane. Formation of cholesteatoma was not observed and the normal migration of the epithelium in the external auditory canal seemed to be maintained. However, we were concerned that tubal dysfunction could eventually induce the retraction and atrophy of the tympanic membrane to ultimately form a cholesteatoma. We therefore recommend patients such as this to be evaluated periodically because of the risk of tubal dysfunction and cholesteatoma.

Volume displacement of the gerbil eardrum pars flaccida as a function of middle ear pressure

The pars flaccida (PF) is a small region of the eardrum, with elasticity and histology completely different from the rest of the membrane, which has often been attributed a pressure regulating function for the middle ear (ME). In this paper, the volume displacement of the PF as a function of ME pressure is discussed. The deformation of the PF was measured in vitro in five Mongolian gerbil ears, by means of an opto-electronic moiré interferometer. Volume displacement was determined at small intervals in three sequential pressure cycles, in the range of +/- 0.4 kPa, +/- 2 kPa, and again +/- 0.4 kPa. The displacement was found to be a highly non-linear function of pressure, with a strong increase up to 0.4 kPa ME over- or underpressure and remaining nearly unchanged for pressures beyond 0.4 kPa. In all animals, maximal volume displacement was less than 0.5 microl, or 0.2% of total ME air volume. Clear hysteresis was found between the deformations at the same pressure level in the increasing and decreasing parts of the pressure cycles. Membrane behavior in the first 0.4 kPa pressure cycle was significantly different from that in the second 0.4 kPa cycle, which followed the 2 kPa pressure cycle. The results indicate that the ME pressure change regulation function of the PF is limited to very small pressure changes of a few hundred Pa around ambient pressure, and that larger ME pressures cause at least short-term changes in the membrane's behavior.

Tympanic Membrane Perforations in the Diabetic Rat: A Model of Impaired Wound Healing

Animal models of type I and type II diabetes mellitus have been studied intensively in an effort to define the pathophysiology of the diabetic condition. An often-observed clinical manifestation of diabetes is poor wound repair. Thus diabetic animals have emerged as useful models for the study of impaired wound healing. The healing of acute tympanic membrane (TM) perforations in diabetic animals has not been reported. This investigation compares time to closure of a standardized TM perforation in rats with streptozotocin-induced diabetes, Zucker diabetic fatty rats, and normal control rats. The Zucker diabetic fatty rats demonstrate a significantly prolonged time to closure compared with the other two groups. This animal model may be useful for future study of TM wound repair.

[Gunshot injuries of the ENT area caused by blank cartridge weapons]

Different types of gunshot injuries caused by warning weapons are demonstrated. Most important are contract shots, causing major tissue damage that can differ from that caused by classical projectiles. Possible consequences, besides direct trauma to the eye and ear, are airway distress because of extensive swelling and rupture of major neck vessels. The detailed examination includes endoscopy and radiologic imaging. Any major permanent cavity in the tissue bears a high risk of wound infection. For different reasons the fact of a gunshot wound may be kept secret by the victims.

Blast overpressure induced structural and functional changes in the auditory system

Blast overpressure of sufficient intensity can produce injury to various organ systems. Unprotected ears result in the auditory system being the most susceptible. The injuries to the auditory system include: rupture of the tympanic membrane, dislocation or fracture of the ossicular chain, and damage to the sensory structures on the basilar membrane. All these injuries can be characterized as a form of mechanical damage to the affected structure. Injury to the sensory structures on the basilar membrane leads to temporary and permanent loss of hearing sensitivity. The temporary component of the hearing loss shows a time course after removal from the noise which frequently will include an initial increase in hearing loss followed by a recovery period during which threshold may return to preexposure levels or stabilize at a higher level which represents a permanent loss of hearing sensitivity. This type of recovery function suggests that there are damage processes which continue after the traumatic event and that intervention might mitigate some of the damage and hearing loss.

