Central nervous system vasculitis.

PURPOSE OF REVIEW: In the past decade, primary and secondary central nervous system (CNS) vasculitides have been more commonly diagnosed and recognized than previously. With the increasing awareness of these disorders, it is crucial for the treating physician to differentiate between causes of CNS vasculitis and to recognize their marked clinical and pathophysiological heterogeneity. This review focuses on the major forms of primary CNS vasculitis, as well as secondary CNS vasculitis with emphasis on their clinical findings, diagnoses, and treatment. RECENT FINDINGS: The proposal of reversible cerebral vasoconstriction syndromes (RCVS) as a unifying concept for a group of disorders which are characterized by acute-onset severe recurrent headaches, with or without additional neurologic signs and symptoms, and prolonged but reversible vasoconstriction of the cerebral arteries, has been a major breakthrough in this field over the past decade. Recognition of this common mimic (i.e. RCVS) has allowed optimal management of a sizable group of patients previously confused with pathologically documented CNS vasculitis. SUMMARY: Sound treatment decisions are based on accurate diagnosis. It is essential for the clinicians involved in the evaluation of patients with CNS vasculitis to be aware of its mimics especially RCVS. This article provides a comprehensive review of CNS vasculitis and its differential diagnosis. Furthermore, it touches upon workup and treatment of CNS vasculitis.

Perivascular meningeal projections from cat trigeminal ganglia: possible pathway for vascular headaches in man.

Peroxidase-containing cell bodies were found in the ipsilateral trigeminal ganglia after horseradish peroxidase was applied to the proximal segment of the middle cerebral artery in seven cats. Cell bodies containing the enzyme marker were located among clusters of cells that project via the first division. The existence of sensory pathways surrounding large cerebral arteries provides an important neuroanatomical explanation for the hemicranial distribution of headaches associated with certain strokes and migraine.

SUNCT: bilateral hypothalamic activation during headache attacks and resolving of symptoms after trigeminal decompression.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a primary head-pain syndrome, which is often refractory to any medical treatment. Concerning the pathophysiology of SUNCT, hypothalamic involvement ipsilaterally to the pain has been suggested based on the clinical features and one functional imaging case report. Here we now report a new case with SUNCT and the concomitant cerebral activation pattern (fMRI) during the pain attacks. In addition to an activation of several brain structures known to be generally involved in pain processing, bilateral hypothalamic activation occurred during the pain attacks, arguing for a central origin of the headache. Interestingly, this patient became completely pain free after surgical decompression of the ipsilateral trigeminal nerve. We hypothesize that in this case with a central predisposition for trigeminal autonomic cephalgias, a peripheral trigger with ectopic excitation might have contributed to the clinical picture of SUNCT.

Cluster headache variant. Spectrum of a new headache syndrome.

The syndrome of cluster headache variant is characterized by the occurrence of three combined symptoms: atypical cluster headaches, multiple jabs, and background vascular headaches. Atypical cluster headaches are localized headaches that occur several times daily, usually without any headache-free periods. They differ from the typical chronic cluster headache in their location, duration, frequent shifting, and frequency. Multiple jabs are short-lasting, sharp pains of variable severity and location. Background vascular headache is a chronic, continuous often unilateral headache of variable severity that throbs at rest or begins to throb during exertion. We have studied 54 patients between the ages of 14 and 78 years (average age, 40.5 years). Forty-five (83%) patients responded to indomethacin. Complete control was achieved in 50% of the patients. The nine patients who did not respond to indomethacin were depressed. These nine patients responded well to tricyclic antidepressants.

Post-traumatic chronic paroxysmal hemicrania (CPH) with aura.

The authors describe a patient who developed chronic paroxysmal hemicrania (CPH) in close temporal relationship to a head injury. The subsequent attacks of CPH were associated with a typical migrainous sensory and motor aura. Administration of indomethacin 75 mg daily resulted in isolated occurrence of autonomic and aura symptoms in the absence of pain symptoms. The patient became completely asymptomatic on indomethacin 100 mg daily. Migrainous aura may be seen with trigeminal-autonomic headaches and may represent the expression of an aura-susceptibility gene rather than typical migraine headache biology.

Advances in understanding the pathophysiology of headache.

Recent evidence suggests that migraine may not be due to vasoconstriction followed by reactive vasodilation, and tension-type headache may not be due to excess muscle contraction. The prodromes of migraine may have a hypothalamic origin, and the aura and changes in cognition may have a cortical neuronal origin. The pain of migraine and tension-type headache may be generated centrally or enhanced or generated by neurogenic inflammation. Drugs used to treat headache frequently interact with serotonin receptor subtypes: abortive drugs at the 5-HT1 receptor and preventive drugs at the 5-HT2 receptor.

Focal retrograde amnesia associated with vascular headache.

