SUNCT and SUNA

00:01 Now let's talk about the third TAC.

00:03 And this TAC has the shortest duration of episodic headaches.

00:08 And this is SUNCT, which stands for short lasting, unilateral, neuralgia form headaches, with conjunctival injection and tearing.

00:18 It's exactly what it spells.

00:21 SUNCT is characterized by very, very short episodes, 1-600 seconds.

00:26 Attacks of unilateral orbital supraorbital or temporal with a very stabbing and pulsating pain.

00:33 Patients have tonnes of these attacks during the day, 3-200 attacks during the day.

00:38 So that the shortest lasting but then the most during the day.

00:42 Pain is accompanied by ipsilateral conjunctival injection and lacrimation.

00:46 Given the name, it must not be attributable to any other disorder and at least 20 attacks must fulfill these criteria to establish the diagnosis.

00:57 Here we can see how pain is described in patients.

01:00 The pain is a stabbing, burning, pricking or shock like sensation.

01:05 There's maximal intensity within 2-3 seconds.

01:08 And that's maintained for the duration of the attack, again, a very short attack.

01:13 And there are a number of different pain patterns.

01:16 Here we can see graphically some of those pain patterns.

01:20 So there's a single stabs pattern.

01:22 This where patients will have single episodes of very severe short lasting pain that remits goes back down to normal in between.

01:30 We can see groups of stabs where there's multiple stabbing episodes of pain all lasting a very short duration.

01:37 And then the last would be a sawtooth pattern where pain comes on.

01:40 They're very severe episodes that occur, and then that goes away at the resolution of that episode.

01:47 And each of these is consistent with a diagnosis of SUNCT.

01:51 What else do patients describe? Some patients have dull discomfort between the attacks that's more sawtooth pattern.

01:57 Most patients have spontaneous or triggered attacks.

02:00 Triggers can include cutaneous stimulation and neck movement.

02:04 Refractory period after an attack is very rare.

02:08 Nocturnal attacks are also rare, we see them with cluster, we don't see them with SUNCT as frequently.

02:15 And unusual features include bilaterality or alternating sides and that should really prompt diagnostic testing before making this diagnosis.

02:24 There's also a sister syndrome called SUNA, that short-lasting, unilateral, neuralgia form headache with attacks with cranial autonomic features, very prominent autonomic features.

02:35 With SUNA, we don't see the conjunctival injection and tearing that we see with SUNCT.

02:41 But otherwise it's described the exact same way and may really be a subset of SUNCT.

02:47 Similar to SUNCT, the location is more varied but less cutaneous triggers are seen with SUNA.

02:54 So what are some of the secondary causes of both SUNCT and SUNA? Multiple sclerosis can cause lesions that can contribute to these pain episodes.

03:02 Rathke's cleft cyst which is a cyst in the pituitary sellar region can present this way.

03:07 Osteogenesis imperfecta with basilar impression.

03:11 Tumors, a number of different tumors.

03:14 Vascular lesions including this megadolichobasilar artery that's an enlarged basilar artery can present and has been associated with this.

03:23 Infectious causes, iatrogenic causes, dopamine agonists and others.

03:30 What about treatment? How do we treat something SUNCT and SUNA? Well, really, this is usually refractory to many medications.

03:36 Steroids can be used for those acute attacks for those many clusters of attacks.

03:40 During the day, IV lidocaine, subcutaneous lidocaine has been tried.

03:45 There's no response to indomethacin which makes it different from paroxysmal hemicrania.

03:50 A number of AEDs can be tried and are utilized as with the other trigeminal autonomic cephalalgia and Verapamil.

03:58 Botulism toxin can be used.

04:00 Gamma knife is considered in particularly severe cases that are refractory.

04:05 Occasionally on an investigational situation, we would consider DBS to the posterior hypothalamus, there's a hypothalamic component to this.

04:13 Neurovascular decompression, percutaneous balloon compression or surgery.

04:17 And again, these are really reserved for the exceptional and rare cases where this remains refractory to other interventions.