Thursday, March 22, 2007
Central Pontine Myelinolysis
Central pontine mylineolysis
I was given the request last night to scan this womans brain. She was a young lady with a history of alcohol abuse and seizures. I talked to her over the phone to make sure we could get a good medical history before the MRI scan. Her speech was very slurred and she told me she had difficulty swallowing. To my supprise she said she had been in the hospital for 2 weeks, with these symptoms for 3 weeks. I imediatelly thought she infarcted her pons becuase she had no physical weakness in her arms or legs. I figured possible lacunar infarct. To my suprise she was Diagnosed with Central Pontine Mylineolysis from the MRI scan by our Radiologist. This was the first time I had heard of this . I learn Something new everyday. The following is Information on the topic:
Adams et al described central pontine myelinolysis (CPM) as a unique clinical entity. They published their findings in 1958, observing that patients who suffered from alcoholism or malnutrition developed spastic quadriplegia, pseudobulbar palsy, and varying degrees of encephalopathy or coma from acute, noninflammatory demyelination that centered within the basis pontis.
physicians recognize that CPM occurs inconsistently as a complication of severe and prolonged hyponatremia, particularly when corrected too rapidly. Standard of care requires judicious treatment of electrolyte disturbances to reduce the incidence of osmotic myelinolysis.
Central pontine myelinolysis is a neurologic disease caused by severe damage of the myelin sheath of nerve cells in the brainstem, more precisely in the area termed the pons. The most common cause is the rapid correction of low blood sodium levels (hyponatremia). Some scholars postulate that the real cause might be the lack of a substance that is essential for brain activity and is lacking due to malnutrition. The fact that this condition is most frequently observed in patients with general ill health (alcoholism, cachexia etc.) is in accordance with this assumption. Imaging by MRI demonstrates an area of high signal return on T2 weighted images. Frequently observed symptoms in this disorder are weakness, double vision and loss of consciousness. To avoid myelinolysis, the correction of hyponatremia should not exceed 1 mEq/L per hour.
The rapid rise in sodium concentration is accompanied by the movement of small molecules and pulls water from brain cells. Through a mechanism that is only partly understood, the shift in water and brain molecules leads to the destruction of myelin, a substance that surrounds and protects nerve fibers. Nerve cells (neurons) can also be damaged. Certain areas of the brain are particularly susceptible to myelinolysis, especially the part of the brainstem called the pons. Some individuals will also have damage in other areas of the brain, which is called extrapontine myelinolysis (EPM). Experts estimate that 10 percent of those with CPM will also have areas of EPM.
The ideal treatment for myelinolysis is to prevent the disorder by identifying individuals at risk and following careful guidelines for evaluation and correction of hyponatremia. These guidelines aim to safely restore the serum sodium level, while protecting the brain. For those who have hyponatremia for at least 2 days, or for whom the duration is not known, the rate of rise in the serum sodium concentration should be kept below 10 mmol/L during any 24-hour period, if possible
The prognosis for myelinolysis is variable. Some individuals die and others recover completely. Although the disorder was originally considered to have a mortality rate of 50 percent or more, improved imaging techniques and early diagnosis have led to a better prognosis for many people. Most individuals improve gradually, but still continue to have challenges with speech, walking, emotional ups and downs, and forgetfulness.
What research is being done? (source NINDS)
This syndrome is characterized by a gradual neurologic deterioration developing one to several days after complete or partial correction of chronic hyponatremia. Neurologic deterioration may often be preceded by a transient improvement paralling the correction of electrolyte disturbance. Fluctuating levels of conciousness, convulsions, hypoventilation or hypotension may herald the onset of this syndrome. Eventually pseudobulbar palsy and quariparesis develops. Swallowing dysfunction (often with episodes of aspiration) and inability to speak may be dominant features. In severe cases, the patient may develop a "locked-in syndrome" - they are awake but unable to move or communicate. Marked improvement may occur presumably because of reyelination. Although various imaging modalities may be confirmatory, positive diagnostic tests are not essential to diagnose the osmotic demyelination syndrome. If psedubulbar palsy and limb paralysis gradually develop after hyponatremia is corrected, the clinician should strongly suspect a demelinating lesion of the pons. (source)
MRI IMAGING of Potine Myelinolysis
Posted by turbospinecho at Thursday, March 22, 2007
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