Definition: when can we speak of paralysis?
Paralysis is defined by loss of motor skills of one or more muscles. It can affect any muscle in the body and can be definitive Where reversible. When the phenomenon is incomplete and the movements are not absent but very weak, we speak of paresis.
What can cause paralysis?
Professor Lemarquis, neurologist: Paralysis can result from damage to a muscle or the nervous system that allows it to be activated.
The injury of a nerve
the nerve has, among other roles, that of transmit efferent sensory informationgoing from the brain to the muscles, in order to control their voluntary movements. This is the peripheral nervous system. The lesion or section of a nervewhether it is of traumatic origin – therefore due to an accident – or tumoral, namely caused by the presence of a tumor, can cause paralysis.
Spinal cord injury
The spinal cord plays the role of central nervous system : it is the starting point of the nerve fibers that innervate the various muscles and organs of the body. She is inside the spinal canal, itself located in the center of the spine. If it is therefore protected by the bone of the vertebral column, it can however be damaged or cut following an accident, or the presence of a tumor which comes to compress it.
A malfunction in the communication between nerves and muscles
Paralysis can be caused by a communication problem between nerves and muscles. “This is particularly the case during poisoning with curare, which acts competitively by blocking the nicotinic acetylcholine receptors, which prevents the muscles from contracting” explains the neurologist. It therefore acts on the neuromuscular junction.
An autoimmune disease called myasthenia gravishas a similar mode of action: it works by blocking communication between nerves and muscles, leading to muscle weakness.
Neuromuscular disease or muscle dysfunction
In some cases, finally, it is the muscle directly which is affected and no longer works. In neuromuscular diseases, motor unit – made up of the muscle, the nerve/muscle junction and the nerve – malfunctions and the muscle cannot contract normally. This is particularly the case of myopathies or some amyotrophies.
This is also the case during a strong hypoglycemia: the muscle is then no longer supplied with its fuel – glucose – which makes it work. Paralysis of a limb can then be a symptom of hypoglycemia.
Finally, a muscle of the face can be temporarily paralyzed when it undergoes intense cooling: we then speak of “paralysis à frigore”, which means “by the cold”.
What are the different types of paralysis?
Any muscle in the body can be affected by paralysis. The most frequently encountered are the following.
Chilled facial paralysis
The most common peripheral facial paralysis (72%) is so-called facial paralysis in fridge, or Bell’s palsy. This paralysis, the etiology of which is still poorly known, is linked to the herpes virus, which remains dormant in the cells of the relay ganglion of the facial nerve. The virus could be reactivated by exposure of the face to cold, hence the name “frozen” paralysis. It is also called idiopathic facial paralysis because this cause has not yet been demonstrated.
What are the symptoms of facial paralysis?
Facial paralysis can be central Where peripheraldepending on the location of the lesion of the facial nerve.
Most of the timethe nerve is affected in its path outside the brain – either on the right or on the left – which causes paralysis of one half of the face only.
More rarelythe nerve is affected at inside the brainwhich causes facial paralysis center of the whole face.
Symptoms of facial paralysis are quite noticeable. They affect either only part of the face, or all of it:
– absence of expressions and mimicry on the face,
– numbness of the face,
– dry eyes, because blinking is difficult or even impossible,
– Sunken cheeks, drooping mouth,
– Absence of wrinkles on the forehead and at the level of the nasolabial fold.
How to treat facial paralysis?
Treatment for facial paralysis depends on its cause.
When idiopathic, it regresses spontaneously in 80% of cases in 2 and a half months on average. A corticosteroid treatment may be offered to speed up recovery. “The cortisone aims to ‘deflate’ the trapped nerve as it exits the skull” indicates Professor Lemarquis. “It is also important to protect the eyein the case where the eyelids close badly, in particular during sleep with the help of a compress or in the event of wind, thanks to glasses” continues the expert.
When facial paralysis is caused by a shinglesof the antivirals are prescribedand when it is due to a Lyme diseasethem antibiotics prove to be effective.
Finally, in the most severe cases, surgery may be indicated in the event of significant compression of the facial nerve.
Paraplegia: what diseases can cause paralysis of the legs?
Paraplegia may be due to muscle damage (myopathy) or nerves:
Professor Lemarquis: The most spectacular is Guillain-Barré syndrome, which causes ascending paralysis that begins in the feet and can go up to the face and requires rapid diagnosis.
A spinal cord trauma at the level of the thoracic or lumbar vertebrae, during a accident or any other particularly inflammatory lesion as in multiple sclerosis can lead to paralysis of the legs. Finally a brain tumorcan also cause paralysis of the lower limbs depending on its location.
Tetraplegia: what is it due to?
We are talking about tetraplegia when the four limbs are paralyzed. The main causes of tetraplegia are traumatic, by direct lesion of the spinal cord at the level of the cervical vertebrae.
However, other causes are possible:
– A tumor compressing the spinal cord,
– Inflammation or infection of the spinal cord,
– A congenital malformation,
– Multiple sclerosis,
– Vascular thrombosis.
When part or all of the brain no longer works, we are talking about cerebral palsy. In the vast majority of cases, it is linked to a brain damage that occurred in the antenatal or perinatal period, and therefore affects a still maturing brain resulting in a non-progressive motor disorder, such as paralysis or movement coordination disorders. “It can also be caused by a vascular accident, or by the obstruction of a blood vessel, or during a cerebral hemorrhage. Certain infectious diseases, tumors or drugs can also be responsible for cerebral palsy” indicates the Professor Lemarquis.