Migraine Visual Aura

NormalPowerPoint Presentations: Migraine Visual Aura: http://library.med.utah.edu/NOVEL/Wray/PPT/Migraine_Visual_Aura.ppt Shirley H. Wray, M.D., Ph.D., FRCP, Harvard Medical School Childhood Migraine: http://library.med.utah.edu/NOVEL/Wray/PPT/Childhood_Migraine_disease.ppt Shirley H. Wray, M.D., Ph.D., FRCP, Harvard Medical SchoolEpisodic Dimming of VisionThe patient is a 9 year old right handed boy who developed headaches in 1993 at the age of 8. At that time he told his mother that he had bad headaches starting at the back of the head, usually bioccipital, spreading over the top of the head to his forehead. The headaches were short in duration lasting 8 to 15 minutes, responded to Advil, and were accompanied by an unpleasant feeling in his stomach described as nausea. He admitted to photophobia and phonophobia. The headaches were not severe enough for him to lose time from school. He was not seen by a physician at that time. In 1994, he started to complain of transient monocular dimming of vision in his right eye with the objects that he was looking at appearing darker compared to the left eye. There was no loss of vision and no positive phenomena such as photopsias or sparks. At this time, he was referred to an ophthalmologist who documented a normal eye examination. Six months later the episodes of visual dimming OD occurred almost every day, lasting 1 to 2 minutes with full recovery. His pediatrician was consulted and found no abnormality on examination. In 1995 he was referred to a pediatric neurologist because the episodes of dimming of vision now involved both eyes and he complained of loss of vision. The neuropediatrician diagnosed migraine and obtained a brain MRI to rule out an arteriovenous abnormality of some other cerebral cause because: 1. There was no family history of migraine and 2. Headaches were provoked by exertion. The MRI with Gadolinium was normal. An electroencephalogram was normal. RE: Stress: The patient correlated his attacks of visual dimming, with or without headache, to "a bad day at school". He said "everyday is a bad day" and he defined ‘a bad day' as due to: • His fellow students fighting • Boys make fun of him because he has scar tissue on his face following removal of a birth mark • Boys get annoyed with him because he tells them he can't play with them because his eyes are bad. • Other boys think he is stupid because he has bad eyes • They think he is making it up that he has bad eyes. • Also, there is a troublemaker in school and he makes it uncomfortable for all the kids. Kyle likes school and he is in the top 3 in his class. He likes math and science and hates reading and spelling. He is not known to be dyslexic. He is good at sports, plays soccer and basketball. He had two headaches provoked by running. His headache is not precipitated by excitement but more by anxiety. He was referred for evaluation in 1995 and was very articulate in describing his migraine attacks. He classified them as follows: 1. Visual aura alone lasting less than 5 minutes 2. Visual aura for 5 to 10 minutes followed by headache lasting 10 minutes up to 1 hour. 3. Headache alone, average 1 per month lasting 1 hour By 1995, he was experiencing a stereotypic visual aura of a bright light in the center of his visual field "like a bright light bulb". The light bulb seemed to flash on and shimmer and occasionally around the edge of the bright "sunlight" he saw "little sparks". The hallucination looked "like a sparkler going off in front of him"'. He was unable to see past it. He was not frightened by the attacks of visual aura because he knew from experience that his vision would return to normal. RE: Therapy: The approach to therapy was: 1. His mother met with the school teacher in charge of his class to alert her regarding the stressful situation at school. 2. Inderal 20 mg 1 tablet at 7 a.m. before he went to school, 1 tablet at 4 p.m. daily. After a reduction of stress at school and starting on Inderal, the frequency and severity of his headaches improved.This 9 year old boy with visual aura and migraine headaches describes the aura as a bright white light in the center of his vision, flashing on and followed by a blind spot (scotoma) that impairs his vision for a short time. His description is consistent with a diagnosis of a scintillating scotoma highly characteristic of migraine. He tends to get a warning that the aura is coming on but he was unable to describe the warning symptoms. He also stated that on occasions the visual aura is followed by a bifrontal headache that spreads around his head to the occipital region, accompanied by nausea, photophobia