The Enhanced Ciliospinal Reflex in Asymptomatic Patients With Cluster Headache is Due to Preganglionic Sympathetic Mechanisms

An amplified ciliospinal reflex response has been documented in patients with cluster headache, lacking a Horner like syndrome. The mechanism is unknown, Tentatively, it may be due to an increased release of monoamines from post-ganglionic sympathetic nerve endings or an increased density of postsynaptic adrenergic receptors in the dilatator muscle of the iris.
The instillation of a 1% phenylephrine solution into the conjunctival sac induces mydriasis by stimulating postsynaptic adrenergic receptors in the dilatator muscle of the iris, while the instillation of a 2% tyramine solution causes mydriasis by releasing noradrenaline from the presynaptic sympathetic nerve terminals in the iris.
According to these premises, a positive correlation shouId be expected between the ciliospinal reflex response and the pupillary response to tyramine, if the enhanced ciliospinal so-flex response was due to an increased presynaptic release of monoamines. No such correlation was found. Nor was there any positive correlation between the ciliospinal reflex response and the pupillary response to phenylephrine, contradicting an increased density of postsynaptic monoaminergic receptors in the dilatator muscle of the iris as the explanation. However, there was a significant positive correlation between the pupillary responses to phenylephrine and tyramine, ruling out any functionally caused "denervation" hypersensitivity in the dilatator muscle of the iris.
It is concluded that the amplified ciliospinal reflex response in cluster headache patients (lacking a Horner-like syndrome) reflects compensatory pathophysiological mechanisms proximal to the third-order sympathetic neuron.     

Cluster headache pathogenesis: A pupillometric study

Thirty-two cluster headache patients and healthy controls (n = 16-20 for the various tests) were examined by means of a Whitaker pupillometer during pain-free intervals. Eye drops of the sympathomimetic agents tyramine, hydroxyamphetamine, and phenylephrine were instilled into the conjunctival sacs on separate occasions, and pupillary diameters recorded at standard time intervals. The mydriatic responses of the two pupils were compared. A moderate, but statistically significant, basal relative miosis was found on the pain side in cluster headache. The symptomatic-side pupils were less responsive than their counterparts when stimulated with tyramine and hydroxyamphetamine, the difference being statistically significant for the OH-amphetamine test. With the phenylephrine test, however, the mydriasis on the symptomatic side significantly exceeded that of the contralateral pupil. This pattern of reactions does not quite correspond to those of "ordinary" Horner's syndrome (1st, 2nd, and 3rd neuron lesion). There are, however, gross similarities with the recently reported pattern in central sympathetic neuron dysfunction. In cluster headache there is probably a "Horner-like picture" rather than a proper Horner's syndrome.     

Dysfunction of the sympathetic nervous system in cluster headache

Ocular sympathetic function was studied in 13 cluster headache patients during and between attacks and several weeks or months after attacks had subsided. The pupillary response to tyramine eyedrops and facial sweating and flushing in response to body heating and to the taste of chilies were also investigated during remission. Pupillary dilatation lag on the symptomatic side persisted between bouts and correlated significantly with loss of thermoregulatory sweating in the lower part of the forehead. In six patients in remission, pupillary dilatation in response to tyramine eyedrops was impaired on the symptomatic side, whereas five patients showed no sign of ocular sympathetic deficit. These findings indicate that incomplete sympathetic deficit persisted on the symptomatic side in a subgroup of cluster headache patients during remission. In most of this subgroup the pattern of sympathetic deficit was consistent with impaired function of postganglionic cervical sympathetic fibres.     

The Site of Sympathetic Deficit in Cluster Headache

The pattern of autonomic deficit in the face of cluster headache patients resembles the deficit in patients with a postganglionic sympathetic lesion from some other cause; however the presence of abnormal cardiac rhythms and bilateral pupillary reflex deficit in some patients with cluster headache suggests that the lesion might compromise central sympathetic drive. To investigate this possibility, the vasomotor and sudomotor startle reflex was investigated in the hands of sic cluster headache patients with ocular and thermoregulator signs of postganglionic sympathetic deficit in the face; for comparison, responses were also investigated in 15 patients with a lesion in the cervical sympathetic pathway from some other cause. The startle reflex was intact in the hands of the six cluster headache patients, but was diminished ipsilaterally in patients with a central or preganglionic sympathetic lesion and also, surprisingly, in patients with a postganglionic lesion caused by an aneurysm of the internal carotid artery. Ocular sympathetic deficit was greater in patients with an aneurysm of the internal carotid artery than in cluster headache patients or in patients with a postganglionic sympathetic lesion from some other cause; the aneurysm may have compromised neurons with projections to the face and hand, or could have induced transsynaptic degeneration of preganglionic fibers supplying both regions. The findings indicate that central sympathetic drive is not impaired in cluster headache patients; thus, a peripheral lesion probably induces sympathetic deficit on the symptomatic side of the face.     

