Tension-type headache

It is estimated that 75% to 90% of all persons who complain of chronic or frequent headaches suffer from tension headaches. They are the most common type of primary headache, and while they share some characteristics with the more serious migraine, they also display certain distinct differences that set them apart.

Some experts believe that tension headaches and migraines represent two ends of a common spectrum, and that migraines, which are severe but irregular in occurrence, sometimes progress or transform to the less severe, but more frequent, tension-variety headache.

Physical Findings
When a patient is examined by the physician, there are often findings of muscular tenderness. This is often present in the areas of the neck, at the base of the skull, shoulders, upper arms, and the jaw and face. Some people may show signs of clenching the teeth. The scalp and forehead may also be painful when palpated. The neurological examination is usually normal.

Causes

Like migraines, tension headaches seem to be more common in women than in men. Unlike migraines, which often make their initial appearance during adolescence, tension headaches usually begin in middle age. As such, their onset often is equated with the development of adult stresses, anxieties and depression that can characterize mid-life. The name "tension headache" therefore can be said to describe a response by the body to emotional strains and pressures, rather than to excessive muscular tightness and resultant constriction of the scalp arteries, as was once widely presumed. In many such cases, researchers have found that patients complaining of frequent headaches, which are generally not migraines, also exhibit varying degrees of depression, anxiety and worry.

Despite these findings, many physicians and researchers still believe strongly that stress-induced muscular tension in the head, neck and shoulders can bring on tension headaches. This is supported by evidence of muscular tenderness in areas of the neck, the base of the skull, scalp, forehead, face, jaw, shoulders or upper arms in many tension-type headache sufferers. Others show signs of pronounced clenching of the teeth, suggesting that problems related to the temporomandibular joint (TMJ) are causative factors, along with cervical disorders, such as arthritis or degenerative disease of the neck and/or spine, leading to chronic muscular contraction.

Symptoms

The typical tension headache is one that produces a dull, steady, achy pain on both sides of the head. This contrasts which the classic symptom of migraine, which is severe, throbbing or pulsating pain, usually on one side of the head. However, a small proportion of tension-headache patients report that their pain, when at its worst, does at times develop a pulsating quality, a phenomena which physicians sometimes call a tension-vascular headache. This represents one more area where the distinction between tension headaches and migraines becomes somewhat blurred, and tends to support the theory that the two headache types are not actually separate conditions, but opposite ends of common spectrum of primary headache activity.

Many tension headache sufferers describe their pain as producing a sensation of pressure or tightness around the head, as though a band were pulled tightly around it; others compare the feeling to having their head clamped in an ever-tightening vise. The pain usually begins gradually and increases steadily over a period of hours, but while severe and distracting, it rarely becomes overwhelming and physically debilitating, as in a migraine.

Diagnosis

Physicians typically diagnose tension-type headache on the basis of observed differences between its symptoms and those that characterize migraines, cluster headaches and other kinds of chronic craniofacial pain. With all patients who complain of abnormally frequent head pain, however, the physician usually will perform a thorough physical examination, including a medical history and one or more diagnostic procedures, to rule out any underlying serious medical problems that may be producing the headaches as a secondary symptom.

Treatment

Many patients with tension headaches do not seek medical attention or advice, instead choosing to treat themselves with nonprescription analgesics and over-the-counter pain medications. While this works for some people, others, whose tension headaches are severe enough or sufficiently frequent to compel them to seek professional treatment, obtain relief through a course of doctor-prescribed antidepressant or anxiety-reducing medications, such as amitriptyline, nortriptyline or desipramine. When headaches are severe, symptomatic treatment with aspirin, acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) can be helpful. In such cases, care must be taken to avoid medication overuse, as this can lead to "rebound headaches."

Some patients report beneficial results from secondary treatments that help reduce the effects of stress and tension on the body, such as massage, meditation and the use of biofeedback techniques. In some cases, patients also may benefit from the effects of psychotherapy as a means of learning how to cope with stress and tension.

This section includes classification 2.1 Episodic tension-type headache; 2.2 Chronic tension-type headache; and 2.3 Tension-type headache not fulfilling the above criteria.
Migraine and tension-type headache often exist together in the same patient. This was previously called combination headache, or mixed muscle contraction headache. These patients represent a continuum varying from those who have pure migraine to those who with migraine and a moderate amount of tension-type headache, to those with half of each, those with a preponderance of tension-type headache, to those with pure tension-type headache. Therefore, mixed cephalalgia is arbitrary. It is recommended that patients should instead be coded for migraine and for tension-type headache if they have both forms. I would emphasize here, as dicussed further below, that all attempts to determine the migrainous component of headaches believed to be "tension" be considered and actively sought as therapy for migraine may be very beneficial.
Episodic tension-type headaches are described as recurrent episodes of headache lasting minutes to days. The pain is typically pressing/tightening in quality, of mild or moderate intensity, bilateral in location, and does not worsen with routine physical activity. Nausea is absent, but photophobia or phonophobia may be present. The following diagnostic criteria are listed:

A. At least 10 previous headache episodes fulfilling criteria B-D listed below. Number of days with such headache <180/year (<15/month).

