Differential diagnosis of headache

ABDO has awarded this article 2 CET credits (GD). The College of Optometrists The College of Optometrists has awarded this article 2 CET credits. There are 12 MCQs with a pass mark of 60%. Gavin Giovannoni FCP, PhD Differential diagnosis of headache Headache is a very common symptom in optometric practice. Patients presenting with headache and visual symptoms are an important sub-group. Although the majority of headaches are benign, they can be a harbinger of a more serious underlying disease. A systematic clinical approach to headache is essential to make an accurate diagnosis and help triage patients for further clinical investigations. This article covers pain mechanisms, the pathophysiology of migraine, headache classification, a clinical approach to headache, ocular pain syndromes relevant to the practising optometrist, important visual signs to look for and headache associated with raised intracranial pressure. Broadly speaking a headache refers to any head pain. However, the term headache is usually reserved for pain involving the cranium and contiguous structures. A systematic clinical approach to headache is essential to rule out a serious underlying disease, to make an accurate diagnosis, to treat the headache effectively and to know when it is appropriate to refer for a medical opinion and possible investigations. Pain mechanisms and pathophysiology of migraine Headaches arise from the pain-sensitive structures of the head (Figure 1). The brain parenchyma is actually insensitive to pain, but is responsible for the perception of pain. Pain arises from the stimulation of polymodal nociceptive nerve endings. Numerous stimuli are capable of eliciting painful signals and are broadly grouped as mechanical, thermal or chemical stimuli. Nociceptive signals are conveyed to the spinal cord and brain stem by unmyelinated and small myelinated sensory axons, which travel in the trigeminal (Vi-iii), glossopharyngeal (IX), vagus (X) and cervical (1-3) nerves (Figure 1). Most headaches occur as a result of mechanical traction, compression, or chemical irritation of the pain-sensitive structures listed in Table 1. Patients with altered intracranial pressure, which causes compression and traction of intracranial structures, usually present with headache. Recent evidence points to migraine as a primary CNS disorder 1. Focal neuronal dysfunction, probably in the posteroventral hypothalamus, causes alterations in the intracranial blood vessels within pain-producing meningeal structures that give rise to headache pain. Genetic factors are probably responsible for altering the threshold to migraine-specific trigger factors. The nature of focal CNS dysfunction, which causes migraine, has not been established. However, it has been hypothesised to involve depression and activation of brain stem monoaminergic nuclei that are part of the central autonomic, vascular and pain control centers. Vasodilatation of intracranial Table 1 Pain-sensitive structures of the head A. Extracranial Scalp - skin, subcutaneous tissue, and periosteum of skull Joints capsules - particularly the cervical and temporo-mandibular joints Muscles - scalp and paraspinal muscles Paranasal sinuses Teeth Ocular contents B. Intracranial Blood vessels - arteries, veins and venous sinuses Meninges - arachnoid, pia and dura mater Cranial nerves Table 2 Simplified headache classification based on the International Headache Society Classification A. Primary headache syndromes Migraine headache Tension-type headache Cluster headache Chronic Paroxysmal hemicrania B. Secondary headache syndromes Head trauma Vascular disorders Non-vascular intracranial disorders Substances and substance withdrawal Non-cephalic infection Metabolic abnormality Focal diseases of the cranium, neck, eyes, ears, teeth, mouth, or other facial or cranial structures Cranial neuralgias, nerve trunk pain, and deafferentation pain C. Other types of headache or facial pain D. Non-classifiable headache extracerebral blood vessels, with consequent stimulation of trigeminal pain pathways, generates the headache pain associated with migraine. This process is thought to cause release of vasoactive sensory neuropeptides, which augment the pain response. Serotonergic agonists selectively vasoconstrict intracerebral blood vessels via their action on 5-HT1B receptors and inhibit nociceptive transmission via their action on 5-HT1D receptors. Therefore, they are effective as anti-migraine agents and support the above trigemino-vascular hypothesis 2. Headache classification Table 2 is the simplified classification of headache formulated by the International Headache Society 3. The classification distinguishes between primary headache syndromes, where no obvious underlying cause for the headaches can be found, and secondary headache syndromes, where the headache is a symptom of an underlying medical problem. This simple theme of classifying headaches into those with and those without an underlying cause forms the basis of the systematic clinical approach to headache sufferers. History & examination A systematic approach to any clinical problem, and headache is no exception, begins with a thorough history and examination. Table 3 and Figure 2 tabulate the important points that need to be clarified. The onset of the headache is very important, 30 May 5, 2000 OT

