Chronic Daily Headache (CDH)
The fact that the chiropractor only needs to consider five headache types in the differential diagnosis for sufferers of daily or near daily headache greatly eases the burden of diagnosis and management.
What Is CDH?
A patient suffers from CDH when the following criteria are fulfilled.
• 15 headache days per month; or
• 180 headache days per year; and
• Lacking any organic or structural cause.
Let's apply this definition to a couple of practical examples.
Example #1: A 23-year-old male presents with constant headache that started within days of a neck trauma sustained 10 days ago. He has not had a headache-free day in the last eight days.
Question: Is he suffering from CDH?
Answer: No, not yet. If his headache pattern persists for several more weeks, he will be classified as suffering from CDH. In the meantime, organic brain injury and other causes of acute headache need to be considered and dealt with.
Example #2: A 39-year-old female, who has a history of migraine since adolescence, reports with a complaint that her migraines have become more frequent, and she only has 2-3 headache-free days per week. She denies any recent trauma. She has always used aspirin to control her headache but has noticed lesser effectiveness even with greater doses.
Question: Is this longstanding migraine patient suffering from CDH?
Answer: Did you suspect analgesic rebound headache? Yes? Good! Did you also suspect CDH? Yes? Very good.
Now, with these two examples in mind, let us look at what causes CDH.
Etiology of CDH
CDH starts from either pre-existing episodic headache (such as migraine, cervicogenic headache, or tension headache) or as a brand new headache (such as from trauma or illness). Those that start from a pre-existing headache are termed " transformed headache," while those that develop without a prior history of headache are termed "new persistent headache (NPH)."
The transformation of episodic headache into CDH is far more common than the development of NPH. These statistics are commonly reported with regard to the ratio of transformed versus new persistent headaches.
• 80% are transformed from episodic headache
• 20% are new persistent daily headache
This tendency toward transformation is fortunate for both patient and doctor. Why? The answer lies primarily in that NPH requires a far greater clinical workup, since this headache should be considered ominous until shown otherwise.
In some patients, the transformation process is somewhat insidious, while in others the transformation is quite sudden. Why? In part, the answer lies in what triggers the transformation process to occur. Where excessive use of analgesics is seen, the transformation process tends to be gradual. In cases where injury or illness occurs, the transformation tends to be sudden. With this in mind, the following ratios appear intuitive.
• 80% are gradual transformation
• 20% are sudden transformation
Finally, the patient with the sudden transformation is deemed to be the most problematic from a diagnostic point of view. Again, the patient with a sudden onset of NPH requires a far greater clinical workup, since this headache should be considered ominous until shown otherwise.
Next time, we will delve further into CDH and its specific diagnostic subtypes. Until then, talk with all of your friends and patients who suffer from headache. Find out if they have ever suffered from CDH. What did they do to get themselves out of their predicament?
Take this simple quiz and keep it close at hand for future articles. The answers to each question will appear in later articles. In fact, you may want to clip out each article and save the series for future reference. Keep in mind that each of these articles will also appear on DC's website at http://www.ChiroWeb.com/dynamic.
- Can a patient suffer two different headaches simultaneously? A. Yes. B. No.
- Is there a difference between transformed headache versus rebound headache? If so, explain. If not, why are they similar?