What is Hemicrania Continua?
Hemicrania continua is a kind of headache. It’s unique because it responds really well to a drug called indomethacin. People with this condition experience a continuous headache on one side of their head for at least three months. The pain level of the headache can go up and down and is often accompanied by other physical responses like changes in heart rate or sweating. Hemicrania continua was first identified in 1981, and it got its name in 1984.
This particular type of headache is part of a group called trigeminal autonomic cephalalgias according to a recognized international system for categorizing headaches. Main features of headaches in this category include headaches on one side of the head, predominantly in the area associated with the first branch of the trigeminal nerve (the nerve responsible for sensation in the face). Moreover, these headaches are coupled with a mix of other physiological reactions, indicating an increase in relaxation-related body functions and a decrease in stress-related functions. Additional headaches that fall in this category include cluster headaches, paroxysmal hemicrania, short-lasting one-sided headaches accompanied by cranial autonomic symptoms (SUNA), and short-lasting one-sided headaches with symptoms like red eyes and tears (SUNCT).
What Causes Hemicrania Continua?
Hemicrania continua is a type of headache that doesn’t have a known physical cause. The reasons why these headaches – which are part of a group called trigeminal autonomic cephalalgias – occur are not well understood at the moment. Scientists have proposed several theories.
One theory suggests that inflammation in an area inside the head called the cavernous sinus could be a factor. Other theories think the headaches could be due to widening of the arteries inside the brain, an increase in certain chemicals that influence how blood vessels behave, or miscommunication between the main nerves and the part of the nervous system responsible for involuntary processes like heart rate or digestion; this then results in an increase in certain reactions in the head.
On top of these, other areas inside the head seem to be involved too. This is because the pain is not always in the area reached by the main facial nerve called the trigeminal nerve. Plus, cutting this nerve does not always relieve symptoms in all patients.
Risk Factors and Frequency for Hemicrania Continua
Hemicrania continua was previously thought to be a rare headache disorder. Between its discovery and the first 17 years that followed, only around 100 cases were reported. Despite its rareness, it’s believed to make up around 1% of all headache cases, which suggests that this condition is likely underreported and often missed in diagnoses.
Most commonly, hemicrania continua affects young adults between their late 20s and 40s, but it can occur at any age, even into old age. It’s slightly more frequent in women than in men.
- Hemicrania continua was initially seen as a rare type of headache.
- From its discovery until 17 years later, only around 100 cases were documented.
- It’s estimated to constitute about 1% of all headache cases.
- This condition is likely underreported and often not diagnosed correctly.
- It typically affects young adults between their late 20s and 40s.
- However, it can occur in people of any age, even into their 70s.
- It’s slightly more common in women than in men.
Signs and Symptoms of Hemicrania Continua
Hemicrania continua is a condition that causes a persistent, one-sided headache that lasts for at least three months. The affected person usually feels mild to moderate, dull pain which does not generally interfere with daily activities. This pain typically affects areas on the face innervated by the first division of the trigeminal nerve – mainly the forehead and around their eyes. However, pain can also occur in other areas.
This headache is always experienced on the same side. While it is slightly more common on the right side, it can occur on either side. Instances of the headache switching sides or affecting both sides have been reported, although they are rare. Remarkably, about 20% of people with this condition may have brief periods without pain which can last from a single day to several weeks.
Individuals with hemicrania continua can also experience sudden spikes in pain which may last from minutes to days. These spikes in pain vary greatly from person to person – some may experience more than 20 attacks per day, while others may only have one every 4 months. About half of the people with this condition report one severe headache per day. Individuals often describe these severe headaches as the worst headaches of their lives and can become restless, agitated, and have difficulty staying still.
People may experience symptoms similar to migraines during these pain spikes, such as sensitivity to light and sound, nausea, vomiting, but an aura is very rare. Certain triggers, like stress, alcohol, irregular sleep patterns, and periods can also exacerbate the pain.
Just like with other trigeminal autonomic cephalalgias, hemicrania continua is associated with other symptoms on the same side of the head as the pain, especially during pain spikes. These symptoms, which are caused by overactivity in the parasympathetic nervous system and underactivity in the sympathetic nervous system, include forehead sweating, tear production, swelling or redness of the eye, drooping eyelids, pupil constriction, feeling of a foreign body in the eye, stuffy nose, runny nose, and a sense of fullness in the ears.
Testing for Hemicrania Continua
Hemicrania continua is a condition that causes a continuous headache on one side of the head that can sometimes get worse. The International Classification of Headache Disorders (ICHD-3) has suggested some guidelines to diagnosing this condition:
– The headache is only on one side and has been present for more than 3 months, with periods of more intense pain
– You may have one or more of the following symptoms on the same side as your headache:
– Watering or redness of the eye
– A blocked or runny nose
– Swelling of the eyelid
– Sweating on the forehead or face
– Small pupil or drooping eyelid
– A restless feeling, agitation, or the pain getting worse with movement
– The pain improves significantly after doses of a medication called indomethacin
– The headaches are not better explained by another medical condition
These guidelines focus on three main features: the pain is only on one side and has been ongoing for more than 3 months, having similar symptoms on the same side as the headache or agitation during the periods of more severe pain, and finding relief from the medication indomethacin. This medication usually helps within 2 hours of taking it, but the headache can return within 6 to 24 hours of stopping the treatment. Some experts recommend trying this medication for all persistent one-sided headaches. But, a positive response to indomethacin does not rule out other causes of the headache.
