Primary lateral sclerosis

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Primary Lateral Sclerosis
Other namesPLS
Specialty Neurology   OOjs UI icon edit-ltr-progressive.svg
TypesPrimary Lateral Sclerosis (adult-onset), Juvenile Primary Lateral Sclerosis
Differential diagnosis Amyotrophic Lateral Sclerosis, Multiple Sclerosis

Primary lateral sclerosis (PLS) is a very rare neuromuscular disease characterized by progressive muscle weakness in the voluntary muscles. PLS belongs to a group of disorders known as motor neuron diseases. Motor neuron diseases develop when the nerve cells that control voluntary muscle movement degenerate and die, causing weakness in the muscles they control.

Contents

PLS only affects upper motor neurons. [1] There is no evidence of the degeneration of spinal motor neurons or muscle wasting (amyotrophy) that occurs in amyotrophic lateral sclerosis (ALS).

Symptoms and signs

Onset of PLS usually occurs spontaneously after age 50 and progresses gradually over a number of years, or even decades. The disorder usually begins in the legs, but it may start in the tongue or the hands. Symptoms may include difficulty with balance, weakness and stiffness in the legs, and clumsiness. Other common symptoms are spasticity (involuntary muscle contraction due to the stretching of muscle, which depends on the velocity of the stretch) in the hands, feet, or legs, foot dragging, and speech and swallowing problems due to involvement of the facial muscles. Breathing may also become compromised in the later stages of the disease, causing those patients who develop ventilatory failure to require noninvasive ventilatory support. [2] Hyperreflexia is another key feature of PLS as seen in patients presenting with the Babinski's sign. [3] Some people present with emotional lability and bladder urgency, [3] and occasionally people with PLS experience mild cognitive changes detectable on neuropsychological testing, particularly on measures of executive function. [4]

PLS is not considered hereditary when onset is in adulthood; however, juvenile primary lateral sclerosis (JPLS) has been linked to a mutation in the ALS2 gene which encodes the cell-signalling protein alsin. [5]

The issue of whether PLS exists as a different entity from ALS is not clear, as some patients initially diagnosed as having PLS ultimately develop lower motor neuron signs. [6] [7] When this happens it is classed as ALS. [8]

Spasticity

Primary lateral sclerosis (PLS) usually presents with gradual-onset, progressive, lower-extremity stiffness and pain due to muscle spasticity. Onset is often asymmetrical. [2] Although the muscles do not appear to atrophy as in ALS (at least initially), the disabling aspect of PLS is muscle spasticity and cramping, and intense pain when those muscles are stretched, resulting in joint immobility. A normal walking stride may become a tiny step shuffle with related instability and falling.[ citation needed ]

Cause

Researchers do not fully understand what causes PLS, although it is thought it could be due to a combination of environmental and genetic factors. [9] Studies are being done to evaluate the possible causes, although linking causality can be difficult due to the relatively low number of people who are diagnosed with PLS. [ citation needed ]

Juvenile PLS may be caused by the ALS2 gene, although this condition is very rare.[ citation needed ]

Diagnosis

There are no specific tests for the diagnosis of PLS. Therefore, the diagnosis occurs as the result of eliminating other possible causes of the symptoms and by an extended observation period. [10]

Like ALS, diagnosing PLS is a diagnosis of exclusion, as there is no one test that can confirm a diagnosis of PLS. The Pringle Criteria, [11] proposed by Pringle et al., provides a guideline of nine points that, if confirmed, can suggest a diagnosis of PLS. Due to the fact that a person with ALS may initially present with only upper motor neuron symptoms, indicative of PLS, one key aspect of the Pringle Criteria is requiring a minimum of three years between symptom onset and symptom diagnosis. When these criteria are met, a diagnosis of PLS is highly likely. [12] Other aspects of Pringle Criteria include normal EMG findings, thereby ruling out lower motor neuron involvement that is indicative of ALS, and absence of family history for Hereditary Spastic Paraplegia (HSP) and ALS. Imaging studies to rule out structural or demyelinating lesions may be done as well. Hoffman's sign and Babinski reflex may be present and indicative of upper motor neuron damage.[ citation needed ]

Treatment

Treatment for individuals with PLS is symptomatic. Baclofen and tizanidine may reduce spasticity. Quinine or phenytoin may decrease cramps. Some patients who do not receive adequate relief from oral treatment may consider intrathecal baclofen (i.e., infusion of medication directly into the cerebrospinal fluid via a surgically placed continuous infusion pump). However, patients are carefully selected for this type of procedure to ensure that they will likely benefit from this invasive procedure. [2]

