The complaint of headache is one of the most frequently encountered (neurologic) symptoms in pediatric practice. Therefore, it is important for every clinician to develop a coherent approach to this problem. Such an approach emphasizes the importance of history-taking and the physical examination since most of the entities that cause headaches in childhood must be diagnosed clinically, and laboratory tests frequently prove negative or non-diagnostic in these situations. Therefore, in the management of headaches the art of medicine truly is practiced. Subtle and important features of various headache syndromes, and little-known associated features, must be probed for specifically in the history in order to enable the pediatrician to make a confident diagnosis without the use of unnecessary laboratory procedures. Certain patients will obviously require a more extensive work-up to rule out the presence of an intracranial mass lesion or other potentially life-threatening condition.
While headaches may reflect the presence of extra- or intracranial processes, they may also be the result of underlying systemic disorders. Furthermore, headaches in children and adolescents may be secondary to stress, depression, or other psychological factors. Parents often attribute headaches to eye problems, which is indeed infrequently true.
In the approach to the management of headaches it is important to have some understanding of the mechanisms behind pain and of the sensory innervation of the head and intracranial structures. In general, all extracranial structures are pain sensitive. With regard to intracranial structures, the brain, ependymal lining, choroid plexus, and much of the dura and pia-arachnoid over the hemispheric convexities are pain insensitive. The cranial nerves, the dura at the base of the skull (ie, floor of the anterior and posterior fossae), and the middle cranial fossa in the region of the middle meningeal arteries are pain-sensitive regions. The most pain-sensitive intracranial structures are the proximal portions of the large cerebral arteries at the base of the brain, the venous sinuses and the large cerebral veins.
With intracranial processes, when pain occurs, it is usually the consequence of traction or displacement of sensitive structures or dilatation of cerebral vessels. Mass lesions such as tumors, abcesses, and hematomas, and increased intracranial pressure secondary to hydrocephalus, cerebral edema, pseudotumor cerebri, and venous sinus thrombosis, distort and displace blood vessels, dura and cranial nerves. After lumbar puncture there may be a decrease in cerebrospinal fluid pressure resulting in traction on various structures. Intracranial arterial vasodilatation occurs with fever, caffeine and alcohol withdrawal, hypoxia, hypercapnia, nitrites, and as a post-convulsive or concussi ve phenomenon. In some cases, pain may be the result of meningeal irritation from meningitis or subarachnoid hemorrhage.
Extracranially, tension (muscle-contraction) and migraine headaches tend to be the most frequent causes of pain. Primary muscle contraction headaches are the result of tension, while secondary forms are due to eye strain, bite imbalance and cervical abnormalities. Trauma, infections and inflammations of the scalp and scalp arteries as well as disorders affecting the eyes, ears, nose, throat, dentition and periosteum can cause pain that is initially felt locally, but that may generalize to a muscle-contraction headache. Neuralgias and compression of cranial nerves may result in the most excruciating forms of pain.
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In considering innervation, both extracranial and intracranial structures receive pain fibers from the trigeminal (fifth cranial) nerve and the upper three cervical roots (Cl to C3). The sensory innervation to the anterior part of the scalp and face is provided by the trigeminal nerve. The occipital areas and neck are innervated by the upper three cervical roots.
Intracranial innervation is similar. The upper surface of the tentorium, anterior and middle cranial fossae, and middle meningeal arteries receive pain fibers from the trigeminal nerve. Pain from these structures is referred extracranially to structures supplied by the trigeminal nerve, namely the anterior two-thirds of the head and eyes. The inferior surface of the tentorium and structures of the posterior fossa receive their sensory supply from Cl to C3 and distortion or displacement of these structures results in referred pain to the posterior one third of the head and the back of the neck. The ninth and tenth (glossopharyngeal and vagus) cranial nerves also provide sensory innervation to parts of the posterior fossa so that pain is occasionally referred to the ear or throat. Despite this, one must be cautious in the interpretation of referred pain and in utilizing the site of the pain in localization of an intracranial lesion. To dramatize this, posterior fossa lesions can cause frontal and orbital pain, and supratentorial lesions may lead to pain localized to the occiput and back of the neck. This is the result of the unpredictability of how pain-sensitive structures will ultimately be displaced by an intracranial lesion, and of the neuroanatomic association between the descending trigeminal tract and nucleus, and the cervical sensory systems.