Pupil responsiveness in cluster headache: A dynamic TV pupillometric evaluation

In this study the variations in pupil diameter induced by different stimuli (dark-light adaptation, light reflex, electric stimulation of the sural nerve) were investigated in episodic (in the active or remission phases) and in chronic cluster headache (CH) patients. Pupil size monitoring was performed with a monocular, infrared TV pupillometer, and sural nerve stimuli were applied after the pain threshold had been measured as the flexion reflex threshold of the biceps femoris muscle (RIII reflex). The results were compared with those obtained in patients with "peripheral" (third neuron) Horner's syndrome and in healthy sex- and age-matched controls. On the symptomatic side we found an impairment of pupil response to light flashes and nociceptive stimuli; similar findings were sometimes evident on the pain-free side, too. These results substantiate previous observations that in cluster headache a dysfunction of the integrative central nervous system pathways also exists intercritically and mostly bilaterally, involving both autonomic regulation and pain perception mechanisms.     

Cluster Headache in Two Sisters. Pupillary Response to Phenylephrine and Tyramine

Two sisters with cluster headache were studied with respect to the pupillary responses to instillation into the conjunctival sac of a single drop of a 1% solution of phenylephrine and a 2% solution of tyramine. The changes in pupillary diameters were documented by photographic pupillometry prior to and at 15, 30, 60, and 90 minutes after the instillations.
Of the two sisters, one (case A) was examined during a symptom-free interval, when she had been free from cluster headache attacks for 2 1/2 years. When the cluster headaches recurred, retesting was performed. The other sister (case B) had been free from cluster headaches for 9 years, when she was examined.
The findings indicate hypofunction within the postganglionic sympathetic nerve fibers during a cluster headache period. The hypofunction is bilateral, and thus, can not be a consequence of the unilateral cluster headache attacks. During remissions, tyramine induces a marked mydriasis, particularly on the symptomatic side, tentatively indicating an excessive release of stored monoamines.     

Latent dysautonomic pupillary lateralization in cluster headache. A pupillometric study

Forty-five patients with cluster headache in the asymptomatic phase were studied by electronic pupillography, testing autonomic function of both pupils pharmacologically. Topical sympathetically-acting mydriatics, tyramine and cocaine and the cholinoceptor blocker, homatropine, induced defective mydriatic responses on the symptomatic side, indicating latent impairment of sympathetic function. The abnormality was found in interattack intervals of the cluster period or during intercluster phases. The tyramine test can be proposed for objective diagnosis of cluster headache. We postulate that cluster attacks are triggered and lateralized by a permanent latent unilateral sympathetic dysfunction. Lithium reduced the mydriatic response to tyramine of the pupil contralateral to the pain, thus restoring the equilibrium between both pupils; this therapy may correct the asymmetric sympathetic function by attenuating the activity in the asymptomatic side.     

Bilateral Horner's Syndrome in Cluster Type Headaches

SYNOPSIS
A patient with cluster type headaches demonstrated bilateral and alternating ocular sympathetic dysfunction during a spontaneous as well as a nitroglycerin-induced attack. Biochemical evaluation revealed postganglionic pupillary dysfunction on the symptomatic side and preganglionic pupillary dysfunction contralaterally. These findings defy a simple explanation regarding a central or peripheral origin of the oculocephalic sympathetic dysfunction.     

Thermographic and pupillary asymmetry in chronic paroxysmal hemicrania. A case study

Facial temperature was measured thermographically and pupillary diameter recorded photographically during and between episodes of headache and during spontaneous remission of headache in a patient with chronic paroxysmal hemicrania (CPH). Heat loss from the orbit, nose, cheek and temple was 0.75-1.5 degrees C greater on the symptomatic side during headache, and 0.25-0.75 degrees C greater between headache episodes. Heat loss from these regions of the face was symmetrical during remission of headache. Extensive rhinorrhoea, and slight ptosis and miosis were observed during the active phase of CPH. These findings, which are similar to those previously reported in cluster headache, suggest that CPH is associated with an ocular sympathetic deficit and with overactivity in the greater superficial petrosal nerve.     

Coexistence of pupillary and heart sympathergic asymmetries in cluster headache

Ten cluster headache patients and 10 healthy controls were subjected to electrocardiographic and pupillometric procedures in a search for cardiac and pupillary sympathergic asymmetry. Sympathergic stimulation was provoked by hyperventilation and by instilling tyramine into both eyes. In the control group, hyperventilation changed neither the T-wave form and polarity nor the QTc. Tyramine provoked an equal mydriasis on the two sides. In cluster headache sufferers, hyperventilation produced changes in the T-wave form and polarity as well as an increase of the QTc due to a disproportionate shortening of the R-R and Q-T intervals. An unequal mydriasis was noted after tyramine instillation due to less marked response on the symptomatic side. The observed electrocardiographic abnormalities are considered an expression of an asynchronous repolarization attributed to a sympathergic asymmetry. It is postulated that both the cardiac and pupillary sympathetic imbalance associated with cluster headache are central in origin.     

