Headache from a Neuro-Ophthalmic Point of View

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Headache is the most frequent cause for cooperative interaction between neurologists and ophthalmologists. Frequently, patients are seen first by their primary care physicians, and are then referred to ophthalmologists for further testing and management, chiefly to rule out ocular sources of pain. From there, they are commonly referred to neurologists, to be sure that something serious will not be missed. The diagnostic classification of headache is at first glance extraordinarily confusing or overwhelming, considering that the International Headache Society (IHS) has defined 176 different types of headache. This large number can be reduced to a more manageable level, since 90% of all primary headache syndromes are attributable to the two most common types, migraine and tension headache. The fact that there is no clearly defined system that allows for rapid classification of headache, especially cases of primary headache, underscores the importance of a carefully taken history and clinical examination.

Headache from a Neuro-Ophthalmic Point of View

H. Wiethölter and H. Wilhelm

Historical Clues When Evaluating Headache A properly structured history will allow proper classification of 25% of all cases of headache. The most important elements of the history include the frequency, location, duration of episodes, intensity of pain, the course taken during episodes, instigating factors, and a family history of headache (^■ Table 16.1).

Frequency of Headaches

groups of up to several episodes each day. More frequent attacks of head and facial pain (up to 20 times daily) are caused by chronic paroxysmal hemicrania. The daily appearance of chronic headache is often the presenting man- ifestation of a tension headache or an analgesic-induced pain syndrome.

Localization of Headaches

Headaches can be strictly unilateral (as in cluster syndromes), predominantly unilateral (as in migraine), retro- bulbar or retro-orbital (as in cluster syndromes), cervical with pain radiating into the occiput and parietal region (as in cervical neuralgia), or holocephalic (as in tension or analgesic-induced headache).

Duration of Episodes

The episodic pain of SUNCT syndrome (short-lasting unilateral neuralgiform headache with conjunctival injection and tearing) lasts for seconds, the paroxysmal hemicrania

Table 16.1. Checklist of history taking for a work up of headache Frequency

Location

Duration of episodes Intensity of pain Usual course Triggering factors Family history

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Flow diagram. Diagnostic procedures for the workup of chronic headache

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Intensity of Pain

The intensity of pain in headache syndromes is naturally highly subjective and differs substantially from one person to the next. The most intense pain is usually found in cluster headaches, migraine headaches, and paroxysmal hemicrania. Temporal arteritis causes a pain of intermediate intensity, while mild to intermediate levels of discomfort are associated with chronic tension headache. Venous sinus thrombosis commonly causes alternating phases of mild to intermediate pain.

Course of Pain

An intracranial hemorrhage can produce pain that starts precipitously and with full intensity in a stroke like fashion.

Cluster headaches and chronic paroxysmal hemicrania develop within a few minutes. The pain of migraine attains its greatest intensity between 15 min and 2 h of duration. The pain of venous sinus thrombosis has a diurnal course with nocturnal and morning pain, aggravated by the horizontal position during sleep, and partially relieved by erect pos- ture after arising.

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^Note

A steadily progressive intensity of head pain in a patient with no prior history of headache suggests a serious cause, such as obstruction of the flow of cerebrospi- nal fluid (e.g., aqueductal compression), or elevated intracranial pressure (pseudotumor cerebri).

Triggering Factors and Family History

Some headaches have specific triggering factors. For migraine, these include alcohol, changes in the sleep–wake cycle (e.g., jet lag), hunger, hormonal changes (e.g., the menstrual cycle), states of stress or agitation, abrupt cli- mate change, and withdrawal from the use of caffeine.

Attacks of cluster headache can be triggered by alcohol or by vasodilating medications. There are no specific trigger factors for chronic paroxysmal hemicrania or for tension headaches.

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^Pearl

In those with migraine, there is frequently a strongly

Migraine

The most important disease that produces headache is migraine. The pain can arise with or without an antecedent aura. About 7% of men and 14% of women suffer from this malady.

