Chronic Daily Headache
Chronic daily headache (CDH) is a descriptive term rather than a specific diagnosis. It can evolve from any primary headache disorder or can be de novo. Studies in the US and Europe indicate that 4-5% of the general population are affected by CDH. It is becoming more frequent in general practice and is a major reason for consultation in Headache/ Migraine clinics.
Like migraine, CDH can significantly affect an individual’s ability to function within the family, in society, and in the workplace.
In general, headache occurring more often than fifteen days per month, over at least six months and lasting for four hours a day can be considered CDH. The leading cause is chronic tension-type headache followed by chronic migraine.
Chronic Tension Type Headache
People with chronic tension-type headache (CTTH) usually have a history of episodic tension-type headache but may have no history of migraine. Many patients use excessive amounts of analgesics, and they may also have concomitant depression.
CTTH usually present as diffuse or bilateral and frequently involve the posterior head and neck. The I.H.S diagnostic criteria are outlined below.
The overuse of analgesics may convert episodic tension-type headaches into CTTH. These headaches are characterised by a daily low-grade headache that is temporarily controlled by the use of the offending acute medication, only to return as the medication wears off. Over time the offending medication loses effectiveness and escalating medication use occurs. If the medication is abruptly withdrawn, a severe rebound headache results. Prophylactic therapies are usually ineffective. CTTH associated with medication overuse will usually not improve without the patient discontinuing the medication. This leads to a period where the headaches will initially worsen.
The problem of CDH is exacerbated by the fact that many patients do not realise that excessive or frequent self-medication may perpetuate or exacerbate their headache. Explaining the condition to the patient is an important step in encouraging medication withdrawal.
I.H.S. Criteria for diagnosisng Chronic Tension type Headache
A. Headache occurring on ≥15 days per month on average for > 3 months and fulfilling criteria B-D.
B. Headache lasts hours or may be continuous.
C. Headache has at least two of the following characteristics:
- Bilateral location
- Pressing, tightening (non-pulsating) quality
- Mild to moderate intensity
- Not aggravated by routine physical activity
D. Both of the following
- No more than one of photophobia or phonophobia or mild nausea
- Neither moderate or severe nausea nor vomiting
E. Not attributed to another disorder
Chronic migraine is diagnosed when a patient has migraine on fifteen or more days each month over a period of at least six months. Also known as transformed migraine, patients usually have a history of migraine attacks that gradually worsen over a period of months or years.
The I.H.S. criteria for diagnosing chronic migraine are outlined below.
Headache pain and the other symptoms usually associated with migraine become less severe as the frequency increases, but also become less responsive to treatment. As the nature of the headaches transform, many patients will experience ‘breakthrough’ migraine attacks on top of the ‘background’ headache.
Like with CTTH, the overuse of acute treatments for migraine (including analgesics, ergot derivatives and triptans) can be responsible for transforming migraine into a chronic condition. However, the transformation may also occur as part of the natural history of the condition.
In cases of Chronic Migraine, attention should be paid to the possible existence of comorbid conditions such as anxiety and depression, both of which have been shown to be more frequent in patients who have migraine than in non-migraine control subjects. It is believed that migraine and depression share the same etiologies, rather than the depression resulting from the disability caused by chronic migraine. Some features of comorbid depression show improvement when the cycle of CDH is broken. Treatment options for chronic migraine include Amitriptyline or Gabapentin.
The I.H.S. Criteria for diagnosing Chronic Migraine
A. Headache fulfilling criteria B and C on ≥15 days a month for > 3 months
B. Headache has at least two of the following characteristics
- Unilateral location
- Pulsating quality
- Moderate or severe pain intensity
- Aggravation by or causing avoidance of routine physical activity
C. During headache at least one of the following
- Nausea and / or vomiting
- Photophobia / Phonophobia
D. Not attributed to another disorder