Flashcards in CN LANGE - Dementia & Amnestic Disorders V Deck (63):
Memory is a complex function that can be viewed as having different components. Declarative memory:
Conscious memory includes:
1. Working memory --> Permits acute manipulation of newly presented information.
2. Longer-term semantic (factual) memory.
3. Episodic (personal) memory.
Nondeclarative (unconscious) memory includes:
1. Procedural memory to carry out well-learned and seemingly automatic tasks.
2. Emotional memory --> Attaches affective significance to objects or events.
Memory can also be seen as comprising the phases of:
3. Retrieval of information.
Areas important in memory processing:
2. Parahippocampal region of the medial temporal lobe.
3. Neocortical association areas.
--> BILATERAL damage to these regions results in impairment of short-term memory.
Some patients with amnestic syndromes may attempt to ...?
Fill in gaps in memory with false recollections (confabulation) - Can take the form of elaborate contrivances or of genuine memories misplaced in time.
Personal memories (eg name) may be prominently or exclusively impaired in dissociative (psychogenic) amnesia.
A disorder of memory (amnestic syndrome) may occur as ...?
One feature of an acute confusional state or dementia, OR as an isolated abnormality.
Head injuries resulting in loss of consciousness are invariably associated with ...?
An amnestic syndrome.
Patients seen shortly after a severe head injury exhibit ...?
A confusional state in which they are unable to incorporate new memories (anterograde, or posttraumatic amnesia), although they may behave in an apparently normal automatic fashion.
Head injuries - Retrograde amnesia?
Present - Covering a variable period prior to the trauma.
Conditions resulting in cerebral hypoxia or ischemia, such as cardiac arrest or CO poisoning, can produce ...?
Amnestic syndromes because hippocampal neurons involved in memory formation are selectively vulnerable to these insults.
Amnesia tends to occur in patients who have been in coma for at least ...?
Amnesia after cardiac arrest ...?
May be the sole manifestation of neurologic dysfunction, or it may coexist with cerebral watershed syndromes, such as:
1. Bibrachial paresis.
2. Cortical blindness.
3. Visual agnosia.
Amnestic syndromes from CO poisoning are frequently associated with ...?
Acute CO poisoning is suggested by ...?
1. Cherry-red coloration of the skin and mucous membranes.
2. Elevated carboxyhemoglobin levels.
3. Cardiac arrhythmia.
CO poisoning - The CT may show:
Lucencies in the basal ganglia and dentate nuclei.
Bilateral posterior cerebral artery occlusion - The PCA supplies:
1. Medial temporal lobe.
3. Posterior internal capsule.
4. Occipital cortex.
Bilateral PCA occlusion - Ischemia or infarction of this territory may produce:
Transient or permanent amnestic syndrome.
Bilateral PCA occlusion - Frequent causes:
Emboli in the vertebrobasilar system.
Bilateral PCA occlusion - The amnestic syndrome is usually associated with ...?
1. Unilateral/Bilateral hemianopia.
2. Visual agnosia.
3. Alexia without agraphia.
5. Sensory disturbances.
6. Signs of upper midbrain dysfunction (especially impaired pupillary light reflex).
Bilateral PCA occlusion - Which memory tends to be selectively impaired ...?
RECENT memory tends to be selectively impaired, with relative preservation of remote memory and registration.
Bilateral PCA occlusion - The CT shows:
Lucencies, which may or may not be enhanced by use of contrast material, in any combination of the previously mentioned regions.
Transient global amnesia is a syndrome:
Of acute memory loss that tends to occur in middle-aged or elderly patients.
Transient global amnesia - Etiology:
1. Transient cerebral ischemia.
2. Spreading depression (waver of reduced electrical activity in the cerebral cortex).
3. Physical or emotional stress.
Transient global amnesia - The disorder is recurrent in ...% of patients.
FEWER THAN 10% of patients.
Transient global amnesia - Affects ...?
Short-term memory and lasts for up to 24 (typically 6-10h) hours.
Transient global amnesia - Patients appear ...?
Agitated and perplexed and may repeatedly inquire about their whereabouts, the time, and the nature of what they are experiencing.
Transient global amnesia - Knowledge of personal identity is ...?
PRESERVED, as are remote memories and registration.
Transient global amnesia - Why the patient's repeated questions?
BECAUSE new memories cannot be formed, however, which accounts for the patient's repetitive questions.
Transient global amnesia - Retrograde amnesia:
Occurs for a variable period preceding the episode may be present, but this period shrinks as the episode resolves.
Transient global amnesia - Associated symptoms may include:
Transient global amnesia - What is the distinguishing feature?
The patient's obvious concern about the condition.
Transient global amnesia - High-resolution MRI may show ...?
