So let's learn a little bit more about thunderclap headache,
and let's start with an overview what is a thunderclap headache.
Well, it begins suddenly, it really peaks suddenly,
so the severity of the headache should peak within 60 seconds.
It often lasts for a prolonged period of time greater than five minutes,
it can wane a little bit over time, but that peak and rise of severity is very important.
A thunderclap headache is suggestive of aneurismal hemorrhage,
of a subarachnoid hemorrhage, and that's the first thing that we should evaluate.
There are other causes, but our first step should be evaluate for a subarachnoid hemorrhage.
Sometimes, an aneurysm will bleed and then stop bleeding,
and that sentinel bleed is a warning sign that that's an aneurysm
that may subsequently bleed causing subarachnoid hemorrhage
and so thunderclap headache is an important presentation of a sentinel bleed or a related pathology.
And this is described by patients as the worst headache of my life,
but the key is the repetitive onset which we will look at in a couple of slides.
And lets focus on that, I think this point is really important for evaluating this patient
is how quickly that worst headache of my life comes on,
because for most patients, when they have a headache, their head hurts and it hurts a lot,
and maybe the worst headache they can remember,
but the onset of that severe headache,
the onset of that worst headache of my life will help us as clinicians,
to differentiate between migraine, which is benign, and a thunderclap headache,
which is potentially emergent.
So abrupt onset of the worst headache of my life is a very important feature to evaluate.
Headaches that reach maximum intensity within one minute,
meet the criteria for a thunderclap headache
and that's what we're looking for when we evaluate these patients.
Often we see in the setting of subarachnoid hemorrhage associated meningeal irritation
and meningeal signs, and that may be nausea, vomiting, photo or phonophobia.
Some patients may become presyncopal or have frank syncope,
and there can be visual disturbances.
And I think these two graphs really drive home the point of looking at the repetitie of onset.
So with migraine, we see migraine
and how it evolves overtime on the X axis in the level of severity.
How bad is that pain on the Y axis?
Migraine begins not so painful, patients don't have pain.
They can have a prodromal period with their early symptoms
that may herald the onset of their migraine.
The aura, their pain slowly comes on during the aura.
Auras are often visual with problems with scotomas or dark spots in the patient's vision,
or a scotoma that scintillates with bright lights surround it,
and slowly that pain builds to the worst headache that the patient may remember.
And then overtime, naturally or with therapeutic intervention,
the pain will subside in the postdromal period.
So you can see the headache reaches the worst headache
that the patient may remember or feel, but it does so slowly.
And that's different from a thunderclap headache.
With the thunderclap headache, bam.
It's the worst headache that that patient has felt,
and the onset, the repetitie of onset is very quick,
within a minute, the headaches goes from not present at all to the worst headache the patient has felt,
and that's what we're looking for on exam
and when we're evaluating these patients to guide us in one direction or the other.
So, what are some of the causes in differential diagnoses for a thunderclap headache,
the headache with this rapid acute-onset?
Well, there's a few things we need to consider,
that should just come to our mind when we hear this presentation.
Subarachnoid hemorrhage or sentinel bleed, intracranial or intracerebral hemorrhage,
bleeding in the brain, arterial dissection,
and the syndrome called reversible cerebral vasoconstriction syndrome.
It's a vasoconstriction syndrome and so the blood vessels,
the arteries in the brain constrict,
that can cause frank strokes or areas of penumbra ischemic tissue.
It's reversible, it's often caused by a drug or an insult
and when that's removed, over time, it can resolve
and it presents with a sudden onset, rapid onset severe headache,
and those are the critical causes that we need to consider of a thunderclap headache.
There are also some other things, pituitary apoplexy, acute glaucoma, acute hydrocephalus
or increased intracranial pressure, venous sinus thrombus, purulent sinusitis,
so sinusitis can present with this severe onset of headache.
Hypertensive urgency or pheochromocytoma, meningitis, encephalitis,
and sometimes, rarely tumors, often tumors that have bleeding into the tumor
that result in that rapid onset of pain.
So let's walk though some of these causes of a thunderclap headache,
and think about what the condition is, how patients will present.
What are the features and the diagnostic testing that we'll perform?
Again, these are secondary causes of headache
and so our job as clinicians, is to diagnose and evaluate the cause of that headache.
The first is subarachnoid hemorrhage
and we should think of this first as the cause of a thunderclap headache.
Patients present with sudden onset, maximal severity at onset of headache,
often with neck pain and some meningeal signs, neck stiffness.
The diagnostic test of choice is a non-contrast head CT
and this is really the gold standard for evaluating for a subarachnoid hemorrhage.
Within the first six hours from presentation, the CTA is the best,
or excuse me, the CT scan of the brain,
the non-contrast head CT is the best way to evaluate for this condition,
but it can be falsely negative for patients who present outside that six hour window.
In those patients, we consider a lumbar puncture to evaluate for sentinel bleed
or subtle signs of subarachnoid hemorrhage, red blood cells in the spinal tap.
