Causes of Amnesia

• Seizure disorders
  –Retrograde amnesia is most common after a generalized tonic-clonic seizure during the postictal period
  –Some complex partial seizure foci (particularly temporal lobe epilepsy) can also produce “blank” periods of memory

• Toxicologic insults
  –Binge alcohol consumption
  –Benzodiazepine use (e.g., “date rape” drug
  flunitrazepam, also known as Rohypnol)
• Psychogenic causes are relatively common, but should be a diagnosis of exclusion
• Korsakoff's syndrome
• Transient global amnesia
  –A rare, transient, ischemic attack-like condition of proposed vascular etiology
  –Causes abrupt onset of short-term memory loss for minutes to hours
  –Typically occurs in patients older than 50
  –Seen in patients with migraines

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Confusion: Medical causes
(Handbook of Signs & Symptoms (Third Edition))

Brain tumor.

In the early stages of a brain tumor, confusion is usually mild and difficult to detect. As the tumor impinges on cerebral structures, however, confusion worsens and the patient may exhibit personality changes, bizarre behavior, sensory and motor deficits, visual field deficits, and aphasia.

Cerebrovascular disorders.

 Cerebrovascular disorders produce confusion due to tissue hypoxia and ischemia. Confusion may be insidious and fleeting, as in a transient ischemic attack, or acute and permanent, as in a stroke.

Decreased cerebral perfusion.

 Mild confusion is an early symptom of decreased cerebral perfusion. Associated findings usually include hypotension, tachycardia or bradycardia, an irregular pulse, ventricular gallop, edema, and cyanosis.

Fluid and electrolyte imbalance.

The extent of imbalance determines the severity of the patient's confusion. Typically, he'll show signs of dehydration, such as lassitude, poor skin turgor, dry skin and mucous membranes, and oliguria. He may also develop hypotension and a low-grade fever.

Head trauma.

 Concussion, contusion, and brain hemorrhage may produce confusion at the time of injury, shortly afterward, or months or even years afterward. The patient may be delirious, with periodic loss of consciousness. Vomiting, a severe headache, pupillary changes, and sensory and motor deficits are also common.

Heatstroke.

 Heatstroke causes pronounced confusion that gradually worsens as the patient's body temperature rises. Initially, he may be irritable and dizzy; later, he may become delirious, have seizures, and lose consciousness.

Hypothermia.

 Confusion may be an early sign of hypothermia. Typically, the patient displays slurred speech, cold and pale skin, hyperactive deep tendon reflexes, a rapid pulse, and decreased blood pressure and respirations. As his body temperature continues to drop, his confusion progresses to stupor and coma, his muscles become rigid, and his respiratory rate decreases.

Hypoxemia.

Acute pulmonary disorders that result in hypoxemia produce confusion that can range from mild disorientation to delirium. Chronic pulmonary disorders produce persistent confusion.

Infection.

 Severe generalized infection, such as sepsis, typically produces delirium. Central nervous system (CNS) infections, such as meningitis, cause varying degrees of confusion along with a headache and nuchal rigidity.

Metabolic encephalopathy.

Hyperglycemia and hypoglycemia can produce sudden confusion. A patient with hypoglycemia may also experience transient delirium and seizures. Uremic and hepatic encephalopathies produce gradual confusion that may progress to seizures and coma. Usually, the patient also experiences tremors and restlessness.

Nutritional deficiencies.

Inadequate dietary intake of thiamine, niacin, or vitamin B₁₂ produces insidious, progressive confusion and possible mental deterioration.

Seizure disorders.

Mild to moderate confusion may immediately follow any type of seizure. The confusion usually disappears within several hours.

Other causes

Alcohol.

Intoxication causes confusion and stupor, and alcohol withdrawal may cause delirium and seizures.

Drugs.

Large doses of CNS depressants produce confusion that can persist for several days after the drug is discontinued. Opioid and barbiturate withdrawal also causes acute confusion, possibly with delirium. Other drugs that commonly cause confusion include lidocaine, a cardiac glycoside, indomethacin, cycloserine, chloroquine, atropine, and cimetidine.

HERB ALERT:Herbal remedies, such as St. John's wort, can cause confusion, especially when taken in conjunction with an antidepressant or other serotonergic drug.