Signal abnormalities affecting the CA1 field of the hippocampus.
Wernicke encephalopathy is caused by thiamine deficiency and classically produces ...?
1. Acute confusional state.
Korsakoff amnestic syndrome:
Occurs in chronic alcoholism and other malnutrition states, is thought to be caused by thiamine deficiency - Usually preceded by one or more episodes of Wernicke encephalopathy, BUT such a history may be LACKING.
Korsakoff amnestic syndrome - The memory disorder may be related to ...?
Bilateral degeneration of the DORSOMEDIAL THALAMIC NUCLEI.
An amnestic syndrome of variable severity follows recovery from Wernicke encephalopathy in approx. :
3/4 of cases and is often associated with:
2. Other residua such as nystagmus or gait ataxia.
Korsakoff amnestic syndrome - The essential defect is ...?
An inability to form new memories, resulting in significant impairment of short-term memory.
Korsakoff amnestic syndrome - Long-term memory:
Is also frequently affected, although to a lesser extent.
Korsakoff - Patients are typically ...?
APATHETIC and lack insight into their disorder.
They may attempt to reassure the physician that no impairment exists and try to explain away their obvious inability to remember.
--> CONFABULATION is often, BUT NOT invariably, a feature.
Patients who recover from acute viral encephalitis, particularly that caused by HSV, may be left with a permanent + static amnestic syndrome.
Postencephalitic amnesia - The syndrome is similar to that produced by ...?
Chronic alcoholism in that an inability to form new memories is its outstanding feature.
Postencephalitic amnesia - Remote memories are affected ...?
To a lesser extent than are recent ones, and registration is intact.
Postencephalitic amnesia - Confabulation?
Postencephalitic amnesia - Amnesia for the period of the acute encephalitis?
Postencephalitic amnesia - Patients may often exhibit symptoms of ...?
Limbic system disease.
Symptoms of limbic system disease include:
3. Flatness of mood and affect.
4. Inappropriate jocularity and sexual allusions.
7. Repetitive stereotyped motor activity.
8. Absence of goal-oriented activity.
Postencephalitic amnesia - Seizures:
Complex partial seizures, with or without secondary generalization.
Brain tumors as a cause of amnesia:
Rare - Tumors that are located in or compress the 3rd ventricle.
Brain tumor - Amnestic syndrome closely resembles ...?
Korsakoff syndrome. May be accompanied by:
3. Endocrine disturbances.
4. Visual field deficits.
Limbic encephalitis - In many patients, limbic encephalitis is associated with ...?
The production of autoantibodies directed against:
1. Either intracellular or
2. Cell-surface neuronal antigens.
Paraneoplastic limbic encephalitis:
Most often associated with small-cell cancer of the lung, and symptoms typically precede diagnosis of the underlying cancer.
Paraneoplastic limbic encephalitis - Histopathologic findings include:
1. Neuronal loss.
2. Reactive gliosis.
3. Microglial proliferation.
4. Perivascular lymphocytic cuffing affecting white matter of the:
C. Piriform cortex.
D. Inferior frontal lobes.
Paraneoplastic limbic encephalitis - Clinical findings:
1. Profound impairment of recent memory, with less involvement of remote memory and sparing of registration.
2. Confabulation occurs in some cases.
3. Mood disorders.
6. Sleep disturbance.
7. Complex, partial, or generalized seizures.
8. Dementia may develop.
Paraneoplastic limbic encephalitis - Depending on the extent to which gray matter regions outside the limbic system are involved ...?
2. Pyramidal bulbar.
3. Peripheral nerve disturbances may also occur.
Paraneoplastic limbic encephalitis - CSF:
1. Modest mononuclear pleocytosis.
2. Mildly elevated protein.
Paraneoplastic limbic encephalitis - EEG:
Diffuse slowing or bitemporal slow waves and spikes are sometimes seen.
Paraneoplastic limbic encephalitis - MRI:
May reveal abnormal signal intensity in the medial temporal lobes.
Paraneoplastic limbic encephalitis - Auto-antibodies:
1. Anti-Hu (MC) - vs intracellular antigen, usually associated with small-cell lung cancer.
2. Anti-AMPA and GABAb - Cell-surface antibodies. Also observed in limbic encephalitis without cancer.
Paraneoplastic limbic encephalitis - Auto-antibodies against LGI1:
Cell-surface antigen LGI1 - Forms part of a voltage-gated K channel complex.
Seen in some patients with limbic encephalitis without cancer, who often also exhibit SEIZURES + HYPONATREMIA.
The paraneoplastic amnestic syndrome can be ...?
Paraneoplastic amnestic syndrome - Why should we consider Korsakoff?
Should be considered because patients with cancer are susceptible to nutritional deficiency.