Reversible cerebral vasoconstriction syndrome or RCVS,
is the, one of the second causes that we would consider of a thunderclap headache.
This is exactly as it is sounds, vasoconstriction,
so narrowing of the blood vessels in the brain resulting in headache
and sometimes stroke or ischemic tissue.
This is reversible and so it's caused by a number of offending agents
and removal of those offending agents and waiting over time is the intervention of choice.
Patients present with headache that recurs daily or every few days over several weeks.
The headaches tend to be shorter in their duration in subarachnoid headache,
and we look for triggers.
Things like around the peripartum or postpartum period.
Sometimes in certain autoimmune conditions and their number of drugs,
medications like SSRIs that can set off RCVS.
The diagnostic testing that we perform to evaluate for RCVS
is to look at the arteries with angiographic imaging,
and that may be head CTA with a CTA, CT angiography.
MR imaging MRA or MR angiography.
Or in cases where both of those tests are negative
and there's a high index of suspicion we would consider a catheter angiography,
which is a catheter that's put into the cerebral circulation
to evaluate the arteries for those signs of vasoconstriction.
And then the last condition would be cervical artery dissection presenting
with headache, neck pain, potentially with recent neck trauma or manipulation.
This can be seen in patients with connective tissue diseases or certain causes of hypertension.
And the diagnostic test is head and neck CTA to evaluate for the dissection.
Pituitary apoplexy can present with a thunderclap headache.
This is typically in a patient with either a history of pituitary adenoma
or we would consider in patients with pregnancy
or on dopamine agonist therapy which can predispose to hemorrhage into the pituitary region.
Patients present with ophthalmoplegia
and often with a bitemporal hemianopia from compression of the optic chiasm,
or vomiting in visual disturbances. Head CT is used to evaluate for this initially
and if negative, with a high index of suspicion, a brain MRI may be needed.
Third, ventricle colloid cyst is a rare cause of thunderclap headache but it is really cool.
A cyst is a benign structure but this cyst sits right at the Foramen of Monro,
a critical location where CSF drains from the lateral ventricles into the third ventricle.
Obstruction of CSF flow at the Foramen of Monro causes massive increase in ICP abruptly,
and this can cause a thunderclap headache.
The headache lasts for seconds to a day,
can rapidly resolve as the colloid cyst moves out of that Foramen of Monro
and there's a resolution of the obstruction and the treatment of choice is to remove the cyst.
We typically evaluate that with a either head CT initially
and then often brain MRI to demonstrate findings of the colloid cyst.
And then cerebral venous sinus thrombosis or VST, venous sinus thrombosis,
may present in individuals less than 50 years old,
females have a predisposition to this condition.
It can be seen in patients with a hypercoagulable state
or recent postpartum period where patients are hypercoagulable.
Patients presents with papilledema
and potentially seizures, neurologic deficits from elevated increase intracranial pressure.
And we evaluate this by looking at the veins with CT venography or MR venography
to demonstrate evidence of that clot in the cerebral veins, the cerebral sinuses.
So what do we do to evaluate and manage patients who present with a thunderclap headache?
I like this workflow or clinical workflow to evaluate patients
who present with that sudden onset, rapid and very severe headache.
The first questions is, does the patient meet criteria for a thunderclap headache?
If they do, we can proceed down this algorithm.
Our first question is, are we concerned for some of those other causes?
RCVS or arterial dissection, conditions where we need angiographic imaging,
we need to look at the blood vessels, the arteries for that problem.
If we have an index of suspicion because the patient's on a medicine,
this has been a waxing and waning headache,
the patient had recent head trauma or neck manipulation,
then we would move to conduct a head CT without contrast
and a CTA of the head and neck to evaluate for that condition.
And if negative, with a high index of suspicion, we may need to consider further imaging.
If there's not a prominent concern for RCVS or dissection,
then we typically begin with a CT of the head without contrast,
and that's the gold standard to evaluate for subarachnoid hemorrhage
for patients who present in the first six hours from symptoms onset.
If they're outside of that window, we may need to follow the head CTA if negative,
if unremarkable, with a lumbar puncture to increase our sensitivity,
to find those patients who may have normal CTs
but still have evidence of a sentinel bleed or subarachnoid hemorrhage.
And on the lumbar puncture we're looking for increased red blood cells
that are present in tube one, the first tube that we collect and remain present in tube four.
There's no clearing of those red blood cells overtime
that indicates spontaneous production of red blood cells from some cause
and here's subarachnoid hemorrhage as opposed to a traumatic spinal tap.
If patients present inside that six hours and the head CT is positive,
we've made our diagnosis of subarachnoid hemorrhage.
If negative, we look at risk factors and other clinical conditions
that would raise our concern and still may need to consider further imaging for those patients.
In patients who don't meet any of these criteria
and so we don't have an answer for their thunderclap headache,
we may need to evaluate for other less common causes like the colloid cyst
or some of the others that we've discussed
and that would be through consultation with a neurologist.