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Amnesia: Medical causes
(Handbook of Signs & Symptoms (Third Edition))

❑ Alzheimer’s disease. Alzheimer’s disease usually begins with retrograde amnesia, which progresses slowly over many months or years to include anterograde amnesia, producing severe and permanent memory loss. Associated findings include agitation, inability to concentrate, disregard for personal hygiene, confusion, irritability, and emotional lability. Later signs include aphasia, dementia, incontinence, and muscle rigidity.

❑ Cerebral hypoxia. After recovery from hypoxia (brought on by such conditions as carbon monoxide poisoning or acute respiratory failure), the patient may experience total amnesia for the event, along with sensory disturbances, such as numbness and tingling.

❑ Head trauma. Depending on the trauma’s severity, amnesia may last for minutes, hours, or longer. Usually, the patient experiences brief retrograde and longer anterograde amnesia as well as persistent amnesia about the traumatic event. Severe head trauma can cause permanent amnesia or difficulty retaining recent memories. Related findings may include altered respirations and LOC; headache; dizziness; confusion; visual disturbances, such as blurred or double vision; and motor and sensory disturbances, such as hemiparesis and paresthesia, on the side of the body opposite the injury.

❑ Herpes simplex encephalitis. Recovery from herpes simplex encephalitis commonly leaves the patient with severe and possibly permanent amnesia. Associated findings include signs and symptoms of meningeal irritation, such as headache, fever, and altered LOC, along with seizures and various motor and sensory disturbances (such as paresis, numbness, and tingling).

❑ Hysteria. Hysterical amnesia, a complete and long-lasting memory loss, begins and ends abruptly and is typically accompanied by confusion.

❑ Seizures. In temporal lobe seizures, amnesia occurs suddenly and lasts for several seconds to minutes. The patient may recall an aura or nothing at all. An irritable focus on the left side of the brain primarily causes amnesia for verbal memories, whereas an irritable focus on the right side of the brain causes graphic and nonverbal amnesia. Associated signs and symptoms may include decreased LOC during the seizure, confusion, abnormal mouth movements, and visual, olfactory, and auditory hallucinations.

❑ Wernicke-Korsakoff syndrome. Retrograde and anterograde amnesia can become permanent without treatment in this syndrome. Accompanying signs and symptoms include apathy, an inability to concentrate or to put events into sequence, and confabulation to fill memory gaps. The syndrome may also cause diplopia, decreased LOC, head-ache, ataxia, and symptoms of peripheral neuropathy, such as numbness and tingling.

Other causes

❑ Drugs. Anterograde amnesia can be precipitated by general anesthetics, especially fentanyl, halothane, and isoflurane; barbiturates, most commonly pentobarbital and thiopental; and certain benzodiazepines, especially triazolam.

❑ Electroconvulsive therapy. The sudden onset of retrograde or anterograde amnesia occurs with electroconvulsive therapy. Typically, the amnesia lasts for several minutes to several hours, but severe, prolonged amnesia occurs with treatments given frequently over a prolonged period.

❑ Temporal lobe surgery. Usually performed on only one lobe, this surgery causes brief, slight amnesia. However, removal of both lobes results in permanent amnesia.

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Alzheimer's disease: Causes and incidence
(Professional Guide to Diseases (Eighth Edition))

The cause of Alzheimer’s disease is unknown; however, several factors are thought to be implicated in this disease. These include neurochemical factors, such as deficiencies in the neurotransmitter acetylcholine, somatostatin, substance P, and norepinephrine; environmental factors; and genetic immunologic factors. Genetic studies show that an autosomal dominant form of Alzheimer’s disease is associated with early onset and early death, accounting for about 100,000 deaths a year. A family history of Alzheimer’s disease and the presence of Down syndrome are two established risk factors.Alzheimer’s disease isn’t exclusive to the elder population; its onset begins in middle age in 1% to 10% of cases

The brain tissue of patients with Alzhei-mer’s disease has three hallmark features: neurofibrillary tangles, neuritic plaques, and granulovascular degeneration. Examination of the brain after death also finds that it’s atrophic, commonly weighing less than 1,000 g, compared with a normal brain weight of about 1,380 g.

About 360,000new cases of Alzheimer’s are diagnosed each year.

