What is Alternating Hemiplegia?

Alternating hemiplegia is an uncommon condition that impairs nervous system functioning. It usually develops before the age of two and can cause problems throughout a person's lifetime. The disorder is characterized by frequent episodes of partial paralysis that usually affect one side of the body at a time. Symptoms can range from mild, temporary numbness in an extremity or the face to complete loss of muscle coordination and control. There is currently no known cure for alternating hemiplegia, but medications, physical therapy, and home management strategies are available that can help to improve a child's symptoms and quality of life.

The causes of alternating hemiplegia are not well understood. The majority of cases do not appear to have a genetic basis, though there are some reported cases of the condition running in families. Several risks factors for symptomatic episodes have been identified in children who are known to have the condition. Infections, physical trauma, and periods of extreme anxiety increase the chances of experiencing an episode. Environmental factors such as temperature changes, bright lights, and loud, sudden sounds also can set off an attack in a susceptible infant or child.

Most children with alternating hemiplegia have relatively mild symptoms. During an episode, one side of the body becomes weak and numb. It may be difficult or impossible to walk, raise an arm, speak clearly, or focus vision. An attack can last for a few seconds or persist for several hours. In most cases, children regain the ability to coordinate movement after a period of sleep. Alternating hemiplegia can, as the name suggests, affect the opposite side of the body in a subsequent episode.

Serious cases of alternating hemiplegia can be debilitating. It is possible for full paralysis of one or both sides of the body to develop spontaneously and last for days. Muscles in the limbs may become limp, very stiff, or prone to involuntary spasms. Some children with the condition also experience seizures and significant mental impairment. If developmental delays occur in early childhood, patients may have major obstacles with learning and independent living later in life.

There are no specific diagnostic tests that can confirm alternating hemiplegia, and a diagnosis is usually made based on a thorough evaluation of a patient's symptoms and medical history. Brain scans and blood tests are usually performed to look for other potential causes of neurological problems. After making a confident diagnosis, a doctor can explain different treatment and management strategies.

Medications such as flunarizine and antiepileptic drugs may be prescribed in hopes of reducing the severity and frequency of hemiplegia attacks. Many patients are also given sleep aids to help them quickly enter sleeping states should major episodes occur. Parents and caregivers are encouraged to learn about triggers and help their children avoid attacks whenever possible. Special arrangements may be made with schools and therapy clinics to ensure that children receive the help they need to become as independent as possible by the time they reach adulthood.