Central Pontine Myelinolysis: Difference between revisions

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== Clinically Relevant Anatomy<br>  ==
== Clinically Relevant Anatomy<br>  ==


The Pons is situated in the brainstem.  
The Pons is situated in the brainstem;&nbsp; it lies above the medulla, below the midbrain, and anterior to the cerebellum.
 
 
 
[[Image:Pons_and_medulla_oblongata_2.jpg|400px]]&nbsp;[[Image:Brain_Stem.jpg|400px]]


== Mechanism of Injury / Pathological Process<br>  ==
== Mechanism of Injury / Pathological Process<br>  ==
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Central pontine myelinolysis is a concentrated, frequently symmetric, noninflammatory demyelination within the pons. The area involved is usually confined to the basis pontis, but occasionally involves the tegmentum too.<br>  
Central pontine myelinolysis is a concentrated, frequently symmetric, noninflammatory demyelination within the pons. The area involved is usually confined to the basis pontis, but occasionally involves the tegmentum too.<br>  


It is one of the demyelinating condions, and was first described by Adams et al in 1959.<ref>Adams RD, Victor M, Mancall EL. Central pontine myelinolysis: a hitherto undescribed disease occurring in alcoholic and malnourished patients. AMA Arch Neurol Psychiatry. Feb 1959;81(2):154-72</ref>&nbsp;In at least 10% of patients with central pontine myelinolysis, demyelination also occurs in extrapontine regions, including the mid brain, thalamus, basal nuclei, and cerebellum. The exact mechanism that strips the myelin sheath is unknown.  
It is one of the demyelinating condions, and was first described by Adams et al in 1959.<ref>Adams RD, Victor M, Mancall EL. Central pontine myelinolysis: a hitherto undescribed disease occurring in alcoholic and malnourished patients. AMA Arch Neurol Psychiatry. Feb 1959;81(2):154-72</ref>&nbsp;In at least 10% of patients with central pontine myelinolysis, demyelination also occurs in extrapontine regions, including the mid brain, thalamus, basal nuclei, and cerebellum. The exact mechanism that strips the myelin sheath is unknown.<br>


Central pontine myelinolysis occurs most often as a complication of treatment of patients with profound, life-threatening hyponatremia (low sodium) and is a consequence of a rapid rise in serum tonicity following treatment in individuals with chronic, severe hyponatraemia who have made intracellular adaptations to the prevailing hypotonicity.&nbsp;  
Central pontine myelinolysis occurs most often as a complication of treatment of patients with profound, life-threatening hyponatremia (low sodium) and is a consequence of a rapid rise in serum tonicity following treatment in individuals with chronic, severe hyponatraemia who have made intracellular adaptations to the prevailing hypotonicity.&nbsp;  
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In some cases, demyelination occurs outside the pons too; cases which include extrapontine demyelination are labelled "osmotic demyelination syndrome", "extra pontine myelinosis" or "osmotic myelinosis".<ref>Martin RJ. Central pontine and extrapontine myelinolysis: the osmotic demyelination syndromes. J Neurol Neurosurg Psychiatry. Sep 2004;75 Suppl 3:iii22-8</ref>  
In some cases, demyelination occurs outside the pons too; cases which include extrapontine demyelination are labelled "osmotic demyelination syndrome", "extra pontine myelinosis" or "osmotic myelinosis".<ref>Martin RJ. Central pontine and extrapontine myelinolysis: the osmotic demyelination syndromes. J Neurol Neurosurg Psychiatry. Sep 2004;75 Suppl 3:iii22-8</ref>  


Microscopically the lesion shows degeneration and loss of oligodendrocytes with preservation of axons unless the lesion is very advanced.  
Microscopically the lesion shows degeneration and loss of oligodendrocytes with preservation of axons unless the lesion is very advanced.<br>
 
== Clinical Presentation  ==
 
The classic clinical presentation of central pontine myelinolysis is progressive spastic quadriparesis with pseudobulbar palsy.<ref>Laureno R, Karp BI. Myelinolysis after correction of hyponatremia. Ann Intern Med. Jan 1 1997;126(1):57-62</ref>
 
Clinically CPM presents in a biphasic pattern:


<br>
1st phase = acute encephalopathy, caused by the electrolyte abnormalities.


== Clinical Presentation  ==
Once treatment is given causing rapid reversal of this abnormality, the patient improves for 2 to 3 days before progressing onto the classic CPM features. These consist of:


The classic clinical presentation of central pontine myelinolysis is progressive spastic quadriparesis with pseudobulbar palsy.<ref>Laureno R, Karp BI. Myelinolysis after correction of hyponatremia. Ann Intern Med. Jan 1 1997;126(1):57-62</ref><br>
*spastic quadriparesis
*pseudobulbar palsy
*changes in levels of consciousness
*coma or death


== Diagnostic Procedures  ==
== Diagnostic Procedures  ==

Revision as of 21:26, 17 April 2014

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Clinically Relevant Anatomy
[edit | edit source]

The Pons is situated in the brainstem;  it lies above the medulla, below the midbrain, and anterior to the cerebellum.


Pons and medulla oblongata 2.jpg Brain Stem.jpg

Mechanism of Injury / Pathological Process
[edit | edit source]

Central pontine myelinolysis is a concentrated, frequently symmetric, noninflammatory demyelination within the pons. The area involved is usually confined to the basis pontis, but occasionally involves the tegmentum too.

It is one of the demyelinating condions, and was first described by Adams et al in 1959.[1] In at least 10% of patients with central pontine myelinolysis, demyelination also occurs in extrapontine regions, including the mid brain, thalamus, basal nuclei, and cerebellum. The exact mechanism that strips the myelin sheath is unknown.

Central pontine myelinolysis occurs most often as a complication of treatment of patients with profound, life-threatening hyponatremia (low sodium) and is a consequence of a rapid rise in serum tonicity following treatment in individuals with chronic, severe hyponatraemia who have made intracellular adaptations to the prevailing hypotonicity. 

In some cases, demyelination occurs outside the pons too; cases which include extrapontine demyelination are labelled "osmotic demyelination syndrome", "extra pontine myelinosis" or "osmotic myelinosis".[2]

Microscopically the lesion shows degeneration and loss of oligodendrocytes with preservation of axons unless the lesion is very advanced.

Clinical Presentation[edit | edit source]

The classic clinical presentation of central pontine myelinolysis is progressive spastic quadriparesis with pseudobulbar palsy.[3]

Clinically CPM presents in a biphasic pattern:

1st phase = acute encephalopathy, caused by the electrolyte abnormalities.

Once treatment is given causing rapid reversal of this abnormality, the patient improves for 2 to 3 days before progressing onto the classic CPM features. These consist of:

  • spastic quadriparesis
  • pseudobulbar palsy
  • changes in levels of consciousness
  • coma or death

Diagnostic Procedures[edit | edit source]

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Outcome Measures[edit | edit source]

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Management / Interventions
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Differential Diagnosis
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Key Evidence[edit | edit source]

Graff-Radford et al[4] examined the clinical records of patients diagnosed as having CPM identified by a search of Mayo Clinic medical records from January 1, 1999, toh December 31, 2010. Diagnosis was made by clinical and radiologic features. Their objective was to characterize clinical and radiologic features of patients with central pontine myelinolysis (CPM) and identify variables that predict outcome. They concluded: "Clinical outcome in patients with CPM is not predicted by the volume of radiologic T2 signal abnormality on MRI or the severity of hyponatremia. Serial brain imaging is of value because a substantial proportion of patients have normal findings on initial MRI".

Resources
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Recent Related Research (from Pubmed)[edit | edit source]

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References[edit | edit source]

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  1. Adams RD, Victor M, Mancall EL. Central pontine myelinolysis: a hitherto undescribed disease occurring in alcoholic and malnourished patients. AMA Arch Neurol Psychiatry. Feb 1959;81(2):154-72
  2. Martin RJ. Central pontine and extrapontine myelinolysis: the osmotic demyelination syndromes. J Neurol Neurosurg Psychiatry. Sep 2004;75 Suppl 3:iii22-8
  3. Laureno R, Karp BI. Myelinolysis after correction of hyponatremia. Ann Intern Med. Jan 1 1997;126(1):57-62
  4. Jonathan Graff-Radford, Jennifer E. Fugate, Timothy J. Kaufmann, Jay N. Mandrekar, Alejandro A. RabinsteinfckLRMayo Clin Proc. 2011 November; 86(11): 1063–1067