Bilateral Spontaneous Cerebrospinal Fluid Otorrhea Nobumitsu Honda, MD,* Yoshihisa Okouchi, MD,* Hidemitsu Sato, MD,* Tetsuji Sanuki, MD,* Naohito Hato, MD,* Naoaki Yanagihara, MD,† Shingo Murakami, MD,‡ and Kiyofumi Gyo, MD* We present a rare case of bilateral cerebrospinal fluid (CSF) otorrhea via multiple bony defects in the left tegmen and a single defect with the herniated brain tissue on the right side. Initially, the patient complained of left hearing loss and fullness and was diagnosed with serous otitis media. After myringotomy, the pulsating watery discharge suggested CSF otorrhea. Five months after surgical repair of the left side, right-side CSF leakage occurred. The right side was repaired surgically, and the patient recovered without incident. From our findings and a review of the literature, we postulate that bilateral CSF otorrhea resulted mainly from the thinness of the tegmen because of well-pneumatized mastoid air cells and the weakness of the dura after chronic inflammatory changes. In case of spontaneous CSF otorrhea, the roof of tegmen should be assessed bilaterally with care using radiologic examinations so as not to overlook a subclinical condition on the contralateral side. (Am J Otolaryngol 2004;25:68-72. © 2004 Elsevier Inc. All rights reserved.) Cerebrospinal fluid (CSF) otorrhea is a life- threatening disease of the temporal bone be- cause of the high incidence of subsequent bacterial meningitis. It usually occurs second- ary to temporal bone fracture, surgical trauma, middle ear infection, or benign or malignant neoplasm. In some cases, however, it occurs without any predisposing cause. Such spon- taneous CSF otorrhea may be because of a congenital malformation of the inner ear (mostly in children) or a bony or dural defect in the area of the tegmen tympani (mostly in adults). The former is usually accompanied by profound deafness and is often noticed after repeated episodes of bacterial meningitis. Adult-type spontaneous CSF otorrhea usu- ally presents with clinical features similar to serous otitis media (SOM) with a massive dis- charge of clear fluid noticed at myringotomy. 1 This is not as rare as previously thought. May et al 2 documented 56 cases up to 1995, and many reports have been added to the litera- ture subsequently. 3-10 According to these re- ports, most adult cases are ipsilateral and bi- lateral involvement is rare; only 4 out of 106 adult cases were bilateral. 1-30 This article reports an adult case of bilateral spontaneous CSF otorrhea, which was treated surgically via combined transmastoid and middle cranial fossa approaches, with a dis- cussion of this rare condition. CASE REPORT A 49-year-old man attended a local ear, nose, and throat clinic in 1997 because of fullness and hearing loss in the left ear for several weeks. He was diagnosed with SOM and underwent myringotomy, which resulted in a massive pulsating watery discharge. With the suspicion of CSF otorrhea, he was referred to our hospital on an emergency basis. There was no history of head trauma, ear surgery, or middle ear infection. Otoscopic examination revealed watery otorrhea through a perforation in the left ear, whereas the right ear appeared normal. The Valsalva maneuver increased the amount of otorrhea. The otorrhea was positive for glu- cose and beta-2 transferrin, both of which suggested that the fluid was indeed CSF. An From the *Department of Otolaryngology, Ehime Uni- versity School of Medicine, Shigenobu-cho, Onsen- gun, Ehime; †Takanoko Hospital, Takanoko-cho, Mat- suyama-city, Ehime; and ‡Nagoya city University School of Medicine, Mizuho-cho, Mizuho-ku, Nagoya City, Japan. Address correspondence to: Nobumitsu Honda, MD, Department of Otolaryngology Ehime University School of Medicine, Shigenobu-cho, Onsen-gun, Ehime 791- 0925, Japan. E-mail: nobuhon@m.ehime-u.ac.jp 0196-0709/$ - see front matter © 2004 Elsevier Inc. All rights reserved. doi:10.1016/S0196-0709(03)00093-0 68 American Journal of Otolaryngology, Vol 25, No 1 (January-February), 2004: pp 68-72