Locked-in syndrome
| Locked-in syndrome | |
|---|---|
Locked-in syndrome can be caused by stroke at the level of the basilar artery denying blood to the pons, among other causes.
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| Classification and external resources | |
| Specialty | Neurology |
| ICD-10 | G93.8 |
| ICD-9-CM | 344.81 |
| Patient UK | Locked-in syndrome |
| MeSH | D011782 |
Locked-in syndrome (LIS) is a condition in which a patient is aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles in the body except for the eyes. Total locked-in syndrome is a version of locked-in syndrome wherein the eyes are paralyzed as well.[1] Fred Plum and Jerome Posner coined the term for this disorder in 1966.[2][3] Locked-in syndrome is also known as cerebromedullospinal disconnection,[4] de-efferented state, pseudocoma,[5] and ventral pontine syndrome.
Contents
Presentation
Locked-in syndrome usually results in quadriplegia and the inability to speak in otherwise cognitively intact individuals. Those with locked-in syndrome may be able to communicate with others through coded messages by blinking or moving their eyes, which are often not affected by the paralysis. The symptoms are similar to those of sleep paralysis. Patients who have locked-in syndrome are conscious and aware, with no loss of cognitive function. They can sometimes retain proprioception and sensation throughout their bodies. Some patients may have the ability to move certain facial muscles, and most often some or all of the extraocular eye muscles. Individuals with the syndrome lack coordination between breathing and voice.[6] This restricts them from producing voluntary sounds, though the vocal cords are not paralysed.[6]
Causes
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Unlike persistent vegetative state, in which the upper portions of the brain are damaged and the lower portions are spared, locked-in syndrome is caused by damage to specific portions of the lower brain and brainstem, with no damage to the upper brain.
Possible causes of locked-in syndrome include:
- Snakebite cases - More frequently from a krait bite and other neurotoxic venoms, as they cannot, usually, cross the blood–brain barrier
- Amyotrophic lateral sclerosis (aka Lou Gehrig's disease)
- Brainstem stroke
- Diseases of the circulatory system
- Medication overdose [examples needed], or central pontine myelinolysis secondary to rapid correction of hyponatremia
- Multiple sclerosis
- Damage to nerve cells, particularly destruction of the myelin sheath, caused by disease or central pontine myelinolysis secondary to rapid correction of hyponatremia [>1 mEq/L/h])
- A stroke or brain hemorrhage, usually of the basilar artery
- Traumatic brain injury
Diagnosis
Curare poisoning mimics a total locked-in syndrome by causing paralysis of all voluntarily controlled skeletal muscles.[8] The respiratory muscles are also paralyzed, but the victim can be kept alive by artificial respiration, such as mouth-to-mouth resuscitation. In a study of 29 army volunteers who were paralyzed with curare, artificial respiration managed to keep an oxygen saturation of always above 85%,[9] a level at which there is no evidence of altered state of consciousness.[10] Spontaneous breathing is resumed after the end of the duration of action of curare, which is generally between 30 minutes[11] and eight hours,[12] depending on the variant of the toxin and dosage.
Treatment
Neither a standard treatment nor a cure is available. Stimulation of muscle reflexes with electrodes (NMES) has been known to help patients regain some muscle function. Other courses of treatment are often symptomatic.[13] Assistive computer interface technologies, such as Dasher, or OptiKey, combined with eye tracking, may be used to help patients communicate.
Prognosis
It is extremely rare for any significant motor function to return. The majority of locked-in syndrome patients do not regain motor control, but devices are available to help patients communicate. Within the first four months after its onset, 90% of those with this condition die[citation needed]. However, some people with the condition continue to live much longer,[14][15] while in exceptional cases, like that of Kerry Pink[16] and Kate Allatt,[17] a full spontaneous recovery may be achieved.
Research
New direct brain interface mechanisms may provide future remedies; one effort in 2002 allowed a fully locked-in patient to answer yes-or-no questions.[18][19][20] Some scientists have reported that they have developed a technique that allows locked-in patients to communicate via sniffing.[21]
See also
- Akinetic mutism
- Brain death
- Martin Pistorius, author who wrote autobiographical Ghost Boy
- The Diving Bell and the Butterfly, the book
- The Diving Bell and the Butterfly, the film based on the book
- Lock In, a near-future science fiction novel by John Scalzi
References
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- ↑ Page 520 in: Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Oxymoron: Our Love-Hate Relationship with Oxygen, By Mike McEvoy at Albany Medical College, New York. 10/12/2010
- ↑ For therapeutic dose of tubocurarine by shorter limit as given at page 151 in: Lua error in package.lua at line 80: module 'strict' not found.
- ↑ For 20-fold paralytic dose of toxiferine ("calebas curare"), according to: Page 330 in: Lua error in package.lua at line 80: module 'strict' not found.
- ↑ lockedinsyndrome at NINDS
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Piotr Kniecicki "An art of graceful dying". Clitheroe: Łukasz Świderski, 2014, s. 73. ISBN 978-0-9928486-0-6
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Parker, I., "Reading Minds," The New Yorker, January 20, 2003, 52–63
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Further reading
- Piotr Kniecicki (2014). An Art of Graceful Dying. Lukasz Swiderski ISBN 978-0-9928486-0-6 (Autobiography, written while residual wrist movements and specially adapted computer.)
External links
- The Unlock Project
- Locked-in Syndrome Association's guide to communicating without language (French)[dead link]
- Rachel's Communication boards – for when you need to communicate with someone with LIS.
- OptiKey [1].
