Inflammatory polyneuropathy is a multiple lesion of nerve trunks, the substrate of which is an inflammatory reaction of autoimmune genesis. It is manifested by rapidly or slowly progressive sluggish paresis with sensitivity disorder, sometimes with damage to the cranial nerves, paralysis of the respiratory muscles. Diagnostics is carried out using electrophysiological studies, analysis of cerebrospinal fluid, blood analysis and immunological studies. Pathogenetic therapy (glucocorticosteroids, immunoglobulin G, plasmapheresis, cytostatics) and symptomatic (painkillers, anticholinesterase, lipoic acid, physiotherapy).
ICD 10
G61 Inflammatory polyneuropathy
General information
Inflammatory polyneuropathy is an inflammatory process affecting several peripheral nerve trunks at once. Inflammatory nerve damage is predominantly autoimmune in nature and is often accompanied by demyelination — the destruction of the myelin sheath of nerves. Inflammatory polyneuropathy includes several nosologies: acute and chronic inflammatory demyelinating polyneuropathies, serum neuropathy. The incidence is common among children and adults. For inflammatory demyelinating polyneuropathies, it is about 1.7 people per 100 thousand. although some atypical variants are much rarer — according to some data, up to 2 cases per 1 million population. The prevalence of serum polyneuropathy among individuals who have been injected with heterologous sera is at the level of 2-5%. Inflammatory polyneuropathy of any type is a serious disease with a risk of death or disability, therefore, the search for new more effective methods of its therapy is one of the priorities of modern neurology and immunology.
Causes
The etiopathogenesis of inflammatory polyneuropathies is not completely clear. Most researchers tend to consider the autoimmune process as the main pathogenetic mechanism. Inflammatory perivascular processes, activation of macrophages, accumulation of mononuclears are observed in perineural tissues. Antimyelin antibodies are detected in the blood, complement and immunoglobulins, deposits of membranolytic complexes are detected on peripheral nerves. Developing autoimmune inflammation leads to detachment and destruction of myelin with a decrease in the thickness of the nerve trunk by almost 2 times. The result is a violation of nerve impulses, clinically expressed in motor and sensory disorders. In addition to demyelination, multiple inflammatory infiltrates and expansion of the subcellular space are morphologically determined in biopsies of affected peripheral nerves.
Acute inflammatory demyelinating polyneuropathy (OIDP)
It is characterized by an acute debut against the background of subfebrility. Motor disorders come to the fore — sluggish tetraparesis of varying severity: muscle weakness engulfs all limbs and is accompanied by muscular hypotension and tendon hyporeflexia. Half of the patients have pain syndrome. Over time, hypotrophy of the denervated muscles is formed. Sphincter functions are usually not impaired. Possible damage to the cranial nerves, facial muscles. Sensitivity disorders are not found in all cases. 30% of patients have respiratory muscle paresis with respiratory function disorder requiring ventilation.
A typical example of acute inflammatory polyneuropathy is Guillain-Barre syndrome. Rarer forms include atypical and symptomatic. The former are distinguished by the predominance of selective lesions of certain types of nerve fibers, according to which vegetative, motor, craniobulbar, sensory, OIDP are distinguished. Atypical forms also include Fischer syndrome, which is a combination of sluggish tetraparesis, oculomotor disorders (ophthalmoplegia) and ataxia. Symptomatic variants of acute inflammatory polyneuropathy may occur against the background of intoxication and infectious diseases (for example, with diphtheria).
Chronic inflammatory demyelinating polyneuropathy (CIDP)
It has a gradual onset with the symmetrical development of sluggish paresis, accompanied by sensitivity disorders. In some cases (about 15%), the onset is more acute, which allows some clinicians to consider CIDP as a variant of the course of Guillain-Barre syndrome. In typical cases, muscle weakness occurs first in the legs, then spreads to the arms. Characterized by a long progression, taking more than 2 months. In severe cases, at the peak of the disease, there is complete immobility of the patient with paralysis of the respiratory muscles. Approximately 10% of patients require a ventilator. In 15% of cases, there is a lesion of PMN (trigeminal nerve, bulbar and /or oculomotor groups).
Chronic inflammatory polyneuropathy may have several variants of its course. In the monophasic variant, clinical symptoms partially or completely regress after reaching the peak of their manifestation without further exacerbations or relapses. With a progressive course, there is a steady gradual or gradual increase in symptoms. Up to 30% of cases of chronic inflammatory polyneuropathy have a relapsing-remitting course, in which relapses (periods of increase and regression of manifestations) alternate with temporary stabilization of the condition — remission.