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Dissociative amnesia: Causes
(Professional Guide to Diseases (Eighth Edition))

Dissociative amnesia follows severe psychosocial stress, commonly involving a threat of physical injury or death. Amnesia may also occur after thinking about or engaging in unacceptable behavior such as an extramarital affair.

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Confusion: Medical causes
(Professional Guide to Signs & Symptoms (Fifth Edition))

Brain tumor

In the early stages of a brain tumor, confusion is usually mild and difficult to detect. As the tumor impinges on cerebral structures, however, confusion worsens and the patient may exhibit personality changes, bizarre behavior, sensory and motor deficits, visual field deficits, and aphasia.

Cerebrovascular disorders

These disorders produce confusion due to tissue hypoxia and ischemia. Confusion may be insidious and fleeting, as in a transient ischemic attack, or acute and permanent, as in a stroke.

Decreased cerebral perfusion

Mild confusion is an early symptom of decreased cerebral perfusion. Associated findings usually include hypotension, tachycardia or bradycardia, irregular pulse, ventricular gallop, edema, and cyanosis.

Fluid and electrolyte imbalance

The extent of the imbalance determines the severity of the patient’s confusion. Typically, he’ll show signs of dehydration, such as lassitude, poor skin turgor, dry skin and mucous membranes, and oliguria. He may also develop hypotension and a low-grade fever.

Head trauma

Concussion, contusion, and brain hemorrhage may produce confusion at the time of injury, shortly afterward, or months or even years afterward. The patient may be delirious, with periodic loss of consciousness. Vomiting, severe headache, pupillary changes, and sensory and motor deficits are also common.

Heatstroke

This disorder causes pronounced confusion that gradually worsens as body temperature rises. Initially, the patient may be irritable and dizzy; later, he may become delirious, have seizures, and lose consciousness.

Hypothermia

Confusion may be an early sign of this disorder. Typically, the patient displays slurred speech, cold and pale skin, hyperactive deep tendon reflexes, rapid pulse, and decreased blood pressure and respiratory rate. As his body temperature continues to drop, his confusion progresses to stupor and coma, his muscles become rigid, and his respiratory rate decreases.

Hypoxemia

Acute pulmonary disorders that result in hypoxemia produce confusion that can range from mild disorientation to delirium. Chronic pulmonary disorders produce persistent confusion.

Infection

A severe generalized infection, such as sepsis, commonly produces delirium. Central nervous system (CNS) infections, such as meningitis, cause varying degrees of confusion along with headache and nuchal rigidity.

Metabolic encephalopathy

Both hyperglycemia and hypoglycemia can produce sudden confusion. A patient with hypoglycemia may also experience transient delirium and seizures. Uremic and hepatic encephalopathies produce gradual confusion that may progress to seizures and coma. Usually, the patient also experiences tremors and restlessness.

Nutritional deficiencies

Inadequate dietary intake of thiamine, niacin, or vitamin B₁₂ produces insidious, progressive confusion and possibly mental deterioration.

Seizure disorders

Mild to moderate confusion may immediately follow any type of seizure. The confusion usually disappears within several hours.

Thyroid hormone disorders

Hyperthyroidism produces mild to moderate confusion along with nervousness, inability to concentrate, weight loss, flushed skin, and tachycardia. Hypothyroidism produces mild, insidious confusion and memory loss; weight gain; bradycardia; and fatigue.

Other causes

Alcohol

Intoxication causes confusion and stupor, and alcohol withdrawal may cause delirium and seizures.

Drugs

Large doses of CNS depressants produce confusion that can persist for several days after the drug is discontinued. Opioid and barbiturate withdrawal also causes acute confusion, possibly with delirium. Other drugs that commonly cause confusion include lidocaine, cardiac glycosides, indomethacin, cycloserine, chloroquine, atropine, and cimetidine.

Heavy metal poisoning

Chronic ingestion or inhalation of heavy metals (such as lead, arsenic, mercury, and manganese) eventually produces confusion and, typically, weakness and drowsiness. The patient may also experience headache, vomiting, seizures, tremors, gait disturbances, and mental deterioration.

