Subacute combined degeneration of the spinal cord in the elderly
Introduction
Introduction to subacute combined degeneration of the elderly Subacute degeneration of spinal cord (subacute degeneration of spinal cord) is a neurodegenerative disease caused by vitamin B12 deficiency, usually accompanied by pernicious anemia. The main lesions are in the posterior and lateral cords of the spinal cord. The clinical manifestations are deep sensory disturbances and sensory ataxia. And spasticity, accompanied by peripheral sensory disturbances. Some scholars believe that the damage of this disease is not limited to the spinal cord, the optic nerve and the cerebral hemisphere can also occur, and the damage of the spinal cord is not limited to the conduction bundle system of the posterior and lateral cords, and the white matter of the spinal cord can occur. basic knowledge The proportion of the disease: the incidence rate of the elderly over 60 years old is about 0.0001% - 0.0004% Susceptible people: the elderly Mode of infection: non-infectious Complications: anemia optic atrophy
Cause
Subacute combined degeneration of the elderly
(1) Causes of the disease
Subacute combined degeneration of spinal cord is a neurodegenerative disease caused by vitamin B12 deficiency (Vit B12). It is associated with pernicious anemia in the elderly. Common causes are: Vit B12 malabsorption, Such as the lack of internal factors secreted by gastric parietal cells (autoimmune response, atrophic gastritis, postoperative gastrectomy, etc.); small bowel disease (small intestinal malabsorption syndrome, ileal resection, etc.); inadequate intake in the diet; drugs hinder absorption ( Neomycin, etc.); lack of cobalamin protein; parasitic diseases.
(two) pathogenesis
The methionine synthesis dependent on Vit B12 is involved in the formation of myelin, so Vit B12 deficiency can cause myelin loss and degeneration of the central and peripheral nerves; Vit B12 also affects lipid metabolism, and lipid-like metabolic disorders can lead to nerves. Myelin sheath swelling, rupture, causing axonal degeneration; Vit B12 is an essential coenzyme for DNA and RNA synthesis, its lack leads to insufficient RNA synthesis, RNA is a nuclear protein required by nerve cell cytoplasm, and its synthesis is insufficient to cause nerve axis Mutagenicity, particularly prone to the axonal spinal cord, lateral cord, and lack of DNA synthesis, affects cell division of the bone marrow and gastric mucosa to produce anemia and gastrointestinal symptoms.
Prevention
Subacute combined degeneration prevention of the elderly
If you have obvious symptoms of nervous system, do not advocate the use of folic acid treatment, eating fresh animal liver can also help treatment, in addition, physical therapy, acupuncture, physical therapy can help improve symptoms. The prevention of diseases is mainly for the prevention of the cause, such as improving the diet structure, correcting malnutrition, eating more foods containing vitamin B family, and should stop drinking alcohol; as soon as possible, treating diseases such as gastrointestinal tract that can cause malabsorption.
Complication
Subacute combined degeneration complications in the elderly Complications anemia, optic nerve atrophy
Anemia, paralysis, optic atrophy and so on.
Symptom
Subacute combined degeneration symptoms of the elderly spinal cord Common symptoms Inability to respond to depression, depression, fatigue, irritability, gait, instability, vision, reduction of dementia, deep sensory disturbance, peripheral nerve damage
The disease is more than the onset of middle age, subacute or chronic onset, progressive development, most patients have fatigue, weakness, diarrhea, anemia and other symptoms before the onset of nervous system symptoms, the nervous system mainly has the following performance:
Peripheral nerve damage
The earliest appearance, mostly manifested as the toe from the lower extremities, the symmetry of the finger tip, persistent paresthesia: numbness, tingling, chills, burning sensation, physical examination can detect glove-like, sock-like sensory disturbance and nerve trunk tenderness.
2. Spinal cord damage
Mainly involving the posterior and lateral cord, the posterior cord symptoms appear earlier, manifested as obvious deep sensory disturbances in the lower limbs: positional sense, vibration, kinesthetic decline or disappearance; sensory ataxia: patient gait instability, such as Step on cotton, especially at night, finger nose test, unstable knee test, Romberg's sign positive, with the progress of the lesion, the emergence of both lower extremity weakness, and involving the lateral cord, damage to the pyramidal bundle, causing paralysis of the limb, clinical signs It is determined by the degree of damage of the peripheral nerve, the posterior cord, and the pyramidal tract. If the lesion is mainly composed of peripheral nerves, the muscle tension of the limb is reduced, and the tendon reflex is reduced, which is flaccid paralysis; if the lesion is thicker than the pyramidal bundle, It manifests as limb rigidity, increased muscle tone, hyperreflexia, positive pathology, and sphincter dysfunction in the advanced stage of the disease.
3. Cranial nerve damage
In addition to optic nerve involvement, the remaining cranial nerves are unaffected, mainly due to impaired vision, dark spots in the bilateral visual field, reduced visual field, optic atrophy, etc., which may occur in the early or late stages of the disease, or in malignant Among patients with anemia without subacute combined degeneration signs.
4. Mental symptoms
Due to advances in treatment, psychiatric symptoms are rare now, but they are more common before vitamin B12 and liver essence application. They can be characterized as irritability, apathy, impaired cognitive function, unresponsiveness, hallucinations, loss of orientation, depression. , memory loss and even dementia.
Examine
Examination of subacute combined degeneration of the elderly spinal cord
The serum vitamin B12 concentration is less than 100 pg/ml (normally 140 to 900 pg/ml).
Sehilliry test: oral radionuclide 57Co labeled vitamin B12, measured in urine feces, can be found in Vit B12 absorption defects.
In the case of injection of histamine for gastric juice analysis, some patients may find gastric acid deficiency.
Some patients may have visual evoked potentials and abnormalities in somatosensory evoked potentials.
Some patients showed a high signal change in the T2 phase of the spinal cord after MRI, which disappeared after treatment.
Macrophage hyperhemoglobin anemia can be seen in the blood and bone marrow of some patients.
Diagnosis
Diagnosis and differentiation of subacute combined degeneration of the elderly
When Vit B12 concentration is lower than 100pg/ml, Vit B12 is injected once, and if there is reticulocyte increase after 10 days, it is helpful for clinical diagnosis.
Differential diagnosis
According to the middle-aged, subacute or acute onset, progressive aggravation of anemia and spinal cord, lateral cord, pyramidal tract and peripheral nerve damage clinical characteristics, combined with laboratory tests can diagnose the disease, the disease needs early Identify with the following diseases:
1. Spinal cord compression: more root pain first, often from one side, gradually involving the spinal cord half, and finally manifested as symptoms and signs of spinal traverse damage, lumbar puncture can be seen spinal canal obstruction, cerebrospinal fluid protein elevation, CT, MRI Can help identify.
2. Multiple sclerosis: with remission, recurrence alternation as a significant clinical feature, no symmetry of peripheral nerve damage, EMG and evoked potentials can help diagnose.
3. Spinal cord hernia: only the posterior and posterior roots were damaged, not involving the pyramidal tract, Lhermitte's sign was positive, and the serum and cerebrospinal fluid were positive.
4. Peripheral neuropathy: can be expressed as symmetrical distal limb sensation, movement, autonomic dysfunction, but does not involve pyramidal tract, no anemia and serum Vit B12 deficiency.