Physical therapy often helps prevent joint immobility. Speech therapy may be useful for those with involvement of the facial muscles. Physiotherapy treatment focuses on reducing muscle tone, maintaining or improving range of motion, increasing strength and coordination, and improving functional mobility. In PLS, stretching is thought to improve flexibility and can also reduce muscle spasticity and cramps. [3]

Patients with PLS may find it beneficial to have an evaluation, as well as follow-up visits at multidisciplinary clinics, similar to those available for people with ALS. These multidisciplinary clinics may provide patients with the necessary treatment that they require by having an occupational therapist, physical therapist, speech language pathologist, dietician and nutritionist, all in one site. [2]

Prognosis

Patients can often live with PLS for many years and very often outlive their neurological disease and succumb to some unrelated condition. There is currently no effective cure, and the progression of symptoms varies. Some people may retain the ability to walk without assistance, but others eventually require wheelchairs, canes, or other assistive devices.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Motor neuron disease</span> Group of neurological disorders affecting motor neurons

Motor neuron diseases or motor neurone diseases (MNDs) are a group of rare neurodegenerative disorders that selectively affect motor neurons, the cells which control voluntary muscles of the body. They include amyotrophic lateral sclerosis (ALS), progressive bulbar palsy (PBP), pseudobulbar palsy, progressive muscular atrophy (PMA), primary lateral sclerosis (PLS), spinal muscular atrophy (SMA) and monomelic amyotrophy (MMA), as well as some rarer variants resembling ALS.

Neuromyotonia (NMT) is a form of peripheral nerve hyperexcitability that causes spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin. NMT along with Morvan's syndrome are the most severe types in the Peripheral Nerve Hyperexciteability spectrum. Example of two more common and less severe syndromes in the spectrum are Cramp Fasciculation Syndrome and Benign Fasciculation Syndrome. NMT can have both hereditary and acquired forms. The prevalence of NMT is unknown.

<span class="mw-page-title-main">Benign fasciculation syndrome</span> Medical condition

Benign fasciculation syndrome (BFS) is characterized by fasciculation (twitching) of voluntary muscles in the body. The twitching can occur in any voluntary muscle group but is most common in the eyelids, arms, hands, fingers, legs, and feet. The tongue can also be affected. The twitching may be occasional to continuous. BFS must be distinguished from other conditions that include muscle twitches.

Hereditary spastic paraplegia (HSP) is a group of inherited diseases whose main feature is a progressive gait disorder. The disease presents with progressive stiffness (spasticity) and contraction in the lower limbs. HSP is also known as hereditary spastic paraparesis, familial spastic paraplegia, French settlement disease, Strumpell disease, or Strumpell-Lorrain disease. The symptoms are a result of dysfunction of long axons in the spinal cord. The affected cells are the primary motor neurons; therefore, the disease is an upper motor neuron disease. HSP is not a form of cerebral palsy even though it physically may appear and behave much the same as spastic diplegia. The origin of HSP is different from cerebral palsy. Despite this, some of the same anti-spasticity medications used in spastic cerebral palsy are sometimes used to treat HSP symptoms.

<span class="mw-page-title-main">Post-polio syndrome</span> Human disease

Post-polio syndrome is a group of latent symptoms of poliomyelitis (polio), occurring at about a 25–40% rate. These symptoms are caused by the damaging effects of the viral infection on the nervous system. Symptoms typically occur 15 to 30 years after an initial acute paralytic attack. Symptoms include decreasing muscular function or acute weakness with pain and fatigue. The same symptoms may also occur years after a nonparalytic polio (NPP) infection.

Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectively occur with the muscles that help produce speech, often making it very difficult to pronounce words. It is unrelated to problems with understanding language, although a person can have both. Any of the speech subsystems can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication. Dysarthria that has progressed to a total loss of speech is referred to as anarthria. The term dysarthria is from New Latin, dys- "dysfunctional, impaired" and arthr- "joint, vocal articulation".

<span class="mw-page-title-main">Fasciculation</span> Spontaneous, involuntary muscle twitch

A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more serious conditions. When no cause or pathology is identified, they are diagnosed as benign fasciculation syndrome.