Effects of fibroblast growth factor on the healing process of tympanic membrane perforations in an animal model

After traumatic perforation of the tympanic membrane (TM), healing occurs spontaneously in most cases, although occasional perforations will fail to close. Healing of epithelia at any site involves cell movement, with injury providing the stimulus to initiate changes in the behavior of cells that are normally static. Epidermal proliferation at the margins of the TM perforation can be accelerated by using such growth factors as epidermal growth factor, basic fibroblast growth factor (bFGF) and hyaluronan. bFGF is chemotactic and mitogenic for both fibroblasts and endothelial cells and is also mitogenic for keratinocytes. The effect of bFGF is significant in the enhancement of fibroblast production and angiogenesis. In this study, bFGF was used to enhance the healing process of chronic TM perforations in a guinea pig animal model. Chronic perforations were created since acute TMs could heal spontaneously without using any bioactive substance. In all, 30 TMs of 15 guinea pigs were used. A thermal myringotomy loop was employed to create a subtotal TM perforation at the area of the pars tensa. After establishing a permanent, non-infected perforation, bFGF in buffered saline solution was applied as 400 ng/day to 15 ears, while the opposite (control) ear was treated with only saline solution. At 20 days, 13 of 15 perforations treated with bFGF had closed. Light microscopy was used to assess organization of the healed TMs. The effects of bFGF on the healing process of TM perforations were compared in treated and non-treated ears.

Blast injuries: bus versus open-air bombings--a comparative study of injuries in survivors of open-air versus confined-space explosions

OBJECTIVES

To compare injury patterns resulting from explosions in the open air versus within confined spaces.

METHODS

Medical charts of 297 victims of four bombing events were analyzed. Two explosions occurred in the open air and two inside buses. Similar explosive devices were applied in all four incidents. The incidence of primary blast injuries, significant penetrating trauma (Abbreviated Injury Scale score > or = 2), burns, Injury Severity Score, Revised Trauma Score, and mortality were compared between the two populations.

RESULTS

A total of 204 casualties were involved in open-air bombings, 15 of whom died (7.8%). Ninety-three victims were involved in bus bombings, 46 of whom died (49%). The difference in mortality rate was highly significant, p < 0.00001. Primary blast injuries were observed in 25 and 31 victims (34.2% and 77.5% of admitted victims), respectively (p = 0.00003). Median Injury Severity Score was 4 versus 18, respectively (p < 0.0001).

CONCLUSION

Explosions in confined spaces are associated with a higher incidence of primary blast injuries, with more severe injuries and with a higher mortality rate in comparison with explosions in the open air.

Changes in middle ear pressure in daily life

The present study was performed to estimate changes of middle ear pressure (ME-P) during actions of daily life such as nose blowing and sniffing. ME-P was measured in 18 patients with perforation of the eardrum. They were asked to perform actions which included nose blowing and sniffing. Eustachian catheterization and politzerization were also applied. Change of ME-P before and after these actions was recorded using a pressure monitor. Results showed that changes of ME-P after nose blowing with both nostrils closed were large and rapid. The mean value of ME-P after nose blowing was 252 mmH2O. In our previous study, the mean value of cerebrospinal fluid pressure (CSF-P) after nose blowing was 388 mmH2O. Therefore, the pressure gradient across the cochlear windows is about 130 mmH2O during nose blowing. The cochlear windows may have been pressed toward the middle ear side. After sniffing, ME-P was unchanged. These results suggest that nose blowing may be an important cause of perilymphatic fistula (PLF) via the "explosive route", while sniffing is not likely to cause PLF.

Repair of chronic tympanic membrane perforations with long-term epidermal growth factor

Chronic tympanic membrane (TM) perforation is a common problem worldwide. Recent reports have shown epidermal growth factor (EGF) to stimulate healing in approximately 80% of chronic TM perforations in chinchillas when applied in three doses over 1 week. The objective of this controlled study is to evaluate the efficacy of long-term EGF in the closure of TM perforations. Chronic chinchilla TM perforations were treated with EGF for up to 6 weeks. One hundred percent (17 of 17) of treatment group perforations completely healed. However, two new findings with this long dosing scheme were reperforation on long-term follow-up and three TMs with cholesteatomas. It is likely that reperforation was due to a progressive thinning seen with prolonged EGF application. Long-term EGF use is not recommended for the treatment of TM perforations because of possible wound healing impairment and possible cholesteatoma induction.

