Carabid beetle invasion of the ear in Oman

Wilderness and Environmental Medicine. 10, 157-160 (1999)

CASE REPORT

Carabid beetle invasion of the ear in Oman DEEPA BHARGAVA, MS, REGINALD VICTOR, PhD From the Department of Surgery, ENT Division, College of Medicine (Dr Bhargava), and the Department of Biology, College of Science (Dr Victor), Sultan Qaboos University, Sultanate of Oman.

Two cases of human ear invasion by a predaceous beetle, Crasydactylus punctatus Guerin (Coleoptera; Carabidae), are reported from the Sultanate of Oman. The first case was that of a 35-year old woman who suffered a severe otologic injury caused by the biting and chewing of the external auditory canal and the tympanic membrane. The beetle then entered the middle ear and caused sensorineural hearing loss. The second case involved a 22-year-old male from whose ear a specimen of the same species was successfully removed after it was immobilized with 10% lidocaine spray. These cases are presented with discussion. Key words: Arabia, foreign body, human ear, beetle, Carabidae, otological injury

Introduction

Case 1

Insects are often encountered as foreign bodies in human A 35-year-old Omani woman presented to the Accident ears [1-3]. Among animals invading the human body, and Emergency Department, Sultan Qaboos University dead or alive, beetles (Coleoptera) are second to flies Hospital, at 2330 h on February 2, 1998, complaining (Diptera) in importance [4]. Invasion of the living body of excruciating pain and loud noise in her ears. A live by beetles or their larvae is called canthariasis or scar- insect that had crawled into her right ear while she slept abiasis, and infestations have been recorded in gastro- apparently caused this. The patient was in extreme disintestinal tract, urogenital system, nasal sinuses, and ears tress and was crying. On otoscopy, the attending phy[5]. All insect invasions of the ear reported in literature sician found a live insect in the external canal with some fresh blood and immediately instilled 5 ml of olive oil. appear accidental. Larvae of the carpet beetle, Antherenus scrophulariae, After 5-7 min, the patient felt that the insect had stopped have been known to enter the ears of sleeping people moving. On repeat otoscopy, the insect was no longer [6]. Similarly, adult scarabaeids, Cyclocephala borealis visible in the external canal but had crawled into the and Autosericea castanea, invaded the ears of 176 boy middle ear, perforating the tympanic membrane. The pascouts camping in Pennsylvania [6]. John Hanning tient was referred for specialist care. Speke, the famous explorer who tracked down the Microscopic examination revealed a laceration in the source of the Victoria Nile, described an incidence of inferior lateral wall of the external canal with clotted "small black beetles" entering his ear and causing oto- blood. After the canal was cleaned, the insect was visible logical damage. His unconventional methods of extrac- in the middle ear through the perforation in the tympanic tion-using "melted butter" and "penknife"-seem re- membrane (Fig 1). The patient, who had no past history sponsible for the damage [7]. Apart from this legendary of hearing loss or ear disease, was posted for foreign report, no known case of an insect chewing its way into body removal under general anesthesia. The preoperathe middle ear has been recorded. Two cases of ear in- tive audiogram revealed a low-tone conductive hearing vasion by Crasydactylus punctatus, a predaceous carabid loss and a high-tone sensorineural hearing loss (Fig 3, beetle, are presented here. top). With the help of an operating microscope, a Schuknecht pick, and a small Day hook, the insect was maReprint requests to Department of Biology, College of Science, Sultan nipulated in the middle ear so that it could be extracted Qaboos University, P.O. Box 36, PC 123, Sultanate of Oman (Dr Victor). through the perforation in the tympanic membrane. An

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Bhargava and Victor

Fig 1. Diagram illustrating the carabid beetle as seen by the operating microscope.

alligator forceps was used to remove the beetle. The patient was discharged the same day with instructions to keep the ear dry. She was prescribed prophylactic amoxicillin 500 mg three times a day (TID) and paracetomol as required (PRN) for 7 days. Because the preoperative audiogram showed evidence of sensorineural hearing loss, aural antibiotic drops were deferred. Forty-eight hours later, the patient returned with severe otitis externa. This was treated with broad-spectrum

