Headache Table 1: Diagnostic Criteria for Cluster Headache3
A At least 5 headache attacks fulfilling criteria B–D B Severe or very severe unilateral orbital, supraorbital, and/or temporal pain lasting 15–180 minutes if untreated
C Headache is accompanied by at least one of the following symptoms ipsilateral to the pain: • conjunctival injection or lacrimation • nasal congestion and/or rhinorrhoea • eyelid edema • forehead and facial sweating • miosis and/or ptosis • a sense of restlessness or agitation
D Attacks have a frequency from 1 every other day to 8 per day E
Not attributed to another disorder Table 2: Medically Intractable Cluster Headache8
Failed an adequate trial of regulatory approved and conventional treatments according to local national guidelines Adequate trial: • appropriate dose • appropriate length of time • consideration of medication overuse Medication failed due to: • no therapeutic or unsatisfactory effect • intolerable side effects • contraindications to use
Failure of at least 4 classes, where 2 should come from 1–3: 1. verapamil 2. lithium
3. methysergide 4. melatonin 5. topiramate 6. gabapentin
Moreover, they may cause both mortality and significant morbidity, and can induce further pain problems such as anesthesia dolorosa. Previously used approaches have included trigeminal ganglion glycerol injections,10,11
radiofrequency rhizotomy of the Gasserian ganglion,12
gamma knife aimed at the trigeminal nerve,13,14 decompression15 superficialis16
case series of trigeminal nerve root section20,21 or microvascular
and esection or blockade of the N. petrosus or pterygopalatine (sphenopalatine) ganglion.17–19
There are that illustrate all the
issues, including inducing further pain, vision impairment, or indeed death. Moreover, there are also case reports of the complete inefficacy of surgical treatment in CH.21,22
about 10% of patients with CCH will revert to the episodic form,23
procedure should not be less safe than the natural history. Peripheral Approaches
A number of structures have been suggested as peripheral targets of stimulation in CH. These include the occipital nerve, which will be dealt with in detail below as there are now a number of studies available, the ophthalmic branch of the trigeminal nerve (n=1),24 stimulation (n=6)25
and higher cervical stimulation (n=1).26
relative data and promise, occipital nerve stimulation (ONS) is dealt with in more detail below.
126
It must also be remembered that annually so a
Occipital Nerve Stimulation
who reported a series of cases of intractable occipital neuralgia responding to ONS. Detailed phenotyping of these cases in association with a functional imaging study demonstrated that almost all patients had chronic migraine.28
Initial interest in the use of ONS to treat headache dates from Weiner and Read,27
What was remarkable in the ONS patients studied
using functional imaging was that the therapy, while effective in terms of pain, did not seem to alter the brain activation of areas considered to be important in migraine. Instead, it changed thalamic processing. Taken
together with experimental data collected by the authors of this paper,29– 31
it was reasoned that ONS may be helpful in selected patients with other primary headache disorders. It seems likely, given that peripheral distribution of the pain does not predict the outcome of stimulation, that ONS has an important central effect on the brain.32
Six out of the eight
patients initially undergoing this procedure had sufficient benefit to recommend the procedure to others and to make it an option for other neuromodulation approaches.33
Long-term experience over more than
two years demonstrated that device dysfunction almost always led to the return of attacks.34
Thus, it seems unlikely that the useful effect is a
prolonged placebo, although much more needs to be done to establish the mechanism of the useful effect.
Central Nervous System Approaches— Deep Brain Stimulation
Recognizing that all invasive treatments bear the risk of severe side effects, international guidelines for patient selection based on expert consensus were published.35
Criteria for the use of deep brain
stimulation (DBS) include only considering patients with all of the following: CCH and strictly unilateral attacks without side shift, a normal psychological profile, and no medical/neurological condition contraindicating DBS, such as epilepsy/stroke. Only medically intractable patients should be considered for DBS. Considering that more than 50 patients have been operated on and the results published,36
with an
average of 50–70% showing a significant positive response, the question arises of whether it is possible to formulate predictive indicators of which patients will respond to hypothalamic DBS in CH.
Defining the Target Point
The target point for DBS in CH was chosen based on clinical considerations and functional studies, particularly neuroimaging, which revealed the crucial role of the posterior hypothalamic region in CH.37 Neuroimaging with positron-emission tomography (PET) shed light on the genesis of CH, documenting the link between activation in the hypothalamic gray ipsilateral and pain in CH.38
These areas are not
simply involved in the response to first-division nociceptive pain impulses but are inherent to each syndrome, probably in some permissive or dysfunctional role.9,39
Furthermore, using high-resolution
vagus nerve Given its
The co-localization of morphometric and functional changes demonstrates the precise anatomical location for a probable central nervous system lesion in CH. Given that this area is involved in circadian rhythms, sleep–wake cycling,41 system,42
structural 3D magnetic resonance images and voxel-based morphometry, a significant structural difference in gray matter density of the hypothalamus was found in patients with CH compared with healthy volunteers.40
and control of the autonomic
the data suggest a crucial involvement of this hypothalamic area, at least in generation of the acute CH attack. Initially, it was
US NEUROLOGY
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