Effect of Epidermal Growth Factor on Tympanic Membranes with Chronic Perforations: A Clinical Trial

Epidermal growth factor is an important modulator of cell growth, and its role in normal wound healing is well documented. Epidermal growth factor receptors have been identified in tympanic membranes of different animals. The ability of epidermal growth factor to promote healing of tympanic membrane perforations has recently been shown in experimental animals. We performed a double-blind, placebo-controlled study of the effect of epidermal growth factor applied locally on the tympanic membrane for 1 week in patients with chronic perforations. Seventeen adult patients took part in the study, eight in the epidermal growth factor group and nine in the placebo group. Three placebo-treated patients were later treated with epidermal growth factor, and five patients received repeated epidermal growth factor treatment. Perforation size was measured as a percentage of the tympanic membrane area before and at least 1 month (mean, 2.6 months) after treatment. One perforation in the placebo group healed completely, but none of the epidermal growth factor-treated perforations closed. Perforations became slightly smaller in both groups (mean decrease, 0.3% and 2.7% for epidermal growth factor and placebo, respectively), but these changes in size were not statistically significant for either group. At otomicroscopy, a proliferation reaction with thickening of the tympanic membrane and pseudomembrane formation at the perforation edge could be seen in some ears. Histologically, a sample from one epidermal growth factor-treated ear demonstrated signs of hypertrophic epithelium when compared with the morphology of a placebo-treated tympanic membrane. The only complications were two mild infections in the placebo group. Hearing remained stable after epidermal growth factor treatment.

Tympanic membrane wound healing. An overview

This article is a comprehensive overview of tympanic membrane injury and its healing. Its wound healing process is unique from soft tissue because epithelialization occurs before fibrous tissue advancement. Contemporary and future modalities to improve tympanic membrane repair are also discussed in this article.

CT cisternography in congenital perilymphatic fistula of the inner ear

Perilymphatic fistulas of the inner ear constitute abnormal leaks of perilymphatic fluid into the middle ear or mastoid air cell system and represent a rare cause of otorrhea. We report the case of a 5-month-old child presenting with sudden otorrhea. High resolution CT cisternography showed a malformation of the middle ear and a passage of contrast-enhanced CSF into the tympanic cavity through the left oval window. Surgery confirmed a tear of the tympanic membrane as well as a stapes malformation with aplasia of the crura and an associated perilymphatic fistula through a defect in the stapes footplate. The fistula was closed with adipose tissue from the ear lobe.

[Lightening strike injuries of the ear]

Although lightning injuries are quite common, lightning-induced damage to the middle or inner ear and to the vestibular nerve has been reported in only a very few cases. Two case reports are presented: a 22-year-old woman and a 26-year-old man who experienced lightning injuries to several body parts including the ear. Pathophysiology, diagnostic criteria and treatment are discussed.

Effect of artificial airway on ear complications from hyperbaric oxygen

Hyperbaric oxygen treatment is associated with an increased risk of barotrauma to the tympanic membrane and middle ear. An artificial airway may compromise normal eustachian tube function and equilibration of middle ear pressures. This retrospective study was designed to evaluate the risk of middle ear complications in 267 patients receiving hyperbaric oxygen (HBO) therapy and to compare those with and without artificial airways. Charts of all patients were reviewed for middle ear and tympanic membrane complications and myringotomy tube placement. Eighteen of the 267 patients had artificial airways. Seventeen (94%) of these 18 patients developed middle ear or tympanic membrane complications, and 11 (61%) required tympanostomy tubes for pain, hemotympanum, or serous otitis. In contrast, 114 (45.8%) of the 249 patients without airways developed ear complications, and 53 (21.3%) required tympanostomy tubes. These results suggest that patients with an artificial airway who are receiving HBO therapy are at greater risk for developing tympanic membrane and middle ear complications than nonintubated patients. Similarly, patients with artificial airways receiving HBO frequently require placement of tympanostomy tubes.