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Definition

Migraine is a unilateral, frontotemporally located, pulsating, or boring headache. It frequently appears on awakening and worsens with activity after arising. Due to the accompanying light and sound hypersensitivity (photophobia and phonophobia), patients are com- pelled to seek out rest, darkness, and silence. Associated autonomic phenomena include nausea and vomiting.

Initiating trigger factors can be identified by 90% of sufferers. The pain lasts for 4 to 72 h and is commonly relieved by the following night of sleep. Attacks that last more than a day are uncommon.

The source of pain is thought to be a sterile inflammatory reaction within the perivascular tissues of meningeal ves- sels, induced by changes in the neuronal activity of a gen- erator in the region of the brain stem nuclei. It is accompanied by the release of vasoactive preinflammatory substances (neuropeptides).

Initially, an aura is produced by a spreading wave of neuronal activity (“cortical spreading depression”) that moves across the cerebral cortex. This in turn induces a change in cerebral perfusion. Experimental evidence has found that the volume flow of blood decreases in the occipital cortex, and the hypoperfusion then spreads like a wave at a rate of 2 to 3 mm/min in the direction of the frontal cortex. The release of proinflammatory substances that stimulate pain receptors is responsible for the associated pain.

Migraine with Aura

By nomenclature, migraine with aura (previously known as classic migraine, ophthalmic migraine, hemiparetic migraine, hemiplegic migraine, or complicated migraine) is distinguished from migraine without aura (previously known as simple migraine or hemicrania). The aura cor- responds to a disturbance in the occipital cortex, or less commonly to disturbances within the brain stem. Affected

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lines that start at the center of the visual field and gradually expand peripherally with a temporal convexity, leaving be- hind a central zone of transient blindness: a so-called scin- tillating scotoma (^■ Fig. 16.1). Other symptoms of aura include slowly ascending, from distal to proximal, disturbances of sensation in the extremities, dysarthria (disturbances of articulation), or aphasia (disturbances of lan- guage expression or recognition), hemiparesis, and com- plex neuropsychological deficits, especially in the visual system. These include, for example, changes in color perception, changes in the perceived sizes of objects, loss of movement perception, and visual hallucinations (see Chap.

13). Aura symptoms develop slowly over a period of 5 to 10 min, and as a rule, last at most for an hour before subsid- ing. In some cases, aura symptoms occur without a subse- quent headache.

Unusual Types of Migraine

There are several unusual types of migraine. In basilar artery migraine, the auras reflect disturbances in the blood supply to the brainstem and cerebellum. Symptoms include diplopia, vertigo, tinnitus, paresthesias in the face, ataxia,

Ophthalmoplegic migraine takes the form of an oculo- motor disturbance with ptosis and diplopia.

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^Note

The diagnosis of ophthalmoplegic migraine requires the urgent exclusion of an aneurysm at the origin of the posterior communicating artery.

In purely retinal migraine, ischemia of the retina or the an- terior optic nerve can produce monocular visual field defects of varying severity, up to periods of transient amaurosis. The differential diagnosis includes amaurosis fugax, caused by retinal emboli arising from an atheromatous plaque in the carotid artery or from a valve in the heart.

There are a small number of documented reports in which the sequence of events in retinal migraine were recorded by fluorescein angiography, which demonstrated spasms of the retinal arterial tree lasting for several minutes, followed by a period of rebound vasodilation.

Treatment of Migraine

The treatment of migraine is guided by two strategies. In the first, a prophylactic drug is used for long-term suppres- sion. For example, regular use of beta-blocker (especially metoprolol) can be tried, if any one of the following oc- curs:

■ The attacks are described as lasting for longer than 48 h.

■ The use of specific antimigraine medications provides only temporary relief.

■ The intensity of the pain is unbearable.

■ The attacks occur three or more times a month.

■ The attacks are not otherwise manageable.

