Paraparesis is the partial paralysis of both legs due to disrupted nerve signals from the brain to the muscles.
Paraparesis can be caused by genetic factors and viral infections. In this article, we take a closer look at the causes and how to manage the condition.
Paraparesis is the partial paralysis of both legs. It is characterized by progressive weakness and spasms in the legs.
Symptoms can start anytime in life. Most people diagnosed with paraparesis will eventually have difficulty walking and will also see changes in their gait (the way that they walk).
While there is currently no cure for paraparesis, symptoms can be effectively managed and minimized. It usually has no impact on life expectancy.
Paraparesis is caused by degeneration or damage to nerve pathways. There are two main types of paraparesis, separated according to their cause:
Hereditary spastic paraparesis (HSP)
Paraparesis that is linked to genetic factors is called hereditary spastic paraparesis (HSP). It causes the long nerves in the spine to degenerate over time.
These spinal nerves control muscle tone and movement in the lower body. Damage to these nerves can result in the gradual impairment of movement, usually in both legs.
Children of parents with HSP have a 50 percent chance of being diagnosed with paraparesis.
Tropical spastic paraparesis (TSP)
Paraparesis caused by a viral infection is called tropical spastic paraparesis (TSP).
Symptoms can begin long after the original infection, sometimes decades after. TSP affects the spinal cord, compromises the immune system, and can cause muscle weakness and loss of skin sensation in both legs.
TSP typically affects people living in tropical regions, including the Caribbean.
HTLV-1, the virus that can lead to TSP, can be transmitted from person to person. It can be passed from a breast-feeding mother to her baby, through shared use of hypodermic needles, and through unprotected sexual intercourse.
Less than 2 percent of people carrying the virus develop TSP.
People with HSP usually have difficulty walking and have an increased risk of falling. This may be due to exaggerated reflexes, along with spasms, cramps, and stiffness.
People with paraparesis tend to walk on the tips of their toes with their feet turned inward. This gait can result in increased wear in shoes, particularly around the big toe.
About 90 percent of people with inherited paraparesis experience leg muscle weakness, as well as involuntary spasms and stiffness.
The remaining 10 percent have a more complex form of paraparesis with additional symptoms. These may include epilepsy, dementia, and hearing loss. They may also experience problems with balance, coordination, and speech.
The age of onset of HSP varies greatly, even in members of the same family. Because the symptoms develop gradually, it can be difficult for people to identify exactly when their symptoms first started. Mild symptoms may be present for years before a person addresses them.
People with TSP may experience no symptoms for years – even decades – after initial infection.
Symptoms usually start with a gradual weakness in the muscles of both legs, followed by urinary and bowel dysfunction, and erectile dysfunction in men.
During advanced stages of TSP, a person’s arms may also be affected, and they may also develop some problems with their skin.
Doctors can usually diagnose paraparesis once the following conditions have been met:
- A person has the gait and mobility symptoms typical of paraparesis.
- There is a history of paraparesis among immediate family members.
- Other treatable disorders with similar symptoms have been ruled out.
Doctors may also undertake some other specialized tests during diagnosis, including:
- magnetic resonance imaging (MRI)
- scans of the brain and spine
- lumbar puncture
- nerve conduction tests
- electromyography (EMG)
Treatable disorders with similar symptoms to Paraparesis include:
- vitamin B12 deficiency
- genetic movement disorder (dopa responsive dystonia)
- structural spinal cord disorders
Doctors may sometimes use genetic testing to confirm a clinical diagnosis of HSP.
Currently, there is no cure for paraparesis. Symptom management is the main aim of treatment. It usually includes physical therapy and medication, such as muscle relaxants.
Physical therapy and exercises may improve mobility by strengthening muscles and increasing endurance. It can also help reduce the severity of spasms and cramps.
In addition to muscle relaxants, some people may take medication to reduce urinary urgency.
Doctors can monitor the progression of paraparesis with regular neurological examinations.
People diagnosed with paraparesis can expect a normal life expectancy. Up to a quarter of people who have HSP experience no symptoms at all.
Paraparesis symptoms among members of the same family can start at different times, sometimes with more than 50 years difference in the age of onset.
Studies suggest that some genetic causes of paraparesis result in a range of symptom severity.
Most people diagnosed with paraparesis walk independently or with very little support. Some individuals with paraparesis may benefit from the use of crutches, cane, or splints. Very few people with paraparesis will require a wheelchair to maintain mobility.