What are the other Names for this Condition? (Also known as/Synonyms)

• AHC (Alternating Hemiplegia of Childhood)
• Hemiplegia Alterans

What is Alternating Hemiplegia of Childhood? (Definition/Background Information)

• Alternating Hemiplegia of Childhood (AHC) is a rare, neurological disorder characterized by recurring episodes of hemiplegia (paralysis) on either side of the body. The temporary paralysis, which a boy or girl experiences, can last for a few hours or for several days, attacking many different parts of the body
• The risk factors for Alternating Hemiplegia of Childhood are not well-established. However, recent researches indicate that children with a family history of the condition may be vulnerable to AHC. This implies that genetics might be a risk factor for the disorder
• The exact cause of the disorder is still being researched. Recent studies, however, indicate that some cases are caused by inherited genetic mutations in multiple genes
• Apart from paralysis, other common symptoms of the disorder include sporadic eye movements, movement disorders, and progressive cognitive problems. The continuing of symptoms that could last from several hours to days is a potential complication of AHC, causing health issues in the child
• A healthcare professional would assess symptoms and request results from a series of tests, such as metabolic screening, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) scans, and an electro-encephalogram (EEG) to diagnose Alternating Hemiplegia of Childhood
• The treatment for Alternating Hemiplegia of Childhood involves avoiding triggers in the short-term by monitoring the child, as well as drugs for long-term management of the disorder
• At this time, no effective preventive methods against this disease are known, since the cause of the disease is not clearly understood
• Alternating Hemiplegia of Childhood is a progressive disease, potentially affecting various body parts and organs. Therefore, the prognosis is generally not considered good for this condition. However, the severity of the symptoms can be reduced through medication

Who gets Alternating Hemiplegia of Childhood? (Age and Sex Distribution)

• Alternating Hemiplegia of Childhood is a very rare disorder, with an incidence of about 1 in 1 million children
• Both boys and girls can get the disorder, with the symptoms beginning in infancy
• All racial and ethnic groups may be affected

What are the Risk Factors for Alternating Hemiplegia of Childhood? (Predisposing Factors)

• The risk factors for a child developing Alternating Hemiplegia of Childhood are not clear and currently, ongoing research is underway to understand the condition better
• Most children with the condition do not have a family history of AHC. Recent studies, however, indicate that AHC in some children is caused by inherited genetic mutations in multiple genes. Thus, at least in some cases, having a family history of the condition could be a risk factor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Alternating Hemiplegia of Childhood? (Etiology)

• With little knowledge about the etiology of Alternating Hemiplegia of Childhood, the cause of the disorder remains relatively unknown
• Recent research suggests that mutations in the CACNA1A, SCN1A, and ATP1A2 genes may contribute to AHC development

What are the Signs and Symptoms of Alternating Hemiplegia of Childhood?

Common signs and symptoms of Alternating Hemiplegia of Childhood include:

• Hemiplegic attacks: The frequency and severity of attacks vary from one child to another. In many cases, the attacks are triggered by environmental factors such as, extreme temperatures, light, smells, etc.
• Hemiplegic attack alternating with weakness
• Progressive neurological degeneration
• Abnormal ocular movements
• Abnormal movements

How is Alternating Hemiplegia of Childhood Diagnosed?

To diagnose Alternating Hemiplegia of Childhood, a healthcare provider evaluates all of the physical symptoms the patient is exhibiting. After evaluation, further tests are conducted, including:

• Magnetic resonance imaging (MRI) scans to obtain images of the brain and the affected internal organs
• Magnetic resonance angiography (MRA) to help procure images of the blood vessels inside the body
• Electro-encephalogram (EEG) to check electrical activity in the brain
• Metabolic screening is generally performed in a newborn baby to check for the presence of metabolic disorders

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Alternating Hemiplegia of Childhood?

• The hemiplegic attacks that individuals with Alternating Hemiplegia of Childhood experience can last a few hours or many days and may become harmful to their overall health
• If the episodes of hemiplegia are frequent, they could interfere with the normal day-to-day activities of a child and hamper his/her learning process, as well as social interactions

How is Alternating Hemiplegia of Childhood Treated?

Treatment of Alternating Hemiplegia of Childhood is divided into two parts - acute management of hemiplegic attacks and episode prophylaxis. 

• Acute management of attacks involves avoiding any triggers that may lead to an attack. Regular sleep is also recommended, for it has been observed that hemiplegic attacks generally do not occur when the patient is sleeping
• Episode prophylaxis involves avoiding all triggers of an attack. This part of the treatment also involves regular, long-term drug treatment. Calcium channel blockers have also been found to be effective. Other potential treatment measures include:
  • Beta blockers
  • Anticonvulsants 

How can Alternating Hemiplegia of Childhood be Prevented?

Since little is known about the cause of Alternating Hemiplegia of Childhood, no prevention methods currently exist for the condition.

What is the Prognosis of Alternating Hemiplegia of Childhood? (Outcomes/Resolutions)

• The outcome of individuals with Alternating Hemiplegia of Childhood is generally poor, due to the progressive deterioration of multiple parts of the body and organ systems
• Adequate treatment has been shown to reduce the frequency and severity of hemiplegic attacks

Additional and Relevant Useful Information for Alternating Hemiplegia of Childhood:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/