Hemiparesis (hemiplegia)

Hemiparesis ("central") - paralysis of the muscles of one half of the body as a result of damage to the corresponding upper motor neurons and their axons, i.e. motor neurons in the anterior central gyrus or corticospinal (pyramidal) tract, usually above the level of the cervical thickening of the spinal cord. Hemiparesis, as a rule, has a cerebral, rarely spinal origin.

Neurological differential diagnosis, as a rule, begins to be built taking into account the cardinal clinical features that facilitate diagnosis. Among the latter, it is useful to pay attention to the course of the disease and, in particular, to the features of its debut.

The rapid development of hemiparesis is an important clinical sign that allows for faster diagnostic search.

Hemiparesis that develops suddenly or progresses very rapidly:

1. Stroke (the most common cause).
2. Space-occupying lesions in the brain with pseudo-stroke course.
3. Traumatic brain injury.
4. Encephalitis.
5. Postictal state.
6. Migraine with aura (hemiplegic migraine).
7. Diabetic encephalopathy.
8. Multiple sclerosis.
9. Pseudoparesis.

Subacute or slowly developing hemiparesis:

1. Stroke.
2. Brain tumor.
3. Encephalitis.
4. Multiple sclerosis.
5. Atrophic cortical process (Mills syndrome).
6. Hemiparesis of brainstem or spinal (rare) origin: trauma, tumor, abscess, epidural hematoma, demyelinating processes, radiation myelopathy, in the picture of Brown-Sequard syndrome).

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Hemiparesis that develops suddenly or progresses very rapidly

Stroke

When a physician encounters a patient with acute hemiplegia, he usually assumes a stroke. Of course, strokes occur not only in elderly patients with arteriopathy, but also in young patients. In these rarer cases, it is necessary to exclude cardiogenic embolism or one of the rare diseases such as fibromuscular dysplasia, rheumatic or syphilitic angiitis, Sneddon's syndrome, or other diseases.

But first it is necessary to establish whether the stroke is ischemic or hemorrhagic (arterial hypertension, arteriovenous malformation, aneurysm, angioma), or whether there is venous thrombosis. It should be remembered that sometimes hemorrhage into a tumor is also possible.

Unfortunately, there are no reliable methods for differentiating ischemic and hemorrhagic stroke lesions except neuroimaging. All other indirect evidence mentioned in textbooks is not reliable enough. In addition, the subgroup of ischemic stroke, which seems to be uniform, can be caused by hemodynamic disturbances due to extracranial arterial stenosis, as well as by cardiogenic embolism, or arterio-arterial embolism due to plaque ulceration in extra- or intracerebral vessels, or local thrombosis of a small arterial vessel. These different types of stroke require differentiated treatment.

Space-occupying lesions in the brain with pseudo-stroke course

Acute hemiplegia may be the first symptom of a brain tumor, and the cause is usually hemorrhage into the tumor or surrounding tissues from rapidly forming internal tumor vessels with an incomplete arterial wall. Growing neurological deficit and decreased consciousness, together with symptoms of generalized hemispheric dysfunction, are quite characteristic of "apoplectic glioma." Neuroimaging methods are invaluable in diagnosing a tumor with a pseudo-stroke course.

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Traumatic brain injury (TBI)

TBI is accompanied by external manifestations of trauma and the situation that caused the trauma is usually clear. It is advisable to question eyewitnesses to clarify the circumstances of the injury, since the latter is possible when the patient falls during an epileptic seizure, subarachnoid hemorrhage, and falls from other causes.

Encephalitis

According to some publications, in approximately 10% of cases the onset of encephalitis resembles a stroke. Usually, a rapid deterioration in the patient's condition with impaired consciousness, grasping reflexes, and additional symptoms that cannot be attributed to the basin of a large artery or its branches requires urgent examination. Diffuse disturbances are often detected on the EEG; neuroimaging methods may not detect pathology during the first few days; cerebrospinal fluid analysis often reveals minor pleocytosis and a slight increase in protein levels with normal or elevated lactate levels.

Clinical diagnosis of encephalitis is facilitated if meningoencephalitis or encephalomyelitis occurs, and the disease manifests itself as a typical combination of general infectious, meningeal, general cerebral and focal (including hemiparesis or tetraparesis, cranial nerve damage, speech disorders, ataxic or sensory disorders, epileptic seizures) neurological symptoms.

In approximately 50% of cases, the etiology of acute encephalitis remains unclear.

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Postictal state

Sometimes epileptic seizures go unnoticed by others, and the patient may be in a coma or confusion, with hemiplegia (in some types of epileptic seizures). It is useful to pay attention to tongue biting, the presence of involuntary urination, but these symptoms are not always present. Also useful are questioning eyewitnesses, examining the patient's belongings (to search for antiepileptic drugs), and, if possible, a phone call to the patient's home or local clinic to confirm epilepsy based on the outpatient card data. An EEG done after a seizure often reveals "epileptic" activity. Partial seizures that leave behind transient hemiparesis (Todd's paralysis) can develop without aphasia.

Migraine with aura (hemiplegic migraine)

In younger patients, complicated migraine is an important alternative. This is a variant of migraine in which transient focal symptoms such as hemiplegia or aphasia occur before the unilateral headache and, like other migraine symptoms, recur periodically in the anamnesis.

