Cognitive Disorders (part 1) Amnesia and Delirium Sami Adil 15 th Nov. 2015

Amnestic Disorders impairment in the ability to create new memories. Three variations of the amnestic disorder diagnosis, differing in etiology, are offered: amnestic disorder caused by a general medical condition (e.g., head trauma), substance- induced persisting amnestic disorder (e.g., caused by carbon monoxide poisoning or chronic alcohol consumption), and amnestic disorder not otherwise specified for cases in which the etiology is unclear.

The two modifiers are (1) transient, for duration less than 1 month, and (2) chronic, for conditions extending beyond 1 month.

Epidemiology No adequate studies Alcohol disorders Head injury

Etiology Thalamus (dorsomedial and midline nuclei) Hippocampus, the mamillary bodies, and the amygdala Other areas Unilateral Vs. Bilateral Left Vs. Right

Major causes of amnesia General Medical: hypoglycemia, seizures, head trauma, CVA, MS, and others Substance-related: alcohol, BNZ, neurotoxins,

Diagnosis For the diagnosis of amnestic disorder, the (DSM- IV-TR) requires the development of memory impairment as manifested by impairment in the ability to learn new information or the inability to recall previously learned information,‌ and the memory disturbance [must cause] significant impairment in social or occupational functioning.

Clinical Features and Subtypes The central symptoms are (anterograde amnesia) & (retrograde amnesia). Time of trauma Vs time of amnesia Short term Vs. Long term Vs. immediate

With improvement, patients may experience a gradual shrinking of the time for which memory has been lost, although some patients experience a gradual improvement in memory for the entire period.

The onset of symptoms can be sudden, as in trauma, cerebrovascular events, and neurotoxic chemical assaults, or gradual, as in nutritional deficiency and cerebral tumors. The amnesia can be of short duration (specified by DSM-IV-TR as transient if lasting 1 month or less) or of long duration (specified by DSM-IV-TR as persistent if lasting more than 1 month).

Patients may attempt to cover their confusion with confabulatory answers to questions. Characteristically, patients with amnestic disorders do not have good insight into their neuropsychiatric conditions.

Differential Diagnosis Dementia and Delirium Amnestic disorders can be distinguished from delirium, because they occur in the absence of a disturbance of consciousness and are striking for the relative preservation of other cognitive domains.

CharacteristicDementia Amnestic Disorder OnsetInsidiousCan be abrupt Course Progressive deterioration Static or improvement LanguageImpairedIntact Praxis or function ImpairedIntact

Normal Aging Some minor impairment in memory may accompany normal aging, but the DSM-IV-TR requirement that the memory impairment cause significant impairment in social or occupational functioning should exclude normal aging from the diagnosis.

Dissociative Disorders The dissociative disorders can sometimes be difficult to differentiate from the amnestic disorders. Patients with dissociative disorders, however, are more likely to have lost their orientation to self and may have more selective memory deficits than do patients with amnestic disorders. For example, patients with dissociative disorders may not know their names or home addresses, but they are still able to learn new information and remember selected past memories. Dissociative disorders are also often associated with emotionally stressful life events involving money, the legal system, or troubled relationships.

Factitious Disorders Patients with factitious disorders who are mimicking an amnestic disorder often have inconsistent results on memory tests and have no evidence of an identifiable cause. These findings, coupled with evidence of primary or secondary gain for a patient, should suggest a factitious disorder.

Course and Prognosis Depends on etiology Acute and reversible Chronic and static

Treatment The primary approach to treating amnestic disorders is to treat the underlying cause. Although a patient is amnestic, supportive prompts about the date, the time, and the patient's location can be helpful and can reduce the patient's anxiety. Denial

DELIRIUM

Delirium is defined by the acute onset of fluctuating cognitive impairment and a disturbance of consciousness. Delirium is underrecognized by health care workers.

Epidemiology 30 % of inpatients Undiagnosed Poor prognostic sign

Etiology

Criteria: Medical FRAT 1.Medical cause 2.Fluctuating 3.Recent onset 4.Attention 5.Thinking (orientation and perception) Delusions

Delusions can occur (paranoid)

DDx Dementia Depression schizophrenia Fluctuating course

Treatment Treat the cause Environmental Haloperidol and lorazepam DT Eye patch