Hemiplegia (One-Sided Paralysis)

What hemiplegia means

Hemi means half and plegia means paralysis. Hemiplegia means complete or near-complete loss of movement on one side. Hemiparesis means weakness on one side, with some movement left. Doctors often use the words loosely, and many people with "hemiplegia" actually have hemiparesis.

The movement-control areas of each half of the brain control the opposite side of the body, because the nerve pathways cross over in the brainstem. So damage to the left side of the brain causes right hemiplegia, and vice versa. A right-handed person with right hemiplegia often also has aphasia (language difficulty), because language is usually controlled by the left hemisphere. Left hemiplegia is more often linked to neglect of the left side of space and problems with judgment and spatial awareness.

Causes of hemiplegia

In adults

• Stroke: by far the most common cause. A blocked artery (ischemic stroke) or a bleed into the brain (hemorrhagic stroke) damages the motor pathways. Onset is sudden.
• Traumatic brain injury: bruising or bleeding in the brain after a blow to the head. A subdural hematoma can cause weakness that develops over days to weeks, especially in older adults on blood thinners.
• Brain tumors: weakness develops slowly, often with headaches, seizures or personality change.
• Infections: brain abscess and encephalitis.
• Multiple sclerosis: inflammation in the brain or spinal cord can cause one-sided weakness during a relapse.
• Todd's paralysis: temporary one-sided weakness after a seizure, lasting hours up to about 2 days.
• Hemiplegic migraine: a rare migraine type with temporary one-sided weakness. It must be distinguished from a stroke every time.

In children

• Cerebral palsy: hemiplegic cerebral palsy results from brain injury before, during or soon after birth, often a stroke in the womb or newborn period. Parents usually notice early hand preference before 12 months, or a child who crawls or walks unevenly.
• Childhood stroke, including in sickle cell disease and heart conditions.
• Head injury, infection and tumors.
• Alternating hemiplegia of childhood: a rare genetic condition with attacks of paralysis that switch sides.

Symptoms of hemiplegia

The main symptom is weakness or paralysis of the arm, leg and lower face on one side. Other common features:

• Spasticity: stiff, tight muscles that resist movement, developing over weeks after a brain injury. The arm tends to bend at the elbow and wrist, and the leg straightens. See spasticity.
• Changed walking: the leg swings outward in a semicircle (circumduction), and the foot may drag because of foot drop.
• Brisk reflexes and a positive Babinski sign (the big toe goes up when the sole is stroked).
• Loss of sensation on the affected side.
• Balance problems and a higher risk of falls.
• Facial droop and difficulty with speech or swallowing.
• Shoulder pain, as the weak shoulder partly slips out of its socket.
• Fatigue, depression and anxiety, which are very common after a stroke.
• Problems with vision, attention, memory or bladder control, depending on the area of brain affected.

How hemiplegia is diagnosed

Sudden hemiplegia is treated as a stroke until proven otherwise. In the emergency department, the team examines strength, reflexes, speech and vision and does an urgent CT scan of the brain to look for bleeding. CT or MR angiography looks for a blocked artery. MRI shows smaller strokes, tumors, MS plaques and infection.

Other tests may include blood tests (glucose, clotting, infection), an ECG and heart monitoring for atrial fibrillation, an echocardiogram, carotid artery imaging, an EEG if seizures are suspected, and a lumbar puncture if infection or inflammation is suspected.

Hemiplegia in medical coding

In ICD-10-CM, hemiplegia has its own codes. "Hemiplegia, unspecified, affecting unspecified side" (G81.90) is used when the cause and side are not recorded. Hemiplegia caused by a previous stroke is coded separately as a late effect of stroke (in the I69 group). The side affected and whether it is the dominant side are recorded for accurate coding.

Treatment and rehabilitation

Emergency treatment

For an ischemic stroke, clot-busting medicine (thrombolysis) given within 4.5 hours of onset, and removal of the clot with a catheter (thrombectomy) for large artery blockages up to 24 hours in selected patients, can reverse or reduce paralysis. Time matters: every minute of delay loses brain cells. Bleeds, tumors, abscesses and subdural hematomas may need surgery.

Rehabilitation

Most recovery happens in the first 3 to 6 months, but improvement can continue for years with practice. A rehabilitation team may include:

• Physical therapy: strength, balance and walking training, including treadmill and task-specific practice.
• Occupational therapy: relearning daily tasks such as dressing and cooking, and adapting the home. Constraint-induced movement therapy restrains the stronger arm to force use of the weaker one, and has good evidence in selected people.
• Speech and language therapy: for aphasia, slurred speech and swallowing problems.
• Orthotics: an ankle-foot orthosis (AFO) for foot drop, and arm slings or supports for the shoulder.

Managing spasticity

Daily stretching, splints, oral medicines that relax muscles, botulinum toxin injections into specific muscles, and, in severe cases, intrathecal baclofen pumps or surgery.

Preventing another stroke

Blood pressure control, antiplatelet or anticoagulant medicine, statins, diabetes control, stopping smoking and regular activity all reduce the risk of a second stroke.

Hemiplegia and disability

Hemiplegia is a recognized disability. Its impact varies from mild clumsiness to needing help with all daily activities. Many people qualify for disability benefits, workplace accommodations, adapted driving assessments, mobility aids and home modifications. Children with hemiplegic cerebral palsy are entitled to early intervention and school support. Ask your rehabilitation team or a social worker about assessments and local services.

Complications

• Falls and fractures
• Shoulder pain and frozen shoulder
• Muscle shortening (contractures)
• Blood clots in the legs while mobility is low
• Pressure sores
• Depression and social isolation
• Pneumonia from swallowing difficulties

Outlook

Recovery depends on the cause, the size and location of the damage, age and how soon rehabilitation starts. Weakness from Todd's paralysis or a hemiplegic migraine resolves completely. After a stroke, some people recover nearly full movement within weeks, while others have lasting weakness. Early movement in the hand and the ability to shrug the shoulder in the first days are good signs for arm recovery.

Frequently asked questions

What is hemiplegia?

Hemiplegia is paralysis of one side of the body, usually the arm, leg and lower face on the same side. It is caused by damage to the brain or spinal cord, most often a stroke in adults and cerebral palsy in children. Partial weakness on one side is called hemiparesis.

Is hemiplegia a neurological issue?

Yes. Hemiplegia is a neurological condition because it comes from damage to the nervous system, almost always the brain, and not from a problem in the muscles themselves. Damage on one side of the brain causes paralysis on the opposite side of the body.

What is the difference between hemiplegia and hemiparesis?

Hemiplegia means paralysis of one side of the body, with little or no movement. Hemiparesis means weakness of one side, where some movement remains. Hemiparesis is more common, and many people with hemiplegia improve to hemiparesis as they recover.

Can hemiplegia be cured?

It depends on the cause. Temporary hemiplegia after a seizure or migraine resolves fully. After a stroke or brain injury, damaged brain cells do not regrow, but other areas can take over, and rehabilitation can restore a lot of movement. Most gains come in the first 6 months.

Is hemiplegia a disability?

Yes. Hemiplegia is recognized as a disability when it limits daily activities, work or mobility. The level of disability varies widely. People may qualify for disability benefits, workplace accommodations, mobility aids, therapy services and, for children, special education support.