Motor neuron disease in the elderly

Introduction to motor neuron disease in the elderly Motor neuronosis (MND) is a type of degenerative disease that is unclear and selectively invades the motor system or a part of the progression. The range of lesions includes anterior horn cells of the spinal cord, brain cerebral motor nucleus and pyramidal tract. Such diseases include amyotrophic lateral sclerosis, progressive spinal muscular atrophy, progressive bulbar palsy, and primary lateral sclerosis. The elderly are suffering from motor neuron diseases in the elderly after suffering from such diseases. The pathological changes of this disease are mainly the loss of motor nucleus in the anterior horn cells of the spinal cord and the lower part of the brain stem. Many surviving nerve cells shrink and shrink, the cytoplasm is filled with lipofuscin, and the lost cells are replaced by fibrous star cells. Neurons with smaller neurons are affected early, anterior roots are thinner, and large myelinated fibers in motor nerves are not proportionately lost. Skeletal muscles show typical different stages of denervated muscular atrophy. basic knowledge The proportion of illness: 0.005% Susceptible people: the elderly Mode of infection: non-infectious Complications: Spinal muscular atrophy Multiple lung infections

The cause of motor neuron disease in the elderly

Causes:

The etiology has not been known so far. Most scholars believe that some major enzymes in the cell are lacking, the content of RNA and protein synthesis are reduced, the transcription of DNA is damaged, and the motoneurons are prematurely degenerated. It is also believed that this disease may be due to lentivirus. Infection or infection caused by autoimmune reaction, 5% to 10% of cases, with family genetic predisposition, genetic factors of amyotrophic lateral sclerosis, its onset form, clinical manifestations and disease progression are different, so it is called For hereditary or familial amyotrophic lateral sclerosis, the incidence of this disease in the Chamorro family in Guam and the local population in the Kii Peninsula of Japan is high, 50 to 100 times that in other regions, in addition to abnormal calcium metabolism, heavy metal poisoning, glucose Metabolic abnormalities, nutritional disorders or environmental factors are related. As for which mechanism or mechanisms play a major role in the pathogenesis, it is still unclear.

Pathogenesis

The pathological changes of this disease are mainly the loss of motor nucleus in the anterior horn cells of the spinal cord and the lower part of the brain stem. Many surviving nerve cells shrink and shrink, the cytoplasm is filled with lipofuscin, and the lost cells are replaced by fibrous star cells. Neurons with smaller neurons are affected early, anterior roots are thinner, and large myelinated fibers in motor nerves are not proportionately lost. Skeletal muscles show typical different stages of denervated muscular atrophy.

The degeneration of the corticospinal tract is most obvious in the lower part of the spinal cord. The fat staining can be traced to the brainstem and the posterior limb of the internal capsule or even the radiation crown. The reorganization of reactive macrophages after degeneration of the myelin can be seen, and the Batz cells in the motor area are lost. Non-motor fibers in the lateral and front cables are also affected.

The motor nucleus located in the brainstem of the lower part of the brain is degenerated, the sublingual nucleus, the vagus nerve nucleus, the facial nucleus and the trigeminal nucleus are the most severely affected, and the oculomotor nucleus is rarely involved.

Muscles exhibit a typical manifestation of neurogenic atrophy. In subacute and chronic cases, the sprouting of nerve fibers in the muscle can be seen, which may be evidence of nerve regeneration.

Elderly motor neuron disease prevention

1. Maintain an optimistic and happy mood. Long-term mental stress, anxiety, irritability, pessimism and other emotions will make the balance of the cerebral cortex excitatory and inhibition process imbalance, so you need to maintain a happy mood.

Complications of motor neuron disease in the elderly Complications spinal muscular atrophy multiple lung infection

Common muscle atrophy, medullary paralysis, secondary lung infections.

Symptoms of motor neuron disease in the elderly Common symptoms Dementia limb weakness, expression, apathy, muscle atrophy, hoarseness, laryngeal muscle weakness, sensory disturbance, cough sphincter dysfunction, pulmonary infection

symptom

The onset is slow and the course of the disease can be subacute. The symptoms depend on the damaged part. Because motor neuron disease selectively invades the spinal anterior horn cells, the brain in the cranial nerve motor nucleus, and the brain motor cortex pyramidal cells, pyramidal tracts, so if the lower grade motor neurons are dominant, called progressive spinal muscular atrophy If the disease is higher than the upper motor neuron, it is called primary lateral sclerosis; if the upper and lower motor neuron damage exists at the same time, it is called amyotrophic lateral sclerosis; if the lesion is medullary motor neuron degeneration The subject is called progressive medullary paralysis. Clinically, progressive spinal muscular atrophy and amyotrophic lateral sclerosis are the most common.

The main manifestations of this disease, the earliest symptoms are more common in the hand part, the patient feels that the finger movement is weak, stiff, clumsy, the hand muscles gradually shrink, visible muscle bundle tremor. The distal extremities are progressive muscular atrophy. About half of the cases are early in the upper limbs. The size of the hand muscles is atrophy. Later, it extends to the forearm muscles, even the pectoralis major muscles. The back muscles can also shrink, and the calf muscles can also shrink. Muscle atrophy, limb weakness, high muscle tension (stretching sensation), muscle bundle tremor, difficulty in movement, breathing and swallowing disorders. For example, early bilateral bilateral pyramidal tracts may have paraplegia of both lower extremities.

First, the lower motor neuron type:

More than 30 years old. Usually with small muscle weakness in the hand and muscle gradual atrophy, it can spread to one side or both sides, or from one side to the opposite side. Due to the atrophy of the size of the fish muscles, the palms are flat, and the interosseous muscles are atrophied and have claw-like hands. Muscle atrophy is extended upwards, gradually invading the forearm, upper arm and shoulder strap. The fasciculation is common and can be limited to certain muscle groups or widely existed, and it is easy to induce by hand tapping. A small number of muscle atrophy begins with the tibialis anterior and tibialis musculature of the lower extremities or from the extensors of the neck, and can also begin with the proximal muscles of the upper and lower extremities.

Cranial nerve damage is often the earliest invasion of the lingual muscles, with atrophy of the tongue muscles, accompanied by tremors. Later, the sputum, pharynx, laryngeal muscles, and masticatory muscles are gradually weakened, resulting in unclear articulation, difficulty in swallowing, and weakness in chewing. Ball paralysis can occur after the first symptom or following atrophy of the limb.

Late muscles can be atrophied, so that bedridden, and respiratory dysfunction caused by respiratory muscle paralysis.

If the lesion mainly affects the anterior horn of the spinal cord, it is called progressive spinal atrophy, and because it begins in adulthood, it is also called adult spinal muscular atrophy. It is different from infants and adolescents in infancy or juvenile onset. Type of spinal muscular atrophy, the latter two have family genetic factors, clinical manifestations and disease course are also different, and will not be detailed.

Second, the upper motor neuron type:

It manifests as weakness, tightness, and inability to move. Symptoms start with both lower extremities and later affect both upper limbs, and the lower limbs are heavy. The limbs are weak, the muscle tension is increased, and the walking is difficult. The squatting gait is squatting, the sputum reflex is hyperthyroidism, and the pathological reflex is positive. If the lesion involves the bilateral cortical brain stem, pseudo-ball paralysis symptoms, clear pronunciation, swallowing disorder, hyperthyroidism hyperthyroidism. The disease is rare in clinical practice, and it usually starts in adulthood, and the progress is generally slow.

Third, the upper and lower motor neurons mixed type:

Usually the hand muscle weakness, atrophy as the first symptom, usually from one side to the opposite side, with the development of the disease, the upper and lower motor neurons mixed damage symptoms, called amyotrophic lateral sclerosis. In the late course of the disease, the muscles of the whole body are thin and atrophy, so that the head can not be lifted, breathing is difficult, and bedridden. The disease is mostly in the 40 to 60 years old, about 5 to 10% have a family history, and the progress of the disease is different.

Type

According to the most severely damaged nervous system, the clinical symptoms vary according to the location of the lesion. The specific classification is as follows:

1. Amyotrophic lateral sclerosis (ALS): the most common, the age of onset is 40-50 years old, more men than women, the onset of disease is hidden, slowly progressing, clinical symptoms often begin at the distal end of the upper extremity, showing the hand Muscle atrophy, weakness, gradually forward arm, upper arm and scapula belt development; atrophic muscle has obvious fasciculation; at this time, the lower limbs are upper motor sputum, showing increased muscle tone, hyperreflexia, pathological signs positive, symptoms Usually from one side to the other side, the basic symmetry damage, with the development of the disease, can gradually appear medulla, cerebral palsy nerve movement nuclear damage symptoms, tongue muscle atrophy, dysphagia and speech vague; late influence on head muscle strength And respiratory muscles, the main clinical features of ALS: simultaneous damage of upper and lower motor neurons.

