Now let's talk
about the third TAC.
And this TAC has the shortest
duration of episodic headaches.
And this is SUNCT, which stands
for short lasting, unilateral,
neuralgia form headaches,
with conjunctival injection and tearing.
It's exactly what it spells.
SUNCT is characterized by very,
very short episodes, 1-600 seconds.
Attacks of unilateral orbital
supraorbital or temporal
with a very stabbing
and pulsating pain.
Patients have tonnes of
these attacks during the day,
3-200 attacks during the day.
So that the shortest lasting but
then the most during the day.
Pain is accompanied by ipsilateral
conjunctival injection and lacrimation.
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.
Here we can see how pain
is described in patients.
The pain is a stabbing, burning,
pricking or shock like sensation.
There's maximal intensity
within 2-3 seconds.
And that's maintained for the duration of
the attack, again, a very short attack.
And there are a number of
different pain patterns.
Here we can see graphically
some of those pain patterns.
So there's a single
This where patients will have single
episodes of very severe short lasting pain
that remits goes back
down to normal in between.
We can see groups of stabs where there's
multiple stabbing episodes of pain
all lasting a very
And then the last would be a
sawtooth pattern where pain comes on.
They're very severe
episodes that occur,
and then that goes away at the
resolution of that episode.
And each of these is consistent
with a diagnosis of SUNCT.
What else do patients describe?
Some patients have dull discomfort between
the attacks that's more sawtooth pattern.
Most patients have spontaneous
or triggered attacks.
Triggers can include cutaneous
stimulation and neck movement.
Refractory period after
an attack is very rare.
Nocturnal attacks are also
rare, we see them with cluster,
we don't see them with
SUNCT as frequently.
And unusual features include
bilaterality or alternating sides
and that should really prompt diagnostic
testing before making this diagnosis.
There's also a sister
syndrome called SUNA,
that short-lasting, unilateral,
neuralgia form headache
with attacks with cranial
With SUNA, we don't see
the conjunctival injection
and tearing that
we see with SUNCT.
But otherwise it's described the exact same
way and may really be a subset of SUNCT.
Similar to SUNCT,
the location is more varied
but less cutaneous triggers
are seen with SUNA.
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.
Rathke's cleft cyst which is a
cyst in the pituitary sellar region
can present this way.
with basilar impression.
a number of different tumors.
Vascular lesions including
this megadolichobasilar artery
that's an enlarged basilar artery can
present and has been associated with this.
dopamine agonists and others.
What about treatment?
How do we treat
something SUNCT and SUNA?
Well, really, this is usually
refractory to many medications.
Steroids can be used for those acute
attacks for those many clusters of attacks.
During the day, IV lidocaine,
subcutaneous lidocaine has been tried.
There's no response
which makes it different
from paroxysmal hemicrania.
A number of AEDs can be
tried and are utilized as
with the other trigeminal autonomic
cephalalgia and Verapamil.
Botulism toxin can be used.
Gamma knife is considered in particularly
severe cases that are refractory.
Occasionally on an
we would consider DBS to
the posterior hypothalamus,
there's a hypothalamic
component to this.
Neurovascular decompression, percutaneous
balloon compression or surgery.
And again, these are really reserved
for the exceptional and rare cases
where this remains refractory
to other interventions.