Sympathetically maintained pain presenting first as temporomandibular disorder, then as parotid dysfunction

Area of Science:

• Neurology
• Pain Medicine
• Autonomic Dysfunction

Background:

• Complex regional pain syndrome (CRPS) typically affects extremities, presenting with severe pain, swelling, and autonomic dysfunction.
• Sympathetically maintained pain (SMP) is a subtype of CRPS, often linked to nerve injury or trauma.
• CRPS involving the head and neck is exceptionally rare, with only 13 prior cases reported, all associated with trauma.

Observation:

• This report details a case of SMP in the head and neck region.
• The patient exhibited characteristic CRPS symptoms including pain, allodynia, and sudomotor changes.
• Unlike previous cases, this instance of head and neck SMP did not have a clear initiating nerve injury.

Findings:

• The diagnosis of SMP in the head and neck was established based on International Association for the Study of Pain criteria.
• The absence of a discernible initiating nerve injury presents a unique etiological consideration for head and neck SMP.
• This case expands the understanding of potential triggers for CRPS in the head and neck region.

Implications:

• This case highlights that head and neck SMP can occur without overt nerve injury, broadening diagnostic considerations.
• Further research is needed to elucidate the mechanisms underlying SMP in the head and neck without clear trauma.
• Clinicians should consider SMP in the differential diagnosis of chronic head and neck pain, even in the absence of apparent nerve damage.