One-sided weakness of facial muscles

One-sided weakness of facial muscles is caused by pathological processes that affect the facial (VII) nerve. All lesions of the system of facial innervation can be localized at 8 levels:

1. supranuclear damage (central paralysis of the facial nerve);
2. defeat at the level of the nucleus and the root of the facial nerve (processes in the field of the variolium bridge);
3. damage in the region of the posterior cranial fossa (bridge-cerebellar angle);
4. at the entrance to the canal of the temporal bone;
5. in the nerve canal proximal to n. Petrosus superficialis major (to the tear gland);
6. in the channel is proximal to the branch to m. Stapedius;
7. between n. Stapedius and chorda tympani; in the canal distal to the chorda tympani;
8. nerve damage distal to foramen stylomastoideum.

Among pregnant women, as well as patients with diabetes mellitus and arterial hypertension, neuropathy of the nerve VII is more common than in the rest of the population.

[1], [2]

Causes of the one-sided weakness of facial muscles

The main causes of unilateral weakness of facial muscles:

1. Idiopathic neuropathy of the nerve VII (Bell paralysis (Bell)).
2. Family forms of the neuropathy of the VII nerve.
3. Infectious lesions (Herpes simplex is the most common cause, herpes zoster, HIV, poliomyelitis, syphilis and tuberculosis (rarely), cat scratch disease and many others).
4. Metabolic disorders (diabetes, hypothyroidism, uremia, porphyria).
5. Diseases of the middle ear.
6. Post-vaccinal neuropathy of the nerve VII.
7. Syndrome of Rossolimo-Melkerson-Rosenthal (Melkersson, Rosenthal).
8. Craniocerebral injury.
9. Tumors (benign and malignant) of the nerve trunk.
10. Diseases of connective tissue and granulomatous processes.
11. In the picture of alternating syndromes (with vascular and neoplastic lesions of the brain stem).
12. Basal meningitis, carcinomatous, lymphomatous and sarcomatous infiltration of membranes.
13. Tumor of the bridge-cerebellar angle.
14. Multiple sclerosis.
15. Syringobulbia.
16. Arterial hypertension.
17. Diseases of the skull bones.
18. Iatrogenic forms.

The most pronounced paresis of the facial musculature is observed in peripheral lesions of the facial nerve.

Cryptogenic or idiopathic neuropathy of the nerve VII

This is the most frequent reason. They occur more frequently in women in the third trimester of pregnancy (sometimes with relapses during each pregnancy), start acutely, often accompanied by pain in the behind-the-ear area, a taste disorder, hyperacidity and rarely a violation of tearing; often the beginning of the disease at night. It is characterized by the unfolded picture of one-sided prosopoplegia.

[3], [4], [5], [6], [7], [8]

Family forms of neuropathy of the nerve VII are rare

The reason is not known. Often accompanied by spots of hyperpigmentation on the skin and a delay in overall development. Characterized by recurrent isolated paralysis of the facial nerve.

Congenital paralysis of the facial nerve is seen in the picture of Mobius syndrome.

[9], [10], [11], [12], [13], [14]

Infectious lesions

Postinfectious neuropathy of the facial nerve is observed especially often after herpes zoster in the area of the intermediate nerve (Hunt's syndrome with pain and characteristic skin eruptions in the ear or throat, sometimes involving the VIII nerve).

Other causes: HIV infection (accompanied by pleocytosis in the cerebrospinal fluid), syphilis and tuberculosis (rarely with tuberculosis of the mastoid, middle ear or pyramid of the temporal bone); infectious mononucleosis, cat scratch disease, poliomyelitis (sharp parietesis of mimic muscles is always accompanied by paresis and subsequent atrophy of other muscles), idiopathic cranial polyneuropathy (paresis can be one-sided), osteomyelitis of the skull bones, Lyme disease (in children, unilateral facial nerve damage occurs more often, than in adults), childhood infections, leprosy.

Dysmetabolic disorders

Lesions of the facial nerve in diabetes mellitus, hypothyroidism, uremia, porphyria are described as mononeuropathy or in the picture of polyneuropathy.

[15], [16], [17]

Diseases of the middle ear

Otitis and (more rarely) tumors of the middle ear, such as the glomus tumor, can lead to paresis of the facial nerve. Paresis due to these diseases is always accompanied by loss of hearing and appropriate radiographic findings.

[18], [19]

Post-vaccination neuropathy of the facial nerve

This form of neuropathy is sometimes observed after vaccination against diphtheria, pertussis, tetanus and poliomyelitis.

