BMS – Burning Mouth Syndrome

Case:

• UL, 80 years, female, white Caucasian• No teeth• No digestive disorder• No mouse mucosal disorder• Symptom: burning mouth

• Gingival and Tongue• Sometime metallic taste• Sometime bad taste in mouth

General BMS signs and symptoms:

• Constant or intermittent pain or burning in mouth

• Can persist for months or years• Peak at evening or night

http://www.nidcr.nih.gov/OralHealth/Topics/Burning/BurningMouthSyndrome.htm

• Possible causes:

• Anxiety and Depression• Damage to nerves that control pain and taste• Hormonal changes• Dry mouth, which can be caused by many

medicines and disorders such as Sjögren’s syndrome or diabetes

• Nutritional deficiencies• Oral candidiasis• Acid reflux• Poorly-fitting dentures or allergies to denture

materials

http://www.nidcr.nih.gov/OralHealth/Topics/Burning/BurningMouthSyndrome.htm

UL Case

• Discarded causes:

• Dry mouth, which can be caused by many medicines or diabetes

• Nutritional deficiencies• Oral candidiasis• Acid reflux• Poorly-fitting dentures or allergies to denture

materials

p.s.: for three times UL had Oral Candidiasis (OC) treated with Fluconasol. Most of the time her mouth is wet and without OC. Stomach reflux may be present, but it is not a significant symptom.

• Possible causes:

• Anxiety and Depression• Damage of the nerves that control pain and

taste• Dry mouth caused by Sjögren’s syndrome

Above we see the most possible pathological causes. Depression, mental confusion, and sometimes dry mucosa (eye, mouth and vagina) are symptoms. Mouth and tongue burning, metallic and bitter taste and rarely gingival electrical chocks are daily complaints with few exceptions.

BMS in absence of visible mucosal lesion in mouth generally presents:

• Mouth pain• Alteration in taste• Altered salivation

All these symptoms are present in UL.

Burning mouth syndrome: etyology; DP Cerchiari et al. ; Rev. Bras. Otorrionolaringologia; 2006; 72(3):419-24;

Understantding Facial Nerve

All the following information are copied and references are written bellow. Many texts and images are from Yale University School of Medicine and Wikipedia.

Cranial Nerve VII - Facial Nerve Origin

To understand this pathology we must understand nerves and ganglion that control volitional movement and sensory like pain and taste.

“The branchial motor component originates from the motor nucleus of CN VII in the caudal pons. Fibers leaving the motor nucleus of CN VII initially travel medially and dorsally to loop around the ipsilateral abducens nucleus (CN VI) producing a slight bulge in the floor of the fourth ventricle - the facial colliculus.

Fibers then course so as to exit the ventrolateral aspect of the brainstem at the caudal border of the pons in conjunction with the nervus intermedius components of CN VII.”

http://www.yale.edu/cnerves/cn7/cn7_3.html

Nerves: branches from pon

All the following information are copied and references are written bellow. Many texts and images are from Yale University School of Medicine, Wikipedia and Nature

Number Name TypeCN 0 Terminal Purely sensoryCN I Olfactory Purely sensoryCN II Optic SensoryCN III Oculomotor Mainly motorCN IV Trochlear motorCN V Trigeminal Sensory + motorCN VI Abducens Mainly MotorCN VII Facial Sensory + motorCN VIII Vestibulocochlear Mostly sensoryCN IX Glossopharyngeal Sensory + motorCN X Vagus Sensory + motor

CN XI Accessory Mainly motor

CN XII Hypoglossal Mainly motor

Cranial Nerve

http://en.wikipedia.org/wiki/Table_of_cranial_nerves

http://www.nature.com/gimo/contents/pt1/fig_tab/gimo2_F2.html

Trigeminal: receives sensation from the face and innervates the muscles of mastication.

Provides motor innervation to the muscles of facial expression, posterior belly of the digastric muscle, stylohyoid muscle, andstapedius muscle. Also receives the special sense of taste from the anterior 2/3 of the tongue and provides secretomotorinnervation to the salivary glands (except parotid) and the lacrimal gland. Located in and runs through the internal acoustic canal to the facial canal  and exits at the stylomastoid foramen.

http://en.wikipedia.org/wiki/Cranial_nerves /

Facial Nerve: CN VII

Responsible for lachrymal and sublingual glands, tongue, skin, soft palate sensation, and more

It can be noticed that this are the nerve sensation neuron areas that brings pain and burning in UL. Real pain, threshold changes, miss cerebral interpretation or psychological factors are all mixed being more difficult to do an accurate diagnosis.

Brancial motor(special visceral efferent)

Supplies the muscles of facial expression; posterior belly of digastric muscle; stylohyoid, and stapedius.

Visceral motor(general visceral efferent)

Parasympathetic innervation of the lacrimal, submandibular, and sublingual glands, as well as mucous membranes of nasopharynx, hard and soft palate.

Special sensory(special afferent)

Taste sensation from the anterior 2/3 of tongue; hard and soft palates.

General sensory(general somatic afferent)

General sensation from the skin of the concha of the auricle and from a small area behind the ear.

Cranial Nerve VII - Facial Nerve

The facial nerve has four components with distinct functions:

http://www.yale.edu/cnerves/cn7/cn7_20.html

Branchial Motor Component

“The largest component of the facial nerve. Provides voluntary control of the muscles of facial expression (including buccinator, occipitalis and platysma muscles), as well as the posterior belly of the digastric, stylohyoid and stapedius muscles.” Note the branchial motor components of the facial nerve:

Special Sensory Component

“Consists of afferent fibers which convey taste information from the anterior 2/3 of the tongue and the hard and soft palates.”

http://www.yale.edu/cnerves/cn7/cn7_19.html

Peripheral Course

“Chemoreceptors of the taste buds located on the anterior 2/3 of the tongue and hard and soft palates initiate receptor (generator) potentials in response to chemical stimuli.

The taste buds synapse with the peripheral processes of special sensory neurons from CN VII. These neurons generate action potentials in response to the taste bud's receptor potentials. The peripheral processes of these neurons follow the lingual nerve and then chorda tympani to the petrous portion of the temporal bone (similar to the path followed by the efferent visceral motor fibers)”

http://www.yale.edu/cnerves/cn7/cn7_19.html

UL treatment

UL symptoms already last more then seven years. No accurate diagnosis have been defined. Many different neurological disorder drugs have been tried: neurotim (gabapentin), tramal (opioid – generates amnesia!!!), midazolan (gaba receptor), lyrica (peripherical neuropathy - pregabaline), amitril (anti-depressive), oxicontin (narcotic) and others.

Depression , elderly and mood variation directly influence in pain sensation.

In the last year two drugs brought a small mood stability and perhaps a better picture of pain:• Cymbalta (duloxetina) an anti-depressive• Gabaneurin (gabapentine) – against pain in peripheric nerves.

Conclusion

Burning syndrome mouth is a well studied problem, sometimes confounded with ATM and Trigeminal pain.

There is no objective solution for this syndrome. Drugs that act against depression and peripherical nerve pain (like gabapentin) may be useful.

Summarizing, the physician must try many different drugs and its combination, empirically.

In some persons this syndrome disappears in 3 to 6 months, but in UL real or psychological pain or burning persist.

MSc Flavio Lichtenstein

UNIFESP – BioinformaticsBrazil, Sao Paulo

flalix@gmail.com

Coursera: Understanding the BrainPhD Peggy MasonUniversity of Chicago, USA