Fig 2.

amoxicillin 250 mg/clavulanic acid 125 mg TID, diclofenac sodium 25 mg TID for 5 days, and local aural splinting, which involved the insertion of a wick soaked in a steroid/antibiotic cream into the narrowed ear meatus. The patient responded to the treatment, and, after 3 weeks, the external canal was healed, but the perforation in the tympanic membrane persisted. The followup audiogram (Fig 3, bottom) showed a mixed hearing loss, with a 5-1O-db recovery. The patient was offered a tympanoplasty; however, she did not return for further treatment. The beetle (Fig 2) was identified by one of the authors (RV) as C punctatus Guerin (Coleoptera; Carabidae). The identification at the family level was made with the use of standard taxonomic texts in entomology; the genus and species identifications were confirmed after comparing the present specimen with an extensive collection series of this species in the Carabidae drawer of the Oman Natural History Museum, Muscat, the Sultanate of Oman. The photomicrograph (Fig 2) was taken with a Zeiss photomicroscope under incident light illumination.

ease 2 At 1445 h on March 4, 1998, a 22-year-old male medical student presented to the otolaryngology outpatient department with the complaint of a live foreign body in his right ear. After playing football, he stretched out on the grass to rest and the insect invaded his ear. On otoscopy, the live insect was visible in the external canal. It was sprayed with 10% lidocaine. Two metered doses of 10 mg/dose effectively stupefied the insect. The beetle

Photomicrograph of Crasydactylus punctatus Guerin (lOX).

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Figs 3. Top, Preoperative pure tone audiograms showing mixed hearing loss. Bottom, Audiograms 8 weeks postoperative showing some recovery.

was then removed with an alligator forceps. It was subsequently identified as C punctatus. Discussion

Crasydactylus punctatus is a relatively small predaceous ground beetle. It was very abundant during the months of December 1997 to March 1998. The annual variation in abundance seems very irregular, ranging from virtual absence in some years to superabundance in other years. Very little is known about its biology. It has very robust biting and chewing mouthparts, and the otological dam-

age caused in the present case is not surprising. It is a day-active beetle. Personal observations suggested peak activity in early morning and early evening. In the shade of plants and buildings, moderate activity was seen throughout the day. This species burrows into soft and moderately hard ground with relative ease. Like any other carabid, it has a very hard, chitinous exoskeleton, and the hard elytra cover most of the abdomen. Carabid beetle invasion of the human ear has not been previously reported in the literature, and the two cases described here appear to be the first record. Although other beetle invasions have been perceived as otological nuisance, none of these, except the legendary Speke's case [7], caused serious otological damage [6,8]. Speke's case [7] was emulated by the first case reported here; in the former, melted butter was used as the immobilizing medium, whereas in the latter olive oil was used. However, both cases led to surgical intervention, the former with a penknife and the latter with a surgeon's instruments. Removal of live insect foreign bodies has been the subject of several investigations. Many immobilizing and stupefying agents such as mineral oil, alcohol, ether, and lidocaine (2%) have been recommended [1,9-11]. An in vitro study comparing the chemical immobilization and killing of intraaural roaches recommended mineral oil over 2% and 4% lidocaine [3]. In our second case, 10% lidocaine was effective in immobilizing and killing the same species of beetle that survived olive oil immersion and caused otological injury in our first case. In a case where a patient presented with a single cockroach simultaneously lodged in each of his external canals, allowing for a direct comparison, lidocaine was reported as more effective than mineral oil [11]. Other substitutes for lidocaine are bupivacaine, prilocaine, procaine, and cocaine. Bupivacaine is slow acting, prilocaine is neither widely used nor available, procaine is seldom used because of its poor absorption by the mucous membrane, and the use of cocaine is restricted because of its toxicity. Lidocaine, however, is the most widely used topical anesthetic, and it is effective, safe, and easily available. Response to different immobilizing agents is also likely to vary depending on the species of the insect intruder. Thus, an agent that is extremely effective against one taxon may be totally ineffective against another. The carabid beetle invasion resulting in perforated tympanic membrane indicates contamination of the middle ear. The first-line treatment with amoxicillin as the drug of choice is now accepted widely. Oman, however, has a high prevalence of beta-lactamase-producing organisms, and so the second-line treatment with amoxicillin/clavulanic acid is a good choice. The antibiotic

