Spontaneous cerebrospinal fluid (CSF) otorrhoea in Western Australia—an emerging entity?

Background: Spontaneous cerebrospinal fluid (CSF) otorrhea appears to be an emerging clinical entity. The aetiology, characteristics and treatment outcomes of these group of patients are poorly described so we aimed to further investigate this growing cohort. Methods: A retrospective review across the three largest tertiary hospitals in Western Australia (WA) over a 5-year period was conducted. Twenty-eight patients with non-iatrogenic, and non-traumatic spontaneous CSF otorrhea were included. Baseline demographics, presenting symptoms, past medical history, clinical examination, investigation (biochemical and radiological), management and outcomes were analysed. The study was approved by the South Metropolitan Health Services Ethics Committee (approval number RGS0000001008). Results: The majority of patients were female (61%), obese (mean BMI =29.5 kg/m2) and presented with a unilateral middle ear effusion and conductive hearing loss. Beta-trace protein sampling of the fluid was positive for CSF in 26 of the 28 patients. The most frequent site of leak was at the tegmen mastoideum and middle cranial fossa repair was the most commonly performed procedure with excellent outcomes. Only one patient had confirmed benign intracranial hypertension and two patients presented emergently to hospital with meningitis thought to be due to the CSF leak. Conclusions: Spontaneous CSF otorrhea should be suspected in unilateral middle ear effusion of unknown cause, especially occurring in at-risk individuals including those whom are obese and of female gender. Clinical or radiological diagnosis alone appears inadequate in diagnosing a spontaneous CSF leak unless clinicians have a high index of suspicion. This emerging entity does not appear to be solely a consequence of raised intracranial pressure and further studies to elucidate the cause are required.