The trigemino-pupillary response in cluster headache

Central impairment of the integrative neural systems controlling vegetative function and pain perception has been demonstrated in cluster headache (CH). Recently, we described the human pupillary response (trigeminal reflex) to quantified (painless and painful) corneal stimulation with a combined neurophysiological and pharmacological technique. In this study, the trigeminal reflex was evaluated in 26 subjects with episodic cluster headache. During the active phase of the disease, on the side of the pain we observed reduced mydriasis to electrical stimuli with an intensity equal to the corneal reflex threshold, and on both sides to stimuli with intensity that equalled the pain threshold. No difference was found when amplitude of the miotic phase was compared in the different groups. These suggest disordered pupillary activation in response to pain, probably sympathetic in origin, which is bilateral, detectable also during the remission phase and which cannot be explained simply by the antidromic release of pain-related peptides.     

Cervicogenic headache

Eleven female patients with cervicogenic headache (mean age, 43 years; range, 25-59 years) have been examined with the pupillometer. The pupillary diameter was examined in the basal state (that is, the status before pharmacologic stimulation) and after topically administered tyramine (2%), phenylephrine (1%), and hydroxyamphetamine (1%). A total of 51 tests were performed, 35 in the asymptomatic period and 16 during pain attacks. In a control group consisting of 26 age-matched women a total of 39 tests were carried out. Before pharmacologic stimulation (that is, in the "basal state") the pupils were smaller in the asymptomatic (pain-free) period than during pain attacks in the patients and also as compared with that of control individuals. The anisocoria (the difference in pupillary size in the same individual) observed was not significantly different between the patient group and control individuals either in the basal state (before pharmacologic stimulation) or after pharmacologic stimulation. The mydriasis resulting from the instillation of the three sympathicomimetic drugs was symmetrical in both controls and patients both during and between the pain attacks. This finding is in clear contrast to what is found in cluster headache, in which there is a "Horner-like" syndrome on the symptomatic side. These two headaches thus seem to differ essentially with regard to this variable.     

Cluster headache: Further observations on the dissociation of pain and autonomic findings

A 51-year-old male cluster headache patient had during five bouts in the course of 11 years always had the headache attacks on the left side. Autonomic abnormalities were, however, present on the right side. Pupillometrically, there was thus a Horner-like syndrome on the right (non-symptomatic) side, with miosis and a relatively more marked dilatation of that eye subsequent to topical application of a directly working sympathomimetic agent (phenylephrine) than after an indirectly working one (hydroxyamphetamine), whereas this was not the case on the symptomatic side. The findings on evaporimetry were not as clear-cut as the pupillometric findings; however, even facial sweating was consistent with a pathologic condition on the right (non-symptomatic) side. A primary dichotomy of pain and autonomic signs (that is, not due to change of side of pain localization) thus seems to be present in this case.     

Unilateral impairment of pupillary response to trigeminal nerve stimulation in cluster headache

The pupillary constriction induced ipsilaterally by transcutaneous electrical nerve stimulation (TENS) of the infratrochlear nerve was measured, using an electronic pupillometer, in 26 episodic cluster headache (CH) and 15 migraine sufferers tested during an attack-free period and in 16 healthy controls. In controls, TENS gave rise to a miosis which was slow in onset and long-lasting in duration, and which was comparable to that mediated by tachykinins in animals. A similar miotic response was bilaterally observed in migraine patients and in CH patients examined during the inactive phase. In CH sufferers during the cluster period, TENS only elicited a normal pupillary constriction in the asymptomatic eye, whereas the resulting response in the symptomatic eye was markedly decreased. Although the exact mechanism underlying the dysfunction remains to be clarified, these results seem to indicate that ocular trigeminal pathways are involved in CH.     

Chronic paroxysmal hemicrania: From the index patient to the disease

The first patient with chronic paroxysmal hemicrania (CPH), a 41-year-old woman, first seen in 1961, was followed until an adequate treatment was found, 12 years later. Clinically, attack frequency and duration differed widely from the general pattern of cluster headache. Ocular variables, such as intraocular pressure and corneal indentation pulse amplitudes, also differed in our case (clear symptomatic side increment during attacks) and cluster headache. Pupil reactions to directly and indirectly acting sympathicomimetic drugs were also vastly different in our case and cluster headache: no signs of Horner’s syndrome in our patient, while cluster headache exhibits a "Horner-like pattern." In cluster headache, there is a relative hypohidrosis in the forehead on the symptomatic side if body temperature is increased, and a clear hyperhidrosis on direct parasympathomimetic stimulation. This was not so in our case. Indomethacin was highly effective in our case, while "cluster headache drugs," such as ergotamine/sumatriptan, were ineffective. Indomethacin was inactive in cluster headache. Accordingly, our case seemed to differ decisively from cluster headache: CPH had been discovered.     

