In order to appropriately diagnose the cranial neuralgias, it is imperative that the physician is aware of the area of the skin that is supplied by a specific cranial nerve. It is especially evident in the case of neuralgias affecting the ear which can overlap with the same areas as trigeminal neuralgia, and the nerve supplies of the inner ear and periorbital( around the orbit of the eye) neuralgias. The cranial neuralgias resulting in periorbital pain include supraorbital( above the orbit of the eye) and supratrochlear( above the eye muscle) neuralgia, infraorbital( below the orbit), and lacrimal( relating to tear production) neuralgia. These neuralgias are distinct from TN, but represent branches of the trigeminal nerve.
V2
V3
V1
C2
Nerves and sensory territory of peripheral cranial nerves. Legend: V1, V2, V3: first, second, third trigeminal branches respectively C2: branches of second cervical( neck) root.
The first branch of the trigeminal nerve consists of the supraorbital nerve, which passes through the bone notch of the upper edge of the orbit. The nerve supplies to the forehead and scalp, back to the lambdoid suture( line of union between the parietal and occipital bones) can be manually examined. Due to the superficiality of these nerves, most cases of supraorbital neuralgia are secondary to trauma or conditions such as wearing a tight hat or sunglasses. The disorder has a predominance in females, and is not associated with involuntary features( tearing, eye redness, nasal congestion) that distinguishes it from the trigeminal autonomic cephalagias. While the pain is generally thought to
be benign, associated pain has reportedly contributed to suicidal thoughts among some individuals.
The second branch of the trigeminal nerve consists of the infraorbital nerve, which exits the maxillary bone( upper jaw) through the infraorbital foramen( small opening) and supplies nerves to the side of the nose, the upper jaw, and skin of the upper lip. Cases of pure infraorbital neuralgia are rare and tend to be secondary to trauma. Diagnosis is based on location of the symptoms and response to blockade with a numbing medication.
Lacrimal neuralgia from the medial branch of the lacrimal nerve supplies nerves to the anterior temple and lateral eyelid. Tenderness and continued pain at the outer top edge of the orbit can be observed.
The third branch of the trigeminal nerve consists of the auriculotemporal( ATN). The ATN passes beneath the mandibular( lower jaw) condyle( articulated part of the bone) going toward the temporal region and can be felt in the pre-auricular region in front of the tragus( projection in the ear) and supplies the skin covering the front of the helix( incurved rim of the outer ear) and tragus and skin of the temporal region. Similar to other neuralgias, the pain is piercing and sudden. It may be accompanied by facial sweating and flushing termed“ Frey’ s Syndrome,” following the removal of the parotid gland( beside the ear) or trauma to the area. ATN responds well to botulinum toxin type A.
Nerve blockade or blocking or temporarily deadening the nerve is an effective technique that has been successful in the treatment of facial and auricular neuralgias. This technique often uses a combination of a numbing medication, such as lidocaine or bupivacaine, and may be combined with a steroid. A needle is inserted near the particular nerve and the medication is injected. Nerve blockade is often done in the office and is minimally painful. Depending on the case, this technique can provide immediate pain relief that can last weeks to months. However, in some instances it may provide permanent pain relief.
A recent article in Cephalagia authored by Gaul and Resch, discussed the application of capsaicin 8 % in a cutaneous( skin) patch to the head and face to treat nonresponsive nerve pain. Capsaicin, the primary pungent ingredient in hot chili peppers, works with a key receptor in
16 HeadWise ® | Volume 6, Issue 1 • 2016