Stiff-person syndrome Movement disease that is of unknown etiology characterized by progressive rigidity

Stiff-person syndrome (SPS), also known as stiff-man syndrome (SMS), is a rare neurologic disorder of unclear cause characterized by progressive rigidity and stiffness. The stiffness primarily affects the truncal muscles and is superimposed by spasms, resulting in postural deformities. Chronic pain, impaired mobility, and lumbar hyperlordosis are common symptoms.

<span class="mw-page-title-main">Progressive muscular atrophy</span> Medical condition

Progressive muscular atrophy (PMA), also called Duchenne–Aran disease and Duchenne–Aran muscular atrophy, is a disorder characterised by the degeneration of lower motor neurons, resulting in generalised, progressive loss of muscle function.

Progressive bulbar palsy (PBP) is a medical condition. It belongs to a group of disorders known as motor neuron diseases. PBP is a disease that attacks the nerves supplying the bulbar muscles. These disorders are characterized by the degeneration of motor neurons in the cerebral cortex, spinal cord, brain stem, and pyramidal tracts. This specifically involves the glossopharyngeal nerve (IX), vagus nerve (X), and hypoglossal nerve (XII).

Pseudobulbar palsy is a medical condition characterized by the inability to control facial movements and caused by a variety of neurological disorders. Patients experience difficulty chewing and swallowing, have increased reflexes and spasticity in tongue and the bulbar region, and demonstrate slurred speech, sometimes also demonstrating uncontrolled emotional outbursts.

Lytico-bodig (also Lytigo-bodig) disease, Guam disease, or amyotrophic lateral sclerosis-parkinsonism-dementia (ALS-PDC) is a neurodegenerative disease of uncertain etiology endemic to the Chamorro people of the island of Guam in Micronesia. Lytigo and bodig are Chamorro language words for two different manifestations of the same condition. ALS-PDC, a term coined by Asao Hirano and colleagues in 1961, reflects its resemblance to amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Alzheimer's disease.

Mecasermin rinfabate, also known as rhIGF-1/rhIGFBP-3, is a drug consisting of recombinant human insulin-like growth factor 1 (IGF-1) and recombinant human insulin-like growth factor binding protein-3 (IGFBP-3) which is used for the treatment of amyotrophic lateral sclerosis.

<span class="mw-page-title-main">Amyotrophic lateral sclerosis</span> Rare neurodegenerative disease

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most common type of motor neuron disease. Early symptoms of ALS include stiff muscles, muscle twitches, and gradual increasing weakness and muscle wasting. Limb-onset ALS begins with weakness in the arms or legs, while bulbar-onset ALS begins with difficulty speaking or swallowing. Half of the people with ALS develop at least mild difficulties with thinking and behavior, and about 15% develop frontotemporal dementia. Most people experience pain. The affected muscles are responsible for chewing food, speaking, and walking. Motor neuron loss continues until the ability to eat, speak, move, and finally the ability to breathe is lost. ALS eventually causes paralysis and early death, usually from respiratory failure.

Multifocal motor neuropathy (MMN) is a progressively worsening condition where muscles in the extremities gradually weaken. The disorder, a pure motor neuropathy syndrome, is sometimes mistaken for amyotrophic lateral sclerosis (ALS) because of the similarity in the clinical picture, especially if muscle fasciculations are present. MMN is thought to be autoimmune. It was first described in the mid-1980s.

<span class="mw-page-title-main">Epigenetics of neurodegenerative diseases</span> Field of study

Neurodegenerative diseases are a heterogeneous group of complex disorders linked by the degeneration of neurons in either the peripheral nervous system or the central nervous system. Their underlying causes are extremely variable and complicated by various genetic and/or environmental factors. These diseases cause progressive deterioration of the neuron resulting in decreased signal transduction and in some cases even neuronal death. Peripheral nervous system diseases may be further categorized by the type of nerve cell affected by the disorder. Effective treatment of these diseases is often prevented by lack of understanding of the underlying molecular and genetic pathology. Epigenetic therapy is being investigated as a method of correcting the expression levels of misregulated genes in neurodegenerative diseases.

Monomelic amyotrophy Medical condition

Monomelic amyotrophy (MMA) is a rare motor neuron disease first described in 1959 in Japan. Its symptoms usually appear about two years after adolescent growth spurt and is significantly more common in males, with an average age of onset between 15 and 25 years. MMA is reported most frequently in Asia but has a global distribution. It is typically marked by insidious onset of muscle atrophy of an upper limb, which plateaus after two to five years from which it neither improves nor worsens. There is no pain or sensory loss associated with MMA. MMA is not believed to be hereditary.

