Primary Lateral Sclerosis: Difference between revisions

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== Definition/Description  ==
<h2> Definition/Description  </h2>
 
<p>Primary Lateral Sclerosis (PLS) is characterized as being a rare, non-hereditary, idiopathic, slow, and progressive degeneration of the upper motor neurons<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al.">Statland, JM, Barohn, RJ, Dimachkie, MM, Floeter, MK, Mitsumoto, H. Primary lateral sclerosis. Neurol Clin 2015 Nov;33(4):749-60. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26515619 doi: 10.1016/j.ncl.2015.07.007</span>. PLS lies on a continuum of sporadic motor neuron disorders. This spectrum includes other disorders such as progressive muscular atrophy, which involves only lower motor neurons, as well as amyotrophic lateral sclerosis (ALS), characterized by both upper and lower motor neuron involvement. Many patients diagnosed with PLS continue to have high levels of independence for many years<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="gordon et al.">Gordon, PH, Cheng, B, Katz, IB, Pinto, M, Hays, AP, Mitsumoto, H, Rowland, LP. The natural history of primary lateral sclerosis. Neurology. 2006 Mar;66(5):647-53. doi: 10.1212/01.wnl.0000200962.94777.71</span>.  
Primary Lateral Sclerosis (PLS) is characterized as being a rare, non-hereditary, idiopathic, slow, and progressive degeneration of the upper motor neurons<ref name="statland et al.">Statland, JM, Barohn, RJ, Dimachkie, MM, Floeter, MK, Mitsumoto, H. Primary lateral sclerosis. Neurol Clin 2015 Nov;33(4):749-60. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26515619 doi: 10.1016/j.ncl.2015.07.007</ref>. PLS lies on a continuum of sporadic motor neuron disorders. This spectrum includes other disorders such as progressive muscular atrophy, which involves only lower motor neurons, as well as amyotrophic lateral sclerosis (ALS), characterized by both upper and lower motor neuron involvement. Many patients diagnosed with PLS continue to have high levels of independence for many years<ref name="gordon et al.">Gordon, PH, Cheng, B, Katz, IB, Pinto, M, Hays, AP, Mitsumoto, H, Rowland, LP. The natural history of primary lateral sclerosis. Neurology. 2006 Mar;66(5):647-53. doi: 10.1212/01.wnl.0000200962.94777.71</ref>.  
</p>
 
<h2> Epidemiology&nbsp;<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al.">Singer, MA, Statland, JM, Wolfe, GI, Barohn, RJ. Primary lateral sclerosis. Muscle Nerve. 2007 Mar;35(3):291-302. doi: 10.1002/mus.20728</span>  </h2>
== Epidemiology&nbsp;<ref name="singer et al.">Singer, MA, Statland, JM, Wolfe, GI, Barohn, RJ. Primary lateral sclerosis. Muscle Nerve. 2007 Mar;35(3):291-302. doi: 10.1002/mus.20728</ref>  ==
<ul><li>Approximately 2-5% of adults in neuromuscular clinics will be diagnosed with PLS.  
 
</li><li>The age of onset is approximately 50 years and older, though a juvenile form of PLS has been described as well.  
*Approximately 2-5% of adults in neuromuscular clinics will be diagnosed with PLS.  
</li><li>Although the difference is not pronounced, there is a slight male predominance over females in being diagnosed with PLS.
*The age of onset is approximately 50 years and older, though a juvenile form of PLS has been described as well.  
</li></ul>
*Although the difference is not pronounced, there is a slight male predominance over females in being diagnosed with PLS.
<h2> Etiology  </h2>
 
<p>The exact cause of adult-onset PLS remains unknown<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />. PLS is a diagnosis of exclusion, meaning that individuals are diagnosed with the condition when their progressive upper motor neuron dysfunctions cannot be explained by any other possible cause.  
== Etiology  ==
</p>
 
<h2> Clinical Presentation  </h2>
The exact cause of adult-onset PLS remains unknown<ref name="singer et al." />. PLS is a diagnosis of exclusion, meaning that individuals are diagnosed with the condition when their progressive upper motor neuron dysfunctions cannot be explained by any other possible cause.  
<p>PLS is due to upper motor neuron (UMN) degeneration, and therefore clinical presentation is consistent with signs and symptoms of an UMN disorder in the absence of lower motor neuron (LMN) symptoms<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." />. These include;  
 
