What are the other Names for this Condition? (Also known as/Synonyms)

• NIN (Nervus Intermedius Neuralgia)

What is Nervus Intermedius Neuralgia? (Definition/Background Information)

• Nervus Intermedius Neuralgia (NIN) is a highly infrequent nerve pain disorder involving the deep auditory canal, which may then move on to involve the side and back of the head (parieto-occipital region), including with involvement of the lower jaw
• The nervus intermedius forms a part of the facial nerve (cranial nerve 7); the brief episodes of pain on neurovascular compression of the nerve are similar in nature to that seen in trigeminal neuralgia. The pain in Nervus Intermedius Neuralgia may be aggravated by triggering factors in the external ear region
• However, since a complex network of cranial nerves are present in the region, it is difficult to specifically isolate Nervus Intermedius Neuralgia based on the presenting symptoms. Imaging studies of the region is necessary towards establishing a diagnosis of the condition
• In rare cases, Nervus Intermedius Neuralgia may develop from herpes zoster infection, tumor in the region, or multiple sclerosis. Besides pain in the region, salivation, tearing, and altered taste may be noted
• Broadly, the following forms of Nervus Intermedius Neuralgia are recognized:
  • Classical Nervus Intermedius Neuralgia - when the cause remains unidentified, but neurovascular compression of the nerve root is observed
  • Secondary Nervus Intermedius Neuralgia - when it develops secondary to a tumor or a neurological condition such as multiple sclerosis
  • Idiopathic Nervus Intermedius Neuralgia - when the cause is unidentified and neurovascular compression is not observed via diagnostic investigations

The criteria for diagnosis of Nervus Intermedius Neuralgia as outlined by the International Headache Society (IHS) is given below:

• Paroxysmal attacks of unilateral pain in the distribution of nervus intermedius and fulfilling the criterion below:
• Pain has all of the following characteristics:
  • Lasting from a few seconds to minutes
  • Severe in intensity
  • Shooting, stabbing or sharp in quality
  • Precipitated by stimulation of a trigger area in the posterior wall of the auditory canal and/or periauricular region
• Not better accounted for by another ICHD-3 diagnosis

(Source: International Headache Society Classification ICHD-3, London, United Kingdom)