Paroxysmal hemicrania is a type of unilateral trigeminal headache accompanied by autonomic disorders. Typical episodes of the disease are characterized by short-term attacks of very strong throbbing or aching pains in the temple and / or eye socket. Diagnosis is based on anamnestic information and compliance of the clinical picture with the criteria of ICGB II. A specific diagnostic and therapeutic feature of the pathology is the complete elimination of pain syndrome when taking indomethacin. If you are allergic to this drug, other NSAIDs, calcium channel blockers or steroids are used.
ICD 10
G44.0
General information
Paroxysmal hemicrania (PH) is a relatively rare disease. According to research data, its prevalence is approximately 1-2.5% in the population. The average incidence rate is at the level of 55-385 cases per 100,000 population. The pathology was first described by Norwegian neurologists O. Zhastad and I. Dale in 1974. This variant of headache is classically regarded as affecting mainly women, the ratio of female and male patients is approximately 2.5-7:1. The onset of the disease can occur at any age, but usually the first attacks are observed in people of young and middle age categories – from 20 to 40 years.
Causes
The exact etiology of the disease has not yet been established, but factors that can cause episodes of hemicrania have been identified. These include sudden turns of the head, alcohol consumption, stress, psychoemotional overexcitation, relaxation reactions immediately after a stressful situation. Sometimes seizures occur in response to excessive visual stimulation (prolonged TV viewing, smartphone use) or taking certain pharmacotherapeutic agents, for example, nitroglycerin. In women, episodes are more often observed during menstruation. A reliable relationship between the development of the first headache attacks and organic lesions of the central nervous system has not been determined. At the same time, it was found that such clinical manifestations often develop in patients who have suffered a stroke or traumatic brain injury, suffering from neurofibromatosis and arteriovenous malformations with localization of the pathological process in the posterior cranial fossa.
Pathogenesis
The mechanisms of the pain syndrome have not been thoroughly studied. There are several hypotheses. The probable role of vasomotor disorders is indicated by the results of transcranial dopplerography of cerebral vessels, according to which, during paroxysmal hemicrania attacks, the blood flow rate in the basins of the middle cerebral artery decreases ipsilaterally. Evidence of the possible involvement of the hypothalamic-pituitary system in the pathogenesis of the disease is the contralateral or bilateral activation of the posterior part of the hypothalamus during an attack according to neuroimaging data. The dysfunction of the trigeminal system is confirmed by the results of an electrophysiological study – a decrease in the RIII flexor reflex and the latency of the early component of the blinking reflex.
Disruption of the autonomic nervous system in the ictal period is manifested by fluctuations in intraocular pressure and corneal temperature, hyperhidrosis in the forehead area on the sick side. The rate of development of these symptoms indicates a connection between the etiology of seizures and neurogenic activation of functionally conjugated suprasegmental structures of the autonomic nervous and nociceptive systems. This may be due to the release of neuropeptides: calcitonin gene-related peptide (sensitive endings of the trigeminal nerve) and vasoactive intestinal peptide (parasympathetic fibers).
Classification
Depending on the frequency of pain episodes and its clinical features, it is customary to distinguish several forms of paroxysmal hemicrania. The use of such a classification in clinical practice allows for reliable differentiation between variants of pathology and other short-term cephalgias for an adequate choice of appropriate treatment. Taking into account the frequency of PH attacks and their characteristics , the following forms of the disease are distinguished:
- Episodic. It differs in at least two pain periods with the duration of exacerbations from 1 week to 1 year and clinical remissions of at least 30 days. It is determined in 15-25% of patients. The main localization of pain is the temporal region.
- Paroxysmal. Seizures are observed for more than 1 year without pain-free periods or with remissions, the duration of which does not exceed 1 month. It is diagnosed in 75-85% of patients. The epicenter of pain is the ocular-temporal region.
Symptoms
Symptoms of PH during exacerbations occur daily with a multiplicity from 1 to 40, on average – 5-10 attacks per day. The total duration of one episode ranges from 5 to 45 minutes, the average is 13 minutes. The pain syndrome in hemicrania is exclusively unilateral. The side does not change from attack to attack. In typical cases, the maximum severity of pain is observed around the eye socket, in the temple or retroorbital area. Less often – in the frontal, occipital or parietal areas, in the area of innervation of the middle branch of the trigeminal nerve, around the nose or neck. Sometimes there is irradiation in the shoulder, arm on the side of the lesion. The intensity of pain is high, but the nature may vary. Patients describe the pain as unbearable throbbing, burning, drilling, aching, stabbing or resembling a punch.
