Peripheral neuropathy can have many causes, and Refsum disease is one of them. This is a genetically determined disease in which there is an excess of normal values of phytic acid in the blood and urine. The disease leads to disorders of the nervous system, visual function, hearing and smell, heart activity. The main treatment method is diet therapy. In severe cases, plasmapheresis is used.
Description
Refsum disease or syndrome (lat. Heredopathia atactica polyneuritiformis) is a rare lipid metabolism disorder in which phytic acid is not subjected to alpha oxidation. The type of inheritance is autosomal recessive. It is characterized by the accumulation of phytic acid in blood plasma and in tissues (in the brain and spinal cord, peripheral nerve trunks, heart, liver and kidneys). This acid is a derivative of phytol and a component of chlorophyll.
The syndrome was described in 1945 by the Norwegian physician Sigwald Bernhard Refsum (1907-1991), and the biochemical defect underlying it was studied in 1963.
Symptoms of the disease can appear in children or only at an early stage of maturity. It is characterized by such symptoms: peripheral neuropathy, cerebellar symptoms, an increase in protein level in the cerebrospinal fluid, as well as degeneration of the retinitis pigmentosa (acts as the first symptom).
Forms of the disease
Pathology can be diagnosed in various periods of a person's life. Based on this, the following types of Refsum disease are distinguished:
- in adults, the adult form (usually diagnosed after 40 years);
- in adolescents - teenage form (the diagnosis is made during puberty);
- in children - infantile or infantile form (diagnosed from 3 to 10 years).
Hereditary causes
The disease is inherited in an autosomal recessive manner. Caused by a defect in the enzyme phytanoyl-CoA hydroxylase. The mutation effect is the accumulation of phytic acid in various organs, including the peripheral and central nervous system, which leads to peripheral neuropathy, that is, damage to nerve cells. Other potential causes of Refsum disease include mutations in genes encoding proteins that mediate the transport and uptake of substances by peroxisomes. Also considered is the mutation of genes encoding proteins involved in the biogenesis and proliferation of peroxisomes.
Other causes of the disease
Most often, peripheral neuropathies of a sensory or motor nature are caused by systemic diseases such as:
- diabetes;
- alcoholism;
- autoimmune diseases;
- malnutrition;
- endocrine diseases;
- cancer;
- inflammation.
In addition, peripheral neuropathy can be caused by toxins and drugs.
Symptoms
The early diagnosis of Refsum disease in children and adults is very important because it is a potentially treatable disease. First of all, clinical symptoms must be taken into account. A typical course of the disease is manifested by hearing loss, impaired conduction in the myocardium, neuropathy and skin changes similar to fish scales. Late symptoms appear in people at the end of the second decade of life. The result of progressive neuropathy is atrophy and paresis of the muscles of the distal lower extremities. Paralysis over time also extends to the upper limbs. Neuropathy is not only motor in nature, it also includes sensory neurons, causing, for example, pain in the limbs.
Diagnostics
A high concentration of phytic acid can be detected in laboratory tests of blood and urine. In Refsum disease, its pathological values reach 800 μmol / L, when normal values range from - 19 μmol / L.
During an ophthalmological examination, a decrease in visual acuity, a concentric narrowing of the visual fields, atrophy of the optic nerves and degenerative changes in the retina are observed.
When conducting audiometry, hearing impairment is detected.
Electroneuromyography is used to confirm generalized sensory-motor neuropathy and demyelinating features of the nervous system. With a biopsy of the cerebrospinal fluid, an increased level of albumin is observed.
With bone deformities, spinal X-ray, computed tomography and foot radiography are prescribed. The state of the cardiac system is assessed during an ECG study by a cardiologist.
The final diagnosis is made during DNA analysis. Differential diagnosis is also necessary, since Refsum disease can be mistakenly confused with Charcot-Marie-Tooth amyotrophy, polyneuropathy of a different genesis (Degerin-Sott syndrome, diabetic neuropathy, Russi-Levy syndrome, neuropathy with paraneoplastic syndrome, etc.), Friedreich's ataxia.
Peripheral neuropathy during the course of Refsum
Peripheral nerves are composed of various fibers that conduct motor or sensory stimuli. Neuropathies occur due to impaired conductivity of these stimuli. Sensory neuropathy is manifested in the form of numbness, tingling sensations, hypersensitivity or pain. Motor neuropathy is manifested by paresis, awkward movements, muscle cramps and gait disorders. In rare cases, vegetative fibers can be damaged during neuropathy, which manifests itself as cardiac arrhythmia, impaired physiological functions such as urination, bowel movements, sweating or sexual activity.
Treatment of Refsum disease diet
The treatment of motor, sensory neuropathy, skin lesions in the form of fish scales and other symptoms of this disease requires the exclusion of products with phytic acid from the diet. These include fish oil, dairy products, animal fats, green vegetables and greens.
The intake of phytic acid in the body should be reduced to 5 mg per day. To avoid rapid weight loss, the diet should consist of a large amount of carbohydrates.
Diet therapy helps to get rid of the clinical symptoms of the disease. There is a decrease in the severity of polyneuropathy and paresis, normalization of coordination, improvement of the skin condition. Treatment of Refsum's syndrome with a diet is a necessary lifelong condition for a patient with this pathology.
Other treatments
In severe cases, plasmapheresis is used. It helps cleanse the body of excess phytic acid.
To relieve neurological symptoms, the doctor may prescribe anticholinesterase drugs (Galantamine, Neostigmine).
It is also necessary to properly rehabilitate neuropathy. Physiotherapy of neuropathy includes massage procedures, exercises using sensorimotor pads, strengthening and neuromobilizing exercises. Patients diagnosed with neuropathy should wear compression socks and orthopedic shoes.
With severe bilateral hearing loss, the patient needs cochlear implantation.
Forecast
With proper therapy, the disease has a favorable prognosis - you can avoid severe clinical symptoms of the disease and significantly improve the quality of life of the patient. With inadequate treatment or its absence, slow progression of Refsum disease with severe paresis and ataxia, significant visual and hearing impairment, and impaired heart function is observed.