Clusterlike Headache in a Patient With a Pituitary Adenoma. With a Review of Literature

A man had left-sided atypical clusterlike headache for II years before he developed symptoms and signs consistent with acromegaly. Preoperative evaluation revealed raised levels of somatomedin C and growth hormone. An MR indicated a left-sided intrasellar mass measuring 8 x 7.5 x 10 mm. He underwent surgery and microscopy confirmed the diagnosis of a benign hypophyseal adenoma. Postoperatively, the acromegalic features regressed, and for the last 4 years the patient has been completely free from headache attacks. On pharmacological testing of the pupillary response to 19 and 5% phenylephrine and 2% tyramine solutions, there was no convincing evidence of persistent sympathetic dysfunction on the earlier symptomatic side.     

Evaluation of autonomic nervous function by pupil dynamics recording]

Pupil is richly innervated by autonomic nerves. Therefore, its size or movement well reflects the autonomic nervous function. By analyzing dynamics of pupil movement for light stimulus followed by infrared video-pupillography, the abnormality of autonomic nervous system can be expressed in a quantitative manner. Clinical applications of pupillography and pharmacological examination to Horner syndrome, Adie syndrome, diabetes mellitus, pupillary involvement of Beh?et disease, pupil of brain death and patients with chemical sensitivity have been described. Segmental spasm of iris in Horner and Aide syndrome, especially, nasal side of iridoplegia was seen in early stage of Aide syndrome from pupillary dynamics to light stimulus. An involvement of sympathetic nerve subserving iris dilator muscle was confirmed from pupillography, drug reaction to topically applied l-epinephrine in the diabetics. An involvement of cholinergic nerve which subserve the iris sphincter muscle was seen in Beh?et disease when there was no manifest eye involvement. Mild mydriasis in brain death patients was seen under denervation of central nervous system. Dysfunction of sympathetic nerve from pupillary light reflex in chemically sensitive patients for cholinated hydrocarbon pesticides.     

The Blink Reflex in Cluster Headache

To investigate the involvement of the trigeminal system in cluster headache, in twelve subjects the electrically-elicited blink reflex during a symptomatic period was examined. In eleven cases, the amplitude of the contralateral R2 response on the symptomatic side was significantly lower, at the same stimulus intensity, than on the asymptomatic side (p = 0.005). The blink reflex can be useful to evaluate biological and drug-induced phenomena in cluster headache.     

Sympathetic skin responses from frontal region in migraine headache: a pilot study

Frontal sympathetic skin responses (F-SSRs) were recorded to investigate sympathetic nervous system activity in migraine headache (MH). Thirty-five patients with unilateral MH and 10 healthy volunteers were studied by evoking bilateral F-SSRs with electrical stimulation of the median nerve in attack, post-attack and interictal periods. The mean latencies were longer and the maximum amplitudes were smaller on the symptomatic side compared with the asymptomatic side ( P  < 0.05 for both amplitude and latency) in attack and in interictal periods. In five patients, F-SSRs were absent bilaterally, in four patients the responses were absent only on the symptomatic side during the attack period. In the post-attack period, F-SSRs on the symptomatic side had higher amplitudes and shorter latencies compared with the asymptomatic side ( P  < 0.01 for both amplitude and latency). There is an asymmetric sympathetic hypofunction on the symptomatic side in attack and interictal periods, whereas there is a hyperfunction in the post-attack period.     

Combined evaluation of pupillary and cardiovascular responses to cold pressor test in cluster headache patients

Little is known about the structures and mechanisms involved in the pathophysiology of cluster headache (CH). In this study, pupillary and cardiovascular responses to the cold pressor test (CPT) were monitored in CH patients during either an active phase of disease or a remission period in order to evaluate the oculocephalic and cardiovascular functioning of the autonomic nervous system in this form of idiopathic headache. CH patients showed a specific pattern of pupillary response on both sides during both phases of the disease. This response differed from that of controls because of an absent miosis. The pressor response to CPT was more marked in CH patients than in controls. Naloxone pretreatment caused specific and selective changes in both the pupillary and cardiovascular responses of CH patients. These data suggest a systemic sympathetic hyperactivation in response to CPT in CH patients. An oculocephalic sympathetic hypofunction is possibly associated as well as an altered opioid neuromodulation.