Trigeminal neuralgia with lacrimation or SUNCT syndrome?

Trigeminal and Glossopharyngeal Neuralgia

Trigeminal neuralgia and glossopharyngeal neuralgia are craniofacial pain syndromes characterized by recurrent brief shock-like pains in the distributions of their respective cranial nerves. In this article, the authors aim to summarize each condition's characteristics, pathophysiology, and current pharmacotherapeutic and surgical interventions available for managing and treating these conditions.

Lacrimal hyperalgesia: a case series of post-operative painful lacrimation

Lacrimal hyperalgesia is a rare type of periorbital neuralgia triggered by tear production. Two female patients in their mid-forties underwent orbital surgery and, several weeks following their procedures, developed pain when they produced tears. The symptom was described as a sharp, debilitating, and transient periocular pain. A possible mechanism for this lacrimal hyperalgesia is through the formation of an artificial synapse along the superolateral aspect of the orbit. Two mechanisms for this type of hyperalgesia are described herein, which include potential mechanical compression or direct disruption of the normal nerve pathways and microvascular disruption causing ischemic nerve injury. Currently, there is no accepted treatment for this aberrant neuropathic pain caused by lacrimation. Gabapentin therapy was trialed in one of these two patients, who experienced partial improvement with nightly use. In this case series, we describe the clinical and radiographic features associated with this unique type of neuralgia, emphasizing the importance of recognizing it as a complication following orbital surgery.

The changing face of trigeminal neuralgia-A narrative review

OBJECTIVE

This narrative review aims to update the reader on the new classification of trigeminal neuralgia (TN), clinical signs, pathophysiologic evidence, and their implications on management. This review is based on the authors' collective experience and knowledge of the literature in addition to a literature search.

BACKGROUND

In recent years, the phenotype of TN has been intensively studied leading to discrete groups of patients. These include patients with TN with additional continuous pain, and patients with and without neurovascular compression of the trigeminal dorsal root entry zone. A number of associated clinical signs such as tearing and sensory changes need further research.

METHODS

The literature on TN was searched in PubMed with the aims of providing evidence for the recently published third edition of the International Classification of Headache Disorders (ICHD) and update the clinical phenotype and management of the TN subcategories.

RESULTS

The ICHD's new classification for TN is based on reliable clinical data, imaging, and neurophysiologic studies. The TN classification reflects current knowledge and has improved the possibility for clinicians to choose adequate management options. However, there is a lack of effective, safe drugs for the management of TN and sparse, robust data on neurosurgical options.

CONCLUSION

Research into all aspects of TN-diagnosis, pharmacotherapy, surgery, long-term management prognosis, and natural history-is needed. Research should adhere to the ICHD's schema for TN. Improved drugs are needed along with rigorous research into surgical options and their efficacy for different subtypes of TN.

SUNCT/SUNA: Case series presenting in an orofacial pain clinic

AIM

Little is known about short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA). We present our experience with SUNCT/SUNA patients to aid identification and management of these disorders.

METHODS

A retrospective review of patient records of one orofacial pain clinic was performed. Inclusion criteria was a diagnosis of SUNCT/SUNA confirmed with at least one follow-up visit.

RESULTS

Six of the 2464 new patients seen between 2015-2018 met the selection criteria (SUNCT n = 2, SUNA n = 4). Gender distribution was one male to one female and average age of diagnosis was 52 years (range 26-62). Attacks were located in the V1/V2 trigeminal distributions, and five patients reported associated intraoral pain. Pain quality was sharp, shooting, and burning with two patients reporting "numbness". Pain was moderate-severe in intensity, with daily episodes that typically lasted for seconds. Common autonomic features were lacrimation, conjunctival injection, rhinorrhea, and flushing. Frequent triggers were touching the nose or a specific intraoral area. Lamotrigine and gabapentin were commonly used as initial therapy.

CONCLUSIONS

Differentiating between SUNCT/SUNA does not appear to be clinically relevant. Presenting symptoms were consistent with those published, except 5/6 patients describing intraoral pain and two patients describing paresthesia.

