case files neurology
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case files neurology

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hemorrhage, however, this needs to be evaluated by imaging studies such as
a CT head with contrast.
In this particular case the focus should be on the history of trauma the patient
sustained prior to the onset of her delirium. A CT head without contrast will
evaluate for epidural or subdural hematomas, intraparenchymal hemorrhage, or
subarachnoid hemorrhage. Her CT shows a subarachnoid hemorrhage, which
should prompt immediate neurosurgical consultation and management in the
intensive care unit (ICU). A history of illicit drug abuse should cause concern for
other drug use warranting a toxicology screen. Lastly, metabolic disorders such
as hypoglycemia or hyponatremia should be considered. These can be evaluated
by the comprehensive metabolic panel. One key point is that head trauma can
lead to the syndrome of inappropriate antidiuretic hormone secretion (SIADH),
which can cause hyponatremia and delirium or altered mental status.
Delirium: A neurobehavioral disorder with a fluctuating course entailing
inattention and acute alteration in mental status.
Glasgow Coma Scale: The Glasgow Coma Scale (Table 9\u20131) was developed
to delineate categories of head injury and levels of consciousness in patients
with traumatic brain injury. The scale is divided into three categories con-
sisting of eye-opening (E), verbal response (V), and motor response (M).
The maximum score is 15, and the minimum score is 3: GCS = E + M + V.
Subarachnoid hemorrhage: Hemorrhage within the subarachnoid space
that is caused by rupture of an aneurysm, arteriovenous malformation,
neoplasm, angioma, cortical thrombosis, mycotic aneurysm tear, spread
of blood or dissection from an intraparenchymal hemorrhage or trauma.
Babinski sign: Extension of the big toe followed by abduction of the other
toes when the lateral sole of the foot is stimulated. It is performed by
stroking the foot at the heel and moving the stimulus toward the toes. It
is a sensitive and reliable sign of cortical spinal tract disease. It is also
known as the plantar reflex.
Attention: The ability to focus on specific stimuli while excluding others.
Table 9\u20131
4 = Spontaneous 5 = Normal conversation 6 = Normal
3 = To voice 4 = Disoriented conversation 5 = Localizes to pain
2 = To pain 3 = Words, but not coherent 4 = Withdraws to pain
1 = None 2 = No words\u2014only sounds 3 = Decorticate posture
1 = None 2 = Decerebrate
1 = None
Total = E + V + M
Clinical Approach
The presentation of acute mental status change, abnormal attention, and a
fluctuating course should alert the clinician to delirium. Delirium is a disor-
der caused by many different etiologies and is the most common neurobehav-
ioral disorder in hospitals. It has been reported that up to 40% of hospitalized
patients in ICUs have delirium. There are various recognized risk factors for
delirium, the most common being age (particularly older than the age of 80),
preexisting cognitive impairment, dehydration and electrolyte disturbances
and gender (men more so than women).
Patients admitted with delirium to hospitals account for 10\u201324% of all
admissions with up to 26% of these resulting in death. Almost 80% of patients
near the time of death will experience delirium.
The pathophysiology of delirium is not well established, but there is evi-
dence to suggest that there are multiple neurotransmitter abnormalities affect-
ing acetylcholine, dopamine, and serotonin levels that leads to reversible
impairment of cerebral oxidative metabolism.
There is also an inflammatory component to the mechanism of delirium with
some studies showing that cytokines such as interleukin-1 and interleukin-6 are
upregulated. The central nervous system pathways involved in delirium are not
well established, but the ascending reticular formation in the upper brainstem,
prefrontal cortex, posterior parietal cortex, and the thalamus seem to be involved.
Clinical characteristics of delirium include an acute change in mental status
with a fluctuating course, disorganized thinking, and attentional deficits. Other
characteristics are listed in the Table 9\u20132. Delirium should be differentiated from
dementia, which is usually marked by a slow onset chronic cognitive disorder.
Table 9\u20132
Elderly, i.e., >80 years old; gender: men > women 
Preexisting cognitive impairment; number and severity of medical illnesses
Dehydration/electrolyte disturbances; infections: urinary/pulmonary
Hypoxemia/cardiorespiratory failure; malnutrition
Drug abuse: EtOH or hypnotic dependency; sleep disturbance
Fever/hypothermia; polypharmacy/analgesic use
Depression; fractures
Physical trauma; burns
Sleep disturbance; visual/auditory impairment
EtOH, alcohol consumption and/or dependency
The diagnosis of delirium is clinical, with an emphasis on evaluating level
of attention. Attention can be evaluated by serial reversal test (such as asking
the patient to spell a word backwards). The history should include a review of
medications patients take and information obtained from friends or family. The
neurological examination may not show focal signs or may show myoclonus,
dysarthria, tremor, motor abnormalities, or asterixis. Laboratory evaluation
should include a comprehensive metabolic panel, glucose, blood urea nitrogen
(BUN), liver function studies, electrolyte levels, a complete blood count (CBC)
to evaluate for infection, thyroid function studies to evaluate for endocrinopa-
thy, and ammonia to evaluate for hepatic encephalopathy. Arterial blood gas
(ABG) or pulse oximetry should be obtained if the patient has a history of lung
disease or smoking. Urine toxicology studies in those individuals with a history
of drug abuse or at risk for drug abuse should be requested as well. A CT scan
of the head or MRI brain scan needs to be performed with the choice of study
depending on ease of obtaining and clinical scenario. Other studies to consider
depending on the clinical picture include chest radiograph (evaluates for pneu-
monia), electrocardiograph (ECG) (exclude myocardial infarction or arrhyth-
mia), electroencephalograph (EEG), and lumbar puncture if there is concern for
central nervous system (CNS) infection.
The differential diagnosis for delirium is extensive (see Table 9\u20133) and
includes metabolic causes, infections, drug-related causes, primary neurologic
abnormalities, trauma, and perioperative causes. Importantly delirium must
be differentiated from dementia. Typically demented patients have a history
of chronic (>6 months) progression with normal attention (except advanced
cases) and level of consciousness. Perceptual disturbances and fluctuating
course are less common with dementia.
Table 9\u20133
Metabolic disorders: hypoglycemia, hyponatremia, uremia, hypoxia, hypo/
hypercalcemia, endocrinopathies (thyroid, pituitary), vitamin deficiencies, hepatic
encephalopathy, toxic exposures (lead, carbon monoxide, mercury, organic solvents)
Neurological: head trauma, cerebrovascular accidents, brain tumors, epilepsy,
hypertensive encephalopathy
Infections: encephalitis, meningitis, neurosyphilis, HIV, brain abscesses
Drug related: narcotics, sedatives, hypnotics, anticholinergics, antihistamine agents,
beta-blockers, antiparkinson medications, illicit drug (cocaine, amphetamines,
Perioperative: anesthetics, hypoxia, hypotension, fluid and electrolyte abnormalities,
sepsis, embolism, cardiac or orthopedic surgery
Other: cardiovascular, CNS vasculitis, dehydration, sensory deprivation
Treatment is dependent on the etiology of delirium with the use of drug-
related treatments being