Atypical forms of CIDP are represented by a distal variant with damage mainly to the distal parts of peripheral nerves, an asymmetric variant (Lewis-Sumner syndrome, multifocal motor or sensory neuropathy), a focal variant with damage to individual nerve trunks (for example, with a clinic of brachial plexitis, neuritis of several nerves of one limb, lumbosacral plexitis), an isolated variant with selective involvement of only sensitive or only motor nerves in the inflammatory process. Chronic inflammatory polyneuropathy of a symptomatic nature can be observed in systemic diseases (nodular periarteritis, SLE, Sjogren’s disease, systemic vasculitis), chronic infections (HIV, viral hepatitis C, HTVL infections), oncopathology (hepatocellular carcinoma, colon adenocarcinoma), lung sarcoidosis, chronic glomerulonephritis, endocrine pathology (hyperthyroidism , diabetes mellitus).
Serum neuropathy
It most often develops after vaccination against tetanus. It debuts 7-10 days after the introduction of the vaccine with pain in the shoulder girdle, fever and itchy rashes in the shoulder area by the type of urticaria. From the first days of the disease, numbness of the hands occurs, then the weakness of the upper extremities gradually increases, more pronounced in their proximal parts. Most patients develop atrophy of the proximal muscles of the arms and the muscles of the shoulder girdle. In a quarter of cases, arthralgia occurs, in a third — sensitivity disorders in the area of innervation of the axillary nerve. Lymphadenitis is detected in 30% of patients.
Diagnostics
The key feature of the clinical picture of inflammatory polyneuropathy is the lesion of both distal and proximal muscle groups of the extremities, which makes it possible to differentiate it from polyneuropathies of other genesis: toxic, dysmetabolic (hepatic, uremic, diabetic neuropathy) and hereditary (Refsum disease, Charcot-Marie-Tutt neural amyotrophy, Dejerin-Sott syndrome). The presence of sensory disorders distinguishes inflammatory polyneuropathy from motor neuron diseases (ALS, primary lateral sclerosis, spinal amyotrophy) and primary muscle lesions (myotonia, myopathy). The attention of diagnosticians should be attracted by the dissociation usually observed in the clinic of inflammatory polyneuropathy between significant muscle weakness and non-rough muscle atrophy.
Along with clinical signs, it is possible to establish a polyneural type of lesion by conducting electroneuromyography. The examination includes at least a study of the median, ulnar, small and tibial nerves. The diagnosis of inflammatory polyneuropathy is supported by the detection of increased protein content and protein-cell dissociation in the study of cerebrospinal fluid obtained by lumbar puncture. With OIDP, the protein content reaches 5 g / l, protein-cell dissociation is more pronounced, lymphocytosis may occur, but the concentration of lymphocytes usually does not exceed 20 pcs in 1 ml. In CIDP, protein-cell dissociation is observed mainly during the period of onset and exacerbation.
In the acute inflammatory period, leukocytosis and acceleration of ESR may occur in the blood. The analysis for antibodies to glycosides does not have specificity and high sensitivity. However, in some forms of inflammatory polyneuropathy (Fischer syndrome, multifocal polyneuropathy) they can be revealing. In difficult diagnostic cases, neurologists resort to nerve biopsy followed by electron microscopy of the drug, which reveals characteristic demyelinating processes. In some patients with CIDP, MRI of the brain determines the periventricular and subcortical demyelinating foci, indicating the spread of the demyelination process to the central nervous system.
Treatment
Therapy consists of pathogenetic and symptomatic treatment. Glucocorticosteroids (prednisolone, methylprednisolone), human class G immunoglobulin and plasmapheresis are the means of the first-line pathogenetic component of treatment. It should be noted that in different clinical cases, these methods reveal different effectiveness. Thus, in typical forms of inflammatory demyelinating polyneuropathy, corticosteroid therapy shows a good result, in atypical cases, immunoglobulin treatment. In the case of serum neuropathy, antihistamines are additionally prescribed.
Plasmapheresis causes significant improvement in 80% of patients and is used in combination with corticosteroids or immunoglobulin. However, with multifocal motor neuropathy (MMN), plasmapheresis has no effect, and corticosteroids can aggravate the severity of paresis; the only method of first-line therapy remains the introduction of immunoglobulin. The second-line drugs are cytostatics (cyclophosphamide, cyclosporine, azathioprine, methotrexate). Their use is recommended in the absence of the desired results from first-line therapy. Cyclophosphamide is successfully used in MMN.
The symptomatic component of treatment may include anticholinesterase pharmaceuticals (galantamine, ipidacrine, neostigmine), neuropathic pain relievers (amitriptyline, pregabalin, gabapentin), lipoic acid preparations for sensitive disorders, ventilators for respiratory failure. In order to reduce the motor deficit and in the recovery period, physical therapy, massage and physiotherapy are indicated.
Forecast
OIDPs have a predominantly benign course with almost complete recovery in the period from several weeks to 12 months. However, in some cases, a severe form develops with paresis of the respiratory muscles and the risk of death. The mortality rate is about 5%, cases of persistent residual symptoms — up to 15%. With CIDP, in conditions of adequate treatment, stabilization of the condition is achieved in 70% of patients, complete recovery — in 10-15%. The remaining 10-15% of cases are characterized by weakly amenable to therapy with steady progression or remitting course. Serum neuropathy with timely treatment, as a rule, has a favorable prognosis for recovery.