Amyotrophic Lateral Sclerosis (ALS), is a neurodegenerative disease that typically affects adults around 54-67 years of age, although anyone can be diagnosed with the disease. People diagnosed with ALS live on average 2–4 years after diagnosis due to the quick progression of the disease. The progression and severity of ALS is rated by doctors on the ALS Functional Rating Scale, which has been revised and is referred to as ALSFRS-R.

Research on amyotrophic lateral sclerosis has focused on animal models of the disease, its mechanisms, ways to diagnose and track it, and treatments.

Facial onset sensory and motor neuronopathy, often abbreviated FOSMN, is a rare disorder of the nervous system in which sensory and motor nerves of the face and limbs progressively degenerate over a period of months to years. This degenerative process, the cause of which is unknown, eventually results in sensory and motor symptoms — the former consisting mainly of paresthesia followed by numbness, and the latter in muscle weakness, atrophy, and eventual paralysis. In many ways, it is reminiscent of the much better known condition amyotrophic lateral sclerosis, with which it is closely related. There is no cure; treatment is supportive. Life expectancy may be shortened by respiratory complications arising from weakness of the muscles that aid breathing and swallowing. It was first described in four patients by Vucic and colleagues working at the Massachusetts General Hospital in the United States; subsequent reports from the United Kingdom, Europe and Asia point to a global incidence of the disease. It is thought to be exceptionally rare, with only approximately 100 individuals described to date in the medical literature.

References

  1. ↑ "Motor neuron diseases". Archived from the original on April 28, 2009. Retrieved 2009-06-02.
  2. 1 2 3 4 Primary Lateral Sclerosis at eMedicine
  3. 1 2 3 "Primary Lateral Sclerosis". Spastic Paraplegia Foundation. February 15, 2009. Archived from the original on January 16, 2013. Retrieved 2011-05-11.
  4. ↑ Grace, G. M.; Orange, J. B.; Rowe, A; Findlater, K; Freedman, M; Strong, M. J. (2011). "Neuropsychological functioning in PLS: A comparison with ALS". The Canadian Journal of Neurological Sciences. 38 (1): 88–97. doi: 10.1017/S0317167100120803 . PMID   21156436. INIST:23743303.
  5. ↑ Rollins, Yvonne D.; Oskarsson, Björn; Ringel, Steven P. (2011). "Primary lateral sclerosis". In Lisak, Robert; Truong, Daniel; Carroll, William; Bhidayasiri, Roongroj (eds.). International Neurology. John Wiley & Sons. pp. 203–4. ISBN   978-1-4443-1701-5.
  6. ↑ Tartaglia, Maria Carmela; Rowe, Ann; Findlater, Karen; Orange, J. B.; Grace, Gloria; Strong, Michael J. (2007). "Differentiation Between Primary Lateral Sclerosis and Amyotrophic Lateral Sclerosis". Archives of Neurology. 64 (2): 232–6. doi: 10.1001/archneur.64.2.232 . PMID   17296839.
  7. ↑ Gotkine, Marc; Argov, Zohar (2007). "Clinical Differentiation Between Primary Lateral Sclerosis and Upper Motor Neuron Predominant Amyotrophic Lateral Sclerosis". Archives of Neurology. 64 (10): 1545, author reply 1545. doi:10.1001/archneur.64.10.1545-a. PMID   17923644.
  8. ↑ "ICD-11 - Mortality and Morbidity Statistics". icd.who.int.
  9. ↑ "Primary lateral sclerosis (PLS) - Symptoms and causes". Mayo Clinic .
  10. ↑ "Primary Lateral Sclerosis Information Page". National Institute of Neurological Disorders and Stroke. April 23, 2010. Archived from the original on June 6, 2011. Retrieved 2011-05-11.
  11. ↑ Pringle, C. E.; Hudson, A. J.; Munoz, D. G.; Kiernan, J. A.; Brown, W. F.; Ebers, G. C. (1992). "Primary Lateral Sclerosis: Clinical Features, Neuropathology and Diagnostic Criteria". Brain. 115 (2): 495–520. doi:10.1093/brain/115.2.495. PMID   1606479.
  12. ↑ Floeter, Mary Kay; Mills, Reversa (2009). "Progression in primary lateral sclerosis: A prospective analysis". Amyotrophic Lateral Sclerosis. 10 (5–6): 339–46. doi:10.3109/17482960903171136. PMC   3434688 . PMID   19922121.
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