paralyze

Paralyze (verb) refers to causing a person or body part to lose the ability to move. Paralysis (noun) is the loss of voluntary muscle function in a region of the body, typically due to nerve damage or brain injury. The term derives from Greek para- “beside” and lysis “loosening.”

Paralysis can be partial (paresis) or complete, and it can be localized to a single limb or spread to larger regions. Localized forms include monoplegia (one limb), hemiplegia (one side of the body), paraplegia (both legs), and quadriplegia (all four limbs). Distinctions also exist between spastic paralysis, with increased muscle tone and stiff movements, and flaccid paralysis, with decreased tone and floppy limbs.

Paralysis results from disruption of brain, spinal cord, or peripheral nerves. Common causes include stroke or spinal cord injury (central causes that may produce spastic or flaccid paralysis), Guillain-Barré syndrome and poliomyelitis (nerve or nerve-root involvement), multiple sclerosis, Bell’s palsy, tumors, toxins such as botulinum toxin, and various metabolic or infectious conditions.

Diagnosis relies on neurological examination, imaging such as MRI or CT, and electrophysiology including EMG and nerve conduction studies, along with laboratory tests to identify underlying causes. Clinicians distinguish the extent and pattern of motor loss to guide management.

Treatment targets the underlying cause and may include emergency care for acute injury or toxin exposure, physical and occupational therapy, and assistive devices. Medications to reduce spasticity (for example, baclofen or tizanidine) or to address inflammation or seizures may be used. Some cases may benefit from surgery, nerve repair strategies, or intrathecal medication delivery.

Prognosis varies widely; some conditions, such as Bell’s palsy, may recover, while others, including extensive spinal injuries, can be permanent. Ongoing research focuses on neurorehabilitation, nerve repair, and assistive technologies.