There are other conditions that might seem like hemicrania continua, including headaches after a head injury, surgery, or stroke, growths in the brain, problems with arteries or veins, certain drug misuse, cancerous conditions, sinus problems, tooth and jaw issues amongst others.
It’s important to rule out these other potential causes based on your symptoms and the necessary medical tests. You should be asked about any recent accidents you may have had. If you are presenting with hemicrania continua-like headaches, a brain magnetic resonance imaging (MRI) comes recommended. Other imaging techniques could be suggested if they suspect a problem with the blood vessels, like an abnormal bulge or tear in the artery. Symptoms that might indicate this include short-term symptoms, frequent worsening of symptoms, neck pain, neck tenderness, specific neurological symptoms, a particular combination of symptoms (Horner’s syndrome), and a history of trauma.
Treatment Options for Hemicrania Continua
Hemicrania continua, a type of headache, has a defining feature of responding positively to a medication called Indomethacin. Indomethacin is a type of drug called a nonsteroidal anti-inflammatory drug (NSAID), similar to familiar ones like ibuprofen and naproxen, which reduce pain and inflammation. It’s more effective than other NSAIDs, probably because it’s able to reach and affect the central nervous system more. Indomethacin may halt an existing severe headache episode and is also effective in preventing hemicrania continua, which suggests that its effects are not purely due to inflammation reduction.
Patients are usually started on a small dose of Indomethacin, which can be adjusted according to the individual’s response. Often, patients start feeling better within 24 hours, but sometimes it can take up to a week. The dose is increased until the patient is completely symptom-free, or until the dose reaches an upper limit. The eventual mean dose is typically less than 200mg per day.
The long-term therapeutic dose of Indomethacin is kept to a minimum to lessen potential side effects like stomach discomfort, heartburn, nausea, vomiting, dangerous internal bleeding, high blood pressure, kidney failure, and liver failure. Most of these side effects are dose-dependent, so maintaining the lowest possible therapeutic dose is recommended. The treatment is often long-term and in some cases lifelong, although some patients have successfully reduced their dosage without experiencing a recurrence of headaches.
If a patient cannot tolerate Indomethacin due to its side effects, other noninvasive treatments should be tried. Alternatives include melatonin, topiramate, COX-2 inhibitors (such as rofecoxib and celecoxib), gabapentin, corticosteroids, lamotrigine, lithium, amitriptyline, valproate, and naproxen. These drugs aren’t as effective as indomethacin for treating hemicrania continua, but they should be tried before considering more invasive options. Melatonin, which like Indomethacin is a type of NSAID, can also be combined with it to lower the latter’s dose and reduce its side effects. However, high-dose oxygen and sumatriptan are typically not effective in managing hemicrania continua. A drug called galcanezumab, a calcitonin gene–related peptide inhibitor, has been reported successful in relieving pain in patients with hemicrania continua.
Invasive methods of treatment are also available if noninvasive methods aren’t successful. Vagus nerve stimulation is an option, although information on it is limited. Botulinum toxin-A, which is FDA-approved for chronic migraines, is another option considered for hemicrania continua when noninvasive treatment fails or can’t be tolerated. Occipital nerve stimulation and sphenopalatine ganglion blockade (which interrupts a key nerve’s outflow linked to hemicrania continua) are invasive treatments used for managing hemicrania continua. Deep brain stimulation is yet another invasive method that may be used for hemicrania continua that has not responded positively to medication.
What else can Hemicrania Continua be?
When a doctor is diagnosing hemicrania continua, which is a type of headache that continues on one side of your head, he or she will need to rule out several other conditions that can cause similar symptoms. These conditions are:
- Secondary hemicrania continua, which can include eye-related herpes zoster
- Chronic migraine
- Cluster headache
- Paroxysmal hemicrania: This type of headache has short, severe attacks that happen several times a day.
- Medication-overuse headache: This happens when taking pain relief medications too often causes headaches.
It is important that the doctor carries out a thorough examination and the necessary tests to differentiate between these conditions and find the best treatment.
What to expect with Hemicrania Continua
Hemicrania continua is a type of headache that isn’t life-threatening, but it can last for a person’s entire life. Constant headaches, even those that can be treated, can negatively impact a person’s quality of life. One key feature of hemicrania continua is that it typically responds well to treatment with a medication called indomethacin.
Possible Complications When Diagnosed with Hemicrania Continua
The most frequent challenges associated with hemicrania continua are usually linked to the treatment. Most people with this condition need to be treated with indomethacin in the long term. This can sometimes lead to side effects. These may include discomfort in the abdomen, heartburn, feeling nauseous, vomiting, severe bleeding in the stomach or intestines, high blood pressure, and even kidney or liver failure.
Possible Side Effects:
- Abdominal discomfort
- Heartburn
- Nausea
- Vomiting
- Severe bleeding in the stomach or intestines
- High blood pressure
- Kidney failure
- Liver failure
Preventing Hemicrania Continua
Patients should be informed that this illness, although long-lasting, is not life-threatening. Treatment is available, but may need to be sustained over a long period of time. If you know of anything that tends to worsen your headaches, it’s best to try and avoid these things. Exercising regularly is good for you and can help manage the symptoms of this condition. Regular check-ups with your doctor are important to ensure your medication is working properly and to minimize any side effects.
