Syndromes & diagnostic test associated with facial nerve

Orbicularis oris.

• Orbicularis oris is a facial muscle
• All facial muscles are supplied by facial nerve
• Temporalis & Masseter are supplied by Mandibular nerve
• Sternocleidomastoid is supplied by spinal accessory nerve

Ramsay Hunt syndrome is also known as herpes zoster oticus or herpes zoster cephalicus. This syndrome is associated with facial palsy, sensorineural hearing loss, dizziness and herpetic eruptions and is caused by reactivation of a neurotrophic virus, the herpes zoster virus in the geniculate ganglion.

Melkersson Rosenthal syndrome consists of unilateral or bilateral facial paralysis, chronic swelling of the face (especially the lips), and lingua plicata (scrotal tongue)

Marcus Gunn jaw-winking syndrome is usually an acquired condition following abnormal regeneration of the facial nerve. There is associated movement between the orbicularis oculi and the muscles around the mouth, often resulting in elevation of the upper eyelid when the mouth is open and ptosis when the mouth is closed.

Frey’s syndrome or gustatory sweating characterized by sweating, flushing, a sense of warmth, and occasional mild pain over an area of skin of the face while eating foods that produce a strong salivary stimulus. The disorder usually involves the area of skin innervated by auriculotemporal nerve.

The rare Melkersson-Rosenthal syndrome consists of recurrent facial paralysis; recurrent—and eventually permanent—facial (particularly labial) edema; and, less constantly, plication of the tongue. Its cause is unknown

Ref: Harrison’s principle of internal medicine 17th edition, chapter 371.

The Schirmer’s tear test is used to assess lacrimation function of facial nerve.

Schirmer’s test determines whether the eye produces enough tears to keep it moist. This test is used when a person experiences very dry eyes or excessive watering of the eyes. It poses no risk to the subject. A negative (more than 10 mm of moisture on the filter paper in 5 minutes) test result is normal. Both eyes normally secrete the same amount of tears.

It is performed with the help of a 5 x 35 mm strip of Whatman-41 filter paper which is foldei 5 mm from one end and kept in the lower fornix at the junction of lateral one-third and medial two-thirds. The patient is asked to look up and not to blink or close the eyes.

A young person normally moistens 15 mm of each paper strip. Because hypolacrimation occur with aging, 33% of normal elderly persons may wet only 10 mm in 5 minutes. Persons with Sjogren’s syndrome moisten less than 5 mm in 5 minutes.

How to read results of the Schirmer’s test:

•Normal which is >15 mm wetting of the paper after 5 minutes.

•Mild which is 14-9 mm wetting of the paper after 5 minutes.

•Moderate which is 8-4 mm wetting of the paper after 5 minutes.

•Severe which is <4 mm wetting of the paper after 5 minutes.

This patient is suffering from Ramsay Hunt syndrome, a syndrome caused by post primary infection with Herpes Zoster. When it involves the facial nerve patients presents with lower facial nerve palsy and rash on the outer ear and inner ear canal. The prognosis of facial involvement in this condition is worse than in Bell’s Palsy.

• Lesion occuring at the outlet of stylomastoid foramen means LMN palsy, so face sags and is drawn across to opposite side. 
• Chorda tympani nerve is spared at this level hence taste sensation over anterior 2/3 of tongue preserved

Frey’s syndrome (gustatory sweating)

• Gustatory sweating or Frey’s syndrome involves post-parotidectomy facial sweating and skin flushing while eating.
• The symptoms usually occur several months or even years after parotid surgery.
• The likely pathophysiology is aberrant regeneration of postganglionic secretomotor parasympathetic nerve fibres (originating from the otic ganglion) misdirected through several axonal sheaths of post-ganglionic sym­pathetic fibres feeding the sweat glands. These sympathetic fibres are to the sweat glands of the skin in the dissected field.
• The frey’s syndrome is likely due to injury to auriculotemporal nerve with faulty regeneration, therefore Frey’s syndrome is also known as Auriculotemporal syndrome.
• A variant of Frey’s syndrome in which there is gustatory facial flushing but not sweating, occurs following facial paralysis due to faulty regeneration following injury to the facial nerve. So, Frey’s syndrome is not limited to parotid surgery with injury to auriculotemporal nerve.