First bite syndrome – Clinical presentation, Diagnosis and Treatment

First bite syndrome is a clinical condition occurring as a complication of surgeries involving the infratemporal fossa, deep lobe of the parotid gland, parapharyngeal spaces and manipulation or ligature of the external carotid artery. Sometimes it can also be caused by a head and neck tumor itself arising in above locations.

The condition is characterized by unilateral cramping or spasm in the region of the parotid gland resulting in severe pain when the patient takes the first bite of every meal in the postoperative period. The pain often radiates to the ipsilateral ear and diminishes over the next several bites.

The clinical condition was first described by Haubrich in 1986 and the term “first bite syndrome” was used in 1998 by Netterville et al.

Why first bite syndrome happens?

The exact etiology of first bite syndrome is still unknown. Most accepted reasoning is injury to the cervical sympathetic chain during surgery.

Myoepithelial cells of parotid gland receives dual sympathetic and parasympathetic innervation, which act synergistically and not antagonistically.

It is believed that these surgeries may result in sympathetic denervation to the parotid gland, specifically to its myoepithelial cells. Uninhibited release of parasympathetic neurotransmitters (acetylcholine) during salivation and mastication would results in “supramaximal” contraction of the myoepithelial cells causing pain. 

Desensitisation occurs after successive bites and the symptoms improve with mastication, which then reoccur with the first bite of the next meal.

However, these hypothesis has not been proven, because not all patients who have undergone sectioning of the cervical sympathetic chain during surgery have this complication.

There are various other clinical syndromes also which are associated with cervical sympathetic trunk injury. They are tabulated below.

Syndromes associated with cervical sympathetic trunk injury.

Syndromes

Symptoms

Pathogenesis suggested

First biteIntense parotid pain at the first biteIntraparotid sympathetic deafferentation and parasympathetic re-afferentation
HornerPtosis, myosis, enophthalmos, hemifacial anhidrosisDeficient-destructive sympathetic trunk lesion
Pourtour du PetitEyelid retraction, mydriasis, exophthalmos, hemifacial hyperhidrosisIrritating-hyperactive sympathetic trunk lesion
FreyLateral head and neck erythema and excessive sweating triggered by eatingAberrant sympathetic-parasympathetic sprouting
HarlequinErythema and hemifacial hyperhidrosisCervical sympathetic vasomotor and sudomotor nerve lesions

Signs and Symptoms

Most often, first bite syndrome is a minor complication, which often goes unnoticed. Hence the exact prevalence of the disease after head and neck surgeries is unknown. Literature reports an incidence of 7-10% after surgeries of infratemporal fossa, deep lobe of the parotid gland and parapharyngeal space.

In some patients, the symptoms can be very intense making eating difficult which can even affect quality of life.

Patients may even avoid eating due to the severity of this syndrome. Some patients may have pain even while thinking of food, due to the salivation that occurs.

Differential diagnosis

Following are some clinical conditions which may mimic first byte syndrome in clinical presentation

  • Temporo-Mandibular Joint Dysfunction / TMJ Syndrome
  • Glossopharyngeal neuralgia
  • Eagle’s syndrome or stylalgia

Investigations

First bite syndrome is a clinical diagnosis and needs no special investigations for diagnosis, when it occurs during the days following neck surgery.

Imaging is needed when a patient presents with similar condition, in the absence of a history of ipsilateral upper neck surgery. This is to exclude a tumor of the deep lobe of the parotid gland, submandibular gland or ipsilateral parapharyngeal space, as the tumour may only become visible several months after onset of the pain.

Treatment

In most patients the symptoms are tolerable and tends to diminish over time or may resolve spontaneously. There exists no definitive treatment for this condition. But following treatment options are considered in those patients who are very symptomatic.

