What is HSP/PLS?

Learn All About it Below

What We Know About HSP

What is HSP?

What is HSP/PLS? Hereditary Spastic Paraplegia (HSP) is a group of rare, inherited neurological disorders. Their primary symptoms are progressive spasticity and weakness of the leg and hip muscles. Researchers estimate that some 90 different types of HSP exist; the genetic causes are known for about fifty. The HSP incidence rate in the United States is about 20,000 people. The condition is characterized by insidiously progressive lower extremity weakness and spasticity. HSP is classified as uncomplicated or pure if neurological impairment is limited to the lower body.

Symptoms

The hallmark of HSP is progressive difficulty walking due to increasingly weak and stiff (spastic) muscles. Symptoms appear in most people between the second and fourth decade of life, but they can start at any age. Initial symptoms are typically difficulty with balance, stubbing the toe or stumbling. Changes begin so gradually that other people often notice the change first. As the disease progresses, canes, walkers and eventually wheelchairs may become needed, although some people never require assistive devices. Other common symptoms of HSP are urinary urgency and frequency, hyperactive reflexes, difficulty with balance, clonus, Babinski’s sign, diminished vibration sense in the feet, muscle spasms, and congenital foot problems such as pes cavus (high arched foot). Some people may experience problems with their arms or fine motor control of their fingers but for most people, this is not significant.

Diagnosis

HSP is diagnosed via a careful clinical examination, by excluding other disorders that cause spasticity and weakness in the legs, and by an observation period to see if other symptoms develop that indicate another condition, such as PLS. Disorders that can be ruled out with testing are ALS, tropical spastic paraparesis (TSP), vitamin deficiencies (B12 or E), thoracic spine herniated disks, and spinal cord tumors or injuries and multiple sclerosis. HSP can resemble cerebral palsy, however, HSP is degenerative and thereby causes increasing spasticity and weakness of the muscles. Two other disorders with spastic paraplegia symptoms termed Lathyrism and Konzo are caused by toxins in the plants Lathyrus sativus and cassava. HSP is hereditary, and examining family history is important in diagnosing HSP.

What causes the symptoms?

HSP is caused by degeneration of the upper motor neurons in the brain and spinal cord. Upper motor neurons control voluntary movement. The cell bodies of these neurons are located in the motor cortex area of the brain. They have long, hair-like processes called axons that travel to the brainstem and down the spinal cord. Axons relay the messages to move to lower motor neurons that are located all along the brainstem and spinal cord. Lower motor neurons then carry the messages out to the muscles. When upper motor neurons degenerate, the correct messages cannot reach the lower motor neurons, and the lower motor neurons cannot transmit the correct messages to the muscles. As the degeneration continues, spasticity and weakness increase. The legs are affected because degeneration occurs primarily at the ends of the longest nerves in the spinal cord, which control the legs. In some cases, the upper body can be minimally affected as well, leading to problems with the arms or speech and swallowing muscles.

What is the life expectancy?

What is HSP/PLS life expectancy? Life expectancy is normal. However, complications arising from falls or immobility caused by the symptoms of HSP may inadvertently shorten a person’s life.

Treatment

What is HSP/PLS treatment? No treatments are currently available to prevent, stop, or reverse HSP. Treatment is focused on symptom relief, such as medication to reduce spasticity; physical therapy and exercise to help maintain flexibility, strength, and range of motion; assistive devices and communications aids; supportive therapy and other modalities.

What We Know About PLS

What is PLS?

What is HSP/PLS? Primary Lateral Sclerosis (PLS) is a group of rare, degenerative, neurological disorders. They are sporadic, meaning there is no clear familial link, although there are hereditary forms of PLS. PLS is caused primarily by degeneration of the upper motor neurons in the brain and spinal cord, which results in increasing spasticity and weakness of voluntary muscles. The disorder usually begins in the legs but can begin in the upper body or bulbar (speech and swallowing) muscles. The age of onset is generally between 35 and 66 years of age, with a median age of 50.

Symptoms

The hallmark of PLS is progressive weakness and spasticity of voluntary muscles. The first symptoms are often tripping or difficulty lifting the legs. Other people may be the first to notice a change in the affected person’s gait. Occasionally, speaking (dysarthria) and swallowing (dysphagia) difficulties, or arm weakness are the first symptoms. Speech problems can begin with hoarseness, a reduced rate of speaking, excessive clearing of the throat, or slurred speech when a person is tired. In some cases, speech becomes so slurred that others cannot understand it. Drooling can be a problem as well due to weakened bulbar muscles.Wherever symptoms originate, the legs, arms, hands, and speech and swallowing muscles will all eventually be affected. In time, assistive devices are needed, such as canes, walkers, or wheelchairs. Speech therapy and communication aids may become necessary as well.

Diagnosis

PLS is diagnosed via a careful clinical examination, by excluding other disorders that cause progressive spasticity and weakness, and by an extended observation period. Tests include a complete neurological examination, blood work, an MRI of the brain and spine, motor and sensory nerve conduction studies, and cerebrospinal fluid analysis. Some of these tests are repeated periodically. Conditions that can be ruled out with testing are tropical spastic paraparesis (TSP), vitamin deficiencies (B12 or E), thoracic spine herniated disks, spinal cord tumors or injury, cerebral palsy, and multiple sclerosis.

What causes the symptoms?

As noted above, PLS is caused by degeneration of the upper motor neurons in the brain and spinal cord. Upper motor neurons control voluntary movement.

The cell bodies of these neurons are located in the motor cortex area of the brain. They have long, hair-like processes called axons that travel to the brainstem and down the spinal cord. Axons relay the messages to move to lower motor neurons that are located all along the brainstem and spinal cord. Lower motor neurons then carry the messages out to the muscles. Click on the diagram at right to see how upper motor neurons connect to lower motor neurons that innervate leg muscles.

When upper motor neurons degenerate, impulses cannot adequately reach the lower motor neurons and the lower motor neurons cannot deliver the proper message to the corresponding muscle. The result is muscle weakness and spasticity. As the degeneration progresses, symptoms increase.

In PLS, the degenerative process impacts the length of the spinal cord, thus affecting the legs, arms and speech and swallowing muscles. For most patients, the process begins in the legs and then travels up the spinal cord. In some people, the process begins in the brainstem, affecting the speech and swallowing muscles first, and then descends down the spinal cord.

What is the life expectancy?

What is HSP/PLS life expectancy? Life expectancy is normal. However, complications from falls or immobility may inadvertently shorten a person’s life.

Treatment

What is HSP/PLS treatment? No treatments are currently available to prevent, stop, or reverse PLS. Treatment is focused on symptom relief, such as medication to reduce spasticity; physical therapy and exercise to help maintain flexibility, strength, and range of motion; assistive devices and communications aids; and supportive therapy and other modalities.

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