Craig Blackwell, MD

Santa Cruz, CA
Diplomate: American Board of Ophthalmology
Fellow: American Academy of Ophthalmology

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An Ophthalmology Practice in Santa Cruz, CA

Migraine IHS Classification

The International Headache Society has published a document classifying and defining all the known types of headaches. Following are excerpts relating to the Migraine family.

I have not included all the diverse forms, the full text is available on their web site.

International Headache Society Classification

1. Migraine Without Aura


Recurrent headache disorder manifesting in attacks lasting 4-72 hours. Typical characteristics of the headache are unilateral location, pulsating quality, moderate or severe intensity, aggravation by routine physical activity and association with nausea and/or photophobia and phonophobia

Diagnostic criteria:

  1. At least 5 attacks1 fulfilling criteria B-D
  2. Headache attacks lasting 4-72 hours (untreated or unsuccessfully treated)2;3;4
  3. Headache has at least two of the following characteristics:
    1. unilateral location5;6
    2. pulsating quality7
    3. moderate or severe pain intensity
    4. aggravation by or causing avoidance of routine physical activity (eg, walking or climbing stairs)
  4. During headache at least one of the following:
    1. nausea and/or vomiting
    2. photophobia and phonophobia8
  5. Not attributed to another disorder9


1.1 Migraine without aura is the commonest subtype of migraine. It has a higher average attack frequency and is usually more disabling than 1.2 Migraine with aura.

Migraine without aura often has a strict menstrual relationship. In contrast to the first edition of The International Classification of Headache Disorders, this edition gives criteria for A1.1.1 Pure menstrual migraine and A1.1.2 Menstrually-related migraine, but in the appendix because of uncertainty over whether they should be regarded as separate entities.

Very frequent migraine attacks are now distinguished as 1.5.1 Chronic migraine provided that there is no medication overuse. Migraine without aura is the disease most prone to accelerate with frequent use of symptomatic medication, resulting in a new headache which is coded as 8.2 Medication-overuse headache.

Regional cerebral blood flow shows no changes suggestive of cortical spreading depression during attacks of migraine without aura although blood flow changes in the brainstem may occur, as may cortical changes secondary to pain activation. This contrasts with the pathognomonic spreading oligaemia of migraine with aura. In all likelihood spreading depression is therefore not involved in migraine without aura. On the other hand the messenger molecules nitric oxide (NO) and calcitonin-gene-related peptide (CGRP) are clearly involved. While the disease was previously regarded as primarily vascular, the importance of sensitisation of perivascular nerve terminals, and the possibility that attacks may originate in the central nervous system, have gained increasing attention over the last decades. At the same time the circuitry of migraine pain and several aspects of neurotransmission in this system have been recognised. A significant contribution has been made by the advent of the triptans, 5HT1B/D receptor agonists. These drugs have remarkable efficacy in acute attacks and, in view of their high receptor-specificity, their mechanism of action provides new insight into migraine mechanisms. It is now clear that migraine without aura is a neurobiological disorder and clinical as well as basic neuroscience currently advances our knowledge of migraine mechanisms at an increasing speed.

2. Migraine with Aura


Recurrent disorder manifesting in attacks of reversible focal neurological symptoms that usually develop gradually over 5-20 minutes and last for less than 60 minutes. Headache with the features of migraine without aura usually follows the aura symptoms. Less commonly, headache lacks migrainous features or is completely absent.

Diagnostic criteria:

  1. At least 2 attacks fulfilling criterion B
  2. Migraine aura fulfilling criteria B and C for one of the subforms 1.2.1-1.2.6
  3. Not attributed to another disorder1


The aura is the complex of neurological symptoms that occurs just before or at the onset of migraine headache. Most patients with migraine have exclusively attacks without aura. Many patients who have frequent attacks with aura also have attacks without aura (code as 1.2 Migraine with aura and 1.1 Migraine without aura).

Premonitory symptoms occur hours to a day or two before a migraine attack (with or without aura). They include various combinations of fatigue, difficulty in concentrating, neck stiffness, sensitivity to light or sound, nausea, blurred vision, yawning and pallor. The terms prodrome and warning symptoms are best avoided because they are often mistakenly used to include aura.

The majority of migraine auras are associated with headache fulfilling criteria for 1.1 Migraine without aura. For this reason the entity 1.2.1 Typical aura with migraine headache has been singled out below. Migraine aura is sometimes associated with a headache that does not fulfill criteria for migraine without aura and, in other cases, migraine aura may occur without headache. These two subforms are also now distinguished.

Aura with similar features has also been described in association with other well-defined headache types, including cluster headache; the relationships between aura and headache are not fully understood.