Bhargava and Victor

160 treatment for otitis externa is local. After cleaning, the meatus is packed with 12-mm ribbon gauze impregnated with a broad-spectrum antibiotic such as neomycin or gentamycin. We are not aware of any special treatment for insectlbacteria invasions. Some otolaryngologists use steroids to treat inner ear injury, but no definitive evidence supports their use. Because our patient recovered spontaneously to some extent, the use of steroids was not considered necessary. Foreign body removal under general anesthesia is an accepted practice. Because several nerve branches supply the ear, there is no single logical injection site for a nerve block. At least three or four sites have to be injected, and this again is not practical. The otological damage caused by the biting and chewing activity of the beetle in the first case seems more severe than any other case reported in the literature. Other cases reported are Blatella germanica invasion causing tinnitus and otitis extema and one unusual case of a thysanuran insect (silverfish) invading the ear and causing tinnitus and earache [4,12]. Complications in cases of ear invasions by live insects were caused by either the patient's or the physician's attempts at manipulation and removal [7,13]. If a live foreign body like an insect is not removed quickly and cleanly from the external auditory canal, it may move farther into the ear and cause complications.

Acknowledgments

We would like to thank the Sultan Qaboos University for the facilities. One of us (DB) wishes to acknowledge Professor C. S. Grant, Head of Department, General Surgery, for his support and approval, Mrs Helen B. Leopoldo, Secretary, for typing the draft manuscript, and Mr

Majid Al Khanjari, Medical Artist, and staff of CET for help with illustrations. References 1. Schittek A. Insect in the external auditory canal-A new way out. JAm Med Assoc 1980;243:331. 2. Sucharit S. Tick and cockroach as foreign bodies in the ear. J Med Assoc Thailand 1981;64:96-98. 3. Leffler S, Cheney P, Tandberg D. Chemical immobilization and killing of intraaural roaches an in vitro comparative study. Ann Emerg Med 1993;22:1795-1798. 4. Smith KGY. Insects of minor medical importance. In: Lane RP, Crosskey RW; eds. Medical Insects and Arachnids. London, England: Chapman and Hall; 1993:576593. 5. Theodorides I. The parasitological, medical and veterinary importance of Coleoptera. Acta Trop 1950;7:48-60. 6. Maddock DR, Fehn CF. Human ear invasions by adult scarabaeid beetles. J Econ Entomol 1958;51:546-547. 7. Rice E. Captain Sir Richard Francis Burton: The Secret Agent Who Made the Pilgrimage to Mecca, Discovered Kamasutra and Brought the Arabian Nights to the West. New York, NY: Scribner's; 1990. 8. Roth Y. The dung beetle. Maladera matrida, as a new otologic nuisance. Harefuah 1989;116:468-469. 9. Abelson TI, Witt WI. Otolaryngologic procedures. In: Roberts JR, Hedges JR, eds. Clinical Procedures in Emergency Medicine. 2nd ed. Philadelphia, PA: WB Saunders; 1991:1027-1028. 10. Fritz S, Kelen GD, Sivertson KT. Foreign bodies of the external auditory canal. Emerg Med Clin North Am 1987; 5:183-192. 11. O'Toole K, Paris PM, Stewart RD. Removing cockroaches from the auditory canal. Controlled trial. N Engl J Med 1985;312:1197. 12. Kwok P, Hawke M. Blatella germanica causing tinnitus and otitis externa. J Otolaryngol 1986;15:257. 13. Fernandez-BIasini N, Bunker R. Traumatic facial palsy. Arch OtolaryngoI1969;90:137-138.