</p>
== Clinical Presentation  ==
<ul><li>Spasticity  
 
</li><li>Hyperreflexia  
PLS is due to upper motor neuron (UMN) degeneration, and therefore clinical presentation is consistent with signs and symptoms of an UMN disorder in the absence of lower motor neuron (LMN) symptoms<ref name="statland et al." />. These include;  
</li><li>Weakness
 
</li></ul>
*Spasticity  
<p>Other key features include stiffness and increasing difficulty maintaining balance with the progression of the disorder. PLS may affect the bulbar region in the medulla, causing degeneration to the lower cranial nerves<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." />. Bulbar signs and symptoms include;  
*Hyperreflexia  
</p>
*Weakness
<ul><li>Dysphagia  
 
</li><li>Dysarthria  
Other key features include stiffness and increasing difficulty maintaining balance with the progression of the disorder. PLS may affect the bulbar region in the medulla, causing degeneration to the lower cranial nerves<ref name="statland et al." />. Bulbar signs and symptoms include;  
</li><li>Pseudobulbar affect/ emotional lability
 
</li></ul>
*Dysphagia  
<p>PLS is classified as slowly progressive. The typical pattern of progression is spreading from side to side, region to region<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." />. It may start in the bulbar region and descend down to the limbs, or it may start in the lower extremities, progress to arms, and then bulbar region. Symptoms spread slowly over many years before plateauing<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." />.&nbsp;<br />  
*Dysarthria  
</p>
*Pseudobulbar affect/ emotional lability
<h2> Prognosis  </h2>
 
<p>A distinctive clinical feature of PLS is that it has a very slow progression, leading it to be considered to have a more benign prognosis in comparison to ALS<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />. The longevity of individuals with PLS is unclear, but it has been estimated to be 7.9 years or longer. Individuals with PLS and minimal EMG changes appear to have a decreased ability to ambulate independently in comparison to those without EMG changes. Nonetheless, patients may still be able to ambulate without aids after several years of being diagnosed. It is common for patients to be diagnosed with PLS but later diagnosed with ALS instead. Due to their similar course of progression, misdiagnosis can occur. A detailed spectrum of PLS categories have been detailed<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="gordon et al." /><span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." /><span style="font-size: 13.28px;">.</span>  
PLS is classified as slowly progressive. The typical pattern of progression is spreading from side to side, region to region<ref name="statland et al." />. It may start in the bulbar region and descend down to the limbs, or it may start in the lower extremities, progress to arms, and then bulbar region. Symptoms spread slowly over many years before plateauing<ref name="statland et al." />.&nbsp;<br>  
</p>
 
<h2> Interventions  </h2>
== Prognosis  ==
<h4> Physical Therapy&nbsp;  </h4>
 
<p>Treatment for primary lateral sclerosis is symptom-directed<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />. The most common symptoms of someone with PLS include leg weakness, spasticity, spastic bulbar weakness, dysarthria, dysphagia, urinary urgency, and incontinence. Spasticity and muscle weakness are symptoms that can be treated by physiotherapists. Poorly managed spasticity can lead to soft tissue contractures, immobility, and a decrease in function<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="stevenson">Stevenson VL. Rehabilitation in practice: spasticity management. Clin Rehabil. 2010 Apr;24(4):293-304. doi: 10.1177/0269215509353254</span>. Physical interventions that include, active or passive movement (depending on which one the patient can tolerate), will help minimize changes in maintaining the range of movement and preventing the formation of contractures. Physical therapists may also consider splinting if the patient experience frequency spasms. Strengthening exercises prescribed by physiotherapists may also help PLS patients who experience weakness in their legs and decrease the high progression to gait aids.  
A distinctive clinical feature of PLS is that it has a very slow progression, leading it to be considered to have a more benign prognosis in comparison to ALS<ref name="singer et al." />. The longevity of individuals with PLS is unclear, but it has been estimated to be 7.9 years or longer. Individuals with PLS and minimal EMG changes appear to have a decreased ability to ambulate independently in comparison to those without EMG changes. Nonetheless, patients may still be able to ambulate without aids after several years of being diagnosed. It is common for patients to be diagnosed with PLS but later diagnosed with ALS instead. Due to their similar course of progression, misdiagnosis can occur. A detailed spectrum of PLS categories have been detailed<ref name="gordon et al." /><ref name="singer et al." /><span style="font-size: 13.28px;">.</span>  
</p><p>Swallowing therapy may also be used in patients experiencing symptoms of dysphagia to prevent the progression of needing feeding-tube placement<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />. A focus on exercise-based swallowing intervention has been shown to improve functional swallowing and swallowing physiology<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="sura">Sura L, Madhavan A, Carnaby G, Crary MA. Dysphagia in the elderly: management and nutritional considerations. Clin Interv Aging. 2012 Jan 1;7(7):287-98. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22956864 doi: 10.2147/CIA.S23404</span>.  
 
