Cluster Headache

A thorough history is essential to the diagnosis of cluster headaches. Patients will reveal that they experience ten out of ten unilateral pain, most often located intra or supraorbitally. Patients must have at least one autonomic symptom ipsilateral to the side with pain.

The autonomic symptoms are as follows:

• Conjunctival injection or lacrimation (90% of patients)
• Nasal congestion or rhinorrhea (84% of patients)
• Eyelid edema or forehead/facial swelling (59% of patients)
• Miosis or ptosis (unknown percentage)

Up to 33% of patients will also experience general allodynia; this is more common in women, patients with recent attacks, those who had a low age at the time of onset, and those with comorbid depression or migraines. There is often suicidal ideation associated with the attacks, but the risk of actual suicide is low. 

Unlike patients with migraines, these patients are unlikely to hold still. Many patients pace or rock in place; there are descriptions of patients even banging their heads to distract themselves from the headache. Attacks typically last anywhere from 15 minutes to 3 hours. They can occur up to eight times a day, although most commonly, patients experience attacks twice a day, usually at night. Most patients will have attacks for weeks to months and then have remission for months up to years. This pattern usually lasts up to fifteen years.[1][2][3][4][7]

Triggers include:

• Watching TV
• Alcohol
• Hot weather
• Stress
• Use of nitroglycerin
• Sexual activity
• Glare

The diagnosis is clinical. While there are some lab abnormalities, such as increased histamine in the blood during attacks, and anatomical changes found on a morphology study, these have not been found to be useful in a clinical setting. A questionnaire asking about headache duration (less than 180 minutes) and autonomic symptoms (conjunctival injection or lacrimation) has a sensitivity of 81% and a specificity of 100%. Clinicians must have a degree of suspicion, as cluster headaches are usually misdiagnosed, and patients do not receive a clinical diagnosis for up to five years.[2]

There are two sides to the treatment of cluster headaches: treatment of the acute attack and preventative treatment.

Acute treatment

Perhaps the most well-known treatment for cluster headaches is 100% oxygen therapy. This approach is a level A recommendation and is unique to cluster headaches vs. all other types of headaches. At least 66% of patients respond to oxygen therapy. It is effective in less than 10 minutes. Oxygen use carries no risks or side effects, making it an excellent choice for treatment. Unfortunately, insurance often will not pay for oxygen therapy for the cluster headache patient, and it can be difficult to obtain.

Triptans are the only other level A recommended treatment. Delivery of these drugs can be subcutaneous sumatriptan or zolmitriptan delivered via nasal spray. An oral medication of any form is not recommended, as the time of onset is often longer than the headache is.

Other treatment options include intranasal lidocaine (with reported 33% response), octreotide, and ergotamine. Unfortunately, 10% to 20% of patients with chronic cluster headaches develop drug resistance. Patients should be instructed to avoid triggers, especially alcohol. While there is no proof that smoking cessation will decrease the risk of headaches, patients should also be encouraged to stop smoking. 

Preventative treatment

The only level A recommended treatment for the prevention of cluster headaches is a suboccipital blockade. Adverse events are nonserious, including transient injection site pain and low-level headache. 

Verapamil is the most widely prescribed preventative drug. It is recommended to do regular ECGs to monitor cardiac function when a patient is using this drug. Curiously, despite verapamil's popularity among providers, it only has a level C recommendation. 

Other pharmacological options include lithium, oral steroids, valproic acid, melatonin, and intranasal capsaicin.

There has been much research into electrical stimulation. Sites of stimulation include the sphenopalatine ganglion, occipital nerve, and vagus nerve. Deep brain stimulation of the hypothalamus has been very successful and has been proven quite useful in the treatment of drug-resistant patients. Vagus nerve stimulation can be an option with a nonimplanted device.[1][2][3][8][9]

Cluster headache often goes undiagnosed for years. Other differential diagnoses are as follows:

• Migraine: the most common description of this headache is a unilateral "throbbing" headache. Patients tend to lie quietly in a dark room. It is associated with fatigue, nausea, photophobia, phonophobia, and vomiting. Up to 50% of patients can have bilateral autonomic symptoms; this is the most common condition with which cluster headache is confused.
• Paroxysmal hemicrania: this is a unilateral headache that only lasts 2 to 30 minutes. It responds to indomethacin.
• Short-Lasting Unilateral Neuralgiform Headaches with Conjunctival Injection and Tearing (SUNCT syndrome): this is an extremely rare unilateral headache lasting 5 to 240 seconds. They can occur three to 200 times a day and are usually refractory to treatment.
• Tension headache: this is a bilateral headache that is described as a dull ache or squeezing ache. It is associated with fatigue, pericranial muscle tenderness, or sleep disturbances. 
• Trigeminal neuralgia: this is an inconsistent, paroxysmal headache described as an electrical, sharp, or stabbing pain in the trigeminal distribution. Events last for a few seconds.[2]

Episodic: 85% to 90% of patients. Patients experience daily attacks for weeks to months and then have a remission lasting months or years. Patients typically have 1 to 2 episodes a year, most often in spring or autumn.