Acute management of individual attacks is usually success- ful for pain of a moderate intensity, using an initial dose of metoclopramide followed by a nonsteroidal anti-inflammatory drug (NSAID). The use of NSAIDs alone (i.e., without metoclopramide or a similar agent) is seldom adequate, since the analgesics are frequently not absorbed from the gastrointestinal tract because of poor or absent gastrointestinal motility. For more severe attacks, use of ergotamine preparations or of serotonin agonists (e.g., sumatriptan) can be effective. The triptans have a beneficial effect, reduc- ing nausea and vomiting, photophobia, and phonophobia.

Their disadvantage is a short half-life, and they are contra- indicated in coronary ischemia, Raynaud’s syndrome, and hypertension.

Fig. 16.1. The most common visual aura of migraine appears as a unilateral (binocular) geometric zigzag figure that usually begins in the center of the visual field and gradually extends to the periph- ery over a period of 15 to 30 min. The aural images can be very bright and colorful. The term fortification scotoma is sometimes used to describe the figure, due to the similarity in appearance to the ground plan of a seventeenth century fortification

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Cluster Headache

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Definition

Cluster headache (also called erythroprosopalgia) is characterized by its occurrence within specific, time- limited periods that last from 2 weeks to 2 months (clusters), separated by longer, asymptomatic intervals.

The individual attacks are always unilateral and last from 30 to 90 min. They occur frequently with an almost clock-like periodicity and for a few patients always at the same time, usually during sleep. The intensity of the pain is severe and often unbearable. The quality of the pain is described variously as “boring” or

“piercing,” and is concentrated in the retro-orbital and periorbital regions. There are typical autonomic paraphenomena, including rhinorrhea, ptosis, miosis, lacrimation, and facial flushing. Patients with cluster headache do not withdraw, as is common among mi- graineurs. They pace restlessly back and forth, finding no rest until the attack subsides.

In the course of time, a chronic form of cluster headache can develop, in which the individual cluster periods lose their time-limited character, becoming more or less continuous. Triggering factors include alcohol, nitroglycerin preparations, high altitudes, or intense sunlight. With a prevalence of 0.04 to 0.09%, cluster headache is an uncommon disorder, and it affects men much more frequently than it does women (8:1).

In the differential diagnosis, cluster headache is most frequently confused with trigeminal neuralgia, though as a rule the unilateral pain of tic douloureux is more commonly referred to the jaw or the ear. The stabbing pains of trigeminal neuralgia last only a fraction of a second to a few seconds.

At the first onset of cluster headaches, the attacks can be confused with acute angle-closure glaucoma, given the ret- robulbar or retro-orbital distribution of pain. During the diagnostic workup, a firmly palpable resistance to palpa- tion of the globe supports diagnosis of an acute glaucoma.

In addition, a dissection of the carotid artery can present with severe unilateral pain, ptosis, miosis, and a largely ret- robulbar distribution of pain. Fortunately, it is also usually accompanied by other signs and symptoms of neural dys- function that allow a clear distinction to be made.

Cluster headache is one of a group of primary headache disorders termed the trigeminal autonomic cephalalgias (TACs) which are characterized by strictly unilateral pain in the somatic distribution of the trigeminal nerve and ipsilateral autonomic signs, which reflect activation of the parasympathetic pathway (Horner’s syndrome with miosis and ptosis, conjunctival injection, with nasal congestion, rhinorrhea, and swelling of the eyelid, but with normal sweating in the face). Further candidates are paroxysmal hemicrania (5–15 attacks per day, lasting 2–30 min), SUNCT – short-lasting unilateral neuralgiform headache with conjunctival ingestion and tearing – (2–200 attacks/

hour, lasting 5–250 s), and probably the hemicrania conti- nua with continuous headache and a very good response to indomethacin.

Treatment of Cluster Headache

Acute attacks of cluster headache can be effectively aborted by inhalation of 100% oxygen (7 l/min for 15 min). Alter- natively, topical intranasal application of lidocaine or sub- cutaneously injected sumatriptan can be effective.

The management of individual attacks, however, is a temporary solution at best, and a means for aborting the cluster is needed. This can often be done with prednisone, using 60 to 80 mg/day. For prophylaxis, the calcium channel blocker verapamil can be started at a low dose, with gradually increasing doses to a maximum of 240 mg/day.

