Crossed syndromes are neurological disorders involving unilateral cranial nerve damage and contralateral motor and/or sensory disorders. The variety of forms is due to the different level of lesion. Diagnosis is carried out clinically during a neurological examination. To establish the etiology of the disease, MRI of the brain, studies of cerebral hemodynamics, analysis of cerebrospinal fluid are performed. Treatment depends on the genesis of the pathology, includes conservative, surgical methods, restorative therapy.
G46.3 Stroke syndrome in the brain stem (I60-I67+)
Crossed syndromes (alternating syndromes) got their name from the Latin adjective “alternance”, meaning “opposite”. The concept includes symptom complexes characterized by signs of damage to the cranial nerves (TBI) in combination with central motor (paresis) and sensitive (hypesthesia) disorders in the opposite half of the body. Since paresis covers the extremities of half of the body, it is called hemiparesis (“hemi” – half), similarly sensory disorders are designated by the term hemihypesthesia.
Characteristic cross-neurological symptoms occur with a half lesion of the cerebral trunk. Pathological processes may be based on:
- Disorders of cerebral circulation. Stroke is the most common cause that causes crossed syndromes. The etiofactor of ischemic stroke is thromboembolism, a spasm in the system of the vertebral, basilar, cerebral artery. Hemorrhagic stroke occurs when hemorrhage from these arterial vessels.
- Brain tumor. Crossed syndromes appear when the trunk is directly affected by a tumor, when the stem structures are compressed by a nearby neoplasm that increases in size.
- Inflammatory processes: encephalitis, meningoencephalitis, brain abscesses of variable etiology with localization of the inflammatory focus in stem tissues.
- Brain injury. In some cases, alternating symptoms are accompanied by fractures of the skull bones forming the posterior cranial fossa.
Alternating symptom complexes of extra-genital localization are diagnosed with circulatory disorders in the middle cerebral, common or internal carotid artery.
Cranial nerve nuclei are located in various parts of the cerebral trunk. There is also a motor tract (pyramidal pathway) carrying efferent impulses from the cerebral cortex to the neurons of the spinal cord, a sensitive tract conducting afferent sensory impulses from receptors, cerebellar pathways. Motor and sensitive conductive fibers form a cross at the level of the spinal cord. As a result, the innervation of half of the body is carried out by nerve pathways passing in the opposite part of the trunk. Unilateral stem lesion with simultaneous involvement of cranial nerves (CN) nuclei and conducting tracts in the pathological process is clinically manifested by cross-symptomatology characterizing crossed syndromes. In addition, cross-symptoms occur with simultaneous damage to the motor cortex and the extra-genital part of the CN. The pathology of the midbrain is characterized by a bilateral character, does not lead to alternating symptoms.
According to the location of the lesion, extra-stem and stem syndromes are distinguished. The latter are divided into:
- Bulbar — associated with focal lesion of the medulla oblongata, where the nuclei of the IX-XII cranial nerves, the lower legs of the cerebellum are located.
- Pontine — caused by a pathological focus at the level of the bridge involving the nuclei of the IV-VII nerves.
- Peduncular — occur when pathological changes are localized in the legs of the brain, where the red nuclei, upper cerebellar legs are located, the roots of the III pair of CN, pyramidal tracts pass.
The basis of the clinical picture consists of alternating neurological symptoms: signs of dysfunction of the CN on the side of the lesion, sensory and / or motor disorders on the opposite side. Nerve damage is peripheral in nature, which is manifested by hypotension, atrophy, fibrillation of innervated muscles. Motor disorders are central spastic hemiparesis with hyperreflexia, pathological stop signs. Depending on the etiology, alternating symptoms have a sudden or gradual development, accompanied by cerebral symptoms, signs of intoxication, intracranial hypertension.
Jackson’s syndrome is formed when the nucleus of the XII (sublingual) nerve and the pyramidal pathways are affected. It is manifested by peripheral paralysis of half of the tongue: the protruding tongue deviates towards the lesion, atrophy, fasciculations, difficulties in pronouncing difficult-to-articulate words are noted. In the contralateral extremities, hemiparesis is observed, sometimes loss of deep sensitivity.
Avellis syndrome is characterized by paresis of the muscles of the larynx, pharynx, vocal cords due to dysfunction of the nuclei of the lingopharyngeal (IX) and vagus (X) nerves. Clinically, choking, voice disorders (dysphonia), speech disorders (dysarthria) with hemiparesis, hemihypesthesia of opposite extremities are observed. The defeat of the nuclei of all caudal CN (IX-XII pairs) causes a variant of Schmidt, which differs from the previous form by paresis of the sternocleidomastoid and trapezius neck muscles. On the affected side, there is a lowering of the shoulder, limiting the lifting of the arm above the horizontal level. It is difficult to turn the head towards the paretic limbs.
The Babinski-Najotte form includes cerebellar ataxia, nystagmus, Gorner’s triad, cross—paresis, and surface sensitivity disorder. The Wallenberg-Zakharchenko variant reveals a similar clinic, dysfunction of the IX, X and V nerves. It can occur without paresis of the extremities.
Miyar-Gubler syndrome appears in pathology in the area of the nucleus of the VII pair and the fibers of the pyramidal tract, it is a combination of facial paresis with hemiparesis of the opposite side. A similar localization of the focus, accompanied by irritation of the nerve nucleus, causes the Brissot-Sicard form, in which a facial hemispasm is observed instead of facial paresis. The Fauville variant is distinguished by the presence of peripheral paresis of the VI cranial nerve, which gives the clinic of convergent strabismus.