Before or simultaneously with the onset of aura symptoms, regional cerebral blood flow is decreased in cortex corresponding to the clinically affected area and often including an even wider area. Blood flow reduction usually starts posteriorly and spreads anteriorly and is usually above the ischaemic threshold. After one to several hours, gradual transition into hyperaemia occurs in the same region. Cortical spreading depression of Leão has been implicated.

Systematic studies have demonstrated that many patients with visual auras occasionally have symptoms in the extremities. Conversely patients with symptoms in the extremities virtually always also suffer visual aura symptoms. A distinction between migraine with visual aura and hemiparaesthetic migraine is probably artificial and therefore is not recognised in this classification. Patients with motor weakness are classified separately because of the dominantly inherited form, 1.2.4 Familial hemiplegic migraine, and because of clinical differences. The genetic relationship between migraine with aura and familial hemiplegic migraine has not been established.

The previously-defined syndromes migraine with prolonged aura and migraine with acute-onset aura have been abandoned. The great majority of patients with such attacks have other attacks that fulfil criteria for one of the subforms of 1.2 Migraine with aura and should be coded to that diagnosis. The rest should be coded to 1.6.2 Probable migraine with aura specifying the atypical feature (prolonged aura or acute-onset aura) in parenthesis.

3. Typical Aura without Headache


Typical aura consisting of visual and/or sensory symptoms with or without speech symptoms. Gradual development, duration no longer than one hour, a mix of positive and negative features and complete reversibility characterise the aura which is not associated with headache.

Diagnostic criteria:

  1. At least 2 attacks fulfilling criteria B-D
  2. Aura consisting of at least one of the following, with or without speech disturbance but no motor weakness:
    1. fully reversible visual symptoms including positive features (eg, flickering lights, spots or lines) and/or negative features (ie, loss of vision)
    2. fully reversible sensory symptoms including positive features (ie, pins and needles) and/or negative features (ie, numbness)
  3. At least two of the following:
    1. homonymous visual symptoms1 and/or unilateral sensory symptoms
    2. at least one aura symptom develops gradually over ≥5 minutes and/or different aura symptoms occur in succession over ≥5 minutes
    3. each symptom lasts ≥5 and ≤60 minutes
  4. Headache does not occur during aura nor follow aura within 60 minutes
  5. Not attributed to another disorder2


  1. Additional loss or blurring of central vision may occur.
  2. History and physical and neurological examinations do not suggest any of the disorders listed in groups 5-12, or history and/or physical and/or neurological examinations do suggest such disorder but it is ruled out by appropriate investigations, or such disorder is present but attacks do not occur for the first time in close temporal relation to the disorder.


In some patients a typical aura is always followed by migraine headache, but many patients have, in addition, attacks with aura followed by non-migraine headache or even without headache. A small number of patients have 1.2.3 Typical aura without headache exclusively. More commonly, as patients with 1.2.1 Typical aura with migraine headache become older, their headache may lose migraine characteristics or disappear completely even though auras continue. Some individuals, primarily males, have 1.2.3 Typical aura without headache from onset.

In the absence of headache fulfilling criteria for 1.1 Migraine without aura, precise diagnosis of aura and its distinction from mimics that may signal serious disease (eg, transient ischaemic attack) become much more important. This distinction may require investigation. Especially if aura begins after age 40, if negative features (eg, hemianopia) are predominant, or if aura is prolonged or very short, other causes should be ruled out.

4. Retinal Migraine


Repeated attacks of monocular visual disturbance, including scintillations, scotomata or blindness, associated with migraine headache.

Diagnostic criteria:

  1. At least 2 attacks fulfilling criteria B and C
  2. Fully reversible monocular positive and/or negative visual phenomena (eg, scintillations, scotomata or blindness) confirmed by examination during an attack or (after proper instruction) by the patient’s drawing of a monocular field defect during an attack
  3. Headache fulfilling criteria B-D for 1.1 Migraine without aura begins during the visual symptoms or follows them within 60 minutes
  4. Normal ophthalmological examination between attacks
  5. Not attributed to another disorder1


  1. Appropriate investigations exclude other causes of transient monocular blindness.


Some patients who complain of monocular visual disturbance in fact have hemianopia. Some cases without headache have been reported, but their migrainous nature cannot be ascertained. Other causes of transient monocular blindness (amaurosis fugax), such as optic neuropathy or carotid dissection, must be excluded.

The full Headache classification from the IHS website with subsections showing for Migraine:


1.1. Migraine without aura

1.2. Migraine with aura

1.3. Childhood periodic syndromes that are commonly precursors of migraine

1.4. Retinal migraine

1.5. Complications of migraine

1.6. Probable migraine Aggravating factorsTrigger factors (precipitating factors)