Nasociliary Nerve Block for Charlin Syndrome

Indications and Clinical Considerations

Nasociliary nerve block is useful in the diagnosis and treatment of Charlin syndrome, which is also known as nasociliary neuralgia . Although, as with most headache syndromes, the exact cause of the pain from Charlin syndrome is unknown, the pathogenesis of this uncommon source of head and face pain is thought to be the dysfunction of the nasociliary ganglion in a manner analogous to the dysfunction of the sphenopalatine ganglion, which is thought to be the source of cluster headaches. The presenting symptom of patients with Charlin syndrome is severe paroxysms of ocular or retro-orbital pain that radiates into the ipsilateral forehead, nose, and maxillary region. This pain is associated with voluminous ipsilateral rhinorrhea and congestion of the nasal mucosa as well as significant inflammation of the affected eye. The pain of Charlin syndrome has a rapid onset to peak, with attacks lasting 45 to 60 minutes. In some patients these attacks can be triggered by sensory stimulation of the affected areas. Although in many ways similar to a cluster headache (e.g., the retro-orbital location of pain, profuse unilateral rhinorrhea, the rapid onset to peak, and the short duration of attacks), there are many dissimilarities. Unlike in cluster headaches, alcohol does not seem to trigger attacks of Charlin syndrome, and the seasonal and chronobiologic patterns so characteristic of cluster headaches appear to be absent ( Table 12-1 ). Furthermore, blockade of the sphenopalatine ganglion, which is so effective in the treatment of cluster headaches, is of little value in the treatment of Charlin syndrome, whereas patients with Charlin syndrome uniformly respond to daily nasociliary nerve blocks with local anesthetic, as described later.

TABLE 12-1

Comparison of Cluster Headache and Charlin Syndrome

	Cluster Headache	Charlin Syndrome
Ocular and retro-orbital location	Yes	Yes
Unilateral	Yes	Yes
Rapid onset to peak	Yes	Yes
Severe intensity	Yes	Yes
Attacks occur in paroxysms	Yes	Yes
Duration of attacks is short	Yes	Yes
Pain free between attacks	Yes	Yes
Significant rhinorrhea during attacks	Yes	Yes
Alcohol triggers attacks	Yes	No
Tactile trigger areas	No	Yes
Seasonal pattern of attacks	Yes	No
Chronobiologic pattern of attacks	Yes	Yes
Significant eye inflammation	No	Yes
Responds to sphenopalatine ganglion block	Yes	No
Responds to nasociliary block	No	Yes