Rossolimo-Melkerson-Rosenthal Syndrome

This eponym refers to a hereditary disease characterized by a recurring neuropathy of the facial nerve, recurrent characteristic edema on the face, cheilitis and folded tongue. A full tetrad of symptoms occurs only in 25% of cases; swelling of the lips - in 75%; edema of the face - in 50% of cases; folded tongue - in 20-40% of observations; defeat of the facial nerve - in 30-40% of cases. Prozoplegia can be one-sided and two-sided; The side of the lesion can alternate from relapse to relapse. In families with this disease, there are patients (in different generations) with different variants of incomplete Melkerson-Rosenthal-Rossolimo syndrome. Elements of a "dry" syndrome are described in some patients with this disease.

Head trauma with skull base fracture

Craniocerebral trauma, especially with a fracture of the temporal bone pyramid, often leads to damage to the facial and auditory nerves (with a transverse fracture of the pyramid, the vestibulo-cochlear nerve is immediately involved, if the pyramid is fractured in length, the involvement of the nerve may not appear until 14 days. Otoscopic method). Possible surgical trauma of the trunk of the facial nerve; the cause of neuropathy can be and birth trauma.

Tumors (benign and malignant) in the area of the bridge-cerebellar angle and posterior cranial fossa

Slowly increasing compression of the facial nerve with a tumor, especially cholesteatoma, neurinoma of the VII nerve, meningioma, neurofibromatosis, dermoid or granulomatosis on the basis of the brain (or an aneurysm of the vertebral or main artery), lead to slow progressive paralysis of the facial nerve with the involvement of neighboring formations (eighth, cranial nerves, symptoms of brain stem damage); the appearance of symptoms of intracranial hypertension and other symptoms.

Diseases of connective tissue and granulomatous processes

Such processes as nodular periarteritis, giant cell temporal arteritis, Behcet's disease, Wegener's granulomatosis (granulomatous inflammation of small and medium arteries, mainly affecting the respiratory system and the kidneys) lead to mononeuropathies and polyneuropathies, as well as to the cranial nerves, including the facial nerve.

Heerfordt Syndrome: paresis of the facial nerve (more often bilateral) in sarcoidosis with parotid swelling and visual disorders.

[20], [21], [22], [23]

In the picture of alternating syndromes

Peripheral facial paresis can be a manifestation of defeat of the motor nuclei of the facial nerves in the caudal part of the bridge cover. Common reasons are:

Stem strokes, manifested by Miyar-Goebler syndrome (facial paresis with contralateral hemiparesis) or Fauville's syndrome (facial paresis in combination with homolateral lesion of the distracting nerve and contralateral hemiparesis).

Basal meningitis

Basal meningitis of various etiologies, including carcinomatous or leukemic meningeal infiltration, often lead to facial nerve damage (other cranial nerves are always involved, pareses are often bilateral, characterized by a rapid onset).

[24], [25], [26]

Multiple sclerosis

Multiple sclerosis can often manifest as a lesion of the facial nerve (sometimes recurrent).

Syringobulbia is a rare cause of the pathology of the VII pair (with high localization of the cavity in the brainstem).

Arterial hypertension

Arterial hypertension is a known cause of compression-ischemic neuropathy of the facial nerve; it can lead to unilateral paralysis of facial muscles, apparently due to a violation of microcirculation or a hemorrhage into the canal of the facial nerve.

[27], [28], [29], [30]

Diseases of the skull bones

Such as Paget's disease and hyperostosis cranialis interna (also a hereditary disease leading to recurrent facial nerve neuropathies). In these cases, the decisive word in diagnosis belongs to the X-ray study.

[31]

Iatrogenic forms

Iatrogenic facial nerve neuropathy is described in the form after administration of lidocaine in the face, isoniazid, the use of antiseptic chlorocresol, the use of electrode pastes and some creams (transient weakness of facial muscles).

Sometimes the following additional information concerning the recurring weakness of the facial muscles may be helpful. The latter is observed in 4-7% of all cases of Bell's paralysis.

Recurrent weakness of facial muscles

Main reasons:

1. Idiopathic neuropathy of the facial nerve (including familial).
2. Merkelson-Rosenthal syndrome.
3. Multiple sclerosis.
4. Diabetes.
5. HVDP.
6. Sarcoidosis.
7. Cholesteatoma.
8. Idiopathic cranial polyneuropathy.
9. Arterial hypertension.
10. Intoxication.
11. Myasthenia gravis.
12. Hyperostosis cranialis interna (a hereditary disease manifested by thickening of the inner skull bone plate with tunneled cranial neuropathies).

Diagnostics of the one-sided weakness of facial muscles

General and biochemical blood test; Analysis of urine; electrophoresis of serum proteins; culture of secretion from the ear; audiogram and caloric assays; radiographs of the skull, mastoid process and pyramid of the temporal bone with tomography; CT or MRI; myelography of the posterior cranial fossa; investigation of cerebrospinal fluid; sialography; EMG; serological tests for HIV infection, syphilis, Lyme disease may be needed; it is necessary to exclude tuberculosis.

[32]