Module 2 Part 5 i.e. was its onset sudden or instantaneous over a few seconds, rapid over seconds to minutes, or gradual over minutes to hours? Sudden or instantaneous headache, particularly if a first headache, should alert the practitioner to the possibility of a subarachnoid haemorrhage, especially if there are associated symptoms and signs of meningeal irritation. This type of headache should be treated as a medical emergency. Grading the severity of the headache is sometimes useful diagnostically and helps to assess efficacy of therapy. A simple 10-point scale is the most commonly used with zero representing no pain and 10 the worst pain ever experienced. The location of the headache is very useful diagnostically. Is the pain focal, unilateral or generalised? The nature of the pain should be established. Is the pain dull, sharp, continuous or throbbing? Does it have a sharp shooting component, like electricity? This is described in neurological texts as lancinating, which is usually due to nerve root irritation or neuralgia. Are there associated symptoms accompanying the headache, such as nausea, vomiting, photophobia, phonophobia (pain made worse by loud noise), osmophobia (pain made worse by strong smells) or mechanosensitivity (pain made worse by head movement)? Although these symptoms are non-specific being due to meningeal irritation, they are very common in migraine and aid in making the diagnosis. Are there any premonitory symptoms? These are common in migraineurs (people who suffer from migraine) and include feelings of being detached, energised, strange or even high. Some migraineurs have sensory illusions prior to developing a headache. For example, colours appear brighter, sounds more sharp and smells more acute. Symptoms suggestive of migrainous auras should be actively sought. These differ from premonitory symptoms in that they occur in association with the migrainous headache. Auras also have a characteristic pattern. They are initially positive in nature and are then followed Figure 1 Dermatomes or zones of skin innervation of the trigeminal nerve divisions and upper cervical roots where pain may occur in neuralgias. Note C1 does not have a cutaneous dermatome. C1 innervates the meninges of the posterior cranial fossa. C1 stimulation causes neck stiffness an important sign of meningeal irritation which occurs in meningitis and subarachnoid haemorrhage by negative neurological symptoms. For example, migraineurs with visual auras usually describe a wave of moving lights, which usually take the form of zigzag lines that are followed by a scotoma. The auras usually obey the cortical rules of representation, in that they do not cross the vertical meridian. The tempo of the aura is important and takes minutes rather than seconds to develop. Although visual auras are most frequently associated with migraines, other areas of the cortex can be involved producing for example tinnitus, paraesthesia, weakness, aphasia, etc. It is useful to enquire about physical activity during the peak of the headache - this helps diagnostically and therapeutically. Patients with severe migraine tend to lie down, preferably in a dark and quiet room. Cluster headache sufferers on the other hand tend to move around during the height of their attack. A careful history of relieving and aggravating factors should be taken. Postural changes and manoeuvres, which alter intracranial pressure, are useful to assess whether or not the headache is due to a change in intracranial pressure. Pain made worse by lying down, coughing or straining and relieved by standing up suggests intracranial hypertension. The response of the pain to over the counter analgesics, massage, stress, exercise and eating help to guide therapy of the primary headache syndromes. Establishing whether there are any obvious precipitating factors such as red wine, mature cheeses, Chinese food, ice-cream, Table 4 Fundoscopic signs of papilloedema A. History Headache Onset Severity Location Radiation Nature of pain Associated symptoms Premonitory symptoms Positive or negative neurological symptoms Activity during headache Effect of headache on daily activities Relieving and aggravating factors Precipitating factors Pattern (headache diary) Frequency Intermittent or cluster Diurnal or nocturnal Family history B. Examination Signs of raised intracranial pressure Cranial pathology Table 3 Points to clarify on history and examination hunger, exercise, sex, caffeine withdrawal, bright light or sun exposure, reading, the wearing of hats, menstruation, etc, helps diagnostically. When a patient presents with an intermittent headache, it is important to establish the pattern of the headaches, including the frequency. If they occur very frequently, for example daily, it is useful to enquire how many pain-free days the patient has had in