Behavioral Science

Cognitive Disorders 115
AMNESTIC SYNDROMES
How do amnestic syndromes differ
from dementia?
Which brain structures are affected
in amnestic syndromes?
Damage to mediotemporal structures
is associated with what vitamin
deficiency?
Name at least four other etiologies
of amnestic syndromes.
In amnestic syndromes, the disturbance
of function is isolated to memory, while
other cognitive functions remain
relatively intact (unlike dementia).
The bilateral mediotemporal structures
(eg, mammillary bodies, hippocampus,
fornix)
Thiamine deficiency. Often this is
related with chronic alcohol abuse
(Korsakoff syndrome)
1. Traumatic brain injury
2. Herpes encephalitis
3. Cerebrovascular disease
4. Hypoxia
CLINICAL VIGNETTES
A 79-year-old African American woman has dementia. Her son has heard about the
genetic basis for Alzheimer disease and is worried about his risk of developing the
disease. Looking over her chart you see that she was high functioning 10 years prior
and then first suddenly became rather mildly cognitively impaired about 7 years
ago. She continued at that level until 5 years ago when she developed significant
memory problems and needed some part-time help at home. Two years ago she
again got worse and required assisted living. What do you tell her son about his
risks of Alzheimer disease?
His risk is the same as the normal population. The patient’s history with a
“stepwise decline” is suggestive of vascular dementia, not AD.
You are on the psychiatric consult service and called to see a psychotic patient in
the ICU. The resident there tells you that the patient—a 57-year-old woman with
no prior psychiatric history—is having new-onset schizophrenia. She seemed fine
this morning, but this evening she has hallucinations and is yelling at the nursing
staff. What is the likely diagnosis in this patient? What can be done to help, aside
from medications?
This patient most likely has delirium and almost absolutely does not have
schizophrenia. You should be wary of diagnosing an older individual with a newonset
psychotic disorder, especially when underlying medical illness is actively
involved. Delirium is so common in acutely sick patients that it is called “ICU
psychosis.” First and foremost, trying to alleviate the medical condition (or stopping
the offending medication) which has precipitated the delirium is the first course
of action. Environmental factors may help, such as cues to help orient patients to
time, date, and place.