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Disease Profile

Transient global amnesia

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Summary

Transient global amnesia (TGA) is a condition characterized by sudden onset of memory loss and confusion. During an episode of TGA, a person is not able to make new memories. The person may be disoriented in regard to time and place, but can remember who they are and can recognize family members. TGA typically lasts for several hours, but can last up to ten hours. Since no memories are made during a TGA episode, the person will never remember what happened during this period, but all other memory is usually intact. Most people have only one episode of TGA during their lifetime. The underlying cause of TGA is unclear. There is no specific treatment for TGA as it usually resolves on its own.[1][2][3]

Symptoms

The signs and symptoms of tansient global amnesia (TGA) have been clearly defined by the medical community:[1][3][4]

  • The main sign of TGA is being temporarily unable to form new memories. This is called prominent anterograde amnesia. During the episode of TGA, the person will seem disoriented in time and often ask questions about the date or their environment over and over again. This may be described as the person sounding like a "broken record." 
  • During the TGA episode, the person may forget memories from the recent past (retrograde amnesia). The period of memory loss varies and may extend back hours to days or weeks, but only in rare instances, years.
  • Other cognitive functions (ability to think) are not affected. In other words, even during the TGA episode, the person will know who they are and will be able to recognize and name familiar objects and people. The person is able to perform normal complex daily tasks such as driving or cooking.
  • No other neurological problems are noticed during an exam. For example, reflexes, balance and coordination are normal.
  • The TGA episode lasts between 1 and 10 hours (6 hours is the average). When the episode is over, the person will be able to make new memories again, but there will be no memories from the time during the episode. 
  • Within 24 hours of the end of the TGA episode, any memories from the past lost during the episode will completely return. This does not include the time during the episode when no new memories could be made. In rare cases, some people may not remember an additional short period of time just before the TGA episode. 
  • Other less common symptoms include headache, nausea, dizziness, anxiety, and feelings of tingling and numbness in hands, feet, arms or legs.

Cause

There is currently no consensus on an underlying cause of transient global amnesia (TGA). Possible mechanisms that have been proposed include:[2][4]

  • A vascular etiology, such as venous flow abnormalities
  • Hypoxia (deficiency of oxygen supply) and/or ischemia (deficiency of blood supply)
  • A relation to migraine (some studies have shown that history of migraine is associated with TGA)
  • Epilepsy
  • Psychological factors

However, none of these theories clearly and consistently explain the features of TGA.[4] Because no one theory appears to apply to all people with TGA, some speculate that TGA may have multiple different causes.[4]

Events that reportedly may trigger an episode of TGA include:[2][5]

  • Sudden immersion in cold or hot water
  • Physical exertion
  • Emotional distress or psychological stress
  • Pain
  • Medical procedures
  • Head trauma
  • Sexual intercourse
  • A Valsalva maneuver

There is a distinct form of TGA that may occur following excessive alcohol consumption, large sedative doses of barbiturates, the use of several illicit drugs, or sometimes, relatively small doses of benzodiazepines.[2]

    Treatment

    There is no specific treatment for transient global amnesia (TGA). Fortunately, this condition resolves on its own, typically within hours of onset.[1] Most people with TGA do not experience repeat episodes.[1][5]

    People with repeat episodes of TGA should document the circumstances triggering the event. For some, it may be possible to prevent TGA by avoiding triggers. However, for many this is not possible. Possible triggers of TGA include:[5][7]

    • Sudden immersion in cold or hot water
    • Strenuous physical activity
    • Sexual intercourse
    • Medical procedures, such as angiography or endoscopy
    • Mild head trauma
    • Acute emotional distress (e.g., from bad news, conflict or being overworked)
    • Exposure to high altitudes

    Much of what we know about treatment of recurrent TGA comes from single case reports. These reports emphasize the need to rule out all other possible causes of recurrent TGA type episodes, such as transient epileptic amnesia, vascular disease, heart conditions, and adverse drug events, as this will affect treatment.[8][9][10][11]

    The cause of transient global amnesia is not known, but migraines seem to be associated in many cases. We found a single report of metoprolol use for treatment of recurrent TGA in a man with a history of migraine.[7]

    Organizations

    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Social Networking Websites

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • The Mayo Clinic Web site provides further information on Transient global amnesia.
    • The Merck Manual provides information on this condition for patients and caregivers.

    In-Depth Information

    • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
    • The Merck Manual for health care professionals provides information on Transient global amnesia.
    • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
    • PubMed is a searchable database of medical literature and lists journal articles that discuss Transient global amnesia. Click on the link to view a sample search on this topic.

    References

    1. Roy Sucholeiki. Transient Global Amnesia. Medscape Reference. April 22 2016; https://emedicine.medscape.com/article/1160964-overview.
    2. Juebin Huang. Transient Global Amnesia. Merck Manual. September, 2015; https://www.merckmanuals.com/professional/neurologic-disorders/function-and-dysfunction-of-the-cerebral-lobes/transient-global-amnesia.
    3. Williamson J and Larner AJ. Transient global amnesia. Br J Hosp Med (Lond). December 2015; 76(12):C186-8. https://www.ncbi.nlm.nih.gov/pubmed/26646345.
    4. Sarah Kremen. Transient Global Amnesia. UpToDate. Waltham, MA: UpToDate; November, 2016;
    5. Transient global amnesia. MayoClinic. July 18, 2014; https://www.mayoclinic.org/diseases-conditions/transient-global-amnesia/basics/causes/con-20032746.
    6. R. Rhys Davies and A.J. Larner. Familial Transient Global Amnesia. Case Rep Neurol. September-December, 2012; 4(3):236-239.
    7. Berlit P. Successful prophylaxis of recurrent transient global amnesia with metoprolol. Neurology. 2000 Dec 26; 55(12):1937-8. https://www.ncbi.nlm.nih.gov/pubmed11134409.
    8. Tsai MY1, Tsai MH, Yang SC, Tseng YL, Chuang YC. Transient global amnesia-like episode due to mistaken intake of zolpidem: drug safety concern in the elderly. J Patient Saf. 2009 Mar; 5(1):32-4. https://www.ncbi.nlm.nih.gov/pubmed19920437.
    9. Grande LA, Loeser JD, Samii A. Recurrent transient global amnesia with intrathecal baclofen. Anesth Analg. 2008 Apr; 106(4):1284-7, table of contents. https://www.ncbi.nlm.nih.gov/pubmed18349207.
    10. Vyhnálek M1, Bojar M, Jerabek J, Hort J. Long lasting recurrent familiar transient global amnesia after betablocker treatment withdrawal: case report. Neuro Endocrinol Lett. 2008 Feb; 29(1):44-6. https://www.ncbi.nlm.nih.gov/pubmed18283253.
    11. Taylor RA1, Wu GF, Hurst RW, Kasner SE, Cucchiara BL. Transient global amnesia heralding basilar artery thrombosis. Clin Neurol Neurosurg. 2005 Dec; 108(1):60-2. https://www.ncbi.nlm.nih.gov/pubmed.
    12. Arena JE and Rabinstein AA. Transient global amnesia. Mayo Clin Proc. February, 2015; 90(2):264-272. https://www.ncbi.nlm.nih.gov/pubmed/25659242.

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