Persistent vegetative state

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Name of Symptom/Sign:
Persistent vegetative state
Classifications and external resources
ICD-10
ICD-9 780.03

A persistent vegetative state (PVS) is a condition of patients with severe brain damage in whom coma has progressed to a state of wakefulness without detectable awareness.


Contents

[edit] History

The syndrome was first described 1940 by Ernst Kretschmer after whom it also has been called Kretschmer Syndrome.[1]

The term was coined in 1972 by Scottish spinalsurgeon Bryan Jennett and American neurologist Fred Plum to describe a syndrome that seemed to have been made possible by medicine's increased capacities to keep patients' bodies alive.[2]

[edit] Signs and symptoms

Patients in a persistent vegetative state are usually considered to be unconscious and unaware. They are unresponsive to external stimuli, except, possibly, pain stimuli. Unlike coma, in which the patient's eyes are closed, patients in a vegetative state often open their eyes. Their eyes might be in a relatively fixed position, or track moving objects, or move in a disconjugate (i.e. completely unsynchronised) manner. They may experience sleep-wake cycles, or be in a state of chronic wakefulness. They may exhibit some behaviors that can be construed as arising from partial consciousness, such as grinding their teeth, swallowing, smiling, shedding tears, grunting, moaning, or screaming without any apparent external stimulus.

[edit] Diagnosis

Many patients emerge from a vegetative state within a few weeks, but those who do not recover within 30 days are said to be in a persistent vegetative state. The chances of recovery depend on the extent of injury to the brain and the patient's age, with younger patients having a better chance of recovery than older patients. Generally adults have a 50 percent chance and children a 60 percent chance of recovering consciousness from a PVS within the first 6 months. After a year, the chances that a PVS patient will regain consciousness are very low and most patients who do recover consciousness experience significant disability. The longer a patient is in a PVS, the more severe the resulting disabilities are likely to be. Rehabilitation can contribute to recovery, but many patients never progress to the point of being able to take care of themselves.

[edit] Controversy, recoveries, possible contributing factors

In the United States, it is estimated that there may be between 15,000-40,000 patients who are in a persistent vegetative state, but due to poor nursing home records exact figures are hard to determine.[3]

Recovery after long periods of time in a PVS state have been reported on several occasions and are often treated as spectacular events. In fact on March 7, 2007, a woman named Christa Lilly awakened from a vegetative state after 6 years of being in a coma that involved her eyes being open most of the time, tracking moving objects. She spoke to family and a local news group saying she was fine. The hardest part she said was learning how to speak again. Sadly she slipped into the vegetative state after 3 days. Some authorities insist that PVS is an irreversible condition and therefore conclude that these recoveries involve cases in which there was not truly PVS. Some cases of PVS may actually be cases of patients being in an undiagnosed minimally conscious state.

Misdiagnosis of PVS is not uncommon. One study of 40 patients in the United Kingdom reported that 43% of those patients classed as in a PVS were misdiagnosed and another 33% able to recover whilst the study was underway.[4]

Controversy over the true meaning of PVS, for patients, families, and medical ethics, has been raised by a recent experiment using magnetic resonance imaging which revealed that a woman diagnosed with PVS was able to activate predictable portions of her brain in response to the tester's requests that she imagine herself playing tennis or moving from room to room in her house. The brain activity in response to these instructions was indistinguishable from those of healthy patients.[5]

Additional controversy has been caused by the discovery that in many nursing homes and hospitals unheated oxygen is given to non-responsive patients via tracheal intubation. This bypasses the warming of the upper respiratory tract and causes a chilling of aortic blood and chilling of the brain. In a small number of cases, removal of the chilled oxygen has been followed by recovery from the PVS state. Additional research has been recommended to determine if this chilling effect may either delay recovery or even may contribute to brain damage.[6]

[edit] Possible treatment

Recently, the hypnotic drug zolpidem has been cited in various medical reports mainly in the United Kingdom as waking PVS patients, and dramatically improving the conditions of people with brain injuries. More information is available on the BBC world news site under zolpidem[1], and The Guardian[2].

