Korsakoff's syndrome
From Psy3241
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Revision as of 15:17, 14 April 2008
Contents |
Definition
• Korsakoff's syndrome is a memory disorder caused by a deficiency of vitamin B1, also called thiamine
• Named after Sergei Korsakoff the neuropsychiatrist who popularized the theory
History
• First mentioned in 1822 by James Jackson, a physician at Massachusetts General Hospital and professor at Boston Medical School, in a review of the peripheral neuritis of alcoholism
• 1868 Sir Samuel Wilks, a physician at Guy’s Hospital, London, gave an account of the characteristic mental symptoms in an article on alcoholic paraplegia
• In his doctoral thesis, Korsakoff called the condition “cerebropathia psychica toxaemica”
• The term Korsakoff’s psychosis was introduced by Friedrich Jolly
• Korsakoff emphasized the association of alcoholic polyneuropathy with a specific pattern of mental disturbances by stating: “This mental disorder appears at times in the form of sharply delineated irritable weakness of the mental sphere, at times in the form of confusion with characteristic mistakes in orientation for place, time and situation, and at times as an almost pure form of acute amnesia, where the recent memory is most severely involved, while the remote memory is well preserved . . . Some have suffered so widespread memory loss that they literally forget everything immediately."
• Korsakoff’s psychosis was used originally to describe the combination of alcoholic polyneuropathy and characteristic mental disturbance and Korsakoff’s syndrome was the non-alcoholic form with or without polyneuritis, which resulted from acquired conditions such as head injury, brain tumors, and encephalitis
• Blass and Gibson in 1977 identified a genetically determined disturbance of transketolase, which is a thiamine pyrophosphate-binding factor in fibroblasts
• Individuals who are homozygous for this defect are at an increased risk for developing thiamine deficiency in circumstances of dietary inadequacy
Description
• The most common cause of thiamine deficiency is alcoholism in the U.S.
• Thiamine deficiency can also be seen in patients undergoing dialysis, pregnant women with the condition called hyperemesis gravidarum, and patients after surgery who are given vitamin-free fluids for a prolonged period of time
• Thiamine deficiency is a cause of disability in developing countries where the main source of food is rice lacking the nutritious outer husk
• Wenicke’s syndrome often precedes Korsakoff’s syndrome
• Commonly referred to as Wenicke-Korsakoff’s syndrome
Causes and Symptoms
• The high calorie nature of alcohol is one of the main reasons that alcoholism leads to thiamine deficiency
• A large intake of alcohol substitutes alcohol for other calorie sources that contain more nutrition
• Food intake drops and multiple vitamin deficiencies develop as alcoholism grows
• It is believed that alcohol increases the body’s requirement for B vitamins, while also interfering with the absorption of vitamin B1 from the intestine and impairing the body’s ability to store and use B1.
• Thiamine provides energy to the neurons of the brain in a variety of reactions
• As thiamine becomes unavailable, these reactions cannot be carried out
• Because the end products of these reactions cannot be formed, substrates begin to accumulate and cause damage to the neurons
• The mamillary bodies and the thalamus of the diencephalon is responsible for the symptoms of this syndrome
• Those with Korsakoff’s syndrome have difficulty with their memory
• Anterograde amnesia- the ability to learn new information is greatly affected, while intelligence and memory of past events is relatively unaffected
• Confabulation- a person with Korsakoff’s syndrome fills in the gaps of their memory with fabricated or imagined information
• Complete unawareness of the memory defect and complete lack of worry or concern when it is pointed out
• Involves neuronal loss (damage to neurons), gliosis (result of damage to supporting cells of the central nervous system), and hemorrhage (bleeding in mammillary bodies)
• Other symptoms may include delirium, anxiety, fear, depression, confusion, delusions and insomnia; painful extremities, sometimes bilateral wrist drop, more frequent bilateral foot drop with pain or pressure over the long nerves
Diagnosis
• An individual diagnosed with alcoholism and a sudden onset of memory difficulties should be tested for Korsakoff’s syndrome
• No specific test to diagnose this syndrome
• A careful examination of a patient’s mental state could reveal the syndrome
• Check the patient’s retention of factual information and the ability to learn new information
• A patient just recovering from Wenicke’s syndrome who begins to display memory difficulties is likely to have developed Korsakoff’s syndrome
Treatment
• Immediate administration of thiamine
• Any individual, regardless of the diagnosis of Korsakoff’s syndrome, should receive thiamine
Prognosis
• 15—20% of all patients hospitalized for Wenicke’s syndrome will die of Korsakoff’s syndrome
• Half of those who survive the syndrome will have permanent ataxia (difficulty walking)
• The paralysis of the eye muscles almost always have complete recovery with thiamine treatment
• Improvement in symptoms can take months of thiamine replacement
• Memory-impaired for the rest of their lives
• Usually requires a supervised living situation
Prevention
• Maintaining a diet with sufficient intake of thiamine
• Supplement an inadequate diet with vitamin preparations
• Treat the underlying alcohol addiction
