Overview of Headache
Headache is one of the most common complaints seen by neurologists. Population follow-up shows that 90% of people have had a headache within 1 year, and half of them have a headache that affects their daily life. About 95% of women and 90% of men have had at least one headache in their lifetime. The number of patients with classic migraine in the United States is about 28 per million, and another 20 million have atypical migraine. Chronic daily headache, consisting of chronic tension headache and conversion migraine, accounts for 45% of this population. Emergency department visits with headache as the main symptom are >2%. Individual perception of headache varies widely. Headache manifestations can be mild or severe, but the various headaches are more likely to be qualitatively different. Occasional headaches may be normal, and a small number of patients seek medical attention for their headaches to have an explosive onset or malignant progression.
Headaches often refer to pain of various natures within and outside the skull, including disorders of the five senses and cervical spine and other head neuralgia. Acute, severe headaches may reflect serious underlying disorders that are not limited to the nervous system. The pain-causing mechanism involves action potentials generated by stimulation of nociceptive fibers in the head, face, and neck and their transmission to the brain. The meaning of cranial extensiveness should include the area above the neck. The brain itself does not contain painful sensory nerve endings, and headaches originate from blood vessels or the covering of the brain (meninges). Injuries to the anterior and middle cranial fossa present with a headache in the forehead, while the posterior cranial fossa this head and the back of the neck are painful. Less common causes of headache are, eye, paranasal sinus, dental and neck disorders.
I. Evaluation of headache patients
(a) Medical history A detailed medical history is necessary for the correct diagnosis of headache, and a coordinated doctor-patient relationship and good communication are also necessary for the successful treatment of most headaches, especially inquiring about the site of the headache, the nature of the headache, and its frequency, duration, location, and various associated symptoms (Table 9-1). A family history of headache and the patient’s psychiatric history are also necessary for evaluation.
Table 9-1 Important features of pain in patients with chronic headache
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Headache Nature Department Duration Frequency Associated symptoms
General migraine Pulsatile Unilateral head or bilateral head 6-48h Occasional (often several times per month) Nausea Vomiting Discomfort Photophobia
Classic migraine Pulsatile Unilateral head 3-12h Occasional (often several times per month) Visual aura, nausea discomfort photophobia
Cluster Dramatic Stabbing pain Unilateral head 15-20 min Dense cluster attacks Ipsilateral tearing, facial flushing
(especially orbits) Long remission nasal congestion, Horner’s syndrome
Tensive Dull pressure pain Diffuse, bilateral Often does not stop Often depressed, anxious
Trigeminal neuralgia Tear-like Trigeminal nerve distribution Briefly Several times a month With trigger point (15-60 seconds)
Atypical facial pain Dull pain Unilateral or bilateral lateral Often non-stop Often depressed, occasionally psychotic
Lower headache Dull or throbbing pain unilateral facial 6-48hr Occasional Nausea, vomiting
Sinus headache Dull or stabbing pain Unilateral or bilateral sinus area with variation Occasional or frequent Runny nose
(ii) Physical examination A careful neurological and general physical examination should be performed in every patient complaining of headache. Occasionally, clues to the etiology of the headache may be obtained from the examination (Table 9-2), but patients and physicians often perform appropriate exclusionary tests for psychological comfort in order to determine that the headache is not the result of a serious condition.
Table 9-2 Significant physical examination findings in the evaluation of headache
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Physical findings Possible etiology
Optic nerve atrophy, optic papillary edema Occupancy damage, hydrocephalus, benign intracranial pressure increase
Facial neurological abnormalities (hemianopsia, aphasia) Occupational damage
Neck stiffness Subarachnoid hemorrhage, meningitis, cervical arthritis
Retinal hemorrhage Ruptured aneurysm, malignant hypertension
Cephalic spread Arteriovenous malformation
Temporal artery thickening
Pain with trigger points Trigeminal neuralgia
droopy lids, actinic nerve palsy, dilated pupils cerebral aneurysm
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(iii) Ancillary examinations
A detailed history of headache and an accurate and comprehensive physical examination (including the nervous system) are the basis for the diagnosis of headache, and the following tests should be done if abnormalities are found. If the neurological examination is normal, no further tests will be performed. Diagnostic tests are available for headache patients with the following conditions: (1) a history suggestive of a specific diagnosis (e.g. , epilepsy G or brain tumor); (ii) changes in headache characteristics; and (iii) atypical headache symptoms (e.g., trigeminal neuralgia at an age less than 30 years). Several conditions that need to be alerted in headache
1.Electroencephalography To exclude structural damage such as neoplastic organisms and make EEG examination, it is better to choose imaging examination represented by CT/MRI of the head. EEG is not recommended as a routine test for headache patients to rule out intracranial structural damage in headache, but it has some value for EEG in some patients with headache-type epilepsy.
