ACQUIRED METABOLIC DSE Flashcards
The main features
of the reversible ________ are confusion,
typified by disorientation and inattentiveness and accompanied
in certain special instances by asterixis, tremor, and myoclonus,
usually without signs of focal cerebral disease.
metabolic encephalopathies
At normal temperature and pH, hemoglobin
is 90 percent saturated at an oxygen partial pressure of
_______mm Hg and still 75 percent saturated at 40 mm Hg;
60
Through a mechanism termed _______
there is a compensatory dilatation of resistance
vessels in response to a reduction in cerebral perfusion,
which maintains blood flow at a constant rate
autoregulation,
In total cerebral ischemia, the
tissue is depleted of its sources of energy in about ________min,
although longer periods are tolerated under conditions
of_______`
5
hypothermia.
Under conditions of _______, one pattern of damage takes the form of
incomplete infarctions in the border zones between major
cerebral arteries
transient
ischemia
With predominant __________,
neurons in portions of the hippocampus and the deep folia
of the cerebellum are particularly vulnerable
anoxia
There is experimental
evidence that certain excitatory neurotransmitters, particularly
_____, contribute to the rapid destruction of
neurons under conditions of anoxia and ischemia
glutamate
The most
common early change in cases of severe injury is a
_______
loss of the distinction between the cerebral gray and
white matter
This represents the most severe degree of hypoxia,
usually caused by circulatory arrest; it is manifest by a
state of complete unawareness and unresponsiveness
with abolition of all brainstem reflexes.
Bra i n Death Syn d ro m e
Posthypoxic Neu rologic Syndromes
- Persistent corru:l or stupor, described above
- With lesser degrees of cerebral injury, dementia with
or without extrapyramidal signs - Extrapyramidal (parkinsonian) syndrome with cognitive
impairment (discussed in relation to CO poisoning) - Choreoathetosis
- Cerebellar ataxia
- Inten tion or action myoclon us (Lance-Adams syndrome)
- An amnesic state
Watershed syndromes
PCA-MCA:Visual agnosias including Balint syndrome and cortical
blindness (Anton Syndrome)
MCA-ACA: sometimes accompanied
by hip weakness (referred to as a “man-inthe-
barrel” syndrome),
Initial improvement, which appears to be
complete, is followed after a variable period of time (1 to
4 weeks in most instances) by a relapse, characterized by
apathy; confusion, irritability, and occasionally agitation
or mania.
Del ayed Posta noxic Encep h a l opathy a n d
Leu koenceph a l o pathy
that 5 clinical signs at 1 day after
cardiac arrest predicted a poor neurologic outcome or
death:
(1) absent corneal responses, (2) absent pupillary
reactivity, (3) no withdrawal to pain, and (4) the absence
of any motor response. T
hypothermia in coma
They reduced the
core temperature to 33°C (91 °F) within 2 h of the arrest
and sustained this level for 12 h in the first trial, and
between 32°C and 34°C for 24 h in the second study.
treatment of poly myoclonus
clonazepam, 8 to 12 mg daily
in divided doses may be useful but the commonly used
antiepileptic drugs have little effect
Sx of CO when carboxyhemoglobin level reaches 20 to 30 percent of total hemoglobin
headache, nausea, dyspnea,
confusion, dizziness, and clumsiness
CO at 50 to 60 percent are associated with :
with coma, decerebrate
or decorticate posturing, seizures in a few patients, and
generalized slowing of the EEG rhythms
Discrete lesions centered in the
__________ are characteristic of CO poisoning
that had produced coma
globus pallidus bilaterally and sometimes the inner portion of the putamina
the half-life of CO (normally
5 h) is greatly reduced by the administration of
_________,
this additional
treatment is recommended when the carboxyhemoglobin concentration is ____________
of coma or seizures
hyperbaric oxygen at 2 or 3 atmospheres
greater than 40 percent or in the presence
Pathophysiology of mountain sickness
The overexpression of vascular endothelial
growth factor (VEGF), a protein originally noted for its
effects on vascular permeability, has been implicated as
the cause of cerebral edema in
_______
and __________prevent and counteract mountain
sickness to some extent. The most effective preventive
measure is _______ at intermediate
altitudes.
Dexamethasone
acetazolamide
acclimatization by a 2- to 4-day stay
At a level of about
_______ the cerebral disorder takes the form of a confusional
state and one or more seizures may occur; at a level
of _______, there is coma that may result in irreparable
injury to the brain if not corrected immediately by the
administration of glucose
30 mg/ dL,
10 mg/dL
Blood glucose levels of approximately 10 mg/ dL
are associated with deep coma, dilatation of pupils, pale
skin, shallow respiration, slow pulse and hypotonia,
what had in the past been termed the _____
of hypoglycemia
“medullary phase”
The major clinical differences between hypoglycemic
and hypoxic encephalopathy lie in the setting and
the mode of evolution of the neurologic disorder. The
effects of hypoglycemia usually unfold more_______, rather than in a few seconds or
minutes.
slowly, over a period of 30 to 60 min
Pathophysiology of DKA in the brain
accumulation of fructose and sorbitol in the brain
In hyperosmolar nonketotic hyperglycemia, the blood
glucose is extremely high, _______ but
ketoacidosis does not develop,
more than 600 mg/ dL,