</p>
== Interventions  ==
<h4> Medical and Surgical  </h4>
 
<p>Currently, there is no cure for primary lateral sclerosis. Therefore, treatment primarily focuses on relieving symptoms and preserving function. Depending on the patient’s presentation, treatments may include the following <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." /><span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />:  
==== Physical Therapy&nbsp;  ====
</p>
 
<ul><li>Oral medications such as balcofen, dantrolene, and tizanadine for muscle spasticity  
Treatment for primary lateral sclerosis is symptom-directed<ref name="singer et al." />. The most common symptoms of someone with PLS include leg weakness, spasticity, spastic bulbar weakness, dysarthria, dysphagia, urinary urgency, and incontinence. Spasticity and muscle weakness are symptoms that can be treated by physiotherapists. Poorly managed spasticity can lead to soft tissue contractures, immobility, and a decrease in function<ref name="stevenson">Stevenson VL. Rehabilitation in practice: spasticity management. Clin Rehabil. 2010 Apr;24(4):293-304. doi: 10.1177/0269215509353254</ref>. Physical interventions that include, active or passive movement (depending on which one the patient can tolerate), will help minimize changes in maintaining the range of movement and preventing the formation of contractures. Physical therapists may also consider splinting if the patient experience frequency spasms. Strengthening exercises prescribed by physiotherapists may also help PLS patients who experience weakness in their legs and decrease the high progression to gait aids.  
</li><li>Surgically implanted balcofen pump  
 
</li><li>Anticholinergic medication or botulism toxin injections for drooling  
Swallowing therapy may also be used in patients experiencing symptoms of dysphagia to prevent the progression of needing feeding-tube placement<ref name="singer et al." />. A focus on exercise-based swallowing intervention has been shown to improve functional swallowing and swallowing physiology<ref name="sura">Sura L, Madhavan A, Carnaby G, Crary MA. Dysphagia in the elderly: management and nutritional considerations. Clin Interv Aging. 2012 Jan 1;7(7):287-98. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22956864 doi: 10.2147/CIA.S23404</ref>.  
</li><li>Feeding tube for dysphagia  
 
</li><li>Assistive devices such as walkers or wheelchairs for gait impairments  
==== Medical and Surgical  ====
</li><li>Physical therapy
 
</li></ul>
Currently, there is no cure for primary lateral sclerosis. Therefore, treatment primarily focuses on relieving symptoms and preserving function. Depending on the patient’s presentation, treatments may include the following <ref name="statland et al." /><ref name="singer et al." />:  
<p>Ultimately, patients are best managed in a multidisciplinary motor neuron disease clinic where the various potential symptoms of primary lateral sclerosis could be comprehensively addressed<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="singer et al." />.  
 
