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Reviewed by
John K. Fink, M.D.,
SPF Medical Advisor
Please see Glossary to help
with medical terms
Index:
What
is HSP?
What is (Apparently
Sporadic) Spastic Paraplegia?
What
are the symptoms?
Why are my symptoms different from others in my
family?
How
does HSP cause symptoms?
How
severe will my symptoms get?
How
is HSP diagnosed?
What
genetic testing is available?
What
is the life expectancy?
What
is the treatment?
What
is the risk of getting HSP?
What
other conditions cause spastic paraplegia
and weakness of muscles?
Other
Questions
What is HSP?
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 30
different types of HSP exist; the genetic causes are
known for eleven. The HSP incidence rate in the United
States is 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. HSP is
classified as complicated or complex if other systems
are involved or if there are other neurological findings
such as seizures, dementia, amyotrophy, extrapyramidal
disturbance, or peripheral neuropathy in the absence of
other disorders such as diabetes mellitus.
Many different names are used for HSP. The most common
are Hereditary Spastic Paraplegia (or Paraparesis),
Familial Spastic Paraparesis (or Paraplegia), and
Strümpell-Lorrain Disease. Others are Spastic
Paraplegia, Hereditary Charcot-Disease, Spastic Spinal
Paralysis, Diplegia Spinalis Progressiva, French
Settlement Disease, Troyer syndrome, and Silver
syndrome.
The disorder was first identified in the late 1800s by
A. Strümpell, a neurologist in Heidelberg, Germany. He
observed two brothers and their father, all of whom had
gait disorders and spasticity in their legs. After the
death of the brothers, Strümpell showed through autopsy
the degeneration of the nerve fibers leading through the
spinal cord. HSP was originally named after Strümpell,
and later after two Frenchmen, Lorrain and Charcot, who
provided more information.
Here's an overview
Chart.
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What is (Apparently
Sporadic) Spastic Paraplegia?
Many individuals with all the signs and symptoms of
HSP do not appear to have similarly affected family
members. Without proof of a
hereditary link, some neurologists call the condition
Spastic Paraplegia or Apparently Sporadic Spastic
Paraplegia. Other clinicians may diagnosis the same
condition as Primary Lateral Sclerosis,
which mimics HSP in how it affects the lower body.
However, current researcher indicates that PLS
eventually affects the arms and speech and swallowing muscles as
well as the leg muscles.
There are many reasons why someone with HSP may not
have a family history. Recessive and x-linked forms skip
generations, which means the disorder may pass silently
for generations and then suddenly appear. In addition,
the age of onset, progression rate and severity vary
widely so that the disease could have gone undiagnosed
in previous generations or an affected individual may
have died before symptom onset. Mistaken parentage or new genetic mutations are also
possible.
Please see HSP
and Heredity for more information on this and
genetic testing.
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What are the
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. Editor's Note: One of
our community members, who is a primary care physician
with HSP, submitted an article about pain
management. Please see
Articles - Pain.
Most people with HSP have uncomplicated HSP. There
are also rare, complicated forms, which have additional
symptoms, such as peripheral neuropathy, ichtyosis (a
skin disorder) epilepsy, ataxia, optic neuropathy,
retinopathy, dementia, mental retardation, deafness, or
problems with speech, swallowing or breathing. These
symptoms may have other causes though, unrelated to HSP.
For example, someone with uncomplicated HSP may have
peripheral neuropathy caused by diabetes.
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Why are my symptoms different from others in my family?
As noted above, the severity of symptoms and age of
onset can vary widely, even within the same family. One
reason is that HSP is a group of genetically different
disorders, not a single disorder. Some differences may
be due to genetic mutations. A child may show symptoms
before a parent and it’s possible for some family
members to have very mild symptoms while others have
more severe symptoms. This may be due to other genes,
environment, nutrition, general health, or factors not
yet understood.
In some families, symptoms tend to start at younger ages
with each generation. Although rare, HSP sometimes shows
“incomplete penetrance”. This means that occasionally,
an individual may have the gene mutation, but for
unknown reasons never develop symptoms of HSP. Such
individuals can still pass HSP to their children.
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How
does HSP cause 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. 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, 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.
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How
severe will my symptoms get?
There is no way to predict rate of progression or
severity of symptoms. Generally, once symptoms begin,
progression continues slowly throughout life. For some
childhood-onset forms, symptoms become apparent,
gradually worsen during childhood, and then stabilize
after adolescence. HSP rarely results in complete loss
of lower limb mobility.
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How is HSP
diagnosed?
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. However, many individuals
with all the signs and symptoms of HSP do not have a
family history. See (Apparently
Sporadic) Spastic Paraparesis.
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What
genetic testing is available?
Athena Diagnostics offers testing for
five different types of HSP out of the 30 or more
different forms of HSP. As more
genes are discovered, it is hopeful that such information
will lead to greater availability of testing.
