'INDOTEST' in atypical hemicrania continua

Hemicrania Continua: a Clinical Perspective on Diagnosis and Management

PURPOSE OF REVIEW

Hemicrania Continua (HC) is a daily and persistent form of headache that is characterized by side-locked pain which is continuous, varies in severity and can be associated with conjunctival injection, lacrimation, nasal congestion, rhinorrhea, eyelid edema, forehead or facial sweating and miosis and/or ptosis.

RECENT FINDINGS

Functional imaging studies have shown activation of subcortical structures such as the posterior hypothalamus and dorsal rostral pons, which are known to disinhibit the trigeminal autonomic reflex, a reflex responsible for autonomic outflow through trigeminal efferents. A similar pathway activation is seen in other Trigeminal autonomic cephalalgias (TAC) which solidifies HC as a TAC. While we also discuss promising treatments in our review, more evidence is needed before making them a standard of therapy for HC. This article aims to review the recent research on the diagnosis and clinical management of this potentially underdiagnosed primary headache disorder.

Hemicrania Continua

Hemicrania continua (HC) is an indomethacin responsive primary chronic headache disorder which is currently classified as a subtype of trigeminal autonomic cephalalgias (TACs). It is not very uncommon. There are >1000 cases of HC in the literature, and it constitutes 1.7% of total headache in the clinic settings. Misdiagnosis for HC is very common at all clinical settings. A diagnosis of HC is missed even by neurologists and headache specialists. It is characterized by a continuous strictly unilateral headache with superimposed exacerbations. Just like other TACs, exacerbations are associated with cranial autonomic symptoms and restlessness. A large number of patients may have migrainous features (nausea, vomiting, photophobia, and phonophobia) during exacerbations phase. The “key” feature of HC is persistent featureless background headaches. However, patients and physicians may focus only on the exacerbation part. As durations, frequency and associated symptoms of exacerbations are highly variables; it may mimic a large number of primary and secondary headache disorders. Migraine and cluster headache are two most common misdiagnosed conditions. Another specific feature of HC is remarkable repose to indomethacin. A “complete” response to indomethacin is as “sine qua non” for HC. However, a few other medications may also be effective in a subset of HC patients. Various surgical procedures have been tried with mixed results in patients who were intolerant to indomethacin or other drugs.

Therapeutical approaches to paroxysmal hemicrania, hemicrania continua and short lasting unilateral neuralgiform headache attacks: a critical appraisal

Background

Hemicrania continua (HC), paroxysmal hemicrania (PH) and short lasting neuralgiform headache attacks (SUNCT and SUNA) are rare syndromes with a difficult therapeutic approach. The aim of this review is to summarize all articles dealing with treatments for HC, PH, SUNCT and SUNA, comparing them in terms of effectiveness and safety.

Methods

A survey was performed using the pubmed database for documents published from the 1st January 1989 onwards. All types of articles were considered, those ones dealing with symptomatic cases and non-English written ones were excluded.

Results

Indomethacin is the best treatment both for HC and PH. For the acute treatment of HC, piroxicam and celecoxib have shown good results, whilst for the prolonged treatment celecoxib, topiramate and gabapentin are good options besides indomethacin. For PH the best drug besides indomethacin is piroxicam, both for acute and prolonged treatment. For SUNCT and SUNA the most effective treatments are intravenous or subcutaneous lidocaine for the acute treatment of active phases and lamotrigine for the their prevention. Other effective therapeutic options are intravenous steroids for acute treatment and topiramate for prolonged treatment. Non-pharmacological techniques have shown good results in SUNCT and SUNA but, since they have been tried on a small number of patients, the reliability of their efficacy is poor and their safety profile mostly unknown.

Conclusions

Besides a great number of treatments tried, HC, PH, SUNCT and SUNA management remains difficult, according with their unknown pathogenesis and their rarity, which strongly limits the studies upon these conditions. Further studies are needed to better define the treatment of choice for these conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-017-0777-3) contains supplementary material, which is available to authorized users.

Hemicrania continua: clinical review, diagnosis and management

Hemicrania continua (HC) is an indomethacin-responsive primary headache disorder which is currently classified under the heading of trigeminal autonomic cephalalgias (TACs). It is a highly misdiagnosed and underreported primary headache. The pooled mean delay of diagnosis of HC is 8.0 ± 7.2 years. It is not rare. We noted more than 1000 cases in the literature. It represents 1.7% of total headache patients attending headache or neurology clinic. Just like other TACs, it is characterized by strictly unilateral pain in the trigeminal distribution, cranial autonomic features in the same area and agitation during exacerbations/attacks. It is different from other TACs in one aspect. While all other TACs are episodic, HC patients have continuous headaches with superimposed severe exacerbations. The central feature of HC is continuous background headache. However, the patients may be worried only for superimposed exacerbations. Focusing only on exacerbations and ignoring continuous background headache are the most important factors for the misdiagnosis of HC. A large number of patients may have migrainous features during exacerbation phase. Up to 70% patients may fulfill the diagnostic criteria for migraine during exacerbations. Besides migraine, its exacerbations can mimic a large number of other primary and secondary headaches. The other specific feature of HC is a remarkable response to indomethacin. However, a large number of patients develop side effects because of the long-term use of indomethacin. A few other medications may also be effective in a subset of patients with HC. Various surgical interventions have been suggested for patients who are intolerant to indomethacin. Several aspects of HC are still not defined. There is a great heterogeneity in types of patients or articles on the HC in the literature. Diagnostic criteria have been modified several times over the years. The current diagnostic criteria are too restrictive in some aspects. We suggest a more accommodating type of criteria for the appendix of International Classification of Headache Disorder (ICHD).