B. Headache lasting from 30 minutes to 7 days.

C. At least 2 of the following pain characteristics:

1. Pressing/tightening (non-pulsating) quality

2. Mild or moderate intensity (may inhibit, but does not prohibit activities)

3. Bilateral location

4. No aggravation by walking stairs or similar routine physical activity

D. Both of the following:

1. No nausea or vomiting (anorexia may occur)

2. Photophobia and phonophobia are absent, or one but not the other is present

E. At least one of the following:

1. History, physical- and neurological examinations do not suggest one of the disorders listed in groups 5-11

2. History and/or physical- and/or neurological examinations do suggest such disorder, but it is ruled out by appropriate investigations

3. Such disorder is present, but tension-type headache does not occur for the first time in close temporal relation to the disorder

About 50% of patients seen in headache clinics are thought to suffer from muscle contraction (tension) headaches (Lance et al., 1965; Diamond and Bates, 1972). In addition, a substantial percentage of patients who visit emergency rooms with headache complaints are eventually diagnosed as having muscle contraction headaches (Leicht, 1980). It is therefore common for physicians in all specialties to be confronted with the patient who complains of pain and tightness over the eyes and in the back of the head and neck. These sensations are variously described as vise-like, pressure, a constricting band, drawing, and aching. Tenderness throughout the trapezius muscles is commonly associated with the above complaints and is most intense along the top of the shoulders and in the upper neck. Many patients also describe pain, pressure, or paresthesia over the vertex of the head. Pain can often be elicited by palpation of the trapezius muscles.
Wolff and his colleagues (Schumaker et al., 1940; Tunis and Wolff, 1954) studied the effect of head pain upon the head and neck muscles. They recorded muscle potentials on a two-channel, ink-writing oscillograph by applying solder electrodes over the frontal, temporal, occipital, and neck muscles. Brief head pain was induced by intravenous injection of histamine. Contraction of the head and neck muscles was observed in association with the pain, but no pain arose from the muscles themselves, probably because of the short duration of the induced head pain.
With respect to the eyes themselves, an irritant introduced into the conjunctival sac sometimes caused, reflexly, contraction of the head and neck muscles and resulted in secondary pain and paresthesia in the head and neck. Abnormally sustained contraction of the ocular muscles produced by placing a 3-diopter vertical prism in front of the dominant eye caused a sustained contraction in the neck muscles, followed by pain in the neck and shoulder.
Observations were made in patients with pain in the occiput and neck associated with inflammation or other dysfunction about the head. It was found that in these subjects, there was sustained contraction of the neck and head muscles. The intensity of pain in the neck and over the back of the head could be modified by changing the state of muscle contraction.
On the basis of these and other studies, it has been assumed that the exceedingly common ``tension headache'' found in emotionally tense, aggressive, frustrated, and anxious individuals is caused by sustained contraction of the head and neck skeletal muscles. It has been suggested that such headaches occur from vasoconstriction of the nutrient arterioles during this period. Evidence for such vasoconstriction is abundant. Tunis and Wolff (1954) found evidence of increased vasoconstriction in a population of headache patients compared to no-headache control subjects. Ostfield et al. (1957), Feuerstein et al. (1976), and Friedman and Merritt (1959) have reported similar results. Wolff (1963) found that the induction of head pain was associated with increases in cephalic vasoconstriction. Thus, it has been postulated that, by producing ischemia of the head and neck skeletal muscles, sustained muscular contraction leads to headache. The validity of this underlying diagnostic assumption is especially important when one considers that many behavioral strategies designed to reduce tension headache (e.g., biofeedback) utilize information regarding muscle tension as an integral part of treatment.
Unfortunately, the evidence for increased muscle contraction as well as vasoconstriction as major factors in the production of ``tension'' headache, is far from clear. Haynes et al. (1975) reported that subjects who report frequent tension headaches have overall higher electromyographic (EMG) resting levels than control subjects. Similar findings were reported by Vaughn et al. (1977) and Philips (1977b). However, EMG frontalis resting levels in tension headache subjects studied by Martin and Mathews (1978) did not differ from those of control subjects. In addition, Bakal and Kaganov (1977) monitored frontalis muscle tension levels in groups of muscle contraction headache subjects and control subjects and found no significant differences between groups. Sutton and Belar (1982) have compared the frontalis EMG levels of medically diagnosed headache patients and non-headache control subjects during baseline, stress, and pleasant thought conditions. They have concluded that no simple, direct relationship exists between headache pain and muscle tension levels. Similarly, Epstein et al. (1978) have found a lack of correlation between EMG changes and treatment outcome in patients with ``tension headache.'' With respect to presumed vasoconstriction during tension headaches, Onel et al. (1961) found that there may be localized vasodilation during such headaches. In this study, the clearance rates of injected radioactive sodium were found to be faster during headache than non-headache states. No significant difference was found in clearance rates between control subjects and headache patients in a non-headache state. In addition, Martin and Mathews (1978) found that injection of amyl nitrate, a vasodilator, during a muscle contraction headache was associated with an increase rather than a decrease in reported head pain and that no such increase was reported following injection of a placebo. Finally, Bakal and Kaganov (1977) found no significant differences in pulse wave velocity among patients with migraine headaches, tension headaches, and control subjects.