Genetic counselors can be found at many major medical
centers or by contacting the National Society of Genetic Counselors
at (610) 872-7608. Gene tests can be used for prenatal
testing.
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What is the
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.
For detailed information about treatment and therapies,
click
here.
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What
is the 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.
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What
is the risk of getting HSP?
There are some thirty different forms of HSP, with three different modes of inheritance: autosomal
dominant, autosomal recessive and X-linked. Each mode
has a different risk factor, which ranges from almost
none to 50%. For detailed information, please click
Heredity and HSP.
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What other conditions cause spasticity and
weakness of muscles?
Muscle spasticity and weakness can also be caused
by other conditions including (but not limited to) Primary Lateral Sclerosis, spinal cord injury or
tumors, cerebral palsy, multiple sclerosis, amyotrophic
lateral sclerosis, vitamin absorption, and thoracic
spine herniated disks.
There is a virus-caused disease called
Tropical Spastic Paraparesis
and conditions called
Lathyrism and
Konzo caused by toxins
in the plants lathyrus sativus and cassava that also
cause muscle spasticity and weakness.
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Does stress affect symptoms?
Many people find the tightness in their muscles worsens
when they are angry, stressed, or upset. This may make
it more difficult to walk and speak. It is unknown exactly
how emotions affect muscle tone, but it may involve
adrenalin levels. Most people also report increased
stiffness in cold weather.
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Is depression normal?
Periods of feeling down about having HSP are normal
and expected. It is not uncommon for people to also
experience periods of clinical depression.
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Do people with
HSP experience memory loss?
Memory
disturbance has been reported in some individuals with HSP due to spastin gene
mutations. In general, it was mild.
Before attributing memory disturbance to HSP, it is important to consider other
causes: stress, anxiety, depression, lack of sleep, medications (including
Baclofen), other health conditions including vitamin B12 deficiency.
If memory disturbance is significant, a cause of concern, or worsening, it would
be important to discuss this with your primary physician and neurologist.
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Are foot problems common?
Yes. Here are a few examples:
• High arched feet (pes cavus). High arches occur
because there is more weakness in the foot muscles that
extend the foot backward and flatten the arch than in
the muscles that flex the foot downward.
• Shortened Achilles tendons. Achilles tendons are often
short, and generally shorten further as HSP progresses.
• Jumping feet (clonus). Clonus is an uncontrollable,
repetitive jerking of muscles that makes the foot jump
rapidly up and down. It occurs when the foot is in a
position that causes a disruption of the signals from
the brain, leading to an automatic stretch reflex.
• Hammer toes or bunions. These may occur due to
imbalances in the strength and tone of muscles that
maintain proper alignment of joints in the feet.
• Cold feet and/or foot swelling. This is most likely
caused by poor circulation. Normally, muscle
contractions in the legs help pump blood from the legs
back to the heart. If the muscles are weakened, or if
the person is relatively inactive, the blood flow from
the legs may be decreased, and fluids may accumulate.
This can cause swelling, or a sensation of "cold feet".
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Can my arms be affected?
Some people may experience problems with their arms or fine motor control of
their fingers. The degeneration in nerves that supply the arms is mild compared
to that which occurs in the nerves that supply the legs. For most people, this
is not significant.
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Can HSP affect sexual function?
The short answer appears to be "yes", although it is
important to remember that sexual desire and/or function
can be affected by many other factors such as
age, stress, depression, fatigue, medical disorders
or medications.
Some people report that stiffness, spasms and cramps
that are part of HSP may either inhibit (or intensify)
orgasm, or that orgasm may bring on leg stiffness, spasms
or clonus. Stiffness of the legs or arms may cause difficulty
using certain positions for intercourse.
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Is HSP an Ataxia?
No. The group of disorders known as Ataxias (such as
Friedreichs Ataxia) are spino-cerebellar disorders in
which there is a disturbance either in the part of the
brain known as the cerebellum or in the connections
to it. HSP does not involve the cerebellum. Ataxias
can be hereditary or sporadic.
The term "ataxia" means without coordination, and can also
refer to a symptom in which there is a lack of muscle
control resulting in a jerky or unsteady movement. People
with HSP may have incoordination as a symptom. This
does not mean they have Ataxia.
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Can I donate blood?
HSP cannot be passed to others through donation of
blood. There is no medical reason why a person with
HSP cannot donate blood.
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When was HSP identified?
In the late 1800's, A. Strümpell, a neurologist in
Heidelberg Germany, described this disorder. He observed
two brothers and their father, who had gait disorders
and spasticity in their legs. After the death of the
brothers, Strümpell was able to show through autopsy
the degeneration of the nerve fibers leading through
the spinal cord. The disorder was originally named after
Strümpell, and after two Frenchmen who later provided
more information about the disorder, Lorrain and Charcot.
Back
to Index
Is HSP more prevalent in certain
ethnic groups?
There is no evidence that HSP is more prevalent in
one ethnic group than another.
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