an average month. Is there a pattern to the headaches? Do they occur in clusters? Is there a diurnal variation? Are they related to the menstrual cycle? Answers to these questions can help the practitioner to classify headache syndromes correctly. A family history of headache should be sought, especially in suspected migraineurs, as the familial incidence of migraine approaches 60% supporting a strong hereditary predisposition. The clinical examination should focus on signs of raised intracranial pressure and focal neurological deficits. It is important that the examiner does a fundoscopic examination to look for the signs of papilloedema (Table 4). This should be followed by an examination of the head and neck looking for clues to the causes of headaches. The scalp should be palpated to see Loss of spontaneous venous pulsations (absent in approximately 20% of the normal population) Increase in the retinal venous to arterial ratio Increased redness and blurring of the disc margin Swelling of the disc with loss of the cup (the disc may be raised depending on the severity) Oedema of the retinal nerve fibre layer Haemorrhages and exudates on and around the disc 31

ot Table 5 Differential diagnosis of orbital and periorbital headache Acute angle closure glaucoma Refractive errors (hyperopia) excessive accommodation Strabismus/amblyopia/diplopia excessive ocular muscle activity Uveitis Posterior scleritis Paranasal or paraorbital sinusitis Cluster headache Migraine Short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) Carotid artery dissection Orbital apex syndromes Orbital myositis Cavernous sinus disease Ophthalmic neuralgia Giant cell, cranial or temporal arteritis Optic neuritis Ophthalmodynia fugax (ice-pick headache syndrome) 32 if there is any tenderness, neuralgic trigger points or thickening of the extracranial arteries. Similarly, the cervical spine, temporomandibular area and the areas over the paranasal sinuses should be palpated to look for focal pathology. Examination of the teeth may be helpful. Exaggerated flattening of the teeth usually indicates bruxism, the habitual grinding of teeth during sleep, which can be associated with early morning headaches. Sharp pain on tapping the teeth may be a clue to the presence of a periapical granuloma or abscess, which can present as non-specific headache. Ocular pain or headache syndromes In the absence of a conjunctival injection or other obvious eye disease, headache and eye pain rarely have an ophthalmic cause, i.e. a white eye is not the cause of a painful eye. Table 5 lists the common causes of ocular pain that should be considered in the differential diagnosis of patients presenting with orbital or periorbital headache. Table 6 Well-established eponyms associated with ophthalmic neuralgia Reader s syndrome Horner s syndrome and painful ophthalmic neuralgia May 5, 2000 OT The following brief reviews are limited to neurologically related topics. Tolosa-Hunt syndrome Painful external ophthalmoplegia due to granulomatous inflammation in the orbital apex and/or cavernous sinus Cluster headache Cluster headaches are much less common than migraine. Eighty-five percent of sufferers are male, typically in their 40s and 50s, usually without a preceding history of headaches. The headaches are typically very severe, unilateral and nocturnal. The pain is usually localised to the face and orbit (retro-orbital), and is associated with ipsilateral tearing, conjunctival injection, nasal congestion and facial flushing. There is a transient oculosympathetic paresis Gradenigo s syndrome VI nerve palsy and ophthalmic and possibly maxillary neuralgia due to inflammation in the apex of the petrous temporal bone. The VII and VIII cranial nerves may also be involved Figure 2 A simple diagnostic algorithm (Horner s Syndrome) which may persist after the attack. The headaches occur in clusters and are commonly precipitated by alcohol. The pain is often so severe that patients may feel suicidal. Unlike migraineurs, cluster headache sufferers often relieve their pain by walking around. History is often typical making a clinical diagnosis relatively easy. Migraine Migraine is a periodic paroxysmal headache affecting up to 10% of the adult population. It is two to three times more common in females, with the majority of subjects suffering their first attack before the age of 30. There is often a positive family history of migraine. Stress, foodstuffs, menstruation and bright lights, to name but a few, may precipitate migraine headaches. The pain is usually unilateral but can be bilateral and is characteristically pulsatile in nature and associated with nausea, vomiting, photophobia, phonophobia, osmophobia and mechanosensitivity. During an attack sufferers tend to lie down in a dark, quiet room. Frequent headaches are often debilitating and affect daily activities. The acute attack lasts for four to 72 hours. A sub-group of migraineurs develops focal neurological symptoms prior to, or during an attack, which are referred to as the aura. Only rarely does a migraine aura present as monocular visual loss.

