A case of idiopathic First Bite Syndrome responding to carbamazepine

Abstract

First Bite Syndrome (FBS) is a painful condition which classically presents as severe pain in the pre‐auricular region, initiated on the first bite of a meal. It is usually associated with a history of upper neck surgery or tumour of the parotid salivary gland or parapharyngeal space (PPS). Some propose that FBS arises from damage to, or resection of, the cervical sympathetic trunk resulting in loss of sympathetic innervation to the parotid salivary gland. Idiopathic FBS has been reported only a handful of times in the literature. We present the case of a 51‐year‐old male, urgently referred to the Department of Oral Medicine, with a 3‐week history of severe, sharp, unilateral pain from the right angle of mandible, intensity described as ‘20/10', occurring only on the first bite of eating. This would diminish over 2 min. Clinical examination revealed tenderness over the right condylar neck and angle of mandible only. FBS was suspected and the patient immediately started on carbamazepine. An urgent MRI displayed no abnormalities of the temporomandibular joints, PPS, trigeminal nerve or parotid gland. Restorative Dentistry review confirmed no odontogenic or occlusal cause and on review, 4 months later the patient reported complete resolution of symptoms on 200 mg of carbamazepine three times daily. This case highlights the importance of taking a thorough pain history. Patients with symptoms of FBS and no history of surgery to the neck should have an MRI to rule out parotid gland or PPS tumour. Carbamazepine can be successful in treating idiopathic FBS and can resolve symptoms completely.

Successful management of an idiopathic first bite syndrome: A case report and review

“…The process involves the secretion of parasympathetic neurotransmitters during oral intake, which leads to a cross‐stimulation of sympathetic receptors, resulting in an autonomic imbalance. Consequently, the myoepithelial cells undergo supramaximal contraction due to an aberrant response to parasympathetic stimulation, ultimately causing excessive contraction and subsequent pain in the parotid region upon the first bite 2,4 . Altogether, the occurrence of pain is attributed to the impairment of sympathetic innervation in the parotid gland.…”

“…Netterville initially described FBS in 1998. FBS refers to intense parotid pain experienced upon the first bite of a meal, without any preceding symptoms 1,2 . The pain gradually diminishes with subsequent bites; thus is most severe during the first bite and the first meal of the day.…”

Clinical and Pain-Related Characteristics of Idiopathic First Bite Syndrome Induced by Taste in Japanese Patients without Diabetes: A Retrospective Study of Five Cases

“…Additionally, the severity of pain necessitated treatment. Treatment for idiopathic FBS or idiopathic parotid pain includes the administration of pharmacological agents [ 16 , 17 , 19 ] and injection of botulinum toxin [ 18 ]; however, the efficacy of these treatments remains to be determined, and a radical cure for idiopathic FBS is lacking. Similar to patients with idiopathic parotid pain [ 16 ], two of our patients responded to neurotropin (Nippon Zoki Pharmaceutical Co., Ltd.).…”

“…However, diabetic neuropathy is another potential cause of FBS. Recent studies have documented parotid pain compatible with FBS in patients with diabetes [ 16 , 17 ].…”

Characterization of Salivary Gland Pain: A Review of the Literature

“…It is described that first bite syndrome is a rare idiopathic disorder. It is thought to be the result of the loss of sympathetic innervation of the parotid gland from the superior cervical ganglion (Wemyss et al, 2019) as a possible complication of the surgery of parapharyngeal spaces (tonsillectomy, resection of SG neoplasms, etc.) (Chiu et al, 2002;Houle & Mandel, 2014;Scholey & Suida, 2015;Topf et al, 2018).…”