</p>
*Oral medications such as balcofen, dantrolene, and tizanadine for muscle spasticity  
<h2> Differential Diagnoses  </h2>
*Surgically implanted balcofen pump  
<p>As PLS is a condition that lies on a continuum of sporadic motor neuron disorders, there are several potential differential diagnosis. The 2 most likely upper motor neuron diseases that is associated with PLS are:  
*Anticholinergic medication or botulism toxin injections for drooling  
</p><p>1. Amyotrophic lateral sclerosis<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." /> <span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="strong and gordon">Strong, MJ, Gordon, PH. Primary lateral sclerosis, hereditary spastic paraplegia and amyotrophic lateral sclerosis: discrete entities or spectrum? Amyotroph Lateral Sc. 2005 Mar;6(1):8-16. doi: 10.1080/14660820410021267</span>  
*Feeding tube for dysphagia  
</p>
*Assistive devices such as walkers or wheelchairs for gait impairments  
<ul><li>ALS presents with lower and/or upper motor deficits and has fast(er) progression; PLS is slower progression and typically only affects upper motor neurons.  
*Physical therapy
</li><li>ALS is more commonly associated with stiffness then PLS (47% vs 4%)  
 
</li><li>Both ALS and PLS can be assoicated with cognitive issues but is not present in its ‘uncomplicated’ forms<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="strong and gordon" />
Ultimately, patients are best managed in a multidisciplinary motor neuron disease clinic where the various potential symptoms of primary lateral sclerosis could be comprehensively addressed<ref name="singer et al." />.  
</li></ul>
 
<p><br />  
== Differential Diagnoses  ==
</p><p>2. Hereditary spastic paraplegias<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="strong and gordon" />  
 
</p>
As PLS is a condition that lies on a continuum of sporadic motor neuron disorders, there are several potential differential diagnosis. The 2 most likely upper motor neuron diseases that is associated with PLS are:  
<ul><li>HSP has spasticity of the lower limbs; PLS is associated with spasticity as well and slight weakness but spasticity can affect speech (spastic dysarthria)  
 
</li><li>Complicated cases of HSP can result in dementia &amp; mental retardation which may mimic cognitive issues possibly present in complicated cases of PLS.
1. Amyotrophic lateral sclerosis<ref name="statland et al." /> <ref name="strong and gordon">Strong, MJ, Gordon, PH. Primary lateral sclerosis, hereditary spastic paraplegia and amyotrophic lateral sclerosis: Discrete entities or spectrum? Amyotrophic Lateral Sclerosis 2005; 6:8-16.</ref>  
</li></ul>
 
<p><br />  
*ALS presents with lower and/or upper motor deficits and has fast(er) progression; PLS is slower progression and typically only affects upper motor neurons.  
</p><p>Other potential, but less specific, differential considerations include:&nbsp;<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="statland et al." />  
*ALS is more commonly associated with stiffness then PLS (47% vs 4%)  
</p>
*Both ALS and PLS can be assoicated with cognitive issues but is not present in its ‘uncomplicated’ forms<ref name="strong and gordon" />
<ul><li>Structural lesions, especially related to the spine (eg. cervical spondylmyelopathy)  
 
</li><li>Infection (eg. HIV, syphilis)  
<br>  
</li><li>Demyelinating disease (eg. mutliple sclerosis)  
 
</li><li>Metabolic / toxic (eg. vitamin E deficiency)  
2. Hereditary spastic paraplegias<ref name="strong and gordon" />  
</li><li>Neurodegenerative (eg. Parkinsons and parkinson's-plus syndromes)
 
</li></ul>
*HSP has spasticity of the lower limbs; PLS is associated with spasticity as well and slight weakness but spasticity can affect speech (spastic dysarthria)  
<p><br />Special care must be taken when diagnosing as PLS can be misdiagnosed as the above examples, and many more<span class="fck_mw_ref" _fck_mw_customtag="true" _fck_mw_tagname="ref" name="kuipers">Kuipers-Upmeijer, J, de Jager, A, Hew, J, Snoek, J, van Weerden, T. Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings. J Neurol Neurosur Ps. 2001 Nov;71:615-20. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11606672</span>.<br />  
*Complicated cases of HSP can result in dementia &amp; mental retardation which may mimic cognitive issues possibly present in complicated cases of PLS.
</p>
 
<h2> References  </h2>
<br>  
<p><span class="fck_mw_references" _fck_mw_customtag="true" _fck_mw_tagname="references" />
 
</p>
Other potential, but less specific, differential considerations include:&nbsp;<ref name="statland et al." />  
 