Table 1 summarizes the facets of the history that must be pursued in all headache cases. When the headaches are paroxysmal or recurrent it is important to ask the duration of symptoms and whether the headaches are getting more or less severe with regard to frequency and severity of pain. This provides a background as to the evolution of the headache syndrome.
The character or quality of the pain must be pursued as well. One needs to ask whether the pain is throbbing or constant. A throbbing or pounding headache generally implies a vascular etiology such as migraine, vasculitis, or a post-con vulsi ve or post-traumatic state. Hypertension infrequently causes headaches, but when it does, it may be throbbing. A constant headache is seen with muscle contraction syndromes due to tension, eye strain with squint, refractive errors, astigmatism, glaucoma and retrobulbar neuritis. A similar headache may accompany malocclusion and sinus conditions. Depressive states lead to constant pain. With psychogenic headaches, the presence of stress at home and at school must be explored. Some children are prone to malingering and may have a history of other complaints, generally relating to gastrointestinal symptomatology. Caution must be exercised, however, because depression may be present, and recurrent head and abdominal pain can be seen with migraine and epilepsy. Tumors may lead to either throbbing or constant pain depending on the effect of intracranial structures. Meningitides and encephalitis also cause either throbbing or constant pain. Sharp, stabbing headaches may be caused by trigeminal neuralgia (tic doulourex). There is frequently a trigger point that activates the pain when touched. In psychiatric conditions the pain is frequently characterized in a bizarre manner, for example, as "a nail driven into the head." However, organic lesions may also lead to such pain.
One may encounter difficulty in understanding the quality of pain in younger children who are unable to characterize a headache as throbbing or constant. To a very young child "it just hurts." Some children, however, will relate to helpful gestures such as the examiner pounding on a table or opening and closing a fist to suggest "throbbing," or squeezing a fist to suggest "constant."
The location of the headaches, and whether they are unilateral or bilateral is also important. This is helpful, because migraine headaches are frequently unilateral, but less so in children than in adults. In children they frequently tend to be bifrontal and bitemporal, and occasionally occipital. Muscle contraction headaches, on the other hand, are usually localized to the back of the head and neck and are bilateral. The site of pain with intracranial mass lesions depends on the location of the mass. As a general rule, as noted previously, supratentorial masses refer pain to frontal areas while infratentorial tumors refer to the occiput and the back of the neck. The pain may be bilateral or unilateral. Sinusitis generally causes pain in the area of the affected sinus. Trigeminal neuralgia manifests most frequently in the regions supplied by the ophthalmic division of the fifth cranial nerve. Depression tends to cause diffuse pain. As a useful tool in localization, it is frequently helpful to ask a child to point to where the pain is felt. The clinician will be greatly helped by this and may be surprised by an unexpected response.
An important entity to always consider when confronted with headaches is temporomandibular joint disease. We have seen a number of children and adolescents presenting with headaches who actually had facial pain upon opening the mouth. The pain was described as sharp and lancinating, and radiated from the angles of the jaw and could be alleviated after ten to 15 minutes with relaxation and resetting of the jaw. The children wore braces and a "click" could be palpated upon opening of the mouth. This illustrates that in childhood the chief complaint of headache may not reflect true head pain and may actually be orbital, facial, or oral pain. Therefore, headache must be substantiated upon direct questioning.
The time of occurrence of a headache may give insight as to etiology. Tumors can cause headaches upon awakening that decrease in intensity after 30 to 60 minutes as the patient assumes an upright posture. Disorders of the frontal sinus, tension (muscle contraction), and depression also lead to morning headaches, as does hypertension. Maxillary sinus problems generally result in afternoon headaches as do those from eye strain and progressive tension. Migraine may present in the morning but can start anytime during the day, as can tumor headaches. Migraine, tumor, and cluster headaches can awaken a child from sleep.