The clinic of paroxysmal hemicrania usually increases rapidly during the first 1-5 minutes. In addition to headaches during an attack, autonomic disorders are determined by the type of local activation of the parasympathetic division of the autonomic nervous system. Clinically, this is manifested by increased lacrimation, injection of conjunctival vessels, a feeling of a rush of heat, nasal congestion and catarrhal secretions. Hyperhidrosis of the forehead, photophobia, edema, drooping eyelid and pupil constriction ipsilateral, moderate nausea also develops. In some patients, these symptoms may precede a headache attack. In rare cases, vegetative manifestations are persistent or absent altogether. Cephalgia does not occur in the intercalative period of PH, only 1/3 of patients note a certain discomfort in the area of localization of the pain syndrome.
Diagnostics
The diagnosis is made by a neurologist on the basis of special criteria corresponding to the International classification of headache II revision (ICGB II). The results of laboratory research methods, neuroimaging in the form of CT and MRI of the brain do not provide diagnostically valuable information and play an auxiliary role in differentiating with organic pathologies of the central nervous system. The patient’s examination program includes the following items:
- Survey. In a conversation with the patient, the doctor details the complaints, finds out the provoking factors, the frequency and duration of cephalgia attacks. The specialist focuses on the concomitant manifestations of increased activity of the parasympathetic nervous system.
- Physical examination. An external examination reveals vegetative disorders. In the neurological status of patients with PH, there may be a decrease in pain, tactful sensitivity and allodynia in the innervation zone of the IV pair of cranial nerves from the lesion.
- Trial treatment. A distinctive feature and an important diagnostic criterion of paroxysmal hemicrania is the complete relief of pain syndrome after taking a standard therapeutic dose of a drug from the NSAID group – indomethacin.
Differential diagnosis is performed with other trigeminal autonomic cephalgias: cluster (bundle) headache, SUNCT syndrome, hemicrania continua. With the first disease, the pain syndrome is localized in the ocular region, the duration of the attack is from 15 to 180 minutes, the frequency does not exceed 10 times a day. With SUNCT syndrome, the pain is of moderate intensity, has a piercing or pulsating character, seizures can be provoked by irritation of trigger zones in the facial area, their duration ranges from 5-240 seconds. Hemicrania continua is characterized by acute constant pain in the eye socket or temple area of medium intensity, which is often provoked by alcohol consumption.
Treatment
Treatment of the disease is exclusively medical, in most cases it is carried out on an outpatient basis. The duration of therapeutic measures depends on the form of PH, therapy can be carried out on an ongoing basis or a short course, several days longer than the duration of exacerbation. The main goal is to stop attacks of cephalgia, to prevent their occurrence. The treatment program is represented by the following pharmacotherapeutic agents:
- Indomethacin. The drug of choice for paroxysmal hemicrania. A persistent therapeutic effect occurs 1-2 days after the start of administration. If indomethacin is ineffective, the diagnosis of PH is subject to revision. An exact justification for this phenomenon has not been found.
- Alternative means. In the presence of an allergy to indomethacin, a neurologist performs an individual selection of another drug. In some cases, medications from the groups of nonsteroidal anti-inflammatory drugs, calcium channel blockers, and steroids are effective.
- Symptomatic remedies. With the constant intake of indomethacin, the probability of the formation of peptic ulcers of the stomach and duodenum increases, therefore, antacids, H2-histamine blockers or proton pump blockers can be additionally used.
Prognosis and prevention
The prognosis in patients with paroxysmal hemicrania is favorable. Rational pharmacotherapy allows you to completely stop the pain syndrome and achieve stable clinical remission. Specific prevention of the disease consists in taking indomethacin or an alternative drug in a dose previously selected by the treating specialist. Non–specific preventive measures involve the refusal to drink alcoholic beverages, the exclusion of all factors that can provoke new attacks of cephalgia – prolonged visual tension, stressful situations, emotional overexcitation, etc.