Module 2 Part 5 SUNCT syndrome Short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT syndrome) is a newly recognised but rare headache syndrome 5. There is a male preponderance with a male to female ratio of approximately 5:1. The syndrome usually has its onset around the fifth and sixth decade. Attacks are characterised by moderate to severe orbital or periorbital headaches, which tend to be burning, electrical, or stabbing in character. Attacks always recur on the same side, with an unpredictable pattern. Periods of remission are variable. Prominent, ipsilateral, conjunctival injection, tearing and rhinorrhea or nasal obstruction accompany the attacks. A typical episode is composed of paroxysms (sudden attacks) of brief pain lasting from 60 seconds up to five minutes. During an attack, the frequency of the paroxysms vary from less than one daily to more than 30 per hour. In the majority of cases, investigations are normal. However, some patients with SUNCT have ipsilateral structural intracranial pathology. The attacks are usually resistant to standard therapies, but respond to indomethacin. Carotid artery dissection Carotid artery dissection often presents with ocular pain localised to the temporal, frontal or orbital area, which may be associated with welllocalised neck pain over the carotid artery 6. Carotid dissections cause an ipsilateral Horner s syndrome, due to damage of the sympathetic plexus that runs in the carotid sheath, in approximately 40% of cases. Dissection may occur in normal arteries in relation to trivial trauma or in association with diseased arteries (e.g. atheroma). Carotid dissection may be associated with stroke due to propagation and embolisation of thrombosis in the distal artery. Distal embolisation of the clot from the dissection can present as transient ischaemic attacks. Orbital apex & cavernous sinus disease Numerous diseases that involve the orbital apex and cavernous sinus present with retro-orbital headache 7. The pain may vary in character but is often exacerbated by eye movement. Associated signs include visual loss, proptosis and restriction of eye movements, ocular palsies and, in the case of cavernous sinus disease, venous congestion of the fundus. Ophthalmic neuralgia Ophthalmic neuralgia usually develops as a complication of herpes zoster that involves the ophthalmic division of the trigeminal nerve. Neuralgia is more common in the elderly. However, it may occur after trauma or other pathologies that result in nerve injury. The pain associated with the condition is characteristically intermittent and is described as lancinating in nature. The pain may be precipitated by sensory stimuli, e.g. a cold breeze, touch or the combing of hair. Patients are often severely disabled and commonly develop a superimposed reactive depression. Certain patients develop a superimposed chronic neuropathic pain disorder. Table 6 lists some well-established eponyms associated with ophthalmic neuralgias. Giant cell, cranial or temporal arteritis Giant cell arteritis (GCA) is a systemic disease of unknown aetiology, characterised pathologically by an inflammatory arteritis of medium sized blood vessels. It is almost exclusively a disease of the elderly, i.e. over 60 years of age. GCA is characterised by periorbital or temporal headaches associated with tender and often nonpulsatile temporal arteries. The temporal arteries may be thickened with localised swelling and redness. Some patients complain of jaw claudication due to involvement of the mandibular artery. Involvement of the posterior choroidal arteries can result in anterior ischaemic optic neuropathy, which characteristically causes a swollen, ischaemic, pale optic disc associated with a characteristic altitudinal visual field defect. Patients with GCA have very high erythrocyte sedimentation rates (ESR). A temporal artery biopsy is required to make a definitive diagnosis. Temporal arteritis is treated actively with corticosteroids. Optic neuritis Optic neuritis is an inflammatory demyelinating