Hemiplegia is the complete paralysis of one side of the body. It involves the arm, the leg, and sometimes the face of the affected side. A related term, hemiparesis, refers to a partial loss of motor function, and is far more common.

The main causes of hemiplegia are brain hemorrhage (hemorrhagic stroke) and diseases of the blood vessels of the cerebrum and brain stem that cause interruption of blood supply to the brain (ischemic stroke). Trauma (brain injury) is another cause of hemiplegia. Other important causes that are less acute in onset include brain tumor or lesion, brain abscess, diseases that destroy the sheath surrounding nerve cells (e.g., multiple sclerosis), blood vessel (vascular) complications of viral or bacterial infection (meningitis), and inflammation of the brain (encephalitis). When a brain lesion causes hemiplegia, the lesion is most likely on the side of the brain opposite to the paralysis. In rare cases it results from infectious disease caused by the poliovirus (poliomyelitis) or a disorder of motor nerve cells (neurons) in the spinal cord, brainstem, and motor cortex (motor system disease).

Hemiplegia Symptoms
Here are a few symptoms of hemiplegia you should watch out for if you suspect that your child has the disorder:
-- Inability to sit up, stand or crawl even when a child is scheduled to reach these developmental milestones.
-- Poor motor skills; the child may not be able to hold an object or manipulate it. This lack of dexterity is usually due to some form of trauma in the part of the brain which controls movement.
-- Lack of coordination and balance; the child may fall over or find it hard to walk around without tripping over themselves every so often.
-- Low IQ; children with hemiplegia usually have a diminished IQ of about 70. This makes it hard for them to understand concepts and they may find it hard to keep up with schoolwork.
-- Stiff or weak muscle tone; this is the most defining characteristic of hemiplegia.