Herb Alert

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Amnesia: Medical causes
(Professional Guide to Signs & Symptoms (Fifth Edition))

Alzheimer’s disease

Alzheimer’s disease usually begins with retrograde amnesia, which progresses slowly over many months or years to include anterograde amnesia and, eventually, severe and permanent memory loss. Associated findings include agitation, inability to concentrate, disregard for personal hygiene, confusion, irritability, and emotional lability. Later signs include aphasia, dementia, incontinence, and muscle rigidity.

Cerebral hypoxia

After recovery from hypoxia (brought on by such conditions as carbon monoxide poisoning or acute respiratory failure), the patient may experience total amnesia for the event along with sensory disturbances such as numbness and tingling.

Head trauma

Depending on the trauma’s severity, amnesia may last for minutes, hours, or longer. Usually, the patient experiences brief retrograde and longer anterograde amnesia as well as persistent amnesia about the traumatic event. Severe head trauma can cause permanent amnesia or difficulty retaining recent memories. Related findings may include altered respirations and LOC; headache; dizziness; confusion; visual disturbances, such as blurred or double vision; and motor and sensory disturbances, such as hemiparesis and paresthesia, on the side of the body opposite the injury.

Herpes simplex encephalitis

Recovery from herpes simplex encephalitis commonly leaves the patient with severe and possibly permanent amnesia. Associated findings include signs and symptoms of meningeal irritation, such as headache, fever, and altered LOC; seizures; and various motor and sensory disturbances, such as paresis, numbness, and tingling.

Hysteria

Hysterical amnesia, a complete and long-lasting memory loss, begins and ends abruptly and is typically accompanied by confusion.

Seizures

In temporal lobe seizures, amnesia occurs suddenly and lasts for several seconds to minutes. The patient may recall an aura or nothing at all. An irritable focus on the left side of the brain primarily causes amnesia for verbal memories, whereas an irritable focus on the right side of the brain causes graphic and nonverbal amnesia. Associated signs and symptoms may include decreased LOC during the seizure, confusion, abnormal mouth movements, and visual, olfactory, and auditory hallucinations.

Vertebrobasilar circulatory disorders

Vertebrobasilar ischemia, infarction, embolus, or hemorrhage may cause complete amnesia that begins abruptly, lasts for several hours, and ends abruptly. Associated findings include dizziness, decreased LOC, ataxia, blurred or double vision, vertigo, nausea, and vomiting.

Wernicke-Korsakoff syndrome

Retrograde and anterograde amnesia can become permanent without treatment in Wernicke-Korsakoff syndrome. Accompanying signs and symptoms include apathy, an inability to concentrate or to put events into sequence, and confabulation to fill memory gaps. The syndrome may also cause diplopia, decreased LOC, headache, ataxia, and symptoms of peripheral neuropathy such as numbness and tingling.

Other causes

Drugs

Anterograde amnesia can be precipitated by general anesthetics, especially fentanyl, halothane, and isoflurane; barbiturates, most commonly pentobarbital; and certain benzodiazepines, especially triazolam.

Electroconvulsive therapy

Sudden onset of retrograde or anterograde amnesia occurs with electroconvulsive therapy. Typically, the amnesia lasts for several minutes to several hours, but severe, prolonged amnesia occurs with treatments given frequently over a prolonged period.

Temporal lobe surgery

Usually performed on only one lobe, this surgery causes brief, mild amnesia. However, removal of both lobes results in permanent amnesia.

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Amnesia: Differential Overview
(Field Guide to Bedside Diagnosis)

❑ Concussion

❑ Alzheimer disease

❑ Drugs

❑ Generalized seizure

❑ Migraine

❑ Transient global amnesia

❑ Psychogenic

❑ Herpes simplex encephalitis

❑ Complex partial seizures

❑ Korsakoff syndrome

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Alzheimer's disease: Causes
(Handbook of Diseases)

Several factors contribute to the progression of Alzheimer’s disease. They include neurochemical factors, such as deficiencies in acetylcholine (a neurotransmitter), somatostatin, substance P, and norepinephrine; environmental factors, such as aluminum and manganese; viral factors, such as slow-growing central nervous system viruses; trauma; and genetic immunologic factors.

The brain tissue of a patient with Alzheimer’s disease typically shows cortical atrophy, the hallmark features being neurofibrillary tangles, neuritic plaques, and granulovascular degeneration.