For patients with non-focal acute severe headache and no clear abnormalities in imaging, lumbar puncture (LP) examination is appropriate, especially for those with abnormal changes in tongue. However, the following conditions are contraindicated: optic papillary edema of the fundus, coagulation disorder or platelet count <5×109/L, inflammation or ulceration of the skin or soft tissues of the lumbosacral region. It is also important to note that the specimen must be sent for routine examination within 2 hours, otherwise the results may be affected. Lumbar puncture manometry or CSF may be useful for some diagnoses.
3.Hematological examination Numerous systemic diseases may have headache complaints or have headache as the first, so the corresponding hematological examination should be selected. The relationship between the more common systemic or local lesions associated with headache and selective blood tests is shown in Table 9-2.
Table 9-2 Blood tests and possible disease diagnosis
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Blood tests that may help diagnose disease
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Serum C-reactive protein, antinuclear antibodies Temporal arteritis, lupus erythematosus, etc.
ANA, rheumatoid factor Rheumatic diseases
HIV antibody assay HIV
Lyme disease antibody assay Lyme disease
Lupus antigen and anticardiolipid measurement Extensive white matter abnormalities on imaging
Prolactin levels, thyroid stimulating hormone (TSH) Pituitary adenoma
Blood count and platelet count, coagulation tests
Anemia, thrombocytopenic thrombocytopenic purpura
Thyroid function measurement, blood glucose, electrolytes, blood calcium, blood phosphorus and BUN, Cr, etc.
Metabolic endocrinopathies (e.g. hypothyroidism, hypercalcemia, etc.), chronic renal insufficiency
Drug monitoring and liver and kidney function tests
Patients with long-term use of anti-sickness agents such as carbamazepine, sodium valproate and non-steroidal drugs for treatment and prevention of headache
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4.CT/MRI examination Patients with headache whose neurological physical examination is normal can easily be considered as non-organic headache, such as acute headache after pituitary adenoma hemorrhage, and the neurological examination can be normal. The neurological examination of Arnold-chiari (type I) malformation can be normal, and even the CT scan of the head and neck can appear “normal”. The diagnosis can be clarified with MRI. Only patients with atypical headache, a history of convulsions or focal neuropathy are suitable for imaging.
Imaging is required for the following headache patients: (1) headache manifestations: first or severe headache, gradually increasing or severe subacute headache, progressive or new daily persistent headache, chronic daily headache, headache often on the same side, headache for which treatment is ineffective. (2) Newly started headache in cancer patients or HIV positive patients, new headache after the age of 50, headache patients with a history of convulsive attacks. (3) Headache with symptoms or signs, such as fever, neck strength, nausea, vomiting, etc. Patients with aura migraine with focal signs and symptoms, patients with optic papilledema, cognitive impairment, and personality changes. CT may be missed or misdiagnosed in the following cases: (1) cerebrovascular disease, such as saccular aneurysm, AVM (especially in the posterior cranial fossa), small SAH, carotid or vertebral artery entrapment, infarction, cerebral vein (sinus) thrombosis, vasculitis (white matter abnormalities), subdural) hematoma. (2) Neoplastic disease, such as posterior cranial fossa neoplasia, meningeal carcinoma, pituitary adenoma (even hemorrhage). (3) Damage to the cervical-medullary region, such as Chiair malformation, meningioma of the greater occipital foramen. (3) Infection, such as meningitis, brain abscess, paranasal sinusitis, etc. If the patient has no residual metal (e.g., silver clips) or pacemakers installed in the skull, MRI is the appropriate choice.
In patients with acute severe headache, if the CT or LP examination is normal, the possibility of unruptured aneurysm should be considered, as the headache may not always be related to bleeding, but may be related to the strain on the aneurysm. Ward et al. concluded that cerebral angiography is appropriate for all headaches associated with suspected aneurysms, AVM, vasculitis, venous (sinus) thrombosis, and arterial wall entrapment, and that CTA angiography is simple and has a high success rate compared with DSA angiography. The diagnosis of aneurysms with large aneurysms is accurate, and it is more economical and faster than DSA. Disadvantages of CTA: ①It cannot show the immediate filling of blood vessels or aneurysms, so it is impossible to determine which side is the main supply branch when detecting bilateral blood supply aneurysms. The sensitivity is only 86% compared with DSA, and is even worse for posterior cranial fossa aneurysms. (3) The amount of contrast agent required is 1.5 times that of DSA, and caution should be exercised in the elderly and those with poor renal function. At present, this test is only considered when acute cerebrovascular disease is suspected and DSA is contraindicated.