Psychotherapy and physical therapy have no recognizable benefit.

Raeder’s Paratrigeminal Syndrome

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Definition

Paratrigeminal syndrome has many different causes. It is recognized as an association between a lesion affect- ing the first division of the trigeminal ganglion and a deficit in the sympathetic innervation of the ipsilateral eye. In addition to sensory loss and pain in the areas served by V1, there is also Horner’s syndrome, with miosis and ptosis but with normal sweating in the face.

The original series reported by Raeder included cases of aggressively invasive neoplasms in the middle cra- nial fossa.

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Tension Headache

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Definition

By tension headache, we mean a holocephalic headache of a dull, oppressive character having a low to intermediate intensity, with low-grade light and sound sensitivity, occasionally producing nausea, but not vomiting. The head pain appears to be driven by increases in muscular activity that are associated with various forms of emotional tension. Aura symptoms, such as visual impairment or paresthesias, are not found. The pain is described as a “tight band encircling [the] head.” By definition, an episodic tension headache, occurring less than 15 days a month, is distinguished from a more frequent or daily, chronic form.

Tension headache is, after migraine, the second most common form of primary headache, meaning that its symptoms are not thought to be caused by some underlying disease. It can present as episodic or as chronic. About 40 of all people are affected. The disorder usually begins at between 25 and 30 years of age. Women are more commonly affected than men are.

Unlike migraine, the pathophysiology of tension headache is poorly understood. It is often paired with terms such as vasomotor headache, muscle-contraction headache, etc.. Controlled studies have been reported showing that the tonus of pericranial muscles is elevated during tension headaches, but it is not correlated with the intensity of the pain. It is thought that a change in the sensory thresh- old level of a central nociceptive system is responsible for this type of headache.

In the differential diagnosis, a number of disorders should be considered. These can lead to similar types of headache and include frontal sinusitis, obstructive hydro- cephalus, slowly growing brain tumors, subdural hemato- mas, and pseudotumor cerebri. In addition, headaches similar to those of the tension headache can be caused by chronic use of analgesics, ergotamine, arterial hypertension, a number of metabolic/endocrine disorders, infec- tions, and substances that can directly elicit the sensation of pain, such as alcohol, nitrates, calcium channel blockers, and organic solvents.

Management of Tension Headaches

Episodic forms of tension headache are usually relieved by the readily available over-the-counter NSAIDs including aspirin, ibuprofen, naproxen, and acetaminophen. For chronic forms of tension headache, relief can often be found with daily use of tricyclic antidepressants, such as nortriptyline or amitriptyline. Effective doses are usually one third or less of those used in the treatment of depression. Starting with low doses (10 mg) taken at bedtime and then gradually increased, relief is usually experienced within a few weeks. Maximal doses for the management of headache should not exceed 100 mg daily. There can be a troublesome side effect of weight gain, when using amitriptyline, but nortriptyline is not thought to have this effect.

Venous Sinus Thrombosis

Thrombosis of the cerebral venous sinuses can be a diagnostic challenge for neurologists and ophthalmologists alike. It often presents as subacute, spontaneous head pain that awakens the sufferer from sleep and which gradually intensifies with a crescendo-like behavior. Thrombotic oc- clusion of the large cerebral venous sinuses is associated with substantial increases in cerebral spinal fluid (CSF) pressure, leading to frank papilledema. Additionally, neurologic deficits such as paraparesis of the legs or focal epi- leptic attacks can occur. Sometimes the initiating event is a bacterial sepsis, causing fever to be one of the signs at pre- sentation. The pain is mostly holocephalic and diffuse, with a varying intensity, and it usually does not respond to over- the-counter analgesics. Characteristically, the pain increases when in a recumbent position, causing the pain to wors- en during sleep, so that the patient awakens with pain.

When the sufferer rises and maintains an erect position, the pain gradually subsides. MRI angiography is especially effective at detecting the cessation of blood flow in a venous sinus.

The cause of venous sinus thrombosis is often obscure and cannot be identified in about 25% of cases. Known risk factors include pregnancy and the puerperium, the use of oral contraceptives, and tobacco use.

