Tearing without pain after trigeminal root section for cluster headache

Management of cluster headache: Treatments and their mechanisms

BACKGROUND

The management of cluster headache is similar to that of other primary headache disorders and can be broadly divided into acute and preventive treatments. Acute treatments for cluster headache are primarily delivered via rapid, non-oral routes (such as inhalation, nasal, or subcutaneous) while preventives include a variety of unrelated treatments such as corticosteroids, verapamil, and galcanezumab. Neuromodulation is becoming an increasingly popular option, both non-invasively such as vagus nerve stimulation when medical treatment is contraindicated or side effects are intolerable, and invasively such as occipital nerve stimulation when medical treatment is ineffective. Clinically, this collection of treatment types provides a range of options for the informed clinician. Scientifically, this collection provides important insights into disease mechanisms.

METHODS

Two authors performed independent narrative reviews of the literature on guideline recommendations, clinical trials, real-world data, and mechanistic studies.

RESULTS

Cluster headache is treated with acute treatments, bridge treatments, and preventive treatments. Common first-line treatments include subcutaneous sumatriptan and high-flow oxygen as acute treatments, corticosteroids (oral or suboccipital injections) as bridge treatments, and verapamil as a preventive treatment. Some newer acute (non-invasive vagus nerve stimulation) and preventive (galcanezumab) treatments have excellent clinical trial data for episodic cluster headache, while other newer treatments (occipital nerve stimulation) have been specifically tested in treatment-refractory chronic cluster headache. Most treatments are suspected to act on the trigeminovascular system, the autonomic system, or the hypothalamus.

CONCLUSIONS

The first-line treatments have not changed in recent years, but new treatments have provided additional options for patients.

Recent advances in the diagnosis and management of cluster headache

Cluster headache, a primary headache disorder, consists of short (15-180 minutes), frequent (up to eight a day), unilateral attacks of facial pain with associated ipsilateral autonomic features and restlessness. The attacks are suspected to be one of the most painful human experiences, and the disorder is associated with a high rate of suicidal ideation. Proper diagnosis is key, as some of the most effective treatments, such as high flow oxygen gas, are rarely used in other headache disorders. Yet diagnostic delay is typically years for this disorder, as it is often confused with migraine and trigeminal neuralgia, and secondary causes may be overlooked. This review covers the clinical, pathophysiologic, and therapeutic features of cluster headache. Recent updates in diagnosis include the redefinition of chronic cluster headache (remission periods lasting less than three months instead of the previous one month), and recent advances in management include new treatments for episodic cluster headache (galcanezumab and non-invasive vagus nerve stimulation).

Cluster headache and TACs: state of the art

Cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks (including SUNCT and SUNA), and hemicrania continua (HC) compose the group of trigeminal autonomic cephalalgias (TACs). Here, we review the recent advances in the field and summarize the current knowledge about the origin of these headaches. Similar to the other primary headaches, the pathogenesis is still much obscure. However, advances are being made in both animal models and humans studies. Three structures clearly appear to be crucial in the pathophysiology of TACs: the trigeminal nerve, the facial parasympathetic system, and the hypothalamus. The physiologic and pathologic functioning of each of these elements and their interactions is being progressively clarified, but critical questions are still open.

Hemicrania Continua Associated with Classic Scintillating Scotoma

Hemicrania continua (HC) is a rare primary headache disorder, characterized by persistent unilateral pain associated with cranial autonomic symptoms and prompt response to indomethacin. While migrainous features (including aura) have been recognized in cluster headache, there have been only single reports of HC with aura. Here, we report the case of a 53-year-old man with constant right-sided headache and superimposed exacerbations to severe pain lasting for several hours. Secondary etiologies were excluded, and a diagnosis of HC was established after prompt and complete response to treatment with indomethacin. During an episode of pain exacerbation, for the first time the patient experienced an episode of transient visual disturbances compatible with scintillating scotoma. We propose a potential link between HC and visual aura, which parallels similar observations in other trigeminal autonomic cephalalgias and more specifically confirms previous observational data on aura in HC, thus highlighting potentially shared pathophysiological mechanisms.

LASH: A Review of the Current Literature

PURPOSE OF REVIEW

The purpose of this review is to evaluate and explain our current understanding of a very rare disorder, long-lasting autonomic symptoms with associated hemicranias (LASH).

RECENT FINDINGS

At present, there are four known cases in the literature of LASH. Its characteristics and reported response to indomethacin link it most closely to the trigeminal autonomic cephalalgias (TACs). Its pathophysiology and epidemiology remain unclear. Variance in the pain and autonomic symptom relationship in the existing TAC literature along with the reports of TAC sine headache suggests that LASH may represent a far end of the spectrum of TACs, with most similarities to paroxysmal hemicrania (PH) and hemicrania continua (HC).

Hemicrania continua with contralateral cranial autonomic features: a case report

BACKGROUND

Hemicrania continua is characterized by continuous strictly unilateral head pain with episodic exacerbations. Episodic exacerbations are associated with ipsilateral cranial autonomic features.

CASE DESCRIPTION

We report a 24-year female with a 2-year history of continuous right-sided headache with superimposed exacerbations. Episodic exacerbations were associated with marked agitation and contralateral cranial autonomic features. The patient showed a complete response to indomethacin within 8 hours.

DISCUSSION

The dichotomy of pain and autonomic features is in accordance with the concept about the possibility of two separate pathways for pain and autonomic features in trigeminal autonomic cephalalgias.

Pathophysiology of trigeminal autonomic cephalalgias

Cluster headache, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) are primary headaches recently classified together as trigeminal autonomic cephalalgias (TACs). The causes of these headaches have long been debated, with "peripheral" hypotheses in opposition to "central" hypotheses. The available information indicates that the pain originates from within the brain in cluster headache. The hypothalamic activation observed during TAC attacks by use of functional neuroimaging, and the success of hypothalamic stimulation as a treatment, confirm that the posterior hypothalamus is crucial in the pathophysiology of these headaches. The posterior hypothalamus is now known to modulate craniofacial pain, and hypothalamic activation occurs in other pain disorders, suggesting that this brain area is likely to have a more complex role in the pathophysiology of TACs than that of a mere trigger. Hypothalamic activation might play a part in terminating rather than triggering attacks, and might also give rise to a central permissive state, allowing attacks to take place.

SUNCT and trigeminal neuralgia attributed to meningoencephalitis

We describe a 46-year-old female with viral meningoencephalitis (likely varicella-zoster virus) who developed a SUNCT syndrome followed a few days later by trigeminal neuralgia. Both disorders resolved in parallel with the resolution of encephalitis, which suggests a causal link. In conclusion, headache attributed to intracranial infection may have the clinical features of SUNCT or TN.