Subacute combined degeneration of the spinal cord in the elderly

　　Subacute combined degeneration of the spinal cord is a neurological degenerative disease caused by a deficiency of vitamin B12 (VitB12), which is often associated with pernicious anemia in the elderly. Common causes include malabsorption of VitB12, intestinal diseases (such as malabsorption syndrome, ileal resection), insufficient intake in the diet, drug interference with absorption (such as neomycin), deficiency of transcobalamin, and parasitic diseases, etc.

　　Due to the degeneration of the spinal cord, the tissues and organs below the injured level may lose the支配 of spinal nerve, resulting in abnormal sensations such as numbness, weakness, and pricking. At the same time, muscle weakness and even atrophy may occur in the areas支配 by motor neurons, with a group-like distribution of sensory abnormalities on both feet. Complications such as bedsores may occur in patients with paralysis.

　　This disease usually onset after middle age, presenting as subacute or chronic onset, progressive development. Most patients have symptoms such as fatigue, weakness, diarrhea, anemia before the appearance of neurological symptoms, and the specific introduction is as follows:

　　1. Peripheral nerve damage

　　This is the earliest symptom, which is often manifested as symmetrical, persistent sensory abnormalities starting from the toes and fingertips of the lower limbs, including numbness, tingling, cold sensation, and burning sensation. On examination,手套样 and 袜套样 sensory disturbances and neural dry pain can be detected.

　　2. Spinal cord damage

　　Spinal cord damage mainly affects the posterior column and lateral column, with symptoms of the posterior column appearing earlier, manifested as significant deep sensory disorders in the lower limbs, including decreased or absent position sense, vibration sense, and kinesthetic sense, as well as sensory ataxia. Patients may experience unsteady gait, especially at night.

　　3. Cranial nerve damage

　　In addition to the involvement of the optic nerve, the other cranial nerves are not affected, and the main manifestations are visual impairment, central scotoma in both eyes, narrowing of the visual field, and atrophy of the optic nerve. These can occur in the early or late stages of the disease, or in patients with pernicious anemia without signs of subacute combined degeneration.

　　4. Psychiatric symptoms

　　Due to the progress in treatment, psychiatric symptoms are now rare, but they were more common before the application of vitamin B12 and liver extract, and could manifest as irritability, apathy, impaired cognitive function, delayed response, hallucinations, loss of orientation, depression, decreased memory, and even dementia.

　　The prevention of diseases mainly focuses on the prevention of etiology, such as improving dietary structure, correcting malnutrition, eating more foods rich in vitamin B group, and should avoid alcohol. Patients should treat gastrointestinal diseases that can cause malabsorption as soon as possible, and it is not recommended to use folic acid treatment for those with obvious neurological symptoms. In addition, physical therapy, acupuncture, and physical therapy are all helpful in improving symptoms.

　　The serum vitamin B12 concentration of patients with this disease is lower than 100pg/ml (normal range is 140-900pg/ml). Taking oral radioactive isotope 57Co-labeled vitamin B12, measuring its content in urine and feces, can find vitamin B12 absorption defect.

　　When performing histamine injection for gastric juice analysis, some patients may be found to have hypochlorhydria. Some patients may have abnormal visual evoked potentials and somatosensory evoked potentials. On the MRI images, there are high signal changes in the posterior column of the spinal cord in the T2 phase, which can disappear after treatment. In addition, general patients' peripheral blood and bone marrow examination can show the phenomenon of macrocytic hyperhemoglobinemia anemia.

　　Patients with senile acute combined demyelinating disease of the spinal cord should pay attention to a light diet, eat more vegetables and fruits to ensure an adequate intake of vitamin B12, and at the same time, pay attention to a reasonable diet, to ensure adequate nutrition, which can help the disease recover better and faster.

　　If this disease is not treated, it usually results in death within a few years, but if it is treated actively within 2-3 months after onset, it is expected to be completely recovered. Therefore, early diagnosis and treatment should be pursued. Once the disease is diagnosed, immediate high-dose vitamin B12 treatment should be given. The general dose of vitamin B12 is 200-500μg per day, intramuscular injection, for 2 weeks continuously, and then changed to 200μg per time, once a week, after the symptoms improve, changed to maintenance dose, 50μg every 3-4 weeks, to prevent recurrence. Vitamin C and vitamin B12 can enhance the efficacy when used together.

　　It should be noted that within the first 2 months, when the red blood cell count is gradually increasing, iron should be supplemented: ferrous sulfate tablets 0.3-0.6g, 3 times a day; or 10% citric acid iron amine solution taken orally, 10ml each time, 3 times a day; or dextran iron injection can also be used, 50-100mg intramuscular injection each time, once every 1-3 days.