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Treatment of Venous Sinus Thrombosis

Treatment usually requires full anticoagulation with hepa- rin, despite the risk of intracerebral hemorrhage. But with timely diagnosis and intervention, the prognosis is usually good. Treatment should be started in an inpatient setting, but once favorable levels of anticoagulation are obtained, most cases can be safely monitored as outpatients.

Pseudotumor Cerebri

(Idiopathic Intracranial Hypertension)

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Definition

Pseudotumor cerebri – more correctly, idiopathic in- tracranial hypertension – is a syndrome characterized by headaches, elevated intracranial pressure, papilledema, and normal CSF values with a normal CT and/or MRI scan showing no space occupying mass and especially no sign of venous sinus thrombosis (see Chap. 8).

The headaches of pseudotumor cerebri are typically holocephalic pressure sensations that are most prominent in the morning. The elevated CSF pressure, whose cause is yet to be determined, results in transient obscurations of vision and binocular papilledema that is often very severe. If un- treated, it usually has a chronic and unremitting course that leads to optic disc gliosis and atrophy, ending in severe, bi- lateral loss of vision. The end stage of the disease causes visual field defects that look identical to those of end-stage primary open-angle glaucoma. Acuity may remain good when all but the central few degrees of visual field have been lost. (For a discussion of management of the pseudotumor cerebri syndrome, see Chap. 8).

Treatment of Pseudotumor Cerebri

Isolated headaches without visual disturbances in patients with a Pickwickian (morbid obesity) body habitus can be managed conservatively. Those few patients who find it possible to lose significant portions of body weight can usually enjoy a complete remission of the headaches. Al- though lumbar puncture (LP) will provide temporary relief of the pain, it is not a useful strategy for long-term management. In some patients, the first LP is followed by a complete remission of the syndrome. For some, however, it is

sheath can often reduce or eliminate the papilledema and preserve vision, but usually has no effect on the headaches).

Drug-Induced Chronic Headache

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Definition

Drug-induced chronic headache is the frequent or daily occurrence of headache, associated with the regular daily use of analgesic drugs.

Patients with what is initially a form of tension headaches can, through the regular daily use of analgesics, develop an unremitting headache that is worse in the morning and is not associated with autonomic symptoms. Chronic use of analgesics by patients with migraine can also lead to an increased frequency and/or severity of their migraine attacks, and these can change into a steady, chronic pain that per- sists between attacks and which is different in character from the usual pulsating migrainous headache.

Treatment of Drug-Induced Chronic Headache Chronic drug-induced headache can be managed only by an absolute cessation of analgesic use. During the period of withdrawal, only the use of medications to suppress nausea and vomiting is permissible.

Conclusion

Headache is always a serious problem when it comes on abruptly and unexpectedly. Nevertheless, there usually is sufficient time to allow taking of a complete history, which often clarifies the source of the problem. Only in a minor- ity of cases is a neuroimaging study necessary:

■ Abrupt onset of severe, unbearable head pain unlike any prior experience (subarachnoid hemorrhage)

■ Fever and a stiff neck coincident with the onset of pain (abscess, purulent sinusitis)

■ Atypical headache with focal neurologic signs

■ Focal neurological symptoms (other than migraine aura)

■ Papilledema or known or suspected elevations in CSF pressure

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^Pearl

Prior to any other diagnostic testing, it should be understood that a complete neurological examination is required, even if not by a neurologist.

Further Reading

Brandt T, Dichgans J, Diener HC (eds) (2004) Therapie und Verlauf neu- rologischer Erkrankungen. Kohlhammer, Stuttgart

Diener HC (ed) (2003) Kopfschmerzen. Referenz-Reihe Neurologie.

Thieme, Stuttgart

Göbel H (2004) Die Kopfschmerzen. Springer, Berlin Heidelberg New York

Jensen O (2006) From basic pain mechanisms to headache. Oxford Uni- versity Press, Oxford

Kiel Headache Clinic. http://www.schmerzklinik.de