Herpes zoster ophthalmicus evolving into headache characterised as hemicrania continua

Postherpetic neuralgia (PHN) is the most common chronic complication of herpes zoster infection. However, a few patients may develop different types of pain after herpetic lesions. We are reporting two patients who developed postherpetic hemicrania continua (HC). Case 1: a 54-year-old woman had a 10-month history of continuous left-sided pain with superimposed exacerbations. The pain started with the onset of herpetic lesions in the ophthalmic division. The lesions subsided in a few weeks. However, the pain persisted and it responded exclusively to indomethacin. Case 2: a 61-year-old woman developed clinical features pertinent to PHN. However, later on, the pattern and associated clinical features changed. The patient fulfilled the criteria of HC and showed a complete response to indomethacin. We suggest that every patient with PHN should be asked for cranial autonomic features and a trial of indomethacin should be given in refractory herpes zoster neuropathy.

Tics in TACs: A Step into an Avalanche? Systematic Literature Review and Conclusions

BACKGROUND

Trigeminal autonomic cephalalgias (TACs) comprise cluster headache, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks, and hemicrania continua. In some cases, trigeminal neuralgia (TN, "tic douloureux") or TN-like pain may co-occur with TACs.

AIM

This article will review the co-occurrence and overlap of TACs and tics in order to contribute to a better understanding of the issue and an improved management of the patients.

METHODS

For performing a systematic literature review Pubmed was searched using a total of ten terms. The articles identified were screened for further articles of relevance.

SUMMARY

TACs are related to tics in various ways. TN or TN-like paroxysms may co-occur with CH, PH, and HC, labeled as cluster-tic syndrome, PH-tic syndrome, and HC-tic syndrome. Such co-occurrence was not only found in the primary TACs but also in secondary headaches resembling TACs. The initial onset of TAC and tic may be simultaneous or separated by months or years. In acute attacks, tic and TAC may occur concurrently or much more often independently of each other. The term "cluster-tic syndrome" was also used in patients with a single type of pain in a twilight zone between TACs and TN fulfilling none of the relevant diagnostic criteria. Short-lasting neuralgiform headache attacks overlap with TN in terms of clinical features, imaging findings, and therapy.

Facial pain in a Neurological Tertiary Care Centre — Evaluation of the International Classification of Headache Disorders

The aim of this study was to examine the diagnostic spectrum of facial pain and to evaluate the clinical features relevant to the differential diagnosis in a neurological tertiary care centre. This is the first investigation comparing the first with the second edition of the International Classification of Headache Disorders (ICHD-I, ICHD-II) in consecutively referred patients comprising a broad spectrum of disorders without restricting the inclusion to certain diagnoses. Studying 97 consecutive patients referred for facial pain, we found trigeminal neuralgia or other types of cranial neuralgia in 38% and 39% according to ICHD-I and ICHD-II, respectively; persistent idiopathic facial pain was diagnosed in 27% and 21%, respectively. The proportion of patients who could not be classified was 24% in ICHD-I and 29% in ICHD-II. Six per cent of the patients had cluster headache or chronic paroxysmal hemicrania, the remaining 5% had various other disorders. The agreement between ICHD-I and ICHD-II was very good to perfect. In ICHD-II, sensitivity and specificity were similar to ICHD-I, the specificity and negative predictive value were imrpoved in single features of trigeminal neuralgia, but were widely unchanged in persistent idiopathic facial pain. The number of patients who could not be classified was larger in ICHD-II than in ICHD-I. Modifying the diagnostic criteria for different types of facial pain, in particular changes in the criteria of persistent idiopathic facial pain, might be helpful in reducing the number of patients with unclassifiable facial pain.

Familial SUNCT

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a rare type of primary headache. In this report we describe the occurrence of SUNCT in a family. Unfortunately, one of the siblings was already dead. However, clear and detailed information from close relatives and her general practitioner confirmed the diagnosis of SUNCT. It is likely that genetic factors contribute to all types of trigeminal autonomic cephalalgias.