In conclusion, the positive rate of diagnostic tests is not high in patients with normal neurological examination. In order to avoid misdiagnosis or omission of some organic diseases, it is important to correctly select and interpret the significance of diagnostic tests.
(D) The diagnostic procedures of headache disorders are shown in the following chart.
II. Classification of headache
The WHO-HIS International Classification of Headache Disorders, Second Edition (ICHD-2) classifies headache disorders into three parts: (1) primary headache; (2) secondary headache; (3) cranial neuralgia, central and primary facial pain and other headaches. Each type of primary headache can be considered a separate disorder, while secondary headaches are generally only symptoms of a particular disorder. If the first episode of a particular type of headache is closely related in time to another disorder that may cause the headache, the headache is a secondary headache, and ICHD-2 refers to it as a headache “due to” that disorder.
The ICHD-2 uses a step-by-step classification.
The first level is the type of headache (type), and there are 14 types of headache in 3 parts, as follows (the numbers in the text are the classification codes)
Part 1: Primary headache 1. migraine; 2. tension-type headache; 3. cluster headache and other trigeminal phytogenic headache; 4. other primary headache
5. Headache due to head and neck trauma; 6. Headache due to head and neck vascular disease; 7. Headache due to non-vascular intracranial disease; 8. Headache due to a substance or withdrawal of a substance; 9. Headache due to infection; 10. Headache due to metabolic disorders; 11. Headache due to lesions of the head, neck, eyes, ears, nose, sinuses, teeth, mouth or other head and facial structures; 12. Cephalalgia; 12. Headache due to mental illness
Part III: Cranial neuralgia, central and primary facial pain and other headaches 13. Cranial neuralgia and central facial pain; 14. Other types of headache, cranial neuralgia, central or primary facial pain;
The second level is the subtype of a headache type, and each subtype can be further subdivided into up to 4 levels, using 4 digits for coding. For example, alcohol-induced delayed headache can be coded as: headache due to a substance or withdrawal of a substance (8), headache due to acute substance application or exposure (8.1), headache due to alcohol (8.1.4), or alcohol-induced delayed headache (8.1.4.2). ～A clinical diagnosis of 1 to 2 levels is sufficient.
III. Diagnostic principles of headache disorders
(1) The attack form of headache can change over time. The diagnosis of headache is mainly based on the current headache performance or within one year, but for the purpose of genetic research or other purposes, all the headache cases since birth can be traced.
(2) The diagnosis of primary headache is based primarily on clinical symptoms, however, not every headache episode can (or needs to) be evaluated and diagnosed. Patients should be asked to describe typical, untreated headache episodes as much as possible, but those episodes that are less typical should be counted when calculating headache frequency. It is recommended that patients keep a headache diary to record the duration and important features of each headache, which will allow accurate calculation of headache frequency and help to distinguish between headache types.
(3) Sometimes only one of the diagnostic criteria for one type of headache is missing, but it does not meet the diagnostic criteria for other types of headaches, so it can be diagnosed as a possible type of headache, such as possible migraine (1.6).
(4) If a patient meets the diagnostic criteria for two or more headache disorders at the same time, the correctness and importance of the diagnosis should be judged based on the medical history data, combined with the diagnostic criteria. More than one headache disorder can co-exist in the same patient, so the diagnosis should be given separately and in order of importance. For example, the following diagnoses can be made: substance abuse headache (8.2), migraine without aura (1.1), and frequent tension-type headache (2.2).
To distinguish primary headache from secondary headache, the diagnosis of primary headache must exclude any possible secondary headache disorder, i.e., one of the following must be met: (1) the history and physical examination do not suggest the presence of any disorder that can cause secondary headache; (2) the disorder is suggested but further examination excludes it; (3) the disorder is present but the first attack of headache is not closely related to the disorder in time. There is no close relationship between the first attack of headache and the disease. In some cases, the diagnosis of a primary headache may be more difficult when the original headache worsens after the development of a disease that can cause the headache, and there are two obvious possibilities: one may be the worsening of the primary headache, and the other may be the development of a new secondary headache in addition to the original primary headache. In general, the possibility of a new secondary headache is more likely if there is: (i) a very close temporal relationship between the two; (ii) a headache that worsens very significantly or is of a different nature than the original primary headache; (iii) sufficient other evidence that the disease can cause the headache to worsen; and (iv) a headache that resolves after the disease is cured or in remission. The last criterion in most secondary headache diagnoses is “improvement or disappearance of the headache within a period of time after the cause of the headache has been removed”, and meeting this criterion is an important part of confirming the causal relationship. However, it is often necessary to make a clinical diagnosis at an early stage, when the headache is likely to be due to the disease. There are many types of headaches, but tension headaches and migraines are the most common.