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,
triggers of HHS
corticosteroids and
phenytoin (which inhibits insulin release),
__________following viral infections
in children, now infrequent, was also associated with
very high levels of ammonia in the blood and encephalopathy
Reye syndrome
EEG of hepatic enceph
EEG abnormality consisting of paroxysms
of bilaterally synchronous slow or triphasic waves
in the delta range, which at first predominate frontally
and are interspersed with alpha activity and later, as the
coma deepens, displace all normal activity
there is a group of patients (most of whom
have experienced repeated attacks of hepatic coma) in
whom an irreversible mild dementia and a disorder of
posture and movement (grimacing, tremor, dysarthria,
ataxia of gait, choreoathetosis) gradually appear
chronic acq uired hepatocerebral degeneration
Pathology of chronic acq uired hepatocerebral degeneration
attributed the syndrome to a loss of
Betz cells in the frontal cortex;
MRI in PSE often demonstrates high signal intensity
in the _____, likely the result of ________
globus pallidus
manganese
deposition.
astrocytes
were seen to contain glycogen inclusions.
Alzheimer
type II astrocytes
Characteristics of Alzheimer
type II astrocytes
swelling of their terminal processes,
cytoplasmic vacuolation (distended sacs of rough endoplasmic
reticulum), formation of folds in the basement
membrane around capillaries, and an increase in both
the number of mitochondria and enzymes that catabolize
ammonia
accumulation of this element is readily discernible as
a pallidal signal hyperintensity on Tl-weighted MRI.
Mn
______ is a prominent finding in cases of
fulminant hepatic failure and is the main cause of death
in patients awaiting liver transplantation
Cerebral edema
Individuals with hepatitis
C who are treated with _________ may develop
a spectrum of problems ranging from subtle cognitive
impairment to a subacutely worsening headache, vomiting,
altered consciousness, and focal neurologic findings
interferon-alpha
this EEG pattern is charac of
The EEG is characterized by diffuse
arrhythmic delta activity; progressing to electrocerebral
silence in patients who fail to survive.
Reye
early diagnosis
and initiation of treatment before the onset of coma have
reduced the fatality rate to
5 to 10 percen
movements resemble those
of chorea or an arrhythmic tremor; asterixis among uremic pts
uremic twitch-convulsive syndrome .
Subdural and intracerebral hemorrhages may complicate
uremia (and dialysis) because of _________
clotting defects and
hypertension
However, some seizures may be
suppressed with relatively low plasma concentrations of
antiepileptic drugs:
, the reason being that serum albumin
is depressed in uremia, increasing the unbound, therapeutically
active portion of a drug.
rapid lowering of serum urea, leaving the brain with a higher concentration of urea than the serum and resulting
in a shift of water into the brain to equalize the osmotic
gradient (reverse urea syndrome). Now it is believed that
the shift of water into the brain is akin to water intoxication
and is a result of the inappropriate secretion of
antidiuretic hormone
” D i a lysis D i s eq u i l i b ri u m “ Syn d ro m e
This i s a subacutely progressive syndrome that i n the past
complicated chronic hemodialysis. Characteristically, the
condition begins with a hesitant, stuttering dysarthria
and aphasia, to which are added facial and then generalized
myoclonus, focal and generalized seizures, personality
and behavioral changes, and intellectual decline.
D i a lysis E n c e p h a l o pathy ( D i a lysis D e m e n t i a )
septic enceph
____percent of
patients become disoriented and confused within hours
of the onset of severe systemic infection;
70
Altered __________
metabolism and circulating cytokines
phenylalanine
______ caused by
hyperlipidemia or hyperproteinemia (isot?nic), hyperg.lycemic
or mannitol-induced hyponatrerma (hypertoruc),
and also cases of water intoxication
pseudohyponatremia
______is the result
of excretion of urine that is hypertonic relative to the
plasma
SIADH
Most cases of
SIADH respond to the restriction of fluid intake-to
________per 24 h if the serum Na is less than 120 mEq/L
and to_________per 24 h if less than 130 mEq/L.
500 mL
1 ,000 mL
3 percent (hypertonic) saline solution is \_\_\_\_\_ mEq/L
513
Sodium loss in these circurnstancs
is attributable to the production by the heart or bram
of a potent polypeptide natriuretic factor.
“cerebral salt wasting”
This is defined as an elevation of
the serum calcium concentration greater than 1 0.5 mg/
dL. If the serum protein content is normal, Ca levels
greater than ______ are required to produce neurologic
symptoms.
12 mg/ dL
In young persons, the most common cause of hypercalcemia
is _______ (either primary or secondary);
in older persons, _____
hyperparathyroidism
osteolytic bone tumors,
______predominates
in the EEG of pts with met avid
High-voltage slow activity
extrapontine myelinolytic foci locations
the internal capsule, deep cerebral white matter and corpus
callosum may occur independently
causes of CPM
More than half the cases
have appeared in the late stages of chronic alcoholism,
often in association with Wernicke disease and polyneuropathy.
The MRI of CPM discloses a characteristic
______ lesion of the pons in typical cases
“batwing”
_____cells usually
associated with Wilson disease.
Opalski
neurologic abnormalities occur in approximately _______percent of cases of adult celiac sprue
10
______
while not specific for celiac disease, do correspond to the
presence of neurologic manifestations
(ataxia and neuropathy);
antigliadin antibodies
causes of acquired dementia
chronic hepatic encephalopathy and
the syndromes of episodic hypoglycemia, chronic hypercalcemia
(in multiple myeloma, metastatic cancer, and
sarcoidosis), hyponatremia, and hypematremia.
At higher doses_________, approximately 10 to
15 percent of patients become overly active, emotionally
labile, and unable to sleep
(equivalent
to 60 to 100 mg/ d of prednisone)
_______(ventricular
enlargement and sulcal widening) has been shown radiologically
in patients with Cushing disease and after a
prolonged period of corticosteroid therapy,
“Cerebral atrophy”
encephalopathy consisting
of confusion, altered consciousness, and prominent
myoclonus in patients with _____
Hashimoto disease
Hashimoto disease: high titers of several
antithyroid antibodies, particularly antibodies against
_________
hyroid peroxidase and thyroglobulin
The encephalopathic symptoms and high
titers of antithyroid antibodies respond well to ____
steroid
therapy
The term________ is now more often
applied to a depressive illness that seems to occur with disproportionate frequency before the symptoms of a
pancreatic cancer become apparent.
Associated with pancreatic cancer and
sequential cerebral emboli from ______
pancreatic encephalopathy
nonbacterial thrombotic (marantic) endocarditis.