Pain Part 9: Trigeminal Autonomic Cephalalgias

The trigeminal autonomic cephalalgias are a group of rare, highly disabling, primary headache syndromes distinctly characterized by the unilaterality of their attacks and presence of cranial autonomic symptoms. Although pain is often localized to the peri-orbital and temporal regions, it is not uncommon for pain to radiate to tooth-bearing areas and mimic toothache or jaw pain. Hence, dental practitioners should be aware of these syndromes to enable appropriate referral and avoid unnecessary, and often irreversible, dental treatments. Many dentists will not have heard of these conditions but must remain vigilant, and ensure that they are not confused with trigeminal neuralgia, so that their patients are appropriately advised and referred. Clinical relevance: The dental practitioners may be the first line of healthcare providers consulted by these patients in the hope of obtaining pain relief. Lack of familiarity with an uncommon condition may lead to poor patient management.

Tic versus TAC: differentiating the neuralgias (trigeminal neuralgia) from the cephalalgias (SUNCT and SUNA)

Trigeminal neuralgia, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform headache attacks with autonomic symptoms (SUNA) are classified as distinct disorders in the International Classification of Headache Disorders 3 beta (ICHD-3 beta). SUNCT and SUNA are primary headache disorders included among the trigeminal autonomic cephalalgias. Trigeminal neuralgia is classified under painful cranial neuropathies and other facial pains. The classification criteria of these conditions overlap significantly which could lead to misdiagnosis. The reported overlap among these conditions has called into question whether they should be considered distinct entities or rather a continuum of the same disorder. This review explores the known overlap and how other features not included in the ICHD-3 beta criteria may better differentiate the "Tics" (trigeminal neuralgia) from the "TACs" (SUNCT and SUNA).

Trigeminal neuralgia (part I): Revisiting the clinical phenotype

Aims

We conducted a cross-sectional study to re-examine the clinical profile of patients with a clinical diagnosis of classical trigeminal neuralgia (CTN).

Methods

Inclusion criteria consisted of the International Headache Society’s published classification of CTN. For the specific purposes of the study, features such as autonomic signs, persistent background pain, attack durations of >2 minutes and reports of pain-related awakening were included. The demographic and clinical phenotype of each patient were carefully recorded for analysis.

Results

The study cohort consisted of 81 patients and based on reported attack duration these were divided into short (≤ 2 minutes, n = 61) and long (> 2 minutes, n = 20) groups for further analysis. The group with short attack duration neatly fit most of the criteria for CTN while the long attack group presents a more challenging diagnosis. There were no significant differences in pain severity, quality and location between the short and long attack groups. The frequency of persistent background pain was significantly higher in the long (70%) compared to the short attack group (29.5%, p = 0.001). There were significantly more reports of pain-related awakenings in the long (55%) than in the short attack groups (29.5%, p = 0.04). There were no significant differences in the frequency of autonomic signs between the short (21.3%) and long attack groups (40%, p = 0.1). In the short attack group, the presence of autonomic signs was significantly associated with longer disease duration, increased pain-related awakenings, and a reduced prognosis.

Conclusion

There are clear diagnostic criteria for CTN but often patients present with features, such as long pain attacks, that challenge such accepted criteria. In our cohort the clinical phenotype of trigeminal, neuralgiform pain with or without autonomic signs and background pain was observed across both short and long attack groups and the clinical implications of this are discussed.

Trigeminal neuralgia (part II): Factors affecting early pharmacotherapeutic outcome

Aims

We conducted a cohort study to examine demographic and clinical features associated with the pharmacotherapeutic outcome in classical trigeminal neuralgia (CTN) patients.

Methods

Patients with a clinical profile indicating a diagnosis of CTN, as per the International Headache Society’s published classification, were enrolled prospectively. Demographic and pain-related characteristics were carefully collected. For the purposes of the study, patients with features such as autonomic signs and longer attack duration were included. All patients were then initiated on a standardised and accepted stepped pharmacotherapeutic protocol for the management of CTN. Initial pain scores and prospectively collected pain scores from pain diaries were used to assess the treatment outcome, with a ≥50% reduction considered significant.