*Structural lesions, especially related to the spine (eg. cervical spondylmyelopathy)  
*Infection (eg. HIV, syphilis)  
*Demyelinating disease (eg. mutliple sclerosis)  
*Metabolic / toxic (eg. vitamin E deficiency)  
*Neurodegenerative (eg. Parkinsons and parkinson's-plus syndromes)
 
<br>Special care must be taken when diagnosing as PLS can be misdiagnosed as the above examples, and many more<ref name="kuipers">Kuipers-Upmeijer, J, de Jager, A, Hew, J, Snoek, J, van Weerden, T. Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings. J Neurol Neurosurg Psychiatry. 2001 Nov;71:615-20. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11606672</ref>.<br>  
 
== References  ==
 
<references />

Revision as of 03:55, 4 May 2017

Definition/Description

Primary Lateral Sclerosis (PLS) is characterized as being a rare, non-hereditary, idiopathic, slow, and progressive degeneration of the upper motor neuronsStatland, JM, Barohn, RJ, Dimachkie, MM, Floeter, MK, Mitsumoto, H. Primary lateral sclerosis. Neurol Clin 2015 Nov;33(4):749-60. Available from: https://www.ncbi.nlm.nih.gov/pubmed/26515619 doi: 10.1016/j.ncl.2015.07.007. PLS lies on a continuum of sporadic motor neuron disorders. This spectrum includes other disorders such as progressive muscular atrophy, which involves only lower motor neurons, as well as amyotrophic lateral sclerosis (ALS), characterized by both upper and lower motor neuron involvement. Many patients diagnosed with PLS continue to have high levels of independence for many yearsGordon, PH, Cheng, B, Katz, IB, Pinto, M, Hays, AP, Mitsumoto, H, Rowland, LP. The natural history of primary lateral sclerosis. Neurology. 2006 Mar;66(5):647-53. doi: 10.1212/01.wnl.0000200962.94777.71.

Epidemiology Singer, MA, Statland, JM, Wolfe, GI, Barohn, RJ. Primary lateral sclerosis. Muscle Nerve. 2007 Mar;35(3):291-302. doi: 10.1002/mus.20728

  • Approximately 2-5% of adults in neuromuscular clinics will be diagnosed with PLS.
  • The age of onset is approximately 50 years and older, though a juvenile form of PLS has been described as well.
  • Although the difference is not pronounced, there is a slight male predominance over females in being diagnosed with PLS.

Etiology

The exact cause of adult-onset PLS remains unknown. PLS is a diagnosis of exclusion, meaning that individuals are diagnosed with the condition when their progressive upper motor neuron dysfunctions cannot be explained by any other possible cause.

Clinical Presentation

PLS is due to upper motor neuron (UMN) degeneration, and therefore clinical presentation is consistent with signs and symptoms of an UMN disorder in the absence of lower motor neuron (LMN) symptoms. These include;

  • Spasticity
  • Hyperreflexia
  • Weakness

Other key features include stiffness and increasing difficulty maintaining balance with the progression of the disorder. PLS may affect the bulbar region in the medulla, causing degeneration to the lower cranial nerves. Bulbar signs and symptoms include;

  • Dysphagia
  • Dysarthria
  • Pseudobulbar affect/ emotional lability

PLS is classified as slowly progressive. The typical pattern of progression is spreading from side to side, region to region. It may start in the bulbar region and descend down to the limbs, or it may start in the lower extremities, progress to arms, and then bulbar region. Symptoms spread slowly over many years before plateauing. 

Prognosis

A distinctive clinical feature of PLS is that it has a very slow progression, leading it to be considered to have a more benign prognosis in comparison to ALS. The longevity of individuals with PLS is unclear, but it has been estimated to be 7.9 years or longer. Individuals with PLS and minimal EMG changes appear to have a decreased ability to ambulate independently in comparison to those without EMG changes. Nonetheless, patients may still be able to ambulate without aids after several years of being diagnosed. It is common for patients to be diagnosed with PLS but later diagnosed with ALS instead. Due to their similar course of progression, misdiagnosis can occur. A detailed spectrum of PLS categories have been detailed.