2. Progressive medullary paralysis: The lesion is confined to the anterior horn cells of the spinal cord and does not affect the upper motor neurons. This type can be divided according to the age of onset and the lesion:

(1) Adult type (distal type): occurs mostly in middle-aged males. It starts from the distal end of the upper extremity and develops from the hand to the proximal end. There is obvious muscle atrophy and muscle weakness, sputum reflexes, and muscle fasciculation. Development to the lower limbs or neck muscles, causing respiratory paralysis, very few can develop from the distal to the proximal.

(2) juvenile type (near-end type): most of them start from adolescence or childhood, have a family history, are autosomal recessive or dominant inheritance, clinically with pelvic and proximal limb muscle weakness and muscle atrophy, walking When the gait is unstable, the abdomen is convex when standing, and the scapula and the proximal muscles of the upper limbs are weak and muscle atrophy, and there is a anterior horn stimulation (muscle beam tremor), and the supine position is not easy to get up.

(3) Infant type: It is an autosomal recessive genetic disease, which occurs in the mother or within one year after birth. The clinical manifestations are muscle weakness and atrophy of the limbs and trunk. Therefore, the fetus in the mother is significantly reduced in fetal movement. Or disappear, the child with morbidity after birth is weak, obvious purpura, systemic flaccid muscle weakness and muscle atrophy, atrophy begins with the pelvic and proximal limbs, develops to the scapula, the neck and the distal extremities, cranial nerve innervation The muscles are also extremely vulnerable, but the muscle tremors are rare in the clinic, and the intelligence, sensory and autonomic functions are relatively intact.

3. Progressive muscular atrophy: after the onset of 40 years old, the symptoms of medullary lesions appear early in the lesion, the patient may have atrophy of the tongue muscle, dysphagia, drinking water cough and language ambiguity, and later damage to the pons and cortex The brain stem bundle can be combined with the performance of pseudobulbar paralysis, such as hyperactivity of the limbs and the pathological reflex.

4. Primary lateral sclerosis: middle-aged men have more morbidity, clinically slow-developing limbs of motor neurons, muscle weakness, increased muscle tone, hyperreflexia and pathological signs, generally less muscle atrophy, Does not affect the sensory and autonomic function, can invade the cortical medullary bundle of the brain stem, showing pseudobulbar paralysis.

The clinical manifestations are the slow progression of tonic muscle weakness. In primary lateral sclerosis, the muscle weakness of the distal part of the limb is the main weakness. In the progressive pseudobulbar medulla, the muscle weakness of the posterior cranial nerve is dominant. Muscle twitching and muscle atrophy can occur many years later. These diseases usually cause a total loss of patient mobility after several years of progression.

Examination of motor neuron disease in the elderly

There was no abnormality in cerebrospinal fluid examination.

EEG, myoelectricity shows neurogenic damage, visible muscle fibrillation potential; muscle biopsy is helpful for diagnosis, but the specificity is not strong.

Diagnosis and diagnosis of motor neuron disease in the elderly

diagnosis

Diagnosis according to middle, old age, slow onset, gradual progress; with upper and lower motor neuron damage characteristics, generally no sensory disturbance; EMG examination shows neurogenic damage and fibrillation potential, generally not difficult to make a diagnosis .

Differential diagnosis

1. Cervical spondylosis can have similar manifestations of amyotrophic lateral sclerosis, while cervical spondylosis often has neck, shoulder, arm pain, finger numbness and objective sensory disturbance, generally no tongue muscle atrophy and tongue muscle fibrillation, cervical X-ray film CT and MRI can confirm cervical spondylosis.

2. Spinal cord and medullary cavity disease The disease is characterized by segmental, isolated pain and temperature sensation, MRI can distinguish this disease from amyotrophic lateral sclerosis.

3. Spinal cord and brainstem tumors Extramedullary tumors often have nerve root pain and conduction beam-type sensory disturbance; brain stem tumors show cross-caries and different degrees of conduction beam-type sensory disturbance, both cerebrospinal fluid examination protein content is increased, spinal cord tumor Caused by spinal canal obstruction, MRI examination is easy to diagnose.

4. Myasthenia gravis patients with early bulbar paralysis can be given neostigmine test, effective for myasthenia gravis.

5. Progressive muscular dystrophy generally has a family history. The lesions are myogenic muscle atrophy, no fasciculation and increased muscle tone, no pyramidal tract signs and hyperreflexia. EMG is beneficial for the identification of myogenic changes. .

6. Repeated episodes of multiple sclerosis, early diplopia, abnormal sensory of the feet, hypotonic vibration, etc. can be identified.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.