Hypokalemic periodic paralysis
- Westphall disease
Your QuestionI have hypokalemic periodic paralysis and plan on having children soon. Could my condition worsen during pregnancy and/or childbirth? Does this condition affect the development of a fetus? How rare is this condition in African Americans?
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Questions on this page
- What is hypokalemic periodic paralysis?
- What are the symptoms of hypokalemic periodic paralysis?
- What causes hypokalemic periodic paralysis?
- How is hypokalemic periodic paralysis inherited?
- Could my hypokalemic periodic paralysis worsen during pregnancy and/or childbirth?
- Can hypokalemic periodic paralysis affect the development of a fetus?
- Is it appropriate to have my child tested for hypokalemic periodic paralysis?
- How rare is hypokalemic periodic paralysis in African Americans?
Attacks usually begin in adolescence, but they can occur before age 10. How often the attacks occur varies. Some people have attacks every day, while others have them once a year. Episodes of muscle weakness usually last between a few hours and a day.
Attacks can occur without warning or can be triggered by factors such as rest after exercise, a viral illness, or certain medications. Often, a large, carbohydrate-rich meal, alcohol, or vigorous exercise in the evening can trigger an attack upon waking the following morning. Although affected individuals usually regain their muscle strength between attacks, repeated episodes can lead to persistent muscle weakness later in life.
People with hypokalemic periodic paralysis have reduced levels of potassium in their blood (hypokalemia) during episodes of muscle weakness. Researchers are investigating how low potassium levels may be related to the muscle abnormalities in this condition.
Mutations in the CACNA1S or SCN4A gene alter the usual structure and function of calcium or sodium channels. The altered channels cannot properly regulate the flow of ions into muscle cells, which reduces the ability of skeletal muscles to contract. Because muscle contraction is needed for movement, a disruption in normal ion transport leads to episodes of severe muscle weakness or paralysis.
A small percentage of people with the characteristic features of hypokalemic periodic paralysis do not have identified mutations in the CACNA1S or SCN4A gene. In these cases, the cause of the condition is unknown.
As far as delivery goes, vaginal delivery is usually possible with monitoring and epidural analgesia, avoiding active maternal expulsive efforts (passive descent of the fetus and elective outlet forceps) and other stimulating factors (carbohydrate loads (IV glucose), maternal stress, betamimetics, epinephrine). Administration of IV potassium supplementation is often necessary. Concerns include that stress during delivery, labor pain, and expulsive efforts during the second stage of labor might combine to result in a paralytic episode. General anesthesia, postoperative stress, glucose-containing IV solutions, and long-acting neuromuscular blockers are also associated with postoperative paralytic episodes.
To access case studies of pregnancy in women with hypokalemic periodic paralysis, you can visit the following link from the Periodic Paralysis News Desk.
You can find other relevant journal articles on the effects of pregnancy and delivery on hypokalemic periodic paralysis through a service called PubMed, a searchable database of medical literature. Information on finding an article and its title, authors, and publishing details is listed here. Some articles are available as a complete document, while information on other studies is available as a summary abstract. To obtain the full article, contact a medical/university library (or your local library for interlibrary loan), or order it online using the following link. Using "hypokalemic periodic paralysis AND pregnancy" as your search term should locate articles. To narrow your search, click on the “Limits” tab under the search box and specify your criteria for locating more relevant articles. Click here to view a search.
The National Library of Medicine (NLM) Web site has a page for locating libraries in your area that can provide direct access to these journals (print or online). The Web page also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can access this page at the following link http://nnlm.gov/members/. You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.
The medical team at delivery should be prepared to support a newborn who experiences an episode of flaccid paralysis within moments or hours of birth, and infants of affected mothers require close monitoring. Feeding and respiration appear to be the major concerns. Some of infants developed respiratory issues during their first moments or hours.
Requests for prenatal testing for conditions such as hypokalemic periodic paralysis that do not affect intellect and have some treatment available are not common. Although most centers would consider decisions about prenatal testing to be the choice of the parents, discussion of these issues is appropriate.
The appropriate time for testing your child is a decision which chould be made with your doctor or a genetics professional. Genetics professionals are a source of information for individuals and families regarding genetic diagnosis, natural history, treatment, mode of inheritance, and genetic risks to other family members. To find a genetics clinic, we recommend that you contact your primary doctor for a referral. Click here to learn more about genetic consultations.
The following online resources can also help you find a genetics professional in your community:
* GeneTests - A searchable directory of US and international genetics and prenatal diagnosis clinics. Go to the following link and click on 'Clinic Directory' to find a genetic service close to you.
* ResourceLink - A database of genetics counseling services, searchable by location, name, institution, type of practice, or specialty. Hosted by the National Society of Genetic Counselors.
- Hypokalemic periodic paralysis. Genetics Home Reference. April 2007; http://ghr.nlm.nih.gov/condition=hypokalemicperiodicparalysis. Accessed 4/20/2010.
- Sternberg D, Tabti N, Hainque B, Fontaine B. Hypokalemic periodic paralysis. GeneReviews. April 28, 2009; http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=hpp. Accessed 4/20/2010.
- Dugdale DC. Hypokalemic periodic paralysis. MedlinePlus. November 30, 2009; http://www.nlm.nih.gov/medlineplus/ency/article/000312.htm. Accessed 4/20/2010.
- Viscomi CM, Ptacek LJ, Dudley D. Anesth Analg. 1999; http://www.anesthesia-analgesia.org/cgi/content/full/88/5/1081. Accessed 9/16/2009.
- Parant O, Gransjean S, Castagno R, Letourneur B, Desprats R, Larrue V. J Gynecol Obstet Biol Reprod (Paris). 2007; http://www.ncbi.nlm.nih.gov/pubmed/17537590. Accessed 9/16/2009.
- Levitt JO. J Transl Med. 2008; http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18426576. Accessed 9/16/2009.
- Cavel-Greant D. Physician's Information Sheet: Pregnancy, Birth and the Periodic Paralysis Patient. Periodic Paralysis News Desk. 2009; http://www.hkpp.org/physicians/birth_pp-1.html. Accessed 9/16/2009.