and phonophobia. Kyle was reluctant in the interview to admit that his headaches can be provoked by a bad day at school. Fortunately he never lost time from school and headache did not interrupt his homework. In the second half of the interview Kyle described another visual phenomenon - macropsia. He observed seeing one foot, possibly the right, larger than the left and his right hand larger than the left hand. Macropsia lasted for a few seconds only. Comment: A number of visual phenomena have been reported in children with migraine. Children, like Kyle, often experience transient monocular visual loss, which has been termed ocular or retinal migraine. The episodes of dimming of vision have no hallucinatory component. The typical duration of monocular visual dimming is 5 to 45 minutes but an attack can last much longer. Visual aura experienced by children with migraine include unformed simple flashes, phosphenes, scotoma, specs, colored or black and white geometric forms or shimmering images. These hallucinations may present in a hemifield distribution but many occur in the center of the visual field, as in this boy. In some children, complex visual hallucinations can occur with multiple images of animals, people and elaborate scenes. In 1971 Hachinski et al presented a paper on "Visual symptoms in childhood migraine" at the 23rd annual meeting of the American Academy of Neurology. Perhaps because of my interest in visual aura, I was invited to discuss the paper. The children were among 244 children with migraine seen at the Hospital for Sick Children in Toronto between 1959 ad 1971. One hundred of these children experienced visual phenomena associated with headache, an incidence of 41%. Sixty-seven of the one hundred were recalled and interviewed independently by a clinician and medical artist regarding visual experiences. The artist encouraged the child to draw what he or she had seen during the attack and these pictures were reproduced without changes. The mean age of onset of headache was 8 years. The mean age of onset of visual phenomena was 9 years. The most common visual symptom in order of frequency were: visual impairment, scotomas, distortion and hallucinations.(10) After the meeting the investigators kindly gave me a collection of the illustrations. The complexity and sophistication of the hallucinations are remarkable. Children with migraine may also experience metamorphopsia, (distortion of an object), micropsia (an object appears smaller) and/or macropsia (an object appears larger) - the Alice in Wonderland Syndrome. Other forms of geometric mosaic vision in which images split into fragments are also described. Macropsia is a less common accompaniment of migraine than micropsia. Kyle describes hemi-macropsia, both the right hand and the right foot appeared larger than normal. (1, 5). Macropsia in migraine is likely to be the result of cerebral abnormality of size constancy, the process by which the perceived size of an object is made independent of the extent of its retinal projection (5). Children with migraine headaches may also experience concurrent events such as hallucinations of movement, paresthesiae, déjà vu or j'amais vu, language disturbance, vertigo, photophobia, amnesia, dissociative states, or autonomic symptoms such as pallor, dizziness or sweating. In most young patients, headache follows the aura within minutes if not immediately. One syndrome requiring emphasis in the differential diagnosis of childhood migraine, is Benign Childhood Epilepsy with occipital spike waves. This idiopathic epilepsy syndrome begins between ages 5 and 9 and ceases spontaneously in the teenage years. Seizures are characterized by blindness, hallucinations of both simple and formed types or both, and it may progress to motor or partial complex seizures. Some children develop nausea and headache following the visual seizure leading to an erroneous diagnosis of migraine. The diagnosis is established by occipital spike-waves occurring during eye closure on electroencephalography.(8)Brain imaging studies suggests that important modulation of the trigeminovascular nociceptive input comes from the dorsal raphe nucleus, locus ceruleus, and nucleus raphe magnus. (7)See pictorial representation: Figures 1 and 2 courtesy PJ Goadsby, M.D. D.Sc. (7) Attached to this case is a PowerPoint presentation showing the Figures.Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. (13, 14) However, it has been challenging to test this hypothesis in human cerebral cortex. Data from functional MRI studies in human visual cortex strongly suggest that an electrophysiological event such as CSD does in fact generate the aura in human visual cortex. (11) Visual aura are characterized by a wave of cerebral hypoperfusion-oligemia that passes across the cortex at the characteristically slow rate of 2 to 6 mm per minute. Woods R.P. et al described a patient who, during positron emission tomography (PET), fortuitously had an attack of common migraine. Highly sophisticated measurements showed a reduction in blood flow that started in the occipital cortex and spread slowly forward into the temporal and parietal lobes bilaterally.(21) (View ID41-1 Migraine/PET Study) Cutrer F. M. et al using perfusion-weighted magnetic resonance imaging (MRI) corroborated the finding of diminished occipital cerebral blood flow during the aura in four patients (6). Cortical hyoperfusion is a response to depressed neuronal function and it is still clearly present when the headache starts. These findings, together with direct evidence that the local oxygen supply is more than adequate, make the notion that migraine is simply a vascular headache untenable. The pain of migraine headache is thought to have a neurogenic basis.(9, 15) The key pathways for the pain are the trigeminovascular input from the meningeal vessels, which passes through the trigeminal ganglion and synapses on second order neurons in the trigeminocervical complex. These neurons, in turn, project through the quintothalamic tract, and after decussating in the brainstem, form synapses with neurons in the thalamus. (Figure 1 Pictorial representation (9)). Activation of these fibers also releases substance P, calcitonin gene-related peptide and other peptides into the vessel wall, which serves to dilate the cerebral vessels and increase the permeability. The throbbing headache is thus induced. Migraine also involves activation of brainstem pathways that normally modulate sensory input and data supports the idea that the pathogenesis of migraine is related to an imbalance in activity between brain stem nuclei regulating antinociception and vascular control. (15) The pathways involved include a reflex connection between neurons and the pons in the superior salivary nucleus which results in a cranial parasympathetic outflow that is mediated through the pterygopalantine, otic and carotid ganglia. This trigeminal-autonomic reflex is present in normal persons and is activated most strongly in patients with trigeminal-autonomic cephalgias (e.g. cluster headache); it may be active in migraine. Brain imaging studies suggests that important modulation of the trigeminovascular nociceptive input comes from the dorsal raphe nucleus, locus ceruleus, and nucleus raphe magnus. (Figure 2 Pictorial representation (9)).In a related disorder, known as hemiplegic migraine, linkage analysis studies have localized the responsible gene to chromosome 19 in one third of families; in other families the gene has localized to chromosome 1; and yet others no linkage has been found. The gene on chromosome 19 codes for a voltage-gated calcium channel protein, which raises the provocative possibility that other forms of migraine are also due to an ion channel disorder. In migraine with and without aura, an underlying genetic factor is implicated, although it is expressed in a recognizable mendelian pattern (autosomal dominant) in a relatively small number of families. The puzzle is how this genetic fault is translated periodically into a regional neurologic deficit, unilateral headache or both.The treatment of migraine is subdivided into two parts. • Control of the individual's acute attack and • Prevention. The time to initiate treatment is during the neurologic - visual prodrome at the very onset of the headache. If the headaches are mild, acetaminophen or another non-steroidal anti-inflammatory drug may suffice to control the pain. For severe headache one of the "triptans", Sumpatriptan, Zolmitriptan and Razatriptan should be prescribed or the ergot alkaloids, particularly Dihydroergotamine which are recognized effective forms of treatment. The triptans are serotonin 5-HT1b/1d receptor agonists. They have three potential mechanisms of action: cranial vasoconstriction, peripheral neuronal inhibition, and inhibition of transmission through second-order neurons of the trigeminocervical complex. These actions inhibit the effects of activated nociceptive trigeminal afferents and, in this way, control acute attacks of migraine. (Figure 2 Pictorial representation(9)) To prevent migraine in individuals with frequent attacks, Propranolol (Inderal) 20 mg. three times daily increasing the dose gradually to 240 mg daily may be beneficial. The drug can be prescribed as a long