Gasperini syndrome is a lesion of the nuclei of V-VIII pairs and the sensitive tract. There is facial paresis, converging strabismus, hypesthesia of the face, hearing loss, possible nystagmus. Contralateral hemihypesthesia of the conductor type is observed, motility is not impaired. The form of Raymond-Sestan is caused by damage to the motor and sensory pathways, the middle cerebellar pedicle. Dissinergia, discoordination, hypermetria are found on the side of the focus, hemiparesis and hemianesthesia are contralateral.
Weber syndrome is a dysfunction of the nucleus of the III pair. It is manifested by drooping of the eyelid, dilation of the pupil, rotation of the eyeball towards the outer corner of the eye, cross hemiparesis or hemihypesthesia. The spread of pathological changes to the cranial body adds visual disturbances (hemianopia) to the indicated symptoms. Benedict’s variant — pathology of the oculomotor nerve is combined with dysfunction of the red nucleus, which is clinically manifested by intentional tremor, athetosis of opposite limbs. Sometimes accompanied by hemianesthesia. In the Notnagel variant, oculomotor dysfunction, cerebellar ataxia, hearing disorders, contralateral hemiparesis are observed, hyperkinesis is possible.
Extra-genital crossed syndromes
Hemodynamic disorders in the subclavian artery system cause the appearance of a vertigo-hemiplegic form: symptoms of vestibulocochlear nerve dysfunction (noise in the ear, dizziness, hearing loss) and cross hemiparesis. The opticohemiplegic variant develops with dyscirculation simultaneously in the orbital and middle cerebral arteries. It is characterized by a combination of optic nerve dysfunction and cross hemiparesis. Asphygmoemiplegic syndrome occurs with occlusion of the carotid artery. There is a hemispasm of facial muscles opposite to hemiparesis. A pathognomonic sign is the absence of pulsation of the carotid and radial arteries.
Crossed syndromes accompanied by spastic hemiparesis lead to the development of joint contractures that aggravate motor disorders. Paresis of the VII pair causes a facial distortion, which becomes a serious aesthetic problem. The result of damage to the auditory nerve is hearing loss, reaching complete hearing loss. Unilateral paresis of the oculomotor group (III, VI pairs) is accompanied by double vision (diplopia), which significantly impairs visual function. The most serious complications occur with the progression of the lesion of the brain stem, its spread to the second half and vital centers (respiratory, cardiovascular).
A neurologist’s examination allows to establish the presence and type of the cross syndrome. The obtained data make it possible to determine the topical diagnosis, that is, the localization of the pathological process. Approximately, the etiology can be judged by the course of the disease. Tumor processes are characterized by a progressive increase in symptoms for several months, sometimes days. Inflammatory lesions are often accompanied by general infectious symptoms (fever, intoxication). In stroke, alternating symptoms occur suddenly, increase rapidly, occur against the background of changes in blood pressure. Hemorrhagic stroke differs from ischemic by a blurred atypical picture of the syndrome, which is due to the lack of a clear border of the pathological focus due to pronounced perifocal processes (edema, reactive phenomena).
Additional studies are being conducted to determine the cause of neurological symptoms:
- Tomography. Brain MRI allows you to visualize an inflammatory focus, hematoma, trunk tumor, stroke area, differentiate hemorrhagic and ischemic stroke, determine the degree of compression of stem structures.
- Ultrasound methods. The most accessible, rather informative method of diagnosing disorders of cerebral blood flow is ultrasound of cerebral vessels. Detects signs of thromboembolism, local spasm of intracerebral vessels. In the diagnosis of occlusion of the carotid, vertebral arteries, ultrasound of extracranial vessels is necessary.
- Neuroimaging of vessels. The most informative way to diagnose acute disorders of cerebral circulation is MRI of cerebral vessels. Visualization of vessels helps to accurately diagnose the nature, localization, and degree of their lesion.
- Examination of cerebrospinal fluid. Lumbar puncture is performed if the infectious and inflammatory nature of the pathology is suspected, which is evidenced by inflammatory changes in the cerebrospinal fluid (turbidity, cytosis due to neutrophils, the presence of bacteria). Bacteriological and virological studies make it possible to identify the pathogen.
Therapy is carried out in relation to the underlying disease, includes conservative, neurosurgical, rehabilitation methods.
- Conservative therapy. General measures include the appointment of decongestants, neuroprotective agents, blood pressure correction. Differentiated treatment is carried out according to the etiology of the disease. Ischemic stroke is an indication for thrombolytic, vascular therapy, hemorrhagic — for the appointment of calcium preparations, aminocaproic acid, infectious lesions – for antibacterial, antiviral, antimycotic therapy.
- Neurosurgical treatment. It may be required for hemorrhagic stroke, damage to the blood supply to the brain of the main arteries, volumetric formations. According to the indications, reconstruction of the vertebral artery, carotid endarterectomy, formation of an extra-intracranial anastomosis, removal of a trunk tumor, removal of a metastatic tumor, etc. is carried out. The question of the expediency of surgical intervention is decided jointly with the neurosurgeon.
- Rehabilitation. It is carried out by the joint efforts of a rehabilitologist, a physical therapy doctor, a masseur. It is aimed at preventing contractures, increasing the volume of movement of paretic limbs, adapting the patient to his condition, postoperative recovery.
Prognosis and prevention
Accordingly, the etiology of crossed syndromes may have a different outcome. Hemiparesis leads to disability of most patients, complete recovery is observed in rare cases. Limited ischemic strokes have a more favorable prognosis if adequate treatment is started quickly. Recovery after hemorrhagic stroke is less complete and longer than after ischemic stroke. Prognostically complex are tumor processes, especially of metastatic genesis. Prevention is non-specific, consists in timely effective treatment of cerebrovascular pathology, prevention of neuroinfections, TBI, oncogenic effects.