disease of the optic nerves, which is strongly associated with multiple sclerosis 8. The condition is usually unilateral and typically causes a central or paracentral scotoma. Predominant signs are visual loss, with a centrocecal scotoma, and an afferent pupillary defect. Retro-orbital pain, which is exacerbated by eye movement, occurs in the majority of patients. Ophthalmodynia fugax Ophthalmodynia fugax (ice-pick headache syndrome) is a brief one to two second stabbing pain involving the eye. Patients suffering from ophthalmodynia fugax usually have numerous attacks during a day. These headaches are common in migraineurs, and are not associated with any significant intracranial pathology. They seldom require any specific therapy. Headaches with important eye signs Headaches, not specifically localised to the eye or orbital region, presenting with ocular signs should alert one to the possibility of intracranial pathology, especially if the headaches have features suggestive of raised intracranial pressure. Possible signs include ocular nerve or gaze palsies, conjugate eye movement disorders, Horner s syndrome, papilloedema and visual field deficits. Raised intracranial pressure Raised intracranial pressure causes a generalised headache that maybe more severe in the occipital region. It is typically made worse by lying down, straining, coughing or any Valsalva manoeuvre which increases intracranial pressures. It is present on awakening and improves during the day. Other symptoms include nausea, vomiting or blurring of vision. Papilloedema, with an enlarged blind spot, is a late manifestation. Transient visual obscurations occur with transient increases in intracranial pressure due to oedema of the retinal nerve fibre layer. False localising neurological signs (e.g. III nerve palsy) imply an intracranial compartment shift. In contrast, low intracranial pressure headaches, which commonly occur post lumbar puncture, are made worse by standing up. These usually resolve spontaneously but occasionally require an epidural blood patch to seal the dural tear, i.e. fresh blood from the patient is taken and injected into the epidural space where it clots and seals the dural tear. Conclusions Headache is a very common clinical problem. Although the majority of headaches are benign, some potentially serious medical disorders present with headache as their initial and/or main symptom. As optometrists often see patients with visual dysfunction and headache, knowledge of the common headache syndromes is vital. This, coupled with a systematic clinical approach, is essential to assess which patients require further investigations and specialist medical referral. About the author Gavin Giovannoni is Clinical Senior Lecturer in Neuroimmunology at the Institute of Neurology. He is also Honorary Consultant Neurologist at the National Hospital for Neurology and Neurosurgery, Queen Square, London. His main interests are inflammatory diseases of the central nervous system. References 1. Hargreaves, R.J. and Shepheard, S.L. (1999) Pathophysiology of migraine - new insights. Can. J. Neurol. Sci. (Suppl. 3): S12-19. 2. May, A. and Goadsby, P.J. (1999) The trigeminovascular system in humans: pathophysiologic implications for primary headache syndromes of the neural influences on the cerebral circulation. J. Cereb. Blood Flow Metab. 19: 115-127. 3. International Headache Society (1988) Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Headache Classification Committee of the International Headache Society. Cephalalgia 8 (Suppl. 7): 1-96. 4. Mathew, N.T. (1997) Cluster headache. Semin. Neurol. 17: 313-323. 5. Pareja, J.A. and Sjaastad, O. (1997) SUNCT syndrome. A clinical review. Headache 37: 195-202. 33

