Primary lateral sclerosis
Encyclopedia
Primary lateral sclerosis (PLS) is a 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.
PLS only affects upper motor neuron
s. There is no evidence of the degeneration of spinal motor neurons or muscle wasting (amyotrophy
) that occurs in amyotrophic lateral sclerosis
(ALS).
(involuntary muscle contraction due to the stretching of muscle. Muscle contraction is dependant on the velocity of the stretch) in the hands, feet, or legs, foot dragging, and speech and swallowing problem
s 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. Hyperreflexia
is another key feature of PLS as seen in patients presenting with the Babinski's sign. Some people present with emotional lability and bladder urgency, and occasionally people with PLS experience mild cognitive changes detectable on neuropsychological testing, particularly on measures of executive function.
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.
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.
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.
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 (ie, 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.
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.
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.
Neuromuscular disease
Neuromuscular disease is a very broad term that encompasses many diseases and ailments that either directly, via intrinsic muscle pathology, or indirectly, via nerve pathology, impair the functioning of the muscles....
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.
PLS only affects upper motor neuron
Upper motor neuron
Upper motor neurons are motor neurons that originate in the motor region of the cerebral cortex or the brain stem and carry motor information down to the final common pathway, that is, any motor neurons that are not directly responsible for stimulating the target muscle...
s. There is no evidence of the degeneration of spinal motor neurons or muscle wasting (amyotrophy
Amyotrophy
Amyotrophy is progressive wasting of muscle tissues. Muscle pain is also a symptom. It can occur in middle age males with type 2 diabetes. It also occurs with Motor Neuron Disease.-See also:* Diabetic amyotrophy* Monomelic amyotrophy...
) that occurs in amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...
(ALS).
Symptoms and progression
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 spasticitySpasticity
Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...
(involuntary muscle contraction due to the stretching of muscle. Muscle contraction is dependant on the velocity of the stretch) in the hands, feet, or legs, foot dragging, and speech and swallowing problem
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
s 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. Hyperreflexia
Hyperreflexia
Hyperreflexia is defined as overactive or overresponsive reflexes. Examples of this can include twitching or spastic tendencies, which are indicative of upper motor neuron disease as well as the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways...
is another key feature of PLS as seen in patients presenting with the Babinski's sign. Some people present with emotional lability and bladder urgency, and occasionally people with PLS experience mild cognitive changes detectable on neuropsychological testing, particularly on measures of executive function.
PLS is not considered hereditary when onset is in adulthood, however, juvenile primary lateral sclerosis
Juvenile primary lateral sclerosis
Juvenile primary lateral sclerosis , also known as primary lateral sclerois , is a rare genetic disorder, with a small number of reported cases, characterized by progressive weakness and stiffness of muscles in the arms, legs, and face...
(JPLS) has been linked to a mutation in the ALS2
ALS2
Alsin is a protein that in humans is encoded by the ALS2 gene. ALS2 orthologs have been identified in all mammals for which complete genome data are available.-External Links:** *...
gene which encodes the cell-signalling protein alsin.
The issue of whether PLS exists as a different entity from ALS
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis , also referred to as Lou Gehrig's disease, is a form of motor neuron disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input...
is not clear as some patients initially diagnosed as having PLS ultimately develop lower motor neuron signs.
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.
Treatment
Treatment for individuals with PLS is symptomatic. BaclofenBaclofen
Baclofen is a derivative of gamma-aminobutyric acid . It is primarily used to treat spasticity and is under investigation for the treatment of alcoholism....
and tizanidine
Tizanidine
Tizanidine is a drug that is used as a muscle relaxant. It is a centrally acting α2 adrenergic agonist. It is used to treat the spasms, cramping, and tightness of muscles caused by medical problems such as multiple sclerosis, spastic diplegia, back pain, or certain other injuries to the spine or...
may reduce spasticity. Quinine
Quinine
Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...
or phenytoin
Phenytoin
Phenytoin sodium is a commonly used antiepileptic. Phenytoin acts to suppress the abnormal brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage-gated sodium channels...
may decrease cramps. Some patients, who do not receive adequate relief from oral treatment, may consider intrathecal baclofen (ie, infusion of medication directly into the cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
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.
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
Spasticity
Spasticity is a feature of altered skeletal muscle performance in muscle tone involving hypertonia, which is also referred to as an unusual "tightness" of muscles...
and cramps.
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.