Results

A total of 86 patients were seen, of whom five had an underlying disorder that could account for the pain. The study cohort therefore consisted of 81 patients, and based on attack duration these were divided into short (≤2 minutes, n = 61) and long (>2 minutes, n = 20) groups, for further analysis. The features of these patients and a discussion on the differential diagnosis have been presented in part 1 of this report. Employing an accepted stepped pharmacotherapeutic protocol for the management of CTN, significant improvement was more frequent in the short (74%) than in the long attack group (50%, p = 0.05). In the short attack group there were statistically significant associations between a poor treatment response and longer disease duration, the presence of autonomic signs and atypical pain descriptors for pain quality ( p < 0.05).

Conclusion

This report supports previous findings that prolonged disease duration and autonomic signs are negative prognostic indicators. The present study now adds long attack duration as a further negative prognostic sign.

Primary headache disorders

Primary headache disorders include migraine, tension-type headaches, and the trigeminal autonomic cephalgias (TACs). "Primary" refers to a lack of clear underlying causative pathology, trauma, or systemic disease. The TACs include cluster headache, paroxysmal hemicrania, and short-lasting neuralgiform headache attacks with conjunctival injection and tearing; hemicrania continua, although classified separately by the International Headache Society, shares many features of both migraine and the TACs. This article describes the features and treatment of these disorders.

Where SUNCT contacts TN: a case report

BACKGROUND

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) and trigeminal neuralgia (TN) are unilateral painful conditions that can share the same triggering factors, autonomic features and the main location, as well as the cyclically recurrent crises. Both these syndromes are associated with a high percentage of findings of vascular malformation touching the trigeminal nerve, suggesting a pathophysiological relationship.

CASE

In this paper, we report a new case with the main purpose to shine a light on the pathophysiology of these conditions.

CONCLUSION

Many authors described a SUNCT case deriving from TN or vice versa, suggesting that these conditions are strongly related. Every case of transformed TN or SUNCT should therefore be reported to gather and compare further information.

Trigeminal autonomic cephalalgias: A review of recent diagnostic, therapeutic and pathophysiological developments

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders that are characterized by strictly unilateral trigeminal distribution pain occurring in association with ipsilateral cranial autonomic symptoms. This group includes cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing. These disorders are very painful, often considered to be some of the most painful conditions known to mankind, and consequently are highly disabling. They are distinguished by the frequency of attacks of pain, the length of the attacks and very characteristic responses to medical therapy, such that the diagnosis can usually be made clinically, which is important because it dictates therapy. The management of TACs can be very rewarding for physicians and highly beneficial to patients.

Trigeminal autonomic cephalgias

1. Trigeminal autonomic cephalgias (TACs) are headaches/facial pains classified together based on:a suspected common pathophysiology involving the trigeminovascular system, the trigeminoparasympathetic reflex and centres controlling circadian rhythms;a similar clinical presentation of trigeminal pain, and autonomic activation. 2. There is much overlap in the diagnostic features of individual TACs. 3. In contrast, treatment response is relatively specific and aids in establishing a definitive diagnosis. 4. TACs are often presentations of underlying pathology; all patients should be imaged. 5. The aim of the article is to provide the reader with a broad introduction to, and an overview of, TACs. The reading list is extensive for the interested reader.

Orofacial pain due to trigeminal autonomic cephalgia with features of short-lasting neuralgiform headache attacks with conjunctival injection and tearing: a case report

BACKGROUND

We present a case of a 64-year-old woman with a presumptive diagnosis of short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome with telangiectasia. Dental procedures were not successful in alleviating the condition.

RESULTS

The patient's symptoms of short unilateral severe pain episodes abated after geographic relocation, although orofacial pain continued. Sphenoid sinus surgery further decreased the patient's chronic pain complaints. The patient's current pain condition is controlled with gabapentin therapy.

