Short-lasting Unilateral Neuralgiform Headaches With Autonomic Signs
Short-lasting unilateral neuralgiform headaches with autonomic signs (SUNHA), which includes SUNCT and SUNA as subclassifications in ICHD, combines characteristics of neuralgiform pain with autonomic signs, such as lacrimation. The differential diagnosis versus cases of TN with lacrimation is extremely difficult. ICHD allows for both diagnoses to be given in a single patient.
Based on the strikingly similar clinical phenotype and associated signs, discussion continues on whether SUNHA is a neuropathic pain related to TN.[96–98] The evidence for this is mixed. The demography is different, as in SUNHA, there is an equal representation of men and women, and the average age of onset is 44 years, whereas in TN, there is an overrepresentation of women and an average age of onset of 52 years. Mechanical precipitation of attacks is a hallmark of TN but is also seen in SUNHA. Refractory periods are considered typical of TN and are very rare in SUNCT patients. Supraorbital nerve blockade has been relatively unsuccessful in SUNCT, whereas nerve blocks are effective in CTN cases with lacrimation. CTN reliably responds to carbamazepine, whereas SUNCT syndrome is characterized by drug resistance from its onset. Imaging studies suggest that SUNHA is related to the trigeminal autonomic cephalalgias, but recent discoveries point to an association between NVC and the painful side in SUNHA. The absence of trigeminal sensory pathway abnormalities would support the view that it is not a neuropathic type of pain.
Headache. 2021;61(6):817-837. © 2021 Blackwell Publishing