Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) with preserved refractory period: report of three cases.
BACKGROUND
Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform attacks with cranial autonomic features (SUNA) are rare primary headache syndromes characterized by spontaneous or triggered attacks of unilateral, brief, multiple, orbitofrontal pain associated with ipsilateral autonomic features. SUNCT is considered as a subset of SUNA. In SUNA, there may be cranial autonomic symptoms other than conjunctival injection and lacrimation, or either of two is present. SUNCT/SUNA can be triggered immediately after or at the decrescendo phase of the ongoing attack without any intervening refractory period. Refractory period is usually present in trigeminal neuralgia. Absent refractory period is thought to reliably differentiate SUNCT/SUNA from trigeminal neuralgia and has been proposed for inclusion into the International Classification of Headache Disorders (ICHD) diagnostic criteria for SUNCT.


METHODS
We report three patients of SUNCT syndrome with preserved intervening refractory period of variable duration observed at different times.


CONCLUSIONS
Trigeminal neuralgias with autonomic features, SUNA and SUNCT share a common pathophysiological mechanism and actually represent a continuum. It is well known that patient with trigeminal neuralgia may transform into SUNCT/SUNA. Similarly, being a continuum, the presence or the absence of refractory period and its duration may change in a patient with SUNCT/SUNA at different time points.


CONCLUSIONS
The presence of refractory period should not exclude the diagnosis of SUNCT in a patient with other clinical features suggestive of SUNCT.
Department of Neurology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, Uttar Pradesh, India. dr_vimalkpaliwal@rediffmail.com
Vimal Kumar
VK
Paliwal
Prabhat
P
Singh
Achal
A
Kumar
Sushil Kumar
SK
Rahi
Rakesh Kumar
RK
Gupta
D006801:Humans; D008297:Male; D008875:Middle Aged; D012032:Refractory Period, Electrophysiological / Q000502:physiology*; D050798:SUNCT Syndrome / Q000175:diagnosis* / Q000503:physiopathology*