So let's talk a little bit more about neuralgiform headaches and here's an overview.
These headaches are defined by their clinical description.
The history is critical in evaluating these patients.
We're looking for descriptions of electric shock like sensation.
Neuralgiform headaches result from irritation,
activation of the nerve and that often results into shooting
or shock like sensation down the nerve.
Patients frequently describe neuropathic symptoms,
numbness, tingling, paresthesia's, burning, those neuropathic descriptions of pain
and that's something we should ask for
and evaluate when taking the history or evaluating a clinical vignette.
The shooting pain should shoot along a nerve distribution.
The pain should follow a nerve, this is a nerve problem,
and critical evaluation on history and physical exam,
looking for where the numbness is involved,
looking for a rash that may develop subsequent to this neuropathic problem
will point us into the direction of a neuralgiform etiology.
At times, the patients pain can be initiated by activation of the nerve,
and so this is one of the few headaches that can be triggered,
and here we see rubbing of the face, eating, chewing
or anything that activate the nerve that's affected can cause the patient to develop a head pain.
The pain should follow the distribution of the nerve
and here we see the course of the trigeminal nerve V1 up in the forehead,
V2 along the check, and V3 along the lower part of the jaw,
and the patient's symptoms and any exam finding should follow the course of that nerve.
This is what we see for trigeminal neuralgia.
Similarly, occipital neuralgia or neuralgiform headache, irritation of the occipital nerve,
results in symptoms in the back of the head often involving the greater occipital nerve
as it exits the fascia and courses over the greater occipital notch
along the head and up the posterior and lateral aspects of the head.
So again we're looking for symptoms that follow the course of these nerves
and may be initiated by activation of those nerves.
What are some of the symptoms that we see in patients?
Well, this is typically unilateral pain, it has a neuralgiform quality,
and it follows the distribution of a nerve,
those key findings on history what points us in this direction.
It means that history is most important for these patients.
There's often not prominent physical exam finding
and our testing looks for the underlying cause,
but often, will not help us to categorize the patient's pain as a neuralgiform in its classification.
Attacks often lasts seconds to minutes, so these are short,
very severe attacks that last a short period of time
but can cluster and be really severe for patients.
Sometimes, sending some patients in such severe episodes to suicidality
or even suicide attempts.
What are some of the types of neuralgiform headaches?
Well, we can see pain involving any nerve,
but there are a few characteristic nerve that I'd like you to know about
and headache syndromes that I'd like for you to know.
The first is trigeminal neuralgia, this is probably the most common,
well-recognized and well-written about neuralgiform headache.
This is irritation that courses along the trigeminal nerve, either V1 or V2 or V3.
Any aspect, any component of that nerve can be affected.
That's different from a occipital neuralgia
which is a neuralgiform headaches involving the greater occipital nerve
and here, you can see, the greater occipital nerve coursing along the back of the head.
Again, symptoms should overlap the distribution of the greater occipital nerve.
Glossopharyngeal neuralgia is a neuralgiform headaches resulting from a dysfunction
and irritation of the glossopharyngeal nerve.
Sometimes this presents with headache,
but many times the other components of the glossopharyngeal nerves function
drives the patient's presentation.
Many patient present with presyncope or syncope,
in addition to a milder degree of headache,
and so sometimes, glossopharyngeal neuralgia is on our differential for presyncope
or syncope in rare cases.
And we can also see a neuralgiform pain from post-herpetic neuralgia
which can be very severe and debilitating with pain developing often during
and then following the rash of a herpes zoster outbreak.
How do we evaluate neuralgiform headaches?
So we said, this is a secondary cause of headache
and we need to do additional imaging either with angiographic imaging or structural imaging,
and our patient with the squamous cell carcinoma,
we need to be considered, we need to consider potential cancer related causes.
Here we see an MRI of the brain with and without contrast
which is important in evaluating neuralgiform causes of headache.
We can see for this patient in the left Meckel's cave, thickening of Meckel's cave,
there's that increased white hyperintensity in Meckel's cave,
suggestive of a dural-based metastasis in someone who has an underlying cancer,
and this would be one potential secondary cause of trigeminal neuralgia.
In there we can see the dural-based metastasis which is, which would be seen in a cancer patient.
We can also see perineural invasion, that's growth of cancer along the nerve's course,
this is particularly commonly associated with head and neck cancers
as in the case in our lecture here,
and those two cancer related conditions could present with new onset trigeminal neuralgia.
In addition to structural imaging, we think of a vessel imaging, either with CTA or MRA.
Here, we see on this CTA, a prominent white area
or hyperdensity just at the area of the MCA and distal ICA,
middle cerebral artery and internal carotid artery, and this is an aneurysm.
An MCA, proximal MCA aneurysm that has compressed cranial nerve V
and caused the development of trigeminal neuralgia,
so patients who present with neuralgiform headaches
and specifically, trigeminal neuralgia,
should undergo vascular imagining to evaluate this type of cause.
And then, what about treatments? What are the things we do to manage these patients?
The first things we could, we'd consider would be medical therapy, medications.
There are some medicines that have weaker evidence, others with more stronger evidence,
and in general, we're turning into antiepileptic agents.
Neuralgiform pain is caused by a nerve that is screaming out, it is overactive,
and we're looking for medicines that reduce that neural activity,
that affect the transmission that occurs from spontaneous activation of the nerve.
We can think about things like lamotrigine, oxcarbazepine, and pregabalin,
which I find to be variably successful in these patients
but do have weaker evidence in the literature.
And then some of the tried and true treatments for neuralgiform pain are carbamazepine or Tegretol.
This is commonly shows up on clinical vignette and test questions,
and we use carbamazepine frequently to manage patients with trigeminal neuralgia.
Sometimes we'll consider baclofen, gabapentin,
increases gaba-inhibitory tone in the brain
and other nerve transmission so it can effective, and phenytoin.
We're looking at mostly antiepileptic medicines when we're managing these patients.
In addition to medical therapy, surgical treatments can be quite effective
for managing trigeminal neuralgia and other neuralgiform headaches.
Microvascular decompression is a surgical procedure for patients
who have a vessel that closely approximates the trigeminal, often the trigeminal nerve.
In microvascular decompression, that touch point is relieved sometimes
with placing a small cotton piece in between the vessel
and the nerve to relieve the irritation along that nerve
and manage the patient's trigeminal neuralgia.
In addition, subcutaneous and local anesthetic nerve blocks are used
particularly for occipital neuralgia
where we can block the occipital nerve
with either a temporary or long-acting anesthetic or steroid agent,
and calm that nerve down and control the patient's pain.
Gamma knife radiosurgery can be used to ablate a nerve
and that can manage patient's pain as well as percutaneous rhizotomy,
which is an ablative procedure that can also be quite effective.
And we use these surgical techniques variably based on the indication
and underlying cause of the patient's neuralgiform headache.