The severity of a headache may occasionally be helpful with regard to etiology. Migraine headaches can be very severe, while contrary to belief, tumor headaches are frequently ignored early in the course of the condition. The pain of tic douloureux is one of the most severe that can be experienced. Muscle contraction headaches are dull and nagging, but if depression is present they may be described as severe. Delusional and hypochondriacal headaches may be described as unbearable.
Questions regarding precipitating factors are often helpful. Changes in posture can affect a headache. Sinus headaches may worsen as the head is bent forward. If cervical disorders are responsible for an occipital headache, movement of the neck will modify the pain. Certain tumors cause headaches with changes in posture. Colloid cysts of the third ventricle, for example, may cause severe headache only when the head is bent forward and cerebrospinal fluid outflow is obstructed. Sudden movement of the head, coughing, sneezing, or straining at bowel movements will frequently make an intracranial headache worse in contradistinction to extracranial headaches.
The mode of onset of a headache can warn of a serious underlying problem. A catastrophic, sudden onset may indicate a ruptured aneurysm or hemorrhage into a tumor. Under such circumstances, questions regarding a stiff neck are critical since subarachnoid hemorrhage will result in nuchal rigidity. In rare instances blood in the CSF may descend into the spinal sac and cause low back pain instead of nuchal rigidity. Occasionally, a seizure disorder may manifest as only headaches, and in such instances the onset is sudden. Migraine begins as aduli headache that gradually builds up to a more severe, throbbing pain. Tension headaches tend to build up as the day progresses.
Frequency of headaches is occasionally helpful. Tension, tumor, and depression may lead to daily headaches although paroxysmal episodes are also likely. Migraine headaches are frequently paroxysmal . occurring weekly, monthly, or several times a year. However, exacerbations can lead to daily headaches lasting several weeks. In young females migraine may manifest in relation to menses. Sinus headaches tend to be seasonal and may be related to allergic symptoms. Cluster headaches represent a specific headache syndrome, possibly related to migraine, where there is recurrent facial pain, generally behind an eye. The pain may radiate and is very severe and the headaches come in daily clusters for several weeks, then abruptly disappear for months to years.
The duration of a headache may indicate etiology. Migraine generally lasts for hours, while neuralgia is brief paroxysms. Tension headaches last much of the day and tumor headaches may as well, but this is variable.
The physical examination may assist in diagnosis. In a child, macrocephaly can be seen with hydrocephalus or tumors. Upon inspection the presence of neurocutaneous stigmata can reflect upon the underlying etiology of headaches. The skin is the "mirror of the brain" for both arise from ectodermal anlagen. The recognition of pigmented cafe-au-lait spots and neurofibromas may lead to the diagnosis of von Recklinghausen's disease and to the identification of an intracranial tumor or optic glioma as the basis of headaches. Adolescents with acne, especially in the nasal area, can develop retrograde infections and intracranial venous sinus thrombosis. A traumatic lesion of the scalp may indicate an underlying subdural or epidural hematoma. Erythema of the face can be present with sinusitis. Examination of the eyes will reveal glaucoma, papilledema, retinal hemorrhage, cranial nerve dysfunction (secondary to increased intracranial pressure or tumor), or refractive errors. Dental, oral and temporomandibular disorders should be excluded. The ears, nose and throat should be carefully examined. In examination of the neck, lymph glands and carotid pulses should be palpated. Difficulty in passive flexion of the neck may indicate cervical spasm or meningismus from meningitis, or subarachnoid hemorrhage. It can also occasionally be seen with posterior fossa tumors with impending herniation. In all cases of headache a careful neurologic examination is indicated. Neurologic deficits should raise the concern of an intracranial mass lesion. However, migraine can result in focal deficits as well. The sinuses should be percussed, for frequently there is underlying tenderness. A chronic subdural hematoma may be suspected from percussion tenderness overlying the site. The resonance of a "cracked pot" may be heard upon percussion of the cranium in the setting of hydrocephalus and split cranial sutures. Auscultation of the neck, orbits and mastoid processes occasionally will reveal an arteriovenous or other vascular malformation. All patients should have their blood pressure checked to rule out systemic hypertension. Fever will indicate otitis media, sinusitis, brain abscess, or other intracranial or systemic infections.