Chronic: 15% to 20% of patients. Patients experience attacks lasting more than a year without remission or remission that lasts less than one month;10% to 20% of these patients will develop drug resistance.

Probable: patients whose attacks fulfill all but one criterion.[2]

Around 25% of patients who experience a cluster headache will never have another one. Another 15% to 20% of patients will have chronic cluster headaches, 10% to 20% of which will develop drug resistance. This condition often resolves in approximately 15 years.

Patients can experience detriments to their mental health. There will be physical burdens and loss of quality of life. Many patients describe suicidal ideation, but actual follow-through action is rare.[1][4]

There is a frequent association with psychiatric conditions, including depression, anxiety, and aggressive behavior. Suicidal attempts are rare, but these conditions do increase the disease burden. There is evidence supporting systemic autonomic function being affected, which is usually subclinical and includes bradycardia, tachycardia, hypertension, and arrhythmias (such as AV block and SA block). The most concerning of the autonomic dysregulation is an increased risk of dysregulation of systemic blood pressure. As in sleep apnea, patients have an increased risk of not undergoing physiological blood pressure dipping during sleep, which can lead to end-organ damage and increases the risk of cardiovascular disease. This situation is accompanied by an increased risk of an abnormal ankle-brachial index (ABI), indicating peripheral arterial disease, which confirms that there is also an increased risk for cardiovascular disease.[1][5][10]

Alcohol is the most common trigger for a pain attack. Most patients recognize this trigger and stop alcohol use on their own, but it may be necessary to provide patients with cessation counseling. While no evidence exists that quitting smoking affects the number of pain attacks, patients should be encouraged to stop. Patients should also be educated on pharmacological triggers, specifically vasodilators. Patients may require aid in lifestyle management, and patients should receive an offer for psychiatric counseling.[2]

• Cluster headaches are unilateral periocular headaches occurring between 15 minutes to 3 hours, with episodes usually occurring twice a day for weeks to months with remissions of months to years.
• There are associated autonomic symptoms on the ipsilateral side.
• Exact etiology and pathophysiology are unknown.
• Acute treatment includes oxygen and nonoral triptans.
• Prophylactic treatment is a suboccipital blockade.

The average cluster headache patient can take approximately five years to diagnose and only after visiting several different clinicians. Cluster headaches are often confused for migraines. The only way to improve diagnosis and management is with an interprofessional team dedicated to the treatment of headaches.

The healthcare provider (i.e., physician, nurse practitioner) must strive to recognize the episodic nature of cluster headaches, autonomic dysregulation, and even the activity of the patient during an attack.

Unfortunately, though oxygen is a level A recommended treatment for cluster headaches, it may not be covered by insurance - this may be due to a lack of understanding about cluster headaches by the insurance companies or a misunderstanding about the price differential between prescribing a triptan versus prescribing oxygen. The out of pocket cost for a patient buying oxygen depends on the state and can be anywhere from $500 to $10000 per year. Some patients ask about welder's oxygen, which is non-medical grade oxygen; however, this is usually not any cheaper than medical oxygen and may have impurities. Practitioners are recommended to refer insurers to the American Headache Society Guidelines during peer to peer conversations. Medicare and Medicaid have ruled that they will not cover oxygen at all for cluster headaches.[1][8][9] Because oxygen is an excellent abortive treatment, the social worker may be involved in the care to ensure that the patient does not lack this therapy because of finances.

The neuroscience or pain nurse should educate the patient on avoidance of alcohol and the importance of getting good sleep. In addition, the patient should be told that smoking cessation is important. The nurse should also emphasize the importance of a stress-free lifestyle and avoiding hot temperatures. Finally, close follow up is essential in preventing future attacks. The members of the interprofessional team should communicate if anyone makes a change in the medication, as one of the common causes of recurrent attacks is a low dose of the prophylactic medication.armacist should review medication dosage, check for drug-drug interactions, and educate patients about side effects.

Outcomes

Verapamil is generally regarded as prophylactic maintenance therapy by healthcare providers despite only a level C recommendation. There is discordance between evidence-based medicine and provider activity.

Cluster headaches require an interprofessional team approach, including physicians, specialists, specialty-trained nurses, and pharmacists, all collaborating across disciplines to achieve optimal patient results.[11] [Level V]

This research was supported (in part or whole) by HCA Healthcare and/or an HCA healthcare affiliated entity. The views expressed in this publication represent those of the author and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities.