Early symptoms of ALS

There is a very rare disease in life called ALS. ALS patients are particularly difficult to treat after they get the disease. There are also many ALS people all over the world. Their health is always threatened by the disease. Even when the disease occurs, they cannot take care of themselves. Many witnesses will experience hemiplegia-like symptoms in the early stages. So what are the early symptoms of ALS?

Clinical manifestations

1. The onset is insidious and the disease progresses slowly.

2. Half of the patients present with limb weakness accompanied by muscle atrophy (5%) and fasciculations (4%), especially in the distal upper limbs. At this time, the tendon reflexes of the limbs are reduced, there are no pyramidal tract signs, and the clinical manifestations are similar to spinal muscular atrophy.

3. As the disease progresses, patients gradually develop typical signs of upper and lower motor neuron damage, manifested as extensive and severe muscle atrophy, increased muscle tension, and positive pyramidal tract signs. 60% of patients have obvious upper and lower motor neuron signs. When the degeneration of lower motor neurons reaches a certain extent, the muscles are widely denervated, and there may be no fasciculations, decreased or absent tendon reflexes, and no pathological signs.

4. About 10% of patients only show progressive muscle atrophy throughout the course of the disease without signs of upper motor neuron damage.

5. About 30% of patients develop the disease initially with involvement of the motor nerve nuclei of the brainstem, manifested by dysphagia, slurred speech, dyspnea, tongue muscle atrophy and fibrillation, which gradually affect the limbs and trunk. Emotional instability (strong crying and laughing) is a sign of upper motor neuron involvement and pseudobulbar palsy.

6. Amyotrophic lateral sclerosis with involvement of the lateral cord of the spinal cord as the first symptom is rare. 9% of patients may have painful cramps, which are manifestations of upper motor neuron damage, mostly in the proximal part of the affected lower limbs, which is common in the early stage of the disease. 10% of patients have subjective paresthesia or numbness in the distal limbs. Unless combined with other peripheral neuropathies, ALS has no objective sensory signs. Bladder and rectal function remain good throughout the course of the disease. Eye movements are usually not impaired.

7. Simple ALS patients generally do not have intellectual impairment. When ALS is accompanied by symptoms and signs of other neurodegenerative diseases, it is called ALS-plus syndrome. This syndrome mainly occurs in the Western Pacific region, Guam, Japan, and North Africa. Associated symptoms and signs include extrapyramidal symptoms, cerebellar degeneration, autonomic and sensory symptoms of dementia, and oculomotor abnormalities.

8. Neuromuscular electrophysiological changes mainly manifest as extensive neurogenic damage. Acute neurogenic damage (2 to 3 weeks after denervation) is characterized by fibrillation potentials, positive sharp waves, bundle fibrillation potentials, and giant potentials. Chronic denervation with regeneration is manifested by a prolonged duration of motor unit action potentials, a significantly increased amplitude, and an increased percentage of polyphasic waves when the muscle contracts slightly. Motor unit loss can be seen when the muscle contracts vigorously. The neurogenic damage of ALS usually affects more than 3 areas (cranial nerve, cervical, thoracic, and lumbar nerve innervation areas). The tongue muscle, sternocleidomastoid muscle and diaphragm can also show neurogenic damage. The latter can be used to distinguish the two because it is less affected in cervical spondylosis (Kang Dexuan 1994). MCV may slightly slow down the evoked potential amplitude and decrease the sensory conduction velocity. Magnetic stimulation motor evoked potential: Transcranial stimulation of cerebral cortical motor neurons and recording of action potentials in the corresponding muscles. This method can measure central motor conduction time and is of great value in determining damage to the corticospinal tract. Muscle biopsy is not necessary for the diagnosis of ALS but may be helpful in some cases to differentiate between neurogenic muscular atrophy and neurological atrophy.