CLINICAL IMPLICATIONS

Diagnostic, etiologic, and therapeutic issues related to SUNCT syndrome are discussed. This case represents the first case report of trigeminal autonomic cephalgia with SUNCT syndrome-like features illustrating possible problematic dental therapies. It is only the third SUNCT case report in the dental literature, and the third case reporting a correlation between SUNCT syndrome and sinusitis.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) with preserved refractory period: report of three cases

BACKGROUND

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) and short-lasting unilateral neuralgiform attacks with cranial autonomic features (SUNA) are rare primary headache syndromes characterized by spontaneous or triggered attacks of unilateral, brief, multiple, orbitofrontal pain associated with ipsilateral autonomic features. SUNCT is considered as a subset of SUNA. In SUNA, there may be cranial autonomic symptoms other than conjunctival injection and lacrimation, or either of two is present. SUNCT/SUNA can be triggered immediately after or at the decrescendo phase of the ongoing attack without any intervening refractory period. Refractory period is usually present in trigeminal neuralgia. Absent refractory period is thought to reliably differentiate SUNCT/SUNA from trigeminal neuralgia and has been proposed for inclusion into the International Classification of Headache Disorders (ICHD) diagnostic criteria for SUNCT.

CASE REPORTS

We report three patients of SUNCT syndrome with preserved intervening refractory period of variable duration observed at different times.

DISCUSSION

Trigeminal neuralgias with autonomic features, SUNA and SUNCT share a common pathophysiological mechanism and actually represent a continuum. It is well known that patient with trigeminal neuralgia may transform into SUNCT/SUNA. Similarly, being a continuum, the presence or the absence of refractory period and its duration may change in a patient with SUNCT/SUNA at different time points.

CONCLUSION

The presence of refractory period should not exclude the diagnosis of SUNCT in a patient with other clinical features suggestive of SUNCT.

SUNCT syndrome successfully treated by gamma knife radiosurgery: case report

BACKGROUND

The SUNCT syndrome (short-unilateral neuralgiform headache with conjunctival injection and tearing) can be very disabling for affected patients and is often refractory to medical management. We report the first case of SUNCT with a successful response to stereotactic radiosurgery without any adverse effect.

CASE

After failing optimal medical treatment, a 82-year old male patient suffering from SUNCT syndrome was treated with Gamma knife radiosurgery. The trigeminal nerve and sphenopalatine ganglion were targeted with a maximum dose of 80 Gy each. The patient had complete pain cessation 2 weeks after the treatment, and remains pain-free with no medication at the latest follow-up 39 months after radiosurgery. He did not have any side effect from the procedure.

CONCLUSION

Gamma knife radiosurgery is an option for medically refractory SUNCT patients.

[Japanese SUNCT patient responsive to gabapentin]

We report a Japanese patient with short lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUCNT) responsive to gabapentin. A 29-year-old man presented with sudden-onset intermittent left-sided orbital headache, which was not accompanied by lacrimation and conjunctival injection. We diagnosed trigeminal neuralgia at first and administered carbamazepine and loxoprofen. However, these medications were entirely ineffective at all and 6 days later, autonomic symptoms including conjunctival injection and tearing appeared. Diagnosis of SUNCT was made and gabapentin was started at up to 800 mg per day. Soon after, the headache and autonomic symptoms disappeared. Gabapantin at 800 mg per day was continued for 3 months and then reduced to 400 mg per day. Soon he had only a slight headache without tearing and conjunctival injection. He has continued to take gabapenin at 400 mg per day until now. This case indicated that headache and autonomic symptoms in SUNCT did not always emerge simultaneously, but they sometimes appear with time lag. Furthermore, the long-term clinical course and therapeutic outcome in SUNCT remain unknown. A therapeutic strategy and optimal dosage of medications including gabapentin should be established for the treatment of SUNCT.

Post-Traumatic Short-Lasting Unilateral Headache With Cranial Autonomic Symptoms (SUNA)

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome is a rare headache syndrome classified among the trigeminal autonomic cephalalgias. It is usually idiopathic, although infrequent secondary forms have been described. Recently the term short-lasting unilateral headache with cranial autonomic symptoms (SUNA) has been defined by the International Headache Society (ICHD-2) as similar to SUNCT with less prominent or absent conjunctival injection and lacrimation. We report two patients with paroxysmal orbito-fronto-temporal pains, phenotypically suggesting SUNA, occurring after traumatic head injury.

