Document Detail

Migrainous scintillating scotoma and headache is ocular in origin: A new hypothesis.
MedLine Citation:
PMID:  16356654     Owner:  NLM     Status:  MEDLINE    
Brain neuronal dysfunction has been implicated in pathogenesis of migraine but direct evidence is lacking. Scintillating scotoma of migraine is generally believed to originate at the visual cortex. While cortical spreading depression is a relatively late physiological alteration in migraine, its protective role in neuronal ischaemia is increasingly being recognized. Atenolol, nadolol, or verapamil prevent migraine but do not readily cross the blood-brain barrier or critically influence any brain or peripheral neuronal function. Typical migraine headache, aura, or scintillating scotoma has not been reported following enucleation or evisceration of the eye. In humans, pain and temperature fibres from only the ophthalmic division of the trigeminal nerve reach the upper cervical spinal segments. Pain in migraine attacks including occipital and nuchal discomfort reflects selective involvement of the ophthalmic nerve. Photophobia is largely a retinal reflex involving the ophthalmic division of the trigeminal nerve. Key clinical features of the migrainous scintillating scotoma are consistent with retinal origin. Spreading depression in the retina is well-established. A subtle regional ocular sympathetic deficit prevails in migraine patients and possibly impairs regulation of intraocular choroidal blood volume and intraocular pressure. Several first-line migraine prophylactic agents lower the intraocular pressure. The neuro-ophthalmological basis for a monocular origin of migrainous scintillating scotomata due to mechanical deformation of the posterior segment of the corneo-scleral envelope consequent to choroidal venous congestion and rise in intraocular pressure is presented. Study of distribution and displaceability of the migrainous scintillating scotoma can settle its site of origin. Headache of migraine possibly arises from a similar mechanical deformation of the anterior eye segment followed by antidromic discharge in the trigeminovascular system. Lateralizing negative deficits such as homonymous hemianopia probably reflect vasospastic complications of migraine. A rational explanation for the most characteristic clinical features of migraine and a new template to elucidate the pharmacological basis of anti-migraine drugs is offered.
Vinod Kumar Gupta
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Publication Detail:
Type:  Journal Article     Date:  2005-12-13
Journal Detail:
Title:  Medical hypotheses     Volume:  66     ISSN:  0306-9877     ISO Abbreviation:  Med. Hypotheses     Publication Date:  2006  
Date Detail:
Created Date:  2006-01-10     Completed Date:  2006-06-22     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7505668     Medline TA:  Med Hypotheses     Country:  Scotland    
Other Details:
Languages:  eng     Pagination:  454-60     Citation Subset:  IM    
Dubai Police Medical Services, P.O. Box 12005, Dubai, United Arab Emirates.
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MeSH Terms
Eye / pathology
Headache / diagnosis*,  etiology
Migraine Disorders / diagnosis*,  etiology
Models, Biological
Neurons / pathology
Scotoma / diagnosis*,  etiology
Vision, Ocular

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