We report the case of a 42-year-old man with repeated attacks of headache associated with retrograde amnesia. Neuropsychological tests before and after the major episode of amnesia showed mild neuropsychological deficits but with spared anterograde memory and learning functions. The amnesia was dense for a period of 15-20 years and included people and events (public and private). There was also a suggestion of amnesia for learned skills. Neurologically he had mild clinical signs and focal EEG-abnormalities in the left fronto-temporal region, but CT, MRI, and SPECT showed no abnormality. Five years after the onset of amnesia there was no recovery of the retrograde memory deficit, but a PET (glucose) scan was normal and neuropsychological testing showed no deficits. An association with migraine has been reported for some non-classical amnesias, but this is the first case of selective retrograde amnesia in a patient with headache as a primary neurological diagnosis.

Activation of trigeminal brain-stem nociceptive neurons by dural artery stimulation.

Vascular head pain is thought to result from activation of trigeminal sensory nerve fibers innervating cranial blood vessels. Support for this hypothesis was sought by searching in the trigeminal brain-stem subnucleus caudalis (SNC) for neuronal responses evoked by electrical stimulation of the middle meningeal artery (MMA). Seventy-eight SNC neurons were found which could be excited by MMA stimulation of the facial skin. These results provide the first report of the existence and functional properties of brain-stem neurons likely to be involved in mediating vascular head pain.

Cluster headache pain vs. other vascular headache pain: differences revealed with two approaches to the McGill Pain Questionnaire.

We compared cluster headache pain and other vascular (migraine and mixed) headache pain on pain intensity ratings and the McGill Pain Questionnaire (MPQ). Cluster headache sufferers reported not only more intense pain and more affective distress, but also different pain qualities than did migraine and mixed headache sufferers. The pain qualities that best distinguished cluster headaches from other vascular headaches were the presence of punctate pressure and thermal sensations and the absence of dull pain. Although cluster headache sufferers and other vascular headache sufferers endorsed different sensory pain qualities, MPQ subscales proved no better than pain intensity ratings at distinguishing these two groups. This finding may have occurred because MPQ subscale scores include an intensity component and do not provide information about specific pain qualities such as that provided by MPQ sensory items. These findings provide evidence that cluster headaches are characterized by distinct pain qualities and are not simply a more intense version of the same vascular headache pain experienced by migraine and mixed headache sufferers. They further suggest than when the MPQ is used to assess specific pain qualities, sensory items and not the sensory subscale are the preferred units for analysis.

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.

Lateralisation of pain in cluster headache.

In 27 patients with cluster headache a careful sensory examination of the entire body was performed. The exam included: the measurement of sensory thresholds with mechanical and electrical stimuli, the assessment of cutaneous and deep hyperalgesia and the ischaemic test of the upper limbs with limbs at rest. In most patients a lateralisation of the findings was observed: cutaneous and deep hyperalgesia were prevalent in the side of cluster headache attacks. The results indicate that in cluster headache, as in other pain syndromes, a lateralisation may be induced throughout the body, probably by phenomena of facilitation in the central nervous system and by activation of reflex arcs.

Trigeminal sensory fiber stimulation induces morphological changes reflecting secretion in rat dura mater mast cells.

Mast cells are involved in allergic reactions, but may also participate in neurogenic inflammation. The morphology of mast cells in rat dura mater and tongue was evaluated by histochemistry, as well as by scanning and transmission electron microscopy following unilateral trigeminal ganglion stimulation (5 min, 5 Hz, 5 ms, and 0.02, 0.1 or 1.0 mA). Mast cells in dura and tongue of normal animals were numerous, perivascular and often in close proximity to nerve fibers. After 5 min of electrical stimulation, mast cells contralateral to the stimulation showed histochemical characteristics of normal peripheral tissue mast cells (Safranin-positive), and by electron microscopy appeared homogeneous with numerous intact electron-dense granules. On the stimulated side, however, the staining characteristics of mast cells showed changes indicating progressive intracellular loss of their granular content. In addition, the total number of stainable mast cells decreased at all three stimulus intensities, but reached significance only at 0.1 and 0.02 mA. Ultrastructural evidence of granule changes consistent with secretion were observed although degranulation was not observed until 20 min after stimulation. There were no mast cell changes after electrical trigeminal stimulation in adult rats treated as neonates with capsaicin to destroy small caliber sensory afferent axons. These results suggest that mast cells may secrete in response to electrical stimulation of trigeminal axons, possibly mediated by antidromic release of neuropeptides, and may participate in the development of neurogenic inflammation.

Management of trigeminal autonomic cephalgias and hemicrania continua.

The trigeminal autonomic cephalgias (TACs) are a group of primary headache disorders characterised by unilateral trigeminal distribution pain that occurs in association with ipsilateral cranial autonomic features. This group of headache disorders includes cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT syndrome). Although hemicrania continua has previously been classified amongst the TACs, its nosological status remains unclear. Despite their similarities, these disorders differ in their clinical manifestations and response to therapy, thus underpinning the importance of recognising them. We have outlined the clinical manifestations, differential diagnoses, diagnostic workup and the treatment options for each of these syndromes.

Vascular head pain selectively activates ventrolateral periaqueductal gray in the cat.