Side-locked headaches: an algorithm-based approach

The differential diagnosis of strictly unilateral hemicranial pain includes a large number of primary and secondary headaches and cranial neuropathies. It may arise from both intracranial and extracranial structures such as cranium, neck, vessels, eyes, ears, nose, sinuses, teeth, mouth, and the other facial or cervical structure. Available data suggest that about two-third patients with side-locked headache visiting neurology or headache clinics have primary headaches. Other one-third will have either secondary headaches or neuralgias. Many of these hemicranial pain syndromes have overlapping presentations. Primary headache disorders may spread to involve the face and / or neck. Even various intracranial and extracranial pathologies may have similar overlapping presentations. Patients may present to a variety of clinicians, including headache experts, dentists, otolaryngologists, ophthalmologist, psychiatrists, and physiotherapists. Unfortunately, there is not uniform approach for such patients and diagnostic ambiguity is frequently encountered in clinical practice.

Herein, we review the differential diagnoses of side-locked headaches and provide an algorithm based approach for patients presenting with side-locked headaches. Side-locked headache is itself a red flag. So, the first priority should be to rule out secondary headaches. A comprehensive history and thorough examinations will help one to formulate an algorithm to rule out or confirm secondary side-locked headaches. The diagnoses of most secondary side-locked headaches are largely investigations dependent. Therefore, each suspected secondary headache should be subjected for appropriate investigations or referral. The diagnostic approach of primary side-locked headache starts once one rule out all the possible secondary headaches. We have discussed an algorithmic approach for both secondary and primary side-locked headaches.

A proposal for revision of hemicrania continua diagnostic criteria based on critical analysis of 62 patients

BACKGROUND

Misdiagnosis of hemicrania continua (HC) is common. It is diagnosed according to the criteria of the International Headache Society (IHS), but in clinical practice, these criteria seem too restrictive and many hemicrania continua-like headaches remain unclassified.

SUBJECTS AND METHODS

We retrospectively studied the patients fulfilling the IHS criteria for HC. In addition, we identified a group of patients who met all criteria minus cranial autonomic features (HC-A) or minus a complete response to indomethacin (HC-I). We compared epidemiological profiles, clinical features and therapeutic responses to drug(s) between the groups. In addition, we reviewed the literature and critically analysed the diagnostic criteria for HC.

RESULTS

Sixty-two patients with a putative diagnosis of HC were identified. Thirty patients (48%) fulfilled the IHS criteria for HC. Thirty-two (52%) patients failed to satisfy one of the features of HC. Thirteen patients (21%) did not show any evidence of cranial autonomic feature during the episodes of the exacerbations (HC-A). Another 19 patients (31%) did not show a complete response to indomethacin (HC-I). Epidemiological and clinical features of all three groups were compared. None of the differences were statistically significant. In review of the literature, we noted that cranial autonomic features, a sense of restlessness/agitation during exacerbations, and response to indomethacin (marked to complete) are the specific features of HC. However, these features may not all be present in all cases.

CONCLUSION

Present diagnostic criteria are too restrictive. We suggest adding the site of pain in the criteria, as described for trigeminal autonomic cephalalgias. Cranial autonomic features, a sense of restlessness during exacerbations, and marked to complete response to indomethacin are three characteristics features of HC. We suggest that the presence of any two may be sufficient to diagnose HC.

Focus on therapy: hemicrania continua and new daily persistent headache

Hemicrania continua (HC) and new daily-persistent headache (NDPH) represent the only two forms of chronic daily headache in Chap. IV "Other Primary Headaches" of the second edition of the International Classification of Headache Disorders. HC and NDPH are rare and poorly defined from a pathophysiological point of view; as a consequence, their management is largely empirical. Indeed, there is a lack of prospective, controlled trials in this field, and treatment effectiveness is basically inferred from the results of sparse open-label trials, retrospective case series, clinical experience and expert opinions. In this narrative review we have summarised the information collected from an extensive analysis of the literature on the treatment of HC and NDPH in order to provide the best available and up-to-date evidence for the management of these two rare forms of primary headache. Indomethacin is the mainstay of HC management. The reported effective dose of indomethacin ranges from 50 to 300 mg/day. Gabapentin 600-3,600 mg tid, topiramate 100 mg bid, and celecoxib 200-400 mg represent the most interesting alternative choices in the patients who do not tolerate indomethacin or who have contraindications to its use. NDPH is very difficult to treat and it responds poorly only to first-line options used for migraine or tension-type headache.