Trigeminal neuralgia during sleep

Pain paroxysms in trigeminal neuralgia (TN) are sudden and extremely intense. Nonetheless, many clinicians who treat TN report that patients are rarely if ever awakened at night by pain attacks. If true, this observation is important as it implies the presence of a powerful sleep protective mechanism. We queried TN patients and their habitual sleep partners about painful awakenings and discovered that such awakenings are in fact quite common. As during the day, pain paroxysms during sleep are typically induced by natural stimuli at TN trigger points. Brief attacks sometimes occur without frankly awakening the patient, but they appear nonetheless to be painful.

Trigeminal autonomic cephalalgias. Part 3: short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a syndrome characterized by severe, strictly unilateral short-lasting (between 5 and 240 seconds) pain localized to orbital, supraorbital, and temporal areas, accompanied by ipsilateral conjunctival injection and lacrimation. It represents 1 of 3 primary headaches classified as trigeminal autonomic cephalalgias (TACs). Although its prevalence is extremely small, SUNCT patients may present at dental offices seeking relief for their pain. It is important for oral health care providers to recognize SUNCT and render an accurate diagnosis. This will avoid the pitfall of implementing unnecessary and inappropriate traditional dental treatments in hopes of alleviating this neurovascular pain. The following article is part 3 of a review on TACs and focuses on SUNCT. Aspects of SUNCT, including epidemiology, genetics, pathophysiology, clinical presentation, classification and variants, diagnosis, medical management, and dental considerations are discussed.

Uso de gabapentina no tratamento da Síndrome SUNCT

Relatamos o caso clínico de duas mulheres com quadro compatível com síndrome SUNCT (cefaléia de curta duração, unilateral, neuralgiforme com hiperemia conjuntival e lacrimejamento). As duas apresentavam exames clínico e neurológico normais e RM com sinais de microangiopatia. A primeira apresentava cefaléia há três anos, que ocorria várias vezes por dia, sempre que mastigava ou bocejava. Havia feito uso várias medicações sem melhora. A dor foi controlada após o uso de 600 mg de gabapentina ao dia. A segunda paciente referia cefaléia há seis meses. A dor era diária, ocorrendo de 20-40 vezes por dia. Na ocasião da primeira avaliação no ambulatório, já fazia uso 600 mg de carbamazepina ao dia e 15 mg de clorpromazina, com melhora parcial. Após introdução de gabapentina- 1200 mg/ dia, a paciente evoluiu sem dor, porém com episódios de hiperemia conjuntival.

Trigeminal Autonomic Cephalalgias: Current and Future Treatments

The trigeminal autonomic cephalgias include cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). The evidence for the current treatment options for each of these syndromes is considered, including oxygen, sumatriptan, and verapamil in cluster headache, indomethacin in paroxysmal hemicrania, and intravenous lidocaine and lamotrigine in SUNCT. Some treatments such as topiramate have an effect in all of these, as well as in migraine and other pain syndromes. The involvement of the hypothalamus in functional imaging studies implies that this may be a substrate for targeting treatment options in the future.

Neuromodulatory approaches to the treatment of trigeminal autonomic cephalalgias

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache syndromes characterised by intense pain and associated activation of cranial parasympathetic autonomic outflow pathways out of proportion to the pain. The TACs include cluster headache, paroxysmal hemicrania and SUNCT (short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing). The pathophysiology of these syndromes involves activation of the trigeminal-autonomic reflex, whose afferent limb projects into the trigeminocervical complex in the caudal brainstem and upper cervical spinal cord. Functional brain imaging has shown activations in the posterior hypothalamic grey matter in TACs. This paper reviews the anatomy and physiology of these conditions and the brain imaging findings. Current treatments are summarised and the role of neuromodulation procedures, such as occipital nerve stimulation and deep brain stimulation in the posterior hypothalamus are reviewed. Neuromodulatory procedures are a promising avenue for these highly disabled patients with treatment refractory TACs.

Coexistence of TACS and Trigeminal Neuralgia: Pathophysiological Conjectures

BACKGROUND

Trigeminal autonomic cephalgias (TACs) and trigeminal neuralgia are short-lasting unilateral primary headaches whose study is providing insights into craniofacial pain mechanisms. We report on 2 patients in whom trigeminal neuralgia coexists with the TACs paroxysmal hemicrania and SUNCT.

