Central pontine myelinolysis
Central pontine myelinolysis The ( ZPM ) (Latin pons, bridge, the bridge pontine concerning; Greek μῦελόν, spinal cord, Mark, λύσις, Lysis, dissolution ) is a neurological disorder in which there especially in damage to the sheath of nerve fibers pons ( brain stem ) comes. It is caused by too rapid correction of a pathologically reduced sodium levels ( hyponatremia) in the organism.
As an alternative, the ZPM applies the extrapontine myelinolysis. This leads to demyelination in the cerebellum, basal ganglia, internal capsule, beams and near the ventricles. Both forms are summarized as osmotically demyelinating disease, they can also occur simultaneously.
Causes
The central pontine myelinolysis is triggered among other things by a too rapid equalization of hyponatremia. When limit is a serum Na of less than 126 mmol / l The risk is increased by a longer-lasting hyponatremia.
Causes of hyponatremia include:
- Very low salt diet with high consumption rates ( in malnutrition or anorexia)
- Side effect of medications (diuretics, carbamazepine )
- Hormonal disorders ( SIADH = syndrome of inadequate ADH secretion increased = Schwartz - Bartter syndrome, mainly in tumor paraneoplastic disorders, central salt wasting syndrome)
- " Water intoxication " in Ertrinkensunfällen or faulty infusion therapy
- Alcoholism
Mechanism
The idea is based on the concept of osmosis (diffusion of semi-permeable membranes). The water follows the electrolyte.
At a loss of sodium from the blood sodium levels slowly sinks in all other compartments of the body. This is in slow decline usually well tolerated. If the hyponatraemia is detected and compensated for by parenteral infusion, it is depending on the speed of the rise in sodium level in a shift of water from the tissues into the blood, because sodium can diffuse into the other compartments (especially in the cells ) is not so surprising. Dehydrating ( dewatering ) of the brain via an unknown mechanism to the destruction of the myelin sheaths. The process is referred to as an osmotic demyelination.
Symptoms and course
About half a week after compensation of hyponatremia, the disease with impairment of consciousness begins to coma, increasing paralysis of all limbs ( quadriplegia ), and disturbance of brain stem function (eye movement disorder, facial paralysis, dysphagia, respiratory paralysis ). The severity of the individual symptoms can range from mild fatigue and unsteadiness to coma with complete paralysis and failure of respiratory function.
The majority of patients recovered to a large extent. The improvement begins earlier than two weeks after the outbreak of the disease, the rehabilitation of severely affected patients often extends over one year. A fatal outcome is possible, cause of death are usually the complications of intensive medical problems to be addressed (eg, pneumonia ).
Diagnosis
- Medical history
- Neurological examination to test the symptoms
- Evoked potentials - especially the AEP
- Lumbar puncture to exclude an inflammatory
- Magnetic resonance imaging ( changes often only after several weeks!)
Treatment
A targeted treatment after rapid rise in serum sodium is not known, neither in the days leading up to the outbreak of the disease or thereafter.
Therefore, it is necessary to treat the symptoms (symptomatic therapy):
- Physiotherapy for paralysis
- Ventilation in respiratory paralysis
- Tracheotomy in severe dysphagia
- Prevention of complications of bed rest (thrombosis, pneumonia, decubitus)
- Speech therapy for dysarthria and dysphagia
Prevention
It is crucial to make only a slow balancing the sodium level after a finding of hyponatremia. Here Recommendations 6-10 mmol / l given per day in the scientific literature. For this purpose two to four times daily laboratory tests are required. The sole use of isotonic infusion solutions does not protect sufficiently against a ZPM, the decisive factor is the rate of sodium increase.