acting preparation in the higher dose range. Under dosing is a major reason for ineffectiveness. If Propranolol is unsuccessful, one of the other beta-blockers, specifically one that does not have agonist properties may be prescribed - Atenolol (40-160 mg per day), Timolol (20 to 40 mg per day), or Metoprolol (100 to 200 mg per day). Calcium channel blockers e.g. Verapamil (320 to 480 mg. per day) or Nifedipine (90 to 360 mg per day) are also reportedly effective in decreasing the frequency and severity of migraine attacks in some patients. (9)1. Abe K, Oda N, Araki R et al. Macropsia, micropsia and episodic illusions in Japanese adolescents. J Am Acad Child Adolesc Psychiatry 1989,28:493-496. http://www.ncbi.nlm.nih.gov/pubmed/2788641 2. Afridi S, Giffin NJ, Kaube H, Friston KJ, Ward NS, Frackowiak RSJ, et al A PET study in spontaneous migraine. Arch Neurol 2005; 62:1270-1275. http://www.ncbi.nlm.nih.gov/pubmed/16087768 3. Afridi SK, Matharu MS, Lee L, Kaube H, Friston KJ, Frackowiak RSJ, Goadsby PJ. A PET study exploring the laterality of brainstem activation in migraine using glyceryl trinitrate. Brain 2005;128:932-939. http://www.ncbi.nlm.nih.gov/pubmed/15705611 4. Bahra A, Matharu MS, Buchel C, Frackowiak RSJ, Goadsby PJ. Brainstem activation specific to migraine headache. Lancet 2001;357:1016-1017. http://www.ncbi.nlm.nih.gov/pubmed/11293599 5. Bregeat P, Klein M. Thiebaut F and Bouniol. . Hemi-macropsie homonyme droite et tumeur occipitale gauche. Rev d'Oto-Neuro-Ophthalmoogie, Paris 1947, 238-240. 6. Cutrer FM, Sorensen AG, Weisskoff RM, Ostergaard L, Sanchez del Rio M, Lee EJ, Rosen BR, Moskowitz MA.. Perfusion-weighted imaging defects during spontaneous migraine aura. Ann Neurol 1998, 43:25-31. http://www.ncbi.nlm.nih.gov/pubmed/9450765 7. Ffytche RJ, Howard RJ. The perceptual consequences of visual loss: "Positive' pathologies of vision. Brain 1999; 122:1247-1260. http://www.ncbi.nlm.nih.gov/pubmed/10388791 8. Gastaut H. A new type of epilepsy: Benign partial epilepsy of childhood with occipital spike-waves. Clin Electroencephalography 1982, 13:13-17. http://www.ncbi.nlm.nih.gov/pubmed/6802526 9. Goadsby PJ, Lipton RB, Ferrari MD. Migraine - Current understanding and treatment. N Engl J Med 2002, 346 (4):257-270. http://www.ncbi.nlm.nih.gov/pubmed/11807151 10. Hachinski VC, Porchawka J, Steele JC. Visual symptoms in the migraine syndrome. Neurology 1973, 23:570-579. http://www.ncbi.nlm.nih.gov/pubmed/4736304 11. Hadjikhani, N. Sanchez del Rio M, Wu O, Schwartz D, Bakker D. Fischl B, Kwong KK, Cutrer FM, Rosen BR, Tootell RBH, Sorensen AG, Moskowitz MA. Mechanisms of migraine aura revealed by functional MRI in human visual cortex. Proc Natl Acad Sci USA 2001;98:4687-4692. http://www.ncbi.nlm.nih.gov/pubmed/11287655 12. Lashley KS. Patterns of cerebral integration indicated by the scotomas of migraine. Arch Neurol Psychiatry 1941;46:331-339. 13. Lauritzen M. Pathophysiology of the migraine aura: the spreading depression theory. Brain 1994;117:199-210. http://www.ncbi.nlm.nih.gov/pubmed/7908596 14. Leao AAP. Spreading depression of activity in cerebral cortex. J Neurophysiol 1944, 7:379-390. 15. Moskowitz MA. The neurobiology of vascular head pain. Ann Neurol 1984, 16:157-168. http://www.ncbi.nlm.nih.gov/pubmed/6206779 16. Olesen J, Larsen B, Lauritzen M. Focal hyperemia followed by spreading oligemia and impaired activation of rCBF in classic migraine. Ann Neurol 1981;9:344-352. http://www.ncbi.nlm.nih.gov/pubmed/6784664 17. Richards W. The fortification illusions of migraines. Sci Am 1971;224(5):88-96. http://www.ncbi.nlm.nih.gov/pubmed/5552581 18. Storer RJ, Akerman S Goadsby PJ. Calcitonin gene-related peptide (CGRP) modulates nociceptive trigeminovascular transmission in the cat. Brit J Pharm 2004;142:1171-1181. http://www.ncbi.nlm.nih.gov/pubmed/15237097 19. Vijayan N, O'Brien MD, Blau JN, Rastegar D, Woods RP, Iacoboni M, Mazziotta JC, Olesen J. Spreading Cerebral Hypoperfusion during Migraine Headache. N Engl J Med 1995;332:1515-1518. http://www.ncbi.nlm.nih.gov/pubmed/7739695 http://www.ncbi.nlm.nih.gov/pubmed/7739696 www.ncbi.nlm.nih.gov/pubmed/7739697 http://www.ncbi.nlm.nih.gov/pubmed/7739698 20. Weiller C, May A, Limmroth V, Juptner M, Kaube H. Schayck RV, Coenen HH, Diener HC . Brain stem activation in spontaneous human migraine attacks. Nature Medicine 1995; 1:658-660. http://www.ncbi.nlm.nih.gov/pubmed/7585147 21. Woods RP, Jacoboni M and Mazziotta JC. Bilateral spreading cerebral hypoperfusion during spontaneous migraine headache. New Eng J Med 1994; 331:1689-1692. http://www.ncbi.nlm.nih.gov/pubmed/7969360KBDmigrainewithvisualaura; vppositivevisualphenomen