In concluding this section on history and examination, it is important to summarize danger signs that are frequently seen with intracranial mass lesions or decompensating vascular anomalies. A severe headache, occurring for the first time, with an acute onset and focal neurologic signs, and/or impaired consciousness, should raise immediate concerns. In such situations a lumbar puncture is usually contraindicated, and an emergency CAT scan is the most appropriate initial study. A lumbar puncture performed in the setting of an expanding mass lesion can result in neurologic deterioration and herniation. If meningitis or encephalitis are suspected, however, a lumbar puncture is the procedure of choice.
LABORATORY TESTS AND PROCEDURES
This section is limited to a summary, since in most cases diagnosis is most dependent on history and examination. Table 3 lists appropriate tests to be ordered as indicated. If the cause of the headaches is elusive, or further definition of the problem is necessary, it is appropriate to consult an otolaryngologist, dentist, ophthalmologist, psychiatrist, psychologist, or neurologist.
Its importance in childhood warrants that migraine be treated separately and that its various forms be discussed. The incidence of migraine in childhood is approximately 4%,' and onset is prior to ten years of age in approximately a quarter of the patients. In very young children, migraine may present without headaches as a migraine equivalent. The diagnosis in these situations may be difficult and only a strong positive family history of migraine or the subsequent development of frank migraine headaches guides the clinician. In many cases diagnosis may have to be made by exclusion. For example, migraine can present as cyclic vomiting or benign paroxysmal vertigo. In order to understand these seemingly bewildering syndromes the mechanism of migraine must be understood.
Migraine is generally thought of as an inherited disorder, where there is an abnormality of neurohumoral control over the caliber of intracranial and extracranial arteries.2"4 Derangements in serotonin metabolism have been implicated.5-10 The initial phase of migraine involves vasoconstriction of intracranial arteries, associated with a rise in serum serotonin levels released from platelets. It has been hypothesized that there may be an abnormal release of serotonin from platelets in migraineurs.1113 The administration of reserpine, which releases serotonin from tissue stores, can precipitate migraine in susceptible individuals. Vasoconstriction results in relative ischemia of various regions of the brain leading to the hallmark of a migraine episode, the aura, or prodrome. The aura is generally brief, lasting five to 30 minutes, and is followed by vasodilatation of extracranial vessels and a pounding headache. During the phase of extracranial vasodilatation serum serotonin levels decrease and urine metabolites of serotonin are found in excess.
The various types of migraine are classified primarily by the aura. In classic migraine, a focal aura is followed by a contralateral throbbing headache. In the more frequent common migraine, the aura is absent or not well delineated and the headache may be unilateral or bilateral. Gastrointestinal symptoms with nausea and/or vomiting are prominent in both forms. The nature of an aura is determined by the site of cerebral ischemia. When the anterior cerebral circulation is affected (branches of the internal carotid artery), there are visual symptoms such as scotomas, visual field defects, hemiparesis, unilateral paresthesias, and dysphasia. In adults, the anterior circulation is most frequently affected. Children, however, may also suffer from basilar artery migraine where prodromal symptoms are ascribable to vascular changes in the distribution of the basilar artery and its branches. This form was initially described by Bickerstaff who noted this variant among adolescent females.14 Bilateral visual loss from ischemia in the region of the posterior cerebral arteries and occipital lobes may occur. Vertigo, ataxia, bilateral sensory symptoms, tinnitus and dysarthria result when the brain stem is affected. In unusual forms there may be coma from ischemia of the ascending reticular activating system. Other types of migraine that manifest less frequently are ophthalmoplegic and hémiplégie forms. These result in transient, and, rarely, permanent neurologic deficits and are categorized under complicated migraine. The previously mentioned migraine equivalents present as paroxysmal episodes of diarrhea, abdominal pain, confusion, and disorders of sleep, mood, and behavior. Given the myriad possible presentations it is understandable if in certain cases the pediatrician or neurologist is hard put to make a clinical diagnosis. Various criteria have been developed to assist in the diagnosis of migraine. The reader is referred to Prensky's criteria15 and Table 4. To diagnose childhood migraine, the major criterion, that of paroxysmal headaches occurring over time, must be fulfilled. Three of six minor criteria must be present as well. Nausea and/or vomiting (gastrointestinal symptoms) are present in approximately 80% of children. An aura is found in 10% to 50% and is usually visual. A throbbing headache is documented in at least half the children and a unilateral headache to a similar degree. Relief with sleep may be a prominent finding, and as mentioned, a positive family history is seen in approximately one half of cases.1,16 All of these parameters must be directly pursued in the history. Photophobia is not included in the criteria, but is present in a majority of patients.
