Crocodile tear syndrome post microvascular decompression of the trigeminal nerve: a case report and literature review

Background: Crocodile tear syndrome (CTS) is a condition characterised by excessive tear secretion in response to eating, drinking, or smelling foods. Traditionally, acquired cases are most commonly reported following facial nerve trauma or paralysis, or in slow-growing facial nerve tumours. More recently, it has been reported following vestibular Schwannoma surgery. We report the first case of crocodile tear syndrome following microvascular decompression of the trigeminal nerve. Case presentation A 61-year-old lady presented with excessive lacrimation and clear rhinorrhoea one month post-operatively from a re-do trigeminal microvascular decompression surgery. The patient experienced similar symptoms following her initial surgery two years prior, which had resolved spontaneously. CT and MRI head, and comprehensive clinical examination showed no evidence of CSF rhinorrhoea or cause of her symptoms. An ENT opinion was sought, and the patient was diagnosed with post-operative crocodile tear syndrome.Literature review revealed no reported cases of CTS following microvascular decompression of the trigeminal nerve. Surgical technique and relevant imaging were reviewed for any possible explanation for the condition. Considering the accepted pathogenesis of CTS, we discuss the aetio-pathogenesis for the development of the condition following this procedure. Conclusions: We conclude CTS should be considered in patients presenting with rhinorrhoea following microvascular decompression of the trigeminal nerve. In patients presenting with post-operative rhinorrhoea after MVD, after excluding CSF leak, CTS should be considered as a potential differential diagnosis. Treatment for CTS in this context may pose a challenge. The patient has undergone botulinum toxin injection of the lacrimal gland and will need long term follow up. This is the first documented case of CTS post microvascular decompression of the trigeminal nerve.