CONCLUSION

Coexistence of trigeminal neuralgia with various TAC forms suggests a pathophysiological relationship between these short-lasting unilateral headaches.

Trigeminal sensory pathway function in patients with SUNCT

OBJECTIVE

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a rare primary headache whose origins are unclear. To seek information on its pathophysiology, we studied the trigeminal Abeta and Adelta pathways by recording trigeminal reflexes and laser evoked potentials (LEPs) in patients with SUNCT.

METHODS

Trigeminal reflexes and LEPs were recorded in 11 consecutive patients. Ten patients had neuroimaging evidence documenting idiopathic SUNCT and one had a posterior fossa tumour that compressed the trigeminal nerve thus causing symptomatic SUNCT.

RESULTS

Whereas the patients with idiopathic SUNCT had normal trigeminal reflex and LEP responses, the patient with symptomatic SUNCT had abnormal responses.

CONCLUSIONS

Our neurophysiological findings show that idiopathic SUNCT spares the trigeminal sensory pathways whereas symptomatic SUNCT does not.

SIGNIFICANCE

Neurophysiological testing can easily differentiate the idiopathic and symptomatic forms of SUNCT. It also suggests that the two forms are pathophysiologically distinct entities.

Posterior hypothalamic activation in paroxysmal hemicrania

OBJECTIVE

Paroxysmal hemicrania (PH) is a severe, strictly unilateral headache that lasts 2 to 30 minutes, occurs more than five times daily, is associated with trigeminal autonomic symptoms, and is exquisitely responsive to indomethacin. The purpose of the study was to determine the brain structures active in PH.

METHODS

Seven PH patients were studied using positron emission tomography (PET). Each patient was scanned in three states: (1) acute PH attack-off indomethacin; (2) pain-free-off indomethacin; and (3) pain-free after administration of intramuscular indomethacin 100 mg. The scan images were processed and analyzed using SPM99.

RESULTS

The study showed no significant activations during state 1 compared with state 2, but there was relative activation of the pain neuromatrix in both states 1 and 2 compared with state 3. This suggests that there is persistent activation of the pain neuromatrix during acute PH attacks and during interictal pain-free states off indomethacin that is deactivated by the administration of indomethacin. In addition, the untreated PH state was associated with significant activation of the contralateral posterior hypothalamus and contralateral ventral midbrain, which extended over the red nucleus and the substantia nigra.

INTERPRETATION

These activated subcortical structures may play a pivotal role in the pathophysiology of this syndrome.

Functional brain imaging in hemicrania continua: implications for nosology and pathophysiology

Hemicrania continua is a strictly unilateral, continuous headache of mild to moderate intensity, with superimposed exacerbations of moderate to severe intensity that are accompanied by trigeminal autonomic features and migrainous symptoms. The syndrome is exquisitely responsive to indomethacin. Its clinical phenotype overlaps with that of the trigeminal autonomic cephalalgias and migraine, in which the hypothalamus and the brain stem, respectively, have been postulated to play central pathophysiologic roles. A recent positron-emission tomography study of a cohort of patients with hemicrania continua demonstrated significant activation of the contralateral posterior hypothalamus and ipsilateral dorsal rostral pons in association with the headache of hemicrania continua. In addition, there was activation of the ipsilateral ventrolateral midbrain, which extended over the red nucleus and the substantia nigra and bilateral pontomedullary junction. No intracranial vessel dilatation was obvious.

SUNCT syndrome: an update

SUNCT (Shortlasting Unilateral Neuralgiform Headache attacks with Conjunctival injection and Tearing) is a syndrome characterised by shortlived (5-240 s), strictly unilateral, orbital/periorbital, moderate-to-severe pain attacks, accompanied by rapidly developing conjunctival injection and lacrimation. Most attacks are triggered by mechanical stimuli, but there are also spontaneous attacks. Symptomatic periods alternate with remissions in an unpredictable fashion. In active periods, the attacks predominate during daytime, with a frequency that ranges from < 1 attack/day to > 30 attacks/h SUNCT is mainly a primary disorder, but is sometimes associated with intracranial structural lesions (symptomatic SUNCT). SUNCT has been included in the group of trigeminal autonomic cephalalgias, which are thought to depend on the activation of the trigeminal system together with the disinhibition of a trigeminofacial autonomic reflex. According to a few reports, SUNCT patients may benefit from carbamazepine, lamotrigine, gabapentin, topiramate or various surgical procedures. However, well-designed clinical trials are required before these therapeutic options can be sufficiently validated.