The diagnosis is relatively easy to establish if there is a family and/or personal history of recurrent headaches. If there is no such history, then the examination will reveal a pathognomonic combination of symptoms constituting a severe neurological deficit and focal abnormalities on the EEG in the presence of normal neuroimaging results.

These symptoms can be relied upon only if they are known to be due to hemispheric dysfunction. If basilar migraine (vertebrobasilar basin) is present, normal neuroimaging results do not yet exclude a more serious cerebral disorder, in which EEG abnormalities may also be absent or minimal and bilateral. In this case, ultrasound Dopplerography of the vertebral arteries is of greatest value, since significant stenosis or occlusion in the vertebrobasilar system is extremely rare in the presence of normal ultrasound data. In case of doubt, it is better to perform an angiographic study than to miss a curable vascular lesion.

Diabetic metabolic disorders (diabetic encephalopathy)

Diabetes mellitus can cause acute hemiplegia in two cases. Hemiplegia is often observed in nonketotic hyperosmolarity. Focal and generalized abnormalities are recorded on the EEG, but neuroimaging and ultrasound data are normal. Diagnosis is based on laboratory studies, which should be widely used in hemiplegia of unknown etiology. Adequate therapy leads to rapid regression of symptoms. The second possible cause is hypoglycemia, which can lead not only to seizures and confusion, but sometimes to hemiplegia.

Multiple sclerosis

Multiple sclerosis should be suspected in young patients, especially when sensorimotor hemiplegia with ataxia occurs acutely and when consciousness is completely preserved. EEG often shows minor abnormalities. Neuroimaging reveals an area of decreased density that does not correspond to the vascular bed and is usually not a space-occupying lesion. Evoked potentials (especially visual and somatosensory) can be of great help in the diagnosis of multifocal CNS lesions. CSF examination data also help the diagnosis if IgG parameters are altered, but unfortunately the CSF may be normal during the first exacerbation(s). In these cases, a definitive diagnosis is only established by subsequent examination.

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Pseudoparesis

Psychogenic hemiparesis (pseudoparesis), which developed acutely, usually appears in an emotional situation and is accompanied by affective and vegetative activation, demonstrative behavioral reactions and other functional-neurological signs and stigmas that facilitate diagnosis.

Subacute or slowly developing hemiparesis

Most often, such disorders are caused by cerebral level damage.

The reasons for this type of weakness are the following:

Strokes

Vascular processes such as stroke in development. Most often there is a gradual progression. This cause can be suspected based on the patient's age, gradual progression, presence of risk factors, noise over the arteries due to stenosis, previous vascular episodes.

Brain tumors and other space-occupying processes

Intracranial space-occupying processes such as tumors or abscesses (most often progressing over several weeks or months) are usually accompanied by epileptic seizures. Meningiomas may have a long-term epileptic history; eventually, the space-occupying process leads to increased intracranial pressure, headache, and increasing mental disorders. Chronic subdural hematoma (mainly traumatic, sometimes confirmed by a history of mild trauma) is always accompanied by headache, mental disorders; relatively mild neurological symptoms are possible. There are pathological changes in the cerebrospinal fluid. Suspicion of an abscess appears in the presence of a source of infection, inflammatory changes in the blood, such as increased ESR, and rapid progression. Symptoms may suddenly appear due to hemorrhage into the tumor, rapidly increasing to hemisyndrome, but not similar to a stroke. This is especially typical for metastases.

Encephalitis

In rare cases, acute hemorrhagic herpes encephalitis can cause a relatively rapidly progressing (subacute) hemisyndrome (with severe cerebral disorders, epileptic seizures, changes in the cerebrospinal fluid), which soon leads to a comatose state.

Multiple sclerosis

Hemiparesis may develop within 1-2 days and be very severe. This picture sometimes develops in young patients and is accompanied by visual symptoms such as retrobulbar neuritis and episodes of double vision. These symptoms are accompanied by urination disorders; often pallor of the optic disc, pathological changes in visual evoked potentials, nystagmus, pyramidal signs; remittent course. In the cerebrospinal fluid, there is an increase in the number of plasma cells and IgG. Such a rare form of demyelination as Balo's concentric sclerosis can cause subacute hemisyndrome.

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Atrophic cortical processes

Local unilateral or asymmetric cortical atrophy of the precentral area: motor impairment may be slowly progressive, sometimes years are needed for hemiparesis to develop (Mills' palsy). The atrophic process is confirmed by computed tomography. The nosological independence of Mills' syndrome has been questioned in recent years.

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Processes in the brainstem and spinal cord

Lesions of the brainstem are rarely manifested by progressive hemi-syndrome; processes in the spinal cord, accompanied by hemiparesis, are even rarer. The presence of cross-symptoms is evidence of such localization. In both cases, the most common cause is volumetric lesions (tumor, aneurysm, spinal spondylosis, epidural hematoma, abscess). In these cases, hemiparesis in the picture of Brown-Sequard syndrome is possible.

Diagnosis of hemiparesis

General somatic examination (general and biochemical), blood test; hemorheological and hemocoagulation characteristics; urine analysis; ECG; if indicated - search for hematological, metabolic and other visceral disorders), CT or (better) MRI of the brain and cervical spinal cord; cerebrospinal fluid examination; EEG; evoked potentials of different modalities; ultrasound Dopplerography of the main arteries of the head.

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