Abstract
Dear Sir The recommendations for defining an intractable or refractory headache recently published in Cephalalgia (1) were very opportune. As expressed by Goadsby et al. (1), they hope that the recommended criteria will stimulate discussion about the definition of an intractable headache. With a view to contributing to the debate, I would like to comment on a few aspects.
A few years ago, also worried about this issue, our research group (Federal University of Pernambuco & University of São Paulo) published criteria to define an intractable or poorly controlled primary headache (2), with the objective of creating specialized centres to treat such patients with pharmacological refractory headache. Coincidently, such criteria were based on the example of the poorly controlled epileptic patients selected for surgical treatment, as mentioned by Goadsby et al. (1). As a result of this discussion, we put together a set of criteria which we would like to share with you as previously published in Migrâneas & Cefaléias (2):
Diagnosis of the primary headache type following the International Headache Society criteria.
Failure of the use of adequate drugs employed as prophylactic treatment for that specific headache, bearing in mind the following items: (i) first-line drugs; (ii) duration of the treatment; (iii) doses and half-life of the drug; and (iv) association of drugs.
Inherent to the type of headache, e.g. transformed migraine (3) by itself is a difficult-to-treat headache.
Neuroimage (magnetic resonance imaging, computed tomography scan, or both) and cerebrospinal fluid without causal abnormalities in order to rule out a secondary headache simulating a primary one.
Six months of therapy in a specialized clinic with headache treatment, with an improvement of <50% in pain intensity and/or frequency of headache attacks.
No improvement of the quality of life of the patient (note that the patient might have experienced an improvement on the intensity/frequency of the headache attacks with the medication, but the intensity of the side-effects of the drugs substantially affects, negatively, the quality of life of the individual).
A few points concerning the proposed criteria were also discussed. First, we must be sure about the type of primary headache we intend to treat in order to choose the best medication in each case. Obviously, the respective therapeutic medication depends on the type of syndrome we wish to treat. Abortive or prophylactic treatment of a migrainous patient is different from treatment of those with cluster headache. Some of the drugs used as prophylactic agents to treat a particular type of headache take weeks to show a good result, such as amitriptyline. On the other hand, the half-life of 3–5 h of propranolol necessitates frequent oral intake of the drug in order to achieve a better control of the crisis. Yet side-effects of the drugs (i.e. drowsiness, fatigue, lethargy, sleep disorders, nightmares, obesity, hormonal imbalance, depression, memory disturbance, impotence, orthostatic hypotension and significant bradycardia) interfere with the patient's quality of life and should be considered before prescription. Benign intracranial hypertension might be present in up to 15% of patients with chronic daily headache, even in the absence of optic disk oedema and presence of venous pulsation on the fundoscopy (4–6), reinforcing the necessity of complementary investigation of the patients in whom prophylactic prescription failed (7). We also emphasized that headache associated with chronic analgesic exposure is probably one of the most frequent types of refractory headache, and in that case the suspension of analgesic drugs is imperative (4).
The conclusion of our previous report was that the establishment of such criteria would better differentiate patients with medically uncontrollable primary headache from those with persistent headache caused by (i) inadequate pharmacological treatment, (ii) wrong diagnosis of the primary headache, or (iii) failure of complementary evaluation with neuroimaging and/or cerebrospinal fluid. Obviously, in a subgroup of those difficult-to-treat headache patients the constant presence of painful symptoms is inherent to the natural evolution of the disease, independent on the classic pharmacological strategy chosen. This opens a new avenue of research involving new drugs and surgical approaches to be used to diminish the painful distress of our patients.