What is it about ?
In order to be able to move, the muscles receive a signal from the brain via the nerves. A problem in any part of this complex process can lead to muscle weakness and / or symptoms of paralysis.
The nervous system consists of a central part (brain, brainstem and spinal cord) and a peripheral part (nerves). We have nerves responsible for movement (motor nerves) and nerves responsible for sensation (sensory nerves).
The central nervous system can be damaged by stroke, a tumor in the brain, a spinal cord injury Where multiple sclerosis (MS). Problems with the peripheral nervous system can result in polyneuropathies, nerve root disorders, the Guillain-Barré syndrome Where nerve compression by pressure.
In addition, the cause of muscle weakness and paralysis symptoms may lie in the muscles themselves or in the passage from the nerves to the muscles. Hormonal disturbances, metabolism issues, or an underlying psychologic condition can also lead to muscle weakness and symptoms of paralysis.
How to recognize them?
In addition to muscle weakness and symptoms of paralysis, you may also be clumsy and / or have uncoordinated movements, involuntary muscle spasms, less reflexes or no reflexes at all, decreased or increased tone muscle mass and a decrease in muscle mass (muscle atrophy). Sensory disturbances are also sometimes observed at the same time.
How is the diagnosis made?
The doctor will examine the nerve channels, for example by testing reflexes and checking muscle strength by muscle group. A precise clinical and neurological examination can already give some indications for the diagnosis.
But other examinations may be necessary to develop it, such as a blood test, a lumbar puncture, imaging (MRI for example) or even specific tests of the functioning of the nervous system.
Neurological disorders
Neurological disorders can be the consequence of:
- a central nervous system defect, which is very characteristically expressed in muscle weakness, clumsiness, uncoordinated movements and sensory disturbances. As part of the clinical examination, the doctor observes Babinski’s sign; the big toe fanned out with the other toes when the soles of the feet were brushed with a semi-sharp object. The doctor also tests the reflexes of the tendons by hitting them with a small hammer. These reflexes are generally moderate to extremely pronounced. Muscle tone also increased (spasticity).
- a peripheral nervous system defect, which is characterized by a decrease in reflexes or their complete absence, a decrease in muscle tone, a gradual decrease in muscle mass, symptoms of paralysis and sensory disturbances.
- a central and peripheral nervous system defect, the amyotrophic lateral sclerosis (ALS) being the most frequent affection. Muscle weakness in random muscles is constantly increasing resulting in muscle atrophy and involuntary muscle contractions. Sometimes muscle tone increases. Babinski’s sign can be positive.
Muscular disorders
Muscle disorders can be congenital or develop over time due to toxic, hormonal and inflammatory factors, as well as factors related to metabolism and alcohol abuse. On physical examination, muscle reflexes are often normal and Babinski’s sign is negative. There is weakness in the muscles and usually a decrease in muscle mass.
Disorders due to problematic signal transfer from nerves to muscles
The best known example is the myasthenia gravis, a rare autoimmune disease. The patient complains of fatigue in the muscles, which worsens with exertion. Reflexes and sensations appear normal and Babinski’s sign is negative.
Other hormonal and metabolic disorders
Hypothyroidism (an underactive thyroid) or hyperthyroidism (overactive thyroid) as well as too high or, on the contrary, insufficient calcium in the blood can cause weakness in the muscles.
What can you do ?
There is not much to do. If you experience weakness or fatigue in the muscles, or if you have problems performing movements correctly, consult the doctor.
What can your doctor do?
Treatment depends on the cause.
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