ot 6. Kerty, E. (1999) The ophthalmology of internal carotid artery dissection. Acta. Ophthalmol. Scand. 77: 418-421. 7. Weber, A.L., Romo, L.V. and Sabates, N.R. (1999) Pseudotumor of the orbit. Clinical, pathologic, and radiologic evaluation. Radiol. Clin. North Am. 37: 151-168. 8. Purvin, V. (1998) Optic neuritis. Curr. Opin. Ophthalmol. 9: 3-9. Suggested reading Acheson, J.F. and Sanders, M.D. (1996) Neuro-ophthalmic aspects of migraine and other headaches. In: Common Problems in Neuro- Ophthalmology. Series 32. Ed. Acheson, J.F. and Sanders, M.D. Saunders, London. Corbett, J.J. (1983) Neuroophthalmic complications of migraine and cluster headaches. Neurol. Clin. 1: 973-995. Goadsby, P.J. (1999) Mechanisms and management of headache. J. R. Coll. Physicians. Lond. 33: 228-234. Kairys, D.J., Tibbetts, C. and Saliba, K. (1983) A standard optometric headache history. J. Am. Optom. Assoc. 54: 165-176. Pearce, J.M.S. (1996) Headache. In: The Oxford Textbook of Medicine. 3rd Edition. Ed. Weatherall, D.J., Ledingham, J.G.G. and Warrell, D.A. Publishers Oxford Medical Publishers, Oxford. Rapoport, A.M. (1994) Severe headache: focus on migraine. Neurology 44 (Suppl. 3): S3-31. Saper, J.R. (1999) Headache disorders. Med. Clin. North Am. 83: 663-690. Spiritus, M. and Boschi, A. (1999) Neuroophthalmologic manifestations of systemic disease. Curr. Opin. Ophthalmol. 10: 314-319. An answer return form is included in this issue. It should be completed and returned to: CPD Initiatives (NOE5), OT, Victoria House, 178-180 Fleet Road, Fleet, Hampshire, GU13 8DA by May 31. Multiple choice questions Differential diagnosis of headache 1. Which one of the following statements is incorrect regarding the visual auras experienced by migraineurs? a. They are initially neurologically positive and then negative b. Initially, they usually take the form of zig-zag patterns c. They obey the cortical rules of representation d. The tempo of the aura usually takes seconds to develop 2. Which one of the following statements is correct regarding migraine? a. It is associated with unilateral oculosympathetic paresis (Horner s syndrome) b. It usually occurs after the age of 30 c. It is typically bilateral d. It is more common in females 3. A unilateral retro-orbital headache followed by a transient Horner s syndrome is most likely to be due to which one of the following? a. An orbital apex syndrome b. Migraine c. Cluster headache d. Temporal arteritis 4. Which one of the following statements is correct regarding optic neuritis? a. It is usually bilateral b. It results in a central scotoma with colour desaturation c. It typically causes an altitudinal visual field defect d. It is usually painless 5. Features of Tolosa-Hunt syndrome are likely to include all of the following except which one? a. Eye pain b. Horner s syndrome c. External ophthalmoplegia d. Papilloedema 6. Cavernous sinus disease is not usually associated with which one of the following? a. Ocular pain exacerbated by eye movement b. Ocular palsies c. Venous congestion of the fundus d. Temporal headaches 7. Features of Raeder s syndrome include which one of the following? a. Non-specific symptoms b. Ptosis c. Mydriasis d. Visual auras 8. Which one of the following Ice-pick headaches usually: a. are non-benign b. are common in migraineurs c. require specific therapy d. are characterised by prolonged chronic attacks 9. Which one of the following Temporal arteritis: a. is treated conservatively b. usually causes visual loss due to involvement of the central retinal artery c. is associated with reduced inflammatory markers d. is a disease restricted mainly to the elderly (over 60 years of age) 10. Which one of the following statements is incorrect regarding carotid artery dissection? a. It is a cause of a painful Horner s syndrome b. It causes a red eye c. It can present with transient ischaemic attacks d. It is associated with neck pain 11. Which one of the following SUNCT syndrome: a. is common b. occurs more commonly in females c. responds to indomethacin d. is commonly associated with intracranial pathology 12. Which one of the following Headaches due to low intracranial pressure: a. always require an epidural blood patch to seal the tear b. are relieved by standing up c. can cause papilloedema d. commonly occur after a lumbar puncture 34 May 5, 2000 OT