2. INTRODUCTION
The whole spectrum of acquired pathological consciousness perturbation states, currently known as
“disorders of consciousness”(DOC), constitutes a behavioural continuum, spanning from acute (e.g.
coma) to chronic neurological syndromes (e.g. minimally conscious state, vegetative state).
3. DEFINITIONS
Consciousness is defined as a state of awareness of self and environment and the ability to respond
to environmental factors.
Arousal (wakefulness) is clinically defined as the ability to open the eyes, spontaneously or on
stimulation.
Arousal is regulated and depends on the intact function of the Ascending Reticular Activating
System (ARAS), a large sub-cortical area of the brain located in the brainstem, the diencephalon
(hypothalamus and thalami), the basal forebrain and the projections to the cerebral cortex.
4. Awareness (awareness of self and environment that is the content of consciousness) is clinically
defined as the observation of patient’s voluntary interaction with the examiner or the environment.
It is regulated and depends on the intact interrelated functions of cerebral cortex and it’s sub-
cortical (mainly thalamic) connections.
Brain death corresponds to an irreversible cessation of all brain functions including brainstem
functions.
Coma is clinically defined by a state of unresponsiveness in which the patient does not open the
eyes, and has no signs of awareness of self or environment
5. Clouding of Consciousness:
Mild form of altered mental status.
Patient has reduced wakefulness or awareness.
Include hyper- excitibility or irritability alternating with drowsiness
Confusional State:
More profound deficit including disorientation and difficulty in following commands due to focal
deficit of cognitive function.
6. Obtundation:
Patient has a lessened interest in the environment. slowed responses to stimulation, and tends to sleep
more than normal with drowsiness in between sleep states.
Stupor:
Only vigorous and repeated stimuli will arouse the individual, and when left undisturbed, the patient
will immediately lapse back to the unresponsive state
Coma:
State of unresponsiveness, patient cannot be aroused by stimuli even with vigorous stimulation.
7. Locked in Syndrome:
Ventral brainstem destruction sparing the RAS.
Patient is mute and quadriplegic but not comatose, with variable preservation of consciousness. Patient
is awake but speechless & motionless with little response to stimuli and Sustained eye opening along
with aphonia or hypophonia.
Persistant Vegetative state:
Vegetative describes an organic body capable of growth and development but devoid of sensation and
thought. Patient have massive bilateral hemisphere damage with intact brainstem. In PVS, patient is
awake but unaware of environment.
8. Minimally conscious state (MCS) is characterized by the presence of arousal with inconsistent but
reproducible goal directed behaviors , e.g. response to command, verbalizations, visual pursuit.
Communication is largely altered. Patient emerge from MCS when they’re able to functionally use
objects an/or functionally communicate on two consecutive clinical assessments
Coma – neither arousal nor awareness
VS- arousal without awareness
MCS- arousal with minimal and partial/fluctuating signs of awareness.
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10.
11. PHYSIOLOGY AND PHYSIOPATHOLOGY ANATOMICAL
SUBSTRATUM OF AROUSAL AND AWARENESS
The Ascending Reticular Activating System (ARAS), the primary arousal structure is located in the
upper pons and in the lower midbrain In the posterior part of the upper two-thirds of the
brainstem.
A ventral pathway projects ARAS to the hypothalamus and to the basal forebrain; a dorsal pathway
projects to the reticular nuclei of the thalamus and a third pathway projects directly into the cortical
regions.
These long-range connections enable Thalamo-cortical close loop circuits K/A mesocircuits which
probably sustain the segregation and integration of information necessary for consciousness
emergence.
12. Efficient arousal needs intact ARAS. Coma/AMS might be
related to a diffuse interference with this arousal system e.g.
metabolic brain dysfunction, global cerebral ischemia or by
interference with one or more critical structures among this
system (e.g. brain stem infarction or haemorrhage).
Therefore after initial stabilization the first approach the
comatose patient consist of complete neurological assessment
to determine the presence or absence of a focal brain lesion.
Red structures : Cortical
Blue structures: Sub-cortical
14. Trauma
Subdural haemorrhage, epidural haemorrhage, subarachnoid haemorrhage, or other types of intracranial
haemorrhage.
Sheer injury or concussion can also present with altered mental state. Though rare, delayed presentations of
intracranial haemorrhage can occur and meningitis can present later as a result of facial or skull fractures
Structural
Structural causes include stroke, ruptured aneurysms causing subarachnoid haemorrhage, seizures, Locked In
syndrome, hydrocephalus, neoplasm, posterior reversible encephalopathy syndrome, and reversible cerebral
vascular Vasoconstriction syndrome.
Seizures can present with subtle findings or as a non-convulsive status epilepticus (NCSE)
15. INFECTIOUS
CNS infections such as meningitis and altered mental state or with unexplained neurologic deficit or
altered mental state without focality.
Autoimmune/other
other causes of AMS include neuro psychiatric lupus, Behecet’s syndrome, vasculitis, acute
disseminated encephalomyelitis and autoimmune limbic encephalitis.
Wernickes encephalopathy is a clinical diagnosis that presents with ataxia, opthalmoplegia and
confusion.
Metabolic
Toxic, electrolyte, endocrine,and hepatic.
16. 1. Electrolytes:
Hypoglycemia, hyponatremia, hypernatremia, severe acidosis and alkalemia, disorders in calcium, Uremia (>100)
2. Endocrine
Hypothyroidism as myxedema coma, hyperthyroidism as thyroid storm, adrenal insufficiency with hypotension,
cushing syndrome.
3. Hepatic
Hepatic encephalopathy
4. Toxins
22. ICU admission
Admission to the ICU depends also on the severity of the disturbance of the consciousness
e.g. a GCS of 8 or less normally warrants tracheal intubation but, even when coma is less