Year : 2008 | Volume
: 52 | Issue : 2 | Page : 202--204
Botulinum Toxin in Treatment of Frey Syndrome - a Brief Report
Abraham Sonny1, Rani Sunder2, Anjan Trikha3,
1 P.G.Student, Department of Anaesthesiology and Intensive care, All India Institute of Medical Sciences, New Delhi, India
2 Assistant Professor, Department of Anaesthesiology and Intensive care, All India Institute of Medical Sciences, New Delhi, India
3 Professor, Department of Anaesthesiology and Intensive care, All India Institute of Medical Sciences, New Delhi, India
Department of Anaesthesiology and Intensive care, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029
Frey syndrome occurs following surgeries around the parotid. A 61-year-old woman post superficial parotidectomy presented after 2 years with symptoms of gustatory sweating. Minor test was positive (9cm2 area). Topical antihyperhydrotics and stellate ganglion blocks provided no benefit. Botulinum toxin was administered intracutaneously. Symptoms resolved with in 48 hours. Minor test was negative at 10 month follow up. Most of the surgical and medical techniques described to treat Frey syndrome have high failure rate with short term relief. Botulinum toxin injection is minimally invasive and produces a long lasting effect.
|How to cite this article:|
Sonny A, Sunder R, Trikha A. Botulinum Toxin in Treatment of Frey Syndrome - a Brief Report.Indian J Anaesth 2008;52:202-204
|How to cite this URL:|
Sonny A, Sunder R, Trikha A. Botulinum Toxin in Treatment of Frey Syndrome - a Brief Report. Indian J Anaesth [serial online] 2008 [cited 2020 Feb 24 ];52:202-204
Available from: http://www.ijaweb.org/text.asp?2008/52/2/202/60623
Frey syndrome (auriculotemporal syndrome) is probably the most frequently occurring late sequelae of surgeries in the parotid region. The syndrome is characterized by sweating and flushing of facial skin over parotid bed following gustatory stimuli and is often accompanied by pain or generalized discomfort in the region causing considerable distress and social embarrassment to the patient  .
A 61-year-old woman underwent superficial parotidectomy for pleomorphic adenoma of the right parotid. Two years later, she presented at our pain clinic with distressing gustatory sweating from the area surrounding the surgical scar. This was associated with pain, sensation of warmth and heaviness in the same region. Minor test was positive. Topical application of aluminum hydroxide did not provide benefit. Ipsilateral stellate ganglion block with 8 ml of 0.25% bupivacaine was given. Though successful block was confirmed by the presence of ipsilateral Horner's syndrome, this provided no relief in her symptoms. Two further blocks were repeated at two week intervals but produced no evident benefit. The option of botulinum toxin injection was considered.
The starch iodine test as described by Minor was performed to determine the area of skin involved  . The affected skin area was painted with iodine solution and dusted with starch powder. To elicit salivation the patient was asked to chew a lemon [Figure 1]. This gustatory stimulus leads to sudoresis in the affected region. Affected area turned deep blue- purple on absorption of wet iodine by starch. The test was positive for an area of 9 cm 2 in the right parotid and infra auricular region [Figure 2].
She received 30 units of botulinum toxin (2.5 U/ 0.1mL, 3 U/ cm 2 ) intracutaneously in the affected area. Symptoms resolved within 48 hours and subsequent Minor test on third day was negative. At 10 month review she was symptom free but complained of an occasional sensation of heaviness after a gustatory stimulus and Minor test continued to be negative.
Frey syndrome is a well known sequelae following parotid surgery, radical neck dissection, thoracocervical sympathectomies, submandibular gland surgery and in diabetic autonomic neuropathy . The severity varies from asymptomatic patients, diagnosed only on Minor test, to patients presenting with distressing gustatory sweating. If an objective starch iodine test according to Minor is performed, 95% of patients who undergo parotidectomy are likely to show evidence of a positive Minor test. When not specifically asked for, only 10% patients report it as a distressing symptom  .
The pathophysiology of Frey syndrome is explained by aberrant regeneration theory. The parasympathetic fibers originating from the glossopharyngeal nerve to the parotid gland pass via the otic ganglion to the auriculotemporal branch of mandibular nerve. These cholinergic secretomotor parasympathetic fibers are sectioned during parotid surgery. Frey syndrome is a consequence of aberrant regeneration of these sectioned cholinergic fibers leading to misdirected and inappropriate innervation of the cutaneous facial sweat glands. They are normally innervated by cholinergic fibers from cervical sympathetic ganglia which are also partly disrupted while raising the skin flap during parotid surgery. This misdirected resprouting accounts for the flushing and sweating of the facial skin in response to gustatory stimuli seen in Frey syndrome  .
A latent period exists between intraoperative auriculotemporal nerve injury and appearance of Frey syndrome due to the time required for regeneration of these fibers. In most reports this interval ranges from two weeks to two years, but latent periods of more than eight years have been reported  . In our patient this period was two years.
Various surgical techniques have been described to prevent as well as to treat Frey syndrome. They were cumbersome, invasive and produced only temporary benefit  . Topical application of antihyperhydrotics (aluminum hydroxide) as well as systemic and topical anticholinergics like scopolamine and glycopyrrolate has been tried. Aluminum salts work by precipitating mucopolysaccharides, causing damage to epithelial cells along the lumen of the sweat gland duct, leading to their obstruction and thus decreased sweat output. While anticholinergics act by blocking the muscarinic acetylcholine receptors on the sweat glands. Limited efficacy, distressing anticholinergic side effects and local irritation at the site of application has limited their use  .
Stellate ganglion block has been described in literature as a treatment for gustatory sweating. It chemically denervates the sympathetic cholinergic innervation of the facial sweat glands from the cervical ganglion  . Though it has shown to give some relief in patients with diabetic autonomic neuropathy it has not been useful in Frey syndrome. This is because the stimulus for gustatory sweating in Frey syndrome is transmitted via the parasympathetic fibers in auriculotemporal nerve which remains unaffected by stellate ganglion block  . This could be the likely reason for its failure in our patient too.
Recently, favorable results have been reported on treatment of Frey syndrome by intracutaneous injections of botulinum toxin. Botulinum toxin, after receptor mediated endocytosis into neuron, breaks down the synaptosome associated protein (SNAP-25) which is essential for exocytosis of acetylcholine vesicles  . Thereby, botulinum blocks the secretion of acetylcholine at the cholinergic synapses of the autonomic nervous system. Gustatory sweating usually ceases within 48 to 72 hours following treatment  . No significant adverse effects have been described. Transient paresis of orbicularis oris has been reported in literature  . No adverse effects were seen in our patient.
There are very few studies with follow up long enough to determine the duration of effect produced by the primary injection. Jens et al observed no recurrence of symptoms in a series of seven patients with Frey syndrome treated with botulinum toxin during a follow up for up to 23 months  . While Rainer et al reported reappearance of symptoms in 12 of 19 patients treated after a mean duration of 17.3 months . Recurrence was effectively treated by reinjecting botulinum toxin. Our patient continues to be asymptomatic till date(10 month).
In conclusion, botulinum toxin injection for gustatory sweating is a successful, minimally invasive therapy for treatment of Frey syndrome.
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