Also helpful in making the diagnosis is the presence of little-known associated features in many patients. Up to 50% may suffer from car-sickness,1 ?? and 20% to 30% from somnambulism.18
TREATMENT OF MIGRAINE
For symptomatic therapy, analgesics like aspirin and acetaminophen are frequently helpful. In adolescents the pain may be more refractory and occasionally codeine has to be added. A significant number of patients benefit from ergotamine tartrate. This agent prevents the painful extracranial arterial vasodilatation phase.19 For true effectiveness, it must be taken at the very onset of migraine episode, for once vasodilatation is well-advanced, the vasoconstrictive effects of ergot are neutralized. Ideally, it should be kept in a wallet or purse so that it can be taken at the first sign of symptoms. Ergot can be taken orally, or as a sublingual preparation. In children where vomiting is a prominent symptom, rectal suppositories are available. Cafergot® contains caffeine which potentiates the vasoconstrictive effects of ergot as well as its absorption. To avoid ergotism it is prudent not to exceed 2 mg/day or 4-6mg/week doses. Symptomatic relief can also be obtained by rest in a dark room, cold compresses, or a cold shower. Some children respond to inhalation of 100% oxygen, which decreases cerebral blood flow.
Daily prophylactic therapy is prescribed only if headaches are frequent and severe. Some children miss classes and schoolwork begins to suffer. When prophylaxis with various drugs is undertaken it should always be done with an endpoint in sight. Generally, six months is a reasonable period. Cyproheptadine, a serotonin antagonist, is occasionally effective and can be given at a dose of 4mg two to three times daily. Its only significant side effect is drowsiness.
Various controlled studies have shown propranolol to be a highly effective agent in prophylaxis. Its anti-migraine activity is the result of blockade of β2-adrenoceptor-mediated extracranial vasodilatation.19 An association between migraine and mitral valve prolapse has been found in some patients.20,21 The efficacy of propranolol in a given individual may in part be determined by this association. Methysergide is also a very effective prophylactic agent. It, too, is a serotonin antagonist. Its use is reserved for severe cases that are refractory to other forms of therapy. It is not comfortably included in the armamentarium of most pediatricians. When utilized, it is usually prescribed for a limited course of three to six months to avoid the most serious complication from this agent, which is peritoneal fibrosis. Its efficacy, however, must not be underestimated. Of non-pharmacologic therapies, biofeedback has been especially promising and should certainly be tried before prolonged or repeat prophylaxis is contemplated.22,23
Certain patients have migraines precipitated by tension, fatigue, alcohol, cheese, monosodium glutamate, hot dogs, chocolate, a missed meal, or bright lights.24,25,26 For others, headaches unfortunately occur at times of relaxation. The above should be kept in mind for an occasional patient can be treated preventively.
CLINICAL DIAGNOSIS OF MIGRAINE
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CLINICAL DIAGNOSIS OF MIGRAINE