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Confusion: Medical causes
(Signs & Symptoms: A 2-in-1 Reference for Nurses)

Brain tumor

In the early stages of a brain tumor, confusion is usually mild and difficult to detect. As the tumor impinges on cerebral structures, however, confusion worsens and the patient may exhibit personality changes, bizarre behavior, sensory and motor deficits, visual field deficits, and aphasia.

Decreased cerebral perfusion

Mild confusion is an early symptom of decreased cerebral perfusion. Confusion may be insidious and fleeting, as in a transient ischemic attack, or acute and permanent, as in stroke. Associated findings usually include hypotension, tachycardia or bradycardia, irregular pulse, ventricular gallop, edema, and cyanosis.

Fluid and electrolyte imbalance

A fluid and electrolyte imbalance can cause confusion. The extent of imbalance determines the severity of the patient’s confusion. Typically, he’ll show signs of dehydration, such as lassitude, poor skin turgor, dry skin and mucous membranes, and oliguria. He may also develop hypotension and a low-grade fever.

Head trauma

Such head trauma as concussions, contusions, and brain hemorrhages may produce confusion at the time of injury, shortly afterward, or months or even years afterward. The patient may be delirious, with periodic loss of consciousness. Vomiting, severe headache, pupillary changes, and sensory and motor deficits are also common.

Heatstroke

Heatstroke causes pronounced confusion that gradually worsens as body temperature rises. Initially, the patient may be irritable and dizzy; later, he may become delirious, have seizures, and lose consciousness.

Heavy metal poisoning

Chronic ingestion or inhalation of heavy metals (such as lead, arsenic, mercury, and manganese) eventually produces confusion and, typically, weakness and drowsiness. The patient may also experience headache, vomiting, seizures, tremors, gait disturbances, and mental deterioration.

Hypothermia

Confusion may be an early sign of hypothermia. Typically, the patient displays slurred speech, cold and pale skin, hyperactive deep tendon reflexes, rapid pulse, and decreased blood pressure and respirations. As his body temperature continues to drop, his confusion progresses to stupor and coma, his muscles develop rigidity, and his respiratory rate decreases.

Hypoxemia

Acute pulmonary disorders that result in hypoxemia produce confusion that can range from mild disorientation to delirium. In advanced stages, chronic pulmonary disorders produce persistent confusion as well as severe dyspnea, disability, cor pulmonale, and severe respiratory failure.

Infection

Severe generalized infection, such as sepsis, commonly produces delirium. Central nervous system (CNS) infections such as meningitis cause varying degrees of confusion along with headache and nuchal rigidity.

Metabolic encephalopathy

Both hyperglycemia and hypoglycemia can produce sudden confusion. A patient with hypoglycemia may also experience transient delirium and seizures. Uremic and hepatic encephalopathies produce gradual confusion that may progress to seizures and coma. Usually, the patient also experiences tremors and restlessness.

Nutritional deficiencies

Inadequate dietary intake of thiamine, niacin, or vitamin B_12, which causes nutritional deficiencies, produces insidious, progressive confusion and possible mental deterioration. Associated CNS abnormalities may become severe enough to induce hallucinations and paranoia.

Seizure disorders

Mild to moderate confusion may immediately follow any type of seizure. The confusion usually disappears within several hours. The patient may have difficulty talking and may fall into deep sleep after the seizures.

Thyroid hormone disorders

Hyperthyroidism produces mild to moderate confusion along with nervousness, inability to concentrate, weight loss, flushed skin, and tachycardia. Hypothyroidism produces mild, insidious confusion and memory loss; weight gain; bradycardia; and fatigue.

Other causes

Alcohol

Intoxication causes confusion and stupor, and alcohol withdrawal may cause delirium and seizures.

Drugs

Large doses of CNS depressants produce confusion that can persist for several days after the drug is discontinued. Opioid and barbiturate withdrawal also causes acute confusion, possibly with delirium. Other drugs that commonly cause confusion include lidocaine, digoxin, indomethacin, cycloserine, chloroquine, atropine, and cimetidine.