Short-lasting Unilateral Neuralgiform Headache with Conjunctival Injection and Tearing Syndrome Treated with Microvascular Decompression of the Trigeminal Nerve: Case Report

OBJECTIVE AND IMPORTANCE

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome is a very rare disorder characterized by short-lasting neuralgiform unilateral pain affecting the orbital-periorbital area and associated with autonomic phenomena consisting mainly of conjunctival injection, tearing, and rhinorrhea. Treatment of this condition is difficult; many drugs and surgical procedures have been tried with variable results. In the literature, two cases have been described with short-term response to microvascular decompression of the trigeminal root. We present the case of a patient with short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome who remains asymptomatic 2 years after microvascular decompression.

CLINICAL PRESENTATION

A 56-year-old woman was referred to our clinic because she had experienced pain in the distribution of the first left trigeminal branch during the previous 2 years. She experienced paroxysms lasting from a few seconds to 1 to 2 minutes superimposed over a dull sensation of pain involving the same territory. The paroxysms had no refractory period and were triggered by touching the eye or the left side of the face, chewing, yawning, washing her hair, and even by light. Although the paroxysms were triggered by light touch or chewing, she was able to talk or touch herself while having the paroxysm. During pain attacks, she experienced tearing and ipsilateral conjunctival injection, eyelid edema and rhinorrhea, as well as intense photophobia. A magnetic resonance imaging scan revealed a vascular structure distorting and compressing the trigeminal root.

INTERVENTION

The patient underwent microvascular decompression of the trigeminal root. At surgery, there was clear compression of the trigeminal root by a superior cerebellar artery loop that was resolved by interposing a Teflon patch. The patient awoke from the operation without pain, and all the accompanying signs and symptoms, such as photophobia, disappeared. The postoperative course was uneventful, and 2 years after treatment, the patient remains asymptomatic.

CONCLUSION

Microvascular decompression could be an alternative therapeutic approach to this rare syndrome.

Posterior hypothalamic and brainstem activation in hemicrania continua

OBJECTIVE

To determine the brain structures involved in mediating the pain of hemicrania continua using positron emission tomography.

BACKGROUND

Hemicrania continua is a strictly unilateral, continuous headache of moderate intensity, with superimposed exacerbations of severe intensity that are accompanied by trigeminal autonomic features and migrainous symptoms. The syndrome is exquisitely responsive to indomethacin. Its clinical phenotype overlaps with that of the trigeminal autonomic headaches and migraine in which the hypothalamus and the brainstem, respectively, have been postulated to play central pathophysiologic roles. We hypothesized, based on the clinical phenotype, that hemicrania continua may involve activations in the hypothalamus, or dorsal rostral pons, or both.

METHODS

Seven patients with hemicrania continua were studied in two sessions each. In one session, the patients were scanned during baseline pain and when rendered completely pain free after being administered indomethacin 100 mg intramuscularly. In the other session, the patients were scanned during baseline pain and when still in pain after being administered placebo intramuscularly. Seven age- and sex-matched nonheadache subjects acted as the control group. The scan images were processed and analyzed using SPM99.

RESULTS

There was a significant activation of the contralateral posterior hypothalamus and ipsilateral dorsal rostral pons in association with the headache of hemicrania continua. In addition, there was activation of the ipsilateral ventrolateral midbrain, which extended over the red nucleus and the substantia nigra, and bilateral pontomedullary junction. No intracranial vessel dilatation was obvious.

CONCLUSIONS

This study demonstrated activations of various subcortical structures, in particular the posterior hypothalamus and the dorsal rostral pons. If posterior hypothalamic and brainstem activation are considered as markers of trigeminal autonomic headaches and migrainous syndromes, respectively, then the activation pattern demonstrated in hemicrania continua mirrors the clinical phenotype, with its overlap with trigeminal autonomic headaches and migraine.