Interventions

Physical Therapy 

Treatment for primary lateral sclerosis is symptom-directed. The most common symptoms of someone with PLS include leg weakness, spasticity, spastic bulbar weakness, dysarthria, dysphagia, urinary urgency, and incontinence. Spasticity and muscle weakness are symptoms that can be treated by physiotherapists. Poorly managed spasticity can lead to soft tissue contractures, immobility, and a decrease in functionStevenson VL. Rehabilitation in practice: spasticity management. Clin Rehabil. 2010 Apr;24(4):293-304. doi: 10.1177/0269215509353254. Physical interventions that include, active or passive movement (depending on which one the patient can tolerate), will help minimize changes in maintaining the range of movement and preventing the formation of contractures. Physical therapists may also consider splinting if the patient experience frequency spasms. Strengthening exercises prescribed by physiotherapists may also help PLS patients who experience weakness in their legs and decrease the high progression to gait aids.

Swallowing therapy may also be used in patients experiencing symptoms of dysphagia to prevent the progression of needing feeding-tube placement. A focus on exercise-based swallowing intervention has been shown to improve functional swallowing and swallowing physiologySura L, Madhavan A, Carnaby G, Crary MA. Dysphagia in the elderly: management and nutritional considerations. Clin Interv Aging. 2012 Jan 1;7(7):287-98. Available from: https://www.ncbi.nlm.nih.gov/pubmed/22956864 doi: 10.2147/CIA.S23404.

Medical and Surgical

Currently, there is no cure for primary lateral sclerosis. Therefore, treatment primarily focuses on relieving symptoms and preserving function. Depending on the patient’s presentation, treatments may include the following :

  • Oral medications such as balcofen, dantrolene, and tizanadine for muscle spasticity
  • Surgically implanted balcofen pump
  • Anticholinergic medication or botulism toxin injections for drooling
  • Feeding tube for dysphagia
  • Assistive devices such as walkers or wheelchairs for gait impairments
  • Physical therapy

Ultimately, patients are best managed in a multidisciplinary motor neuron disease clinic where the various potential symptoms of primary lateral sclerosis could be comprehensively addressed.

Differential Diagnoses

As PLS is a condition that lies on a continuum of sporadic motor neuron disorders, there are several potential differential diagnosis. The 2 most likely upper motor neuron diseases that is associated with PLS are:

1. Amyotrophic lateral sclerosis Strong, MJ, Gordon, PH. Primary lateral sclerosis, hereditary spastic paraplegia and amyotrophic lateral sclerosis: discrete entities or spectrum? Amyotroph Lateral Sc. 2005 Mar;6(1):8-16. doi: 10.1080/14660820410021267

  • ALS presents with lower and/or upper motor deficits and has fast(er) progression; PLS is slower progression and typically only affects upper motor neurons.
  • ALS is more commonly associated with stiffness then PLS (47% vs 4%)
  • Both ALS and PLS can be assoicated with cognitive issues but is not present in its ‘uncomplicated’ forms


2. Hereditary spastic paraplegias

  • HSP has spasticity of the lower limbs; PLS is associated with spasticity as well and slight weakness but spasticity can affect speech (spastic dysarthria)
  • Complicated cases of HSP can result in dementia & mental retardation which may mimic cognitive issues possibly present in complicated cases of PLS.


Other potential, but less specific, differential considerations include: 

  • Structural lesions, especially related to the spine (eg. cervical spondylmyelopathy)
  • Infection (eg. HIV, syphilis)
  • Demyelinating disease (eg. mutliple sclerosis)
  • Metabolic / toxic (eg. vitamin E deficiency)
  • Neurodegenerative (eg. Parkinsons and parkinson's-plus syndromes)


Special care must be taken when diagnosing as PLS can be misdiagnosed as the above examples, and many moreKuipers-Upmeijer, J, de Jager, A, Hew, J, Snoek, J, van Weerden, T. Primary lateral sclerosis: clinical, neurophysiological, and magnetic resonance findings. J Neurol Neurosur Ps. 2001 Nov;71:615-20. Available from: https://www.ncbi.nlm.nih.gov/pubmed/11606672.

References

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