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Confusion: Medical causes
(Nursing: Interpreting Signs and Symptoms)

Brain tumor.In the early stages of a brain tumor, confusion is usually mild and difficult to detect. As the tumor impinges on cerebral structures, however, confusion worsens and the patient may exhibit personality changes, bizarre behavior, sensory and motor deficits, visual field deficits, and aphasia.

Cerebrovascular disorders.Cerebrovascular disorders produce confusion due to tissue hypoxia and ischemia. Confusion may be insidious and fleeting, as in a transient ischemic attack, or acute and permanent, as in a stroke.

Decreased cerebral perfusion.Mild confusion is an early symptom of decreased cerebral perfusion. Associated findings usually include hypotension, tachycardia or bradycardia, an irregular pulse, ventricular gallop, edema, and cyanosis.

Fluid and electrolyte imbalance.The extent and type of fluid and electrolyte imbalance determines the severity of the patient's confusion. Typically, he'll show signs of dehydration, such as lassitude, poor skin turgor, dry skin and mucous membranes, and oliguria. He may also develop hypotension and a low-grade fever.

Head trauma.Concussion, contusion, and brain hemorrhage may produce confusion at the time of injury, shortly afterward, or months or even years afterward. The patient may be delirious, with periodic loss of consciousness. Vomiting, a severe headache, pupillary changes, and sensory and motor deficits are also common.

Heatstroke.Heatstroke causes pronounced confusion that gradually worsens as the patient's body temperature rises. Initially, he may be irritable and dizzy; later, he may become delirious, have seizures, and lose consciousness.

Hypothermia.Confusion may be an early sign of hypothermia. Typically, the patient displays slurred speech, cold and pale skin, hyperactive deep tendon reflexes, a rapid pulse, and decreased blood pressure and respirations. As his body temperature continues to drop, his confusion progresses to stupor and coma, his muscles become rigid, and his respiratory rate decreases.

Hypoxemia.Acute pulmonary disorders that result in hypoxemia produce confusion that can range from mild disorientation to delirium. Chronic pulmonary disorders produce persistent confusion.

Infection.Severe generalized infection, such as sepsis, typically produces delirium. Central nervous system (CNS) infections, such as meningitis, cause varying degrees of confusion along with a headache and nuchal rigidity.

Metabolic encephalopathy.Hyperglycemia and hypoglycemia can produce sudden confusion. A patient with hypoglycemia may also experience transient delirium and seizures. Uremic and hepatic encephalopathies produce gradual confusion that may progress to seizures and coma. Usually, the patient also experiences tremors and restlessness.

Nutritional deficiencies.Inadequate dietary intake of thiamine, niacin, or vitamin B₁₂ produces insidious, progressive confusion and possible mental deterioration.

Seizure disorder.Mild to moderate confusion may immediately follow any type of seizure. The confusion usually disappears within several hours.

Other causes

Alcohol.Intoxication causes confusion and stupor, and alcohol withdrawal may cause delirium and seizures.

Drugs.Large doses of CNS depressants produce confusion that can persist for several days after the drug is discontinued. Opioid and barbiturate withdrawal also causes acute confusion, possibly with delirium. Other drugs that commonly cause confusion include lidocaine, a cardiac glycoside, indomethacin, cycloserine, chloroquine, atropine, cimetidine, and sleeping aids.

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Amnesia: Medical causes
(Nursing: Interpreting Signs and Symptoms)

Alzheimer's disease.Alzheimer��s disease usually begins with retrograde amnesia, which progresses slowly over many months or years to include anterograde amnesia, producing severe and permanent memory loss. Associated findings include agitation, inability to concentrate, disregard for personal hygiene, confusion, irritability, and emotional lability. Later signs include aphasia, dementia, incontinence, and muscle rigidity.

Cerebral hypoxia.After recovery from hypoxia (brought on by such conditions as carbon monoxide poisoning or acute respiratory failure), the patient may experience total amnesia for the event, along with sensory disturbances, such as numbness and tingling.

Head trauma.Depending on the trauma's severity, amnesia may last for minutes, hours, or longer. Usually, the patient experiences brief retrograde and longer anterograde amnesia as well as persistent amnesia about the traumatic event. Severe head trauma can cause permanent amnesia or difficulty retaining recent memories. Related findings may include altered respirations and LOC; headache; dizziness; confusion; visual disturbances, such as blurred or double vision; and motor and sensory disturbances, such as hemiparesis and paresthesia, on the side of the body opposite the injury.