Electrical stimulation of the superior sagittal sinus is an experimental model of migraine which activates neurons within the upper cervical spinal cord. The ventrolateral periaqueductal gray has been proposed as an integrative centre for the autonomic and behavioural responses to deep pain and also receives significant inputs from the upper cervical spinal cord. The noxious-stimulation evoked expression of the immediate-early gene c-fos, was used to determine if sagittal sinus stimulation activates neurons of the ventrolateral periaqueductal gray. The superior sagittal sinus was stimulated in anesthetised cats and Fos-protein was detected in coronal brain sections using standard avidin-biotin immunohistochemistry. A pattern of Fos-positive cells restricted to the caudal ventrolateral periaqueductal gray was revealed suggesting that this region may mediate the pattern of somatic and autonomic responses characteristic of migraine.

Effect of propylene glycol 1,2-dinitrate on cerebral blood flow in rats: a potential biomarker for vascular headache?

Two measurable indices of toxicity that can be correlated with exposure to propylene glycol dinitrate (PGDN) were evaluated along with its metabolism. Propylene glycol dinitrate was administered by rapid i.v. injection to male Fischer-344 rats. These rats demonstrated a dose-response of blood pressure (BP) to doses of PGDN ranging from 0.1 to 30 mg/kg; the maximum fall in systolic BP occurred within 1 min of dosing. The i.v. administration of PGDN to separate groups of animals resulted in an increase in cerebral blood flow that was correlated with the dose, but a clear dose-response was not obtained.

Substance P and enkephalins: a creditable tandem in the pathophysiology of cluster headache and migraine.

Substance P, present in primary sensory neurones, seems to take part in nociceptive transmission within the trigeminal system. Substance P, released by peripheral axons of these neurones, induces vasodilatation, plasma extravasation, miosis, conjunctival and nasal congestion. All these effects bear some similarity to symptoms of cluster headache and migraine attack. Opiates and somatostatin inhibit the release of substance P from primary sensory neurones and relieve both pain and autonomic symptoms of cluster headache attack. Plasma substance P-like immunoreactivity was decreased during spontaneous attack of cluster headache and migraine and during histamine precipitated attack of cluster headache. Taken together these data suggest that substance P and endogenous opioids could be implicated in the pathophysiology of cluster headache and migraine.

Soft occlusal splint therapy in the treatment of migraine and other headaches.

Fifty-seven patients suffering from migraine, tension headache or tension vascular headache were prescribed a soft occlusal splint for night-time wear. Dental, psychosocial/psychiatric and neurological data were recorded prior to commencement of therapy and at the conclusion of a 3 month treatment period. A statistically significant number of patients presenting with migraine or tension vascular headache experienced marked improvement or complete relief of headache symptoms, but most patients suffering from tension headache failed to benefit from splint therapy. A majority of patients displaying intercurrent features of craniomandibular dysfunction experienced reduction in these symptoms also. There was a statistically significant association between TMJ improvement and headache type. Prior to treatment, patients who subsequently benefited from splint therapy in terms of headache improvement had experienced significantly fewer headaches than patients who failed to respond, although headache intensity and duration were similar in both groups. It is suggested that headache type and frequency may be prognostic indicators of the likely success of dental splint therapy in treatment of headache. Nevertheless, the use of occlusal splints in the treatment of patients complaining of headache in the absence of evidence of craniomandibular dysfunction should not be embarked upon until medical examination has excluded the possibility of organic neurological disorder.

Asymmetric mydriatic response to topical tyramine in cluster headache relatives.

A pupillometric study was performed to evaluate the mydriatic response to tyramine, a noradrenaline releaser. There were three groups of subjects: (a) 10 cluster headache patients, in an asymptomatic period; (b) 20 of their close relatives, exempt from this disease; (c) 10 healthy controls. The tyramine was instilled into both eyes of each subject. The controls displayed an isocoric tyramine-induced mydriasis but the cluster headache sufferers and their relatives showed an anisocoric mydriasis. This anisocoric mydriasis was caused by a deficient mydriatic response on one side, which in the cluster patients corresponded to the symptomatic side. The sympathetic abnormality of the iris may be the expression of a functional asymmetry in the hypothalamus. Central sympathetic asymmetry could thus represent a dysgenetic family predisposition to lateralized headache attacks.

Orofacial pain with vascular-type features.

OBJECTIVE: To examine whether a classifiable primary vascular-type craniofacial pain subgroup exists that predominantly affects intraoral structures. STUDY DESIGN: Fifty-five patients were chosen prospectively according to the following inclusion criteria; periodic craniofacial pain that was unilateral, pulsatile, severe, and that may wake the patient from sleep. Accompanying phenomena could include local autonomic and/or systemic signs. Twenty-six cases could be further classified into one of the categories of vascular craniofacial pain. The remaining 29, all with predominantly intraoral pain, were not readily classifiable. RESULTS: Of the 29 patients 70% were women, with an average onset-age of 42.6 years. All reported severe, episodic pain that was usually unilateral and lasted minutes to hours. In all, 55% of patients had autonomic or systemic signs, 48% had pulsatile pain, and 35.4% of patients were awakened by the pain. CONCLUSION: Although clinical similarities were observed within these patients, further studies are needed to confirm vascular orofacial pain as a clear diagnostic category.