  1. Change in behaviour: Manual compression of the painful region by the patient sometimes helps to relieve the pain, leading the patient to press on the painful region preventively before taking the first bite.
  2. Avoidance of sialogogue foods (acid): The pain is usually intense with sialogogue foods. But this was not shown to be so effective.
  3. Non steroidal anti-inflammatory drugs (NSAIDS) and usual analgesic treatments have poor results.
  4. Drugs used for treatment of chronic neuralgia and neuropathic pain such as pregabalin, gabapentin and carbamazepine are used alone or in combination with tricyclic antidepressants (amitriptyline) by some, though they are not demonstrated to be completely effective.
  5. Anaesthetic sprays or local anaesthetic block and tympanic neurectomy or auriculotemporal neurectomy have not been demonstrated to be effective.
  6. Local radiotherapy can lead to resolution of postoperative first bite syndrome, but is a radical procedure associated with risks and/or functional sequelae which itself can worsen quality of patients life.
  7. Total partoidectomy is found to be effective, confirming the role of the parotid gland in the pathogenesis of this syndrome.
  8. Intraparotid injection of botulinum toxin type A is found to be effective both in terms of analgesia and improvement of quality of life and is currently appears to be the most effective first-line treatment option for first byte syndrome. Botulinum toxin inhibits the release of acetylcholine from nerve synapses resulting in reduced contraction of the glandular cells and their secretion.
    However, a standard method has not yet been defined and the protocol varies from three successive injections of 11 units to a single injection of 75 units. Patient may need repeated injections once the effect of botulinum toxin weans off.

References

  1. Laccourreye O, Werner A, Garcia D, Malinvaud D, Huy PT, Bonfils P. First bite syndrome. European Annals of Otorhinolaryngology, Head and Neck Diseases. 2013 Nov 1;130(5):269-73.
  2. Linkov G, Morris LG, Shah JP, Kraus DH. First-Bite Syndrome: Incidence, Risk Factors, Treatment, and Outcomes. Journal of Neurological Surgery Part B: Skull Base. 2012 Feb;73(S 01):A126.
  3. Deganello A, Meccariello G, Busoni M, Franchi A, Gallo O. First bite syndrome as presenting symptom of parapharyngeal adenoid cystic carcinoma. J Laryngol Otol. 2011;125:428-431.
  4. Chiu AG, Cohen JI, Burningham AR, Andersen PE, Davidson BJ. First bite syndrome: a complication of surgery involving the parapharyngeal space. Head & Neck: Journal for the Sciences and Specialties of the Head and Neck. 2002 Nov;24(11):996-9.
  5. Costales-Marcos M, Álvarez FL, Fernández-Vañes L, Gómez J, Llorente JL. Treatment of the first bite syndrome. Acta Otorrinolaringologica (English Edition). 2017 Sep 1;68(5):284-8.
  6. Abdeldaoui A, Oker N, Duet M, Cunin G, Huy PT. First Bite Syndrome: A little known complication of upper cervical surgery. European annals of otorhinolaryngology, head and neck diseases. 2013 Jun 1;130(3):123-9.

Meet the author

Dr Sanu P Moideen is an Indian-born oto-rhino-laryngologist (ENT) based in Cochin, Kerala, India. He is currently working as Post-Doctoral Fellow in Head and Neck Oncology at Regional Cancer Center, Trivandrum, Kerala.

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Comments & DIscussions

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      Dr Sanu P Moideen said:

      @Fj: 1) First bite syndrome usually happens after a surgery in the region of parotid / parapharyngeal space. Patients with trigeminal neuralgia mayn’t give such a surgical history. The diagnosis is made clinically from the typical history of pain during the first bite at each meal.
      2) First bite syndrome occurring after Gamma Knife / Stereotactic radiosurgery for trigeminal neuralgia may be due to the imbalance between sympathetic and parasympathetic innervation. The 3rd branch of Cranial nerve V (Trigeminal nerve) is responsible for parasympathetic secretory innervation to the parotid and submandibular glands, resulting in saliva secretion, via the auriculotemporal nerve and lingual nerve. The sympathetic innervation comes from the superior cervical ganglion, part of the paravertebral chain. Isolated parasympathetic denervation may result in the loss of balance between in innervation, and a sympathetic cross-stimulation can result in pain.
      3) The recurrence rate after Gamma Knife / Stereotactic radiosurgery for trigeminal neuralgia is upto 60%. Hence a disease recurrence also should be considered in your differentials.

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