Herpes simplex encephalitis.Recovery from herpes simplex encephalitis commonly leaves the patient with severe and possibly permanent amnesia. Associated findings include signs and symptoms of meningeal irritation, such as headache, fever, and altered LOC, along with seizures and various motor and sensory disturbances (such as paresis, numbness, and tingling).

Hysteria.Hysterical amnesia, a complete and long-lasting memory loss, begins and ends abruptly and is typically accompanied by confusion.

Seizures.In temporal lobe seizures, amnesia occurs suddenly and lasts for several seconds to minutes. The patient may recall an aura or nothing at all. An irritable focus on the left side of the brain primarily causes amnesia for verbal memories, whereas an irritable focus on the right side of the brain causes graphic and nonverbal amnesia. Associated signs and symptoms may include decreased LOC during the seizure, confusion, abnormal mouth movements, and visual, olfactory, and auditory hallucinations.

Wernicke-Korsakoff syndrome.Retrograde and anterograde amnesia can become permanent without treatment in this syndrome. Accompanying signs and symptoms include apathy, an inability to concentrate or to put events into sequence, and confabulation to fill memory gaps. The syndrome may also cause diplopia, decreased LOC, headache, ataxia, and symptoms of peripheral neuropathy, such as numbness and tingling.

Other causes

Drugs.Anterograde amnesia can be precipitated by general anesthetics, especially fentanyl, halothane, and isoflurane; barbiturates, most commonly pentobarbital and thiopental; and certain benzodiazepines, especially triazolam.

Electroconvulsive therapy.The sudden onset of retrograde or anterograde amnesia occurs with electroconvulsive therapy. Typically, the amnesia lasts for several minutes to several hours, but severe, prolonged amnesia occurs with treatments given frequently over a prolonged period.

Temporal lobe surgery.Usually performed on only one lobe, this surgery causes brief, slight amnesia. Removal of both lobes results in permanent amnesia.

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Amnesia as a complication of other conditions:

Other conditions that might have Amnesia as a complication may, potentially, be an underlying cause of Amnesia. Our database lists the following as having Amnesia as a complication of that condition:

• Anoxia

Amnesia as a symptom:

Conditions listing Amnesia as a symptom may also be potential underlying causes of Amnesia. Our database lists the following as having Amnesia as a symptom of that condition:

• Alcohol-Induced Disorders
• Alcoholic Neuropathy
• Diencephalic syndrome of infancy
• Electrocution
• Hashimoto's encephalitis
• Homen syndrome
• Korsakoff's psychosis
• Nutritional deficiency
• Wernicke-Korsakoff syndrome

Medications or substances causing Amnesia:

The following drugs, medications, substances or toxins are some of the possible causes of Amnesia as a symptom. This list is incomplete and various other drugs or substances may cause your symptoms. Always advise your doctor of any medications or treatments you are using, including prescription, over-the-counter, supplements, herbal or alternative treatments.

• Midazolam Hydrochloride
• Versed
• Dormicum
• Zetran Injection
• Apo-Diazepam

See full list of 11 medications causing Amnesia

Drug interactions causing Amnesia:

When combined, certain drugs, medications, substances or toxins may react causing Amnesia as a symptom.

The list below is incomplete and various other drugs or substances may cause your symptoms. Always advise your doctor of any medications or treatments you are using, including prescription, over-the-counter, supplements, herbal or alternative treatments.

• Prilosec (Omeprazole) and Ativan (Lorazepam) interaction
• Prilosec (Omeprazole) and Dalmane (Flurazepam) interaction
• Prilosec (Omeprazole) and Doral (Quazepam) interaction
• Prilosec (Omeprazole) and Halcion (Triazolam) interaction
• Prilosec (Omeprazole) and Klonopin (Clonazepam) interaction

See full list of 69 drug interactions causing Amnesia

Medical news summaries relating to Amnesia:

The following medical news items are relevant to causes of Amnesia:

• Cough medicine to treat fibromyalgia

Related information on causes of Amnesia:

As with all medical conditions, there may be many causal factors. Further relevant information on causes of Amnesia may be found in:

• Medications that may cause Amnesia
• Hidden causes of Amnesia