[edit] Medical definition

Terminology in this area is somewhat confused. While the term 'persistent vegetative state' is the most frequent in media usage and legal provisions, it is discouraged by neurologists, who favour the use of the Royal College of Physicians (RCP)(1996) typology which refers only to the vegetative state, the continuing vegetative state, and the permanent vegetative state. This typology distinguishes various stages of the condition rather than using one term for them all. In his most recent book The Vegetative State, Jennett himself adopts this usage, on the grounds that "the 'persistent' component of this term...may seem to suggest irreversibility". The Australian National Health and Medical Research Council has suggested "post coma unresponsiveness" as an alternative term.

[edit] Legal definition

As opposed to brain death, PVS is not recognized as death in any known legal system. This legal grey area has led to several court cases involving people in a PVS, those who believe that they should be allowed to die, and those who are equally determined that, if recovery is possible, care should continue. Well-known cases include Paul Brophy, Sunny von Bülow and Tony Bland, whose case created a precedent in the UK. The highly publicised case of Terri Schiavo in the United States involved disputes over a diagnosis of PVS given by several court-appointed doctors. Ultimately the court challenges were unsuccessful and Schiavo's feeding tube was removed, leading to her subsequent death.

[edit] See also

[edit] Notable PVS patients

[edit] Notes and references

  1. ^ Das apallische Syndrom, in .Neurol.Psychiat, 169,576-579 (1940).
  2. ^ "The Vegetative State: Medical facts, ethical and legal dilemmas" (9 page PDF file) Bryan Jennett, University of Glasgow, Scotland.
  3. ^ Hirsch, Joy. (May 2, 2005). "Raising consciousness". The Journal of Clinical Investigation. American Society for Clinical Investigation. 115(5): 1102.
  4. ^ BMJ 1996;313:13-16 (6 July) Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit.
  5. ^ Owen AM, Coleman MR, Boly M, Davis MH, Laureys S, Pickard JD. Detecting awareness in the vegetative state. Science. 2006 Sep 8;313(5792):1402.
  6. ^ Ford GP, Reardon DC. Prolonged unintended brain cooling may inhibit recovery from brain injuries: case study and literature review. Med Sci Monit. 2006 Aug;12(8):CS74-9. Epub 2006 Jul 12.
  • Jennett, B. The vegetative state: Medical facts, ethical and legal dilemmas, New York, CUP, 2002
  • Jennett B, Plum F. (1972). Persistent vegetative state after brain damage. A syndrome in search of a name. Lancet 1 (7753), 734–737. PMID 4111204.
  • Multi-Society Task Force on PVS (1994). Medical aspects of the persistent vegetative state. N Engl J Med (330), 1499–508. PMID 7818633, PMID 8177248.
  • National Health and Medical Research Council, Post-coma unresponsiveness (Vegetative State): a clinical framework for diagnosis, NHMRC, Canberra, 2003 [3]
  • Royal College of Physicians, Guidance on diagnosis and management: Report of a working party of the Royal College of Physicians, London, Royal College of Physicians, 1996
  • Borthwick C (1996) The permanent vegetative state: ethical crux, medical fiction? Issues Law Med. 1996 Fall;12(2):167-85. The author questions the validity of most PVS diagnoses, and the validity of the basic nosology. The fulltext is available on the author's website.
  • Andrews K, Murphy L, Munday R, Littlewood C. (1996). Misdiagnosis of the vegetative state: retrospective study in a rehabilitation unit. BMJ (313), 13–16. PMID 8664760.
  • Ford GP, Reardon DC. "Prolonged unintended brain cooling may inhibit recovery from brain injuries: case study and literature review." Med Sci Monit. 2006 Aug;12(8):CS74-9. Epub 2006 Jul 12. http://www.medscimonit.com/pub/vol_12/no_8/8795.pdf

This article contains text from the NINDS public domain pages on TBI at http://www.ninds.nih.gov/health_and_medical/disorders/tbi_doc.htm and http://www.ninds.nih.gov/health_and_medical/pubs/tbi.htm

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