Migraine Auras Without Headache are not TIAs
ABSTRACT & COMMENTARY
Source: Wijman CAC, et al. Migrainous visual accompaniments are not rare in late life. The Framingham Study. Stroke 1998;29:1539-1543.
Visual symptoms similar to the aura of migraine but not followed by headache can occur for the first time in older adults. Diagnosis is not difficult when the spells are typically migrainous-that is, when there is a build-up or march of positive and negative visual phenomena over a period of 15 or 20 minutes. When the spells are not typical or when they occur for the first time in a person older than 50 years without a history of previous migraine symptoms, then other neurologic diagnoses, such as posterior circulation TIAs or occipital lobe seizures, are a consideration. In such patients, most neurologists feel compelled to order neuroimaging studies to exclude cerebrovascular disease and neoplasm.
As part of the Framingham Study, Wijman and colleagues used questionnaires from 1971 to 1989 to determine the occurrence of sudden visual symptoms in 2110 subjects. Migrainous visual symptoms were reported by 1.23% (26/2110) of subjects (see Table). The mean age ± SD at onset of the episodes was 56 ± 19 years. Seventeen of the 26 subjects were examined by a study neurologist. Only five subjects met the criteria of the International Headache Society for a diagnosis of "migraine aura without headache."1
Table
Characteristics of symptoms in 26 patients
| Characteristic |
|
| Wome17 (65%) > 50 years at onset |
|
| Number of spells > = 10 |
|
| Stereotyped spells |
|
| No headache |
|
| History of migraine |
|
| Spell typical of migraine aura |
|
| Duration in minutes |
|
| 1 < 15 |
|
| 15-60 |
|
| other |
|
Three subjects had strokes 1-27 years after the onset of visual symptoms. In contrast, one-third of 87 subjects with TIAs subsequently developed a stroke (P = 0.03)-two-thirds within six months of the onset of TIAs.
Therefore, Wijman et al conclude that migrainous visual accompaniments are not associated with an increased risk of stroke, and invasive procedures or therapeutic measures generally are not indicated.
COMMENTARY
In this study, there was no increased risk of stroke in association with migrainous visual symptoms confirming the results of previous clinical series of patients with acephalgic migraine.1 This is not a surprising result because the mechanism of migraine auras is likely to be cortical spreading depression rather than ischemia.2 Nevertheless, migraine remains an independent risk factor of ischemic stroke in men older than 40 years.3 There are occasional reports of cerebral infarction associated with migrainous accompaniments,4 and most neurologists have seen patients with persistent visual field defects due to migraine-associated occipital infarction. In addition, amyloid angiopathy is associated with TIAs, usually in the form of paresthesias, which mimic the build-up and march of migrainous accompaniments.5 Therefore, physicians are justified in using non-invasive testing to evaluate patients with late-life migrainous symptoms for underlying cerebrovascular disease. -jjc
References
1. Committee of the International Headache Society. Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Headache Classification. Cephalalgia 1988;8(Suppl 7):1-96.
2. Strupp M, et al. Diffusion-weighted MRI in transient global amnesia: Elevated signal intensity in the left mesial temporal lobe in 7 of 10 patients. Ann Neurol 1998;43:164-70; Neurol Alert 1998;16:86-87.
3. Buring JE, et al. Migraine and subsequent risk of stroke in the Physicians' Health Study. Arch Neurol 1995;52:129-134.
4. Olesen J, et al. Ischaemia-induced (symptomatic) migraine attacks may be more frequent than migraine-induced ischaemic insults. Brain 1993; 116:187-202.
5. Greenberg SM, et al. The clinical spectrum of cerebral amyloid angiography: Presentations without lobar hemorrhage. Neurology 1993;43:2073-2079.
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