It would appear that although some studies suggest that muscle tension in the neck and shoulders may result from head pain and in the tense individual may even generate head pain through vasomotor changes, it remains impossible to presume a reliable etiologic role for muscle tension or vasomotor activity because of conflicting experimental data. To adequately account for tension headache, reference to other personal, social, or physiologic variables must be included. As Haynes et al. (1982) have emphasized, tension headache is a self-report phenomenon, and self reports of pain are under strong historic and immediate social learning influences. Social contingencies from family, friends, and others can have a strong influence on the report of pain. Other factors that may be important in the understanding of such headaches include frequency and types of environmental stressors; cognitive attributions, attention, or structure; differential pain thresholds; physiologic/anatomic factors; and previous experience with pain.
The pain of tension headache may be treated in some cases with simple analgesics or with combination drugs (Glassman et al., 1982), with biofeedback, and, most importantly, with counseling. Even acupuncture may offer relief in some individuals (Loh et al., 1984). The interested reader is directed to the excellent review of this subject by Haynes et al. (1982).
Muscle contraction or tension headache has been characterized as head pain without migrainous features. Typically, the headache is described as bilateral, commonly in an occipital or posterior neck location, variable in intensity, dull, with pressure and tightness in muscles and in association with emotional conflict (Raskin, 1988; Daroff, 1988). They tend to occur on a daily basis but may be intermittent or periodic. On careful analysis there are many overlapping features common to migraine. Features at one time believed to be specific for tension headache, such as neck muscle contraction and precipitation by stress and anxiety, are know known to occur just as often in migraine (Ziegle, 1985). Indeed many patients with daily constant headache, without throbbing and having a "band-like" tightness may respond to antimigrainous therapy.
On further elicitation of the past history many constant daily headaches are indeed "transformed migraine".
There are many, including Raskin (1988), who believe that muscle contraction headaches and migraine headache form a continuum and blend into each other. Even though a headache may be described as "band-like" and constant, careful history may elicit factors favoring vascular headaches. For example, there may be family history of migraine; above average susceptibility to motion sickness, nausea, photophobia, phonophobia and other features that suggest there is migraine-like symptomatology. Standard migraine abortive and prophylactic therapy may then be quite beneficial.
Clearly there are patients with major psychological problems who have psychogenic headaches as a feature of their disorder, but in a majority without features which permit a diagnosis of probable or definite migraine, the distinction is often difficult. Muscle contraction or tension headaches do overlap significantly with migraine, as indicated above, and may respond to similar therapy. Antidepressant therapy in the form of tricyclics may be helpful in both muscle contraction and migraine headaches.
In the International Headache Society Classification, there is a classification 2.3 for headaches of the tension-type, not fulfilling the above criteria. These are headaches which are believed to be a form of tension-type headache, but which do not quite meet the International diagnostic criteria for any of the forms of tension-type headache.
In the description of headache of the tension-type not fulfilling the above criteria, that is category 2.3 in the IHS Classification, it should be noted that chronic tension-type headache associated with disorders of paracranial muscles, called chronic muscle contraction headache, is coded as 2.2.1.
A fourth digit code number for group 2 indicates a likely causitive factor (Olesen, 1988). This includes oral mandibular dysfunction or temporal mandibular joint pain dysfunction syndrome which is discussed elsewhere. It also includes psychosocial stress (DSM III-R criteria). Diagnostic criteria are the following:
.

1) Associated with psychosocial stressors rated 4-6 on a 1-6 scale (1=no stress, 2=mild, 3=moderate, 4=severe, 5=extreme, 6=catastrophic) This includes anxiety and depression or headache as a delusion or an idea. Previously used terms include psychogenic headache, or a conversion cephalalgia. The previously used term psychogenic headache is now coded as 2.1.26 or 2.2.26, that is, episodic- or chronic- tension-type headache associated with a muscular factor, but associated with a somatic delusion or a somatiform disorder. There are also codings to include categories for muscular stress, drug overuse for tension-type headache, and other types (see Olesen, 1988).

At one point an Ad Hoc Committee on Classification of Headache recommended separate categories for "Headaches of Delusional, Conversion, or Hyperchondriacal States" and for "Muscle-Contraction Headache" but others prefer to combine these into a category of "psychogenic headaches" under which there are the subtypes: depression (overt or masked), delusional (in a psychotic), somatoform disorder, chronic post-traumatic, chronic atypical facial pain, and muscle contraction pain (when due to psychogenic factor and not unusual postures or strains) (Daroff, 1988).