Phenytoin cerebellar degeneration
Updates to Article Attributes
Phenytoin cerebellar atrophy occurs after prolonged exposure to phenytoin, usually for the management of epilepsy.
Epidemiology
The most important factor in the development of cerebellar atrophy is the duration of phenytoin exposure 2. Approximately 30% of individuals with long-term phenytoin exposure will develop cerebellar atrophy 2.
Clinical presentation
Although acute phenytoin toxicity can result in transient cerebellar dysfunction, it is chronic exposure to therapeutic levels of phenytoin which results in permanent pancerebellar dysfunction, including ataxia, nystagmus, dysarthria and hypotonia 2.
Pathology
Histological assessment demonstrates loss of Purkinje cells throughout the cerebellum, as well as less marked loss of internal granular layer cells 1.
Radiographic features
CT and MRI are able to demonstrate generalised cerebellar volume loss. A clue to the diagnosis is the commonly associated calvarial thickening also due to long-term phenytoin exposure.
Differential diagnosis
This differential is essentially that of other causes of diffuse cerebellar atrophy.
-<p><strong>Phenytoin cerebellar atrophy</strong> occurs after prolonged exposure to phenytoin, usually for the management of epilepsy. </p><h4>Epidemiology</h4><p>The most important factor in the development of cerebellar atrophy is the duration of phenytoin exposure <sup>2</sup>. Approximately 30% of individuals with long-term phenytoin exposure will develop cerebellar atrophy <sup>2</sup>. </p><h4>Clinical presentation</h4><p>Although acute phenytoin toxicity can result in transient cerebellar dysfunction, it is chronic exposure to therapeutic levels of phenytoin which results in permanent pancerebellar dysfunction, including <a title="ataxia" href="/articles/ataxia">ataxia</a>, <a title="nystagmus" href="/articles/nystagmus">nystagmus</a>, <a title="dysarthria" href="/articles/dysarthria">dysarthria</a> and <a title="hypotonia" href="/articles/hypotonia">hypotonia</a> <sup>2</sup>. </p><h4>Pathology</h4><p>Histological assessment demonstrates loss of <a title="Purkinje cells" href="/articles/purkinje-cells">Purkinje cells</a> throughout the <a title="Cerebellum" href="/articles/cerebellum">cerebellum</a>, as well as less marked loss of internal granular layer cells <sup>1</sup>. </p><h4>Radiographic features</h4><p>CT and MRI are able to demonstrate generalised cerebellar volume loss. A clue to the diagnosis is the commonly associated calvarial thickening also due to long-term phenytoin exposure. </p><h4>Differential diagnosis</h4><p>This differential is essentially that of other causes of <a title="Diffuse cerebellar atrophy" href="/articles/diffuse-cerebellar-atrophy">diffuse cerebellar atrophy</a>. </p>- +<p><strong>Phenytoin cerebellar atrophy</strong> occurs after prolonged exposure to phenytoin, usually for the management of epilepsy. </p><h4>Epidemiology</h4><p>The most important factor in the development of cerebellar atrophy is the duration of phenytoin exposure <sup>2</sup>. Approximately 30% of individuals with long-term phenytoin exposure will develop cerebellar atrophy <sup>2</sup>. </p><h4>Clinical presentation</h4><p>Although acute phenytoin toxicity can result in transient cerebellar dysfunction, it is chronic exposure to therapeutic levels of phenytoin which results in permanent pancerebellar dysfunction, including <a href="/articles/ataxia">ataxia</a>, <a href="/articles/nystagmus">nystagmus</a>, <a href="/articles/dysarthria">dysarthria</a> and <a href="/articles/hypotonia">hypotonia</a> <sup>2</sup>. </p><h4>Pathology</h4><p>Histological assessment demonstrates loss of <a href="/articles/purkinje-cells">Purkinje cells</a> throughout the <a href="/articles/cerebellum">cerebellum</a>, as well as less marked loss of internal granular layer cells <sup>1</sup>. </p><h4>Radiographic features</h4><p>CT and MRI are able to demonstrate generalised cerebellar volume loss. A clue to the diagnosis is the commonly associated calvarial thickening also due to long-term phenytoin exposure. </p><h4>Differential diagnosis</h4><p>This differential is essentially that of other causes of <a href="/articles/diffuse-cerebellar-atrophy">diffuse cerebellar atrophy</a>. </p>
References changed:
- 1. Frangoise Gray, Charles Duyckaerts, Umberto De Girolami. Escourolle and Poirier's Manual of Basic Neuropathology. <a href="https://books.google.co.uk/books?vid=ISBN9780199929054">ISBN: 9780199929054</a><span class="ref_v4"></span>
- 2. Barry S. Fogel, Donna B. Greenberg. Psychiatric Care of the Medical Patient. <a href="https://books.google.co.uk/books?vid=ISBN9780190226299">ISBN: 9780190226299</a><span class="ref_v4"></span>
Systems changed:
- Central Nervous System
Image 1 CT (non-contrast) ( create )
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