Jacksonian seizure is a separate type of focal epilepsy characterized by motor, sensory or mixed paroxysms that begin locally with preserved consciousness and spread through the body in a certain sequence. As a rule, it is based on an organic substrate. Disease is diagnosed according to the clinic, EEG, MRI or CT of the brain. Treatment is carried out with antiepileptic pharmaceuticals, dehydration and resorption agents. In cases resistant to anticonvulsant therapy, surgical treatment is possible — focal resection.
Jacksonian seizure is a variant of focal epilepsy, in which epileptiform excitation occurs in the cortex of the pre— and/or post-central gyrus and often has a local character, although it can diffusely spread leading to secondary generalization of the epiprime. For the first time, a clinical description of such epileptic paroxysms was given in 1827 by the French physician Bravet. In 1863, an English neurologist J. Jackson conducted a more detailed study of cortical epilepsy. His comparison of the type of paroxysm with the localization of the focus of epiactivity in various parts of the cortex of the central sulcus of the brain formed the basis for studying the functional significance of various cortical zones.
Jacksonian seizure occurs as a consequence of organic cerebral pathology (tumors, abscess, cerebral vascular aneurysms, etc.). At any age, its appearance acts as a kind of signal indicating the occurrence of organic brain damage. In this regard, Jacksonian seizure is of increased interest to clinicians in general and specialists in the field of neurology in particular.
The etiofactors of the occurrence of Jacksonian seizure can be intracranial volumetric formations (intracerebral tumor, cerebral cyst, cysticercosis, echinococcosis, brain abscess, solitary tuberculosis), infectious lesions (neurosyphilis, chronic arachnoiditis, encephalitis, pachymeningitis), traumatic brain injuries, vascular anomalies (aneurysms and arteriovenous malformations of the brain). Perinatal factors often play a role in the occurrence of Jacksonian seizure in children: fetoplacental insufficiency and fetal hypoxia, intrauterine infections, birth trauma of the newborn, etc.
Some authors point out that the role of hereditary predisposition in the form of increased convulsive readiness of the brain cannot be excluded in the occurrence of Jacksonian seizure. Although, of course, the value of this factor is much less significant than in genoine (primary) epilepsy.
Convulsive paroxysms of the Jackson type have a very variable character. Their common feature is the local occurrence in a separate area of the body (more often in the arm or face) and the subsequent spread, called the “Jackson march”. A characteristic feature is the unilateral nature and spread of paroxysm in accordance with the projection of body parts on the cortex of the anterior central gyrus. Jackson’s paroxysms can be sensorimotor, only motor (motor) or only sensitive (sensory).
“Motor jackson” occurs with epileptogenic excitation of the precentral gyrus cortex. It is manifested by convulsions that usually begin in the muscles of the thumb and gradually spread to the entire upper limb, face, and then leg. At the beginning of the paroxysm from the muscles of the face, its spread goes to the arm (from the hand to the shoulder), then to the leg from the hip down. In rare cases, seizures begin with the 1st toe and spread upward to the entire leg, arm and face. Convulsions are clonic in nature with a preceding short tonic phase. They may stop suddenly, but more often they pass in the reverse order of their occurrence. “Sensory Jackson” is caused by the excitation of the cortex of the postcentral gyrus, has a similar motor propagation sequence, but is associated with sensitive disorders (paresthesia, loss of sensitivity).
In some cases, Jackson’s paroxysm is limited to the place of its origin and does not have a significant spread. Such an attack is called simple and proceeds without loss of consciousness. During the “Jackson’s march”, loss of consciousness is often observed. In the case of generalization of paroxysm, convulsions pass to the other side, consciousness is lost. With the development of an epileptic status, it can be localized only in the muscles of the face, affect the musculature of one limb, or has the character of following one after another attack of the “Jackson march”.
As a rule, at the beginning, Jacksonian seizure proceeds with simple paroxysms starting from the same place. Sometimes patients are able to stop the progression of seizures by holding a limb. Over time, epiprimes occur with an increasing spread of seizures, and their relief by holding the limb is no longer possible. After a paroxysm, there is often a temporary paresis of the limb from which the epiprime began. The increase in the duration and severity of postparoxysmal paresis indicates a tumor process.
With the location of the epileptic focus in the dominant hemisphere, motor aphasia is possible. Occasionally there are paroxysms that occur in the form of transient paralysis of the arm or leg. Depending on the underlying disease, other neurological symptoms are noted in the clinical picture along with Jackson’s epiprimes.
It is not difficult to establish a diagnosis in the presence of typical focal seizures. A more difficult task for a neurologist is to diagnose the underlying causal disease that caused the occurrence of Jackson’s paroxysms. During the diagnosis, the anamnesis of the disease is carefully examined, a neurological examination is carried out, the mental status of the patient is analyzed. Jacksonian seizure should be differentiated from myoclonic epilepsy and seizures in hysterical neurosis. An epileptologist and a psychiatrist can take part in this process along with a neurologist.
Electroencephalography in the interparoxysmal period can register focal cortical discharges of epiactivity provoked by light and sound stimuli. The basic rhythm can be changed in accordance with the causal pathology. EEG video monitoring in many cases allows us to obtain a picture of the ictal EEG, which is characterized by peak-wave activity, which transforms into a polypic wave in the final stages of paroxysm.
The best method of diagnosing the organic pathology of the brain underlying Jacksonian seizure is MRI of the brain. If there are contraindications to its implementation, it is possible to use a CT scan of the brain. These neuroimaging methods make it possible to diagnose/exclude a brain tumor, cyst, abscess, the consequences of TBI, signs of encephalitis, etc.
Therapy includes 2 components: antiepileptic (anticonvulsant) and treatment of the underlying disease. Without the effective implementation of the second component of treatment, the relief of Jacksonian seizure is impossible. Anticonvulsant therapy is carried out in the form of monotherapy or complex treatment using phenobarbital, valproic acid, lamotrigine, primidone, benzobarbital. In parallel, dehydration agents (acetazolamide, furosemide, hydrochlorothiazide) and resorption treatment (hyaluronidase, aloe) are prescribed.
In cases where Jacksonian seizure occurs against the background of a tumor, cyst, arteriovenous malformation, a consultation with a neurosurgeon is necessary to resolve the issue of surgical treatment. However, even after the removal of the organic cause, there is often a persistent persistence of Jackson seizures. In such cases, with resistance to anticonvulsant therapy and a high frequency of epilepsy, the issue of surgical treatment of epilepsy is considered. Operations for dissection of adhesions, removal of scar-altered membranes have shown little effectiveness. After they were carried out, only a temporary disappearance of paroxysms was noted. A more radical method of treatment is focal resection, in which the areas of the cortex responsible for epiactivity are removed. The consequence of the operation is paralysis of the limb, the removal of the motor zones of which was performed. Over time, muscle strength in paretic limbs increases, but paresis, expressed to one degree or another, remains for life. In addition, there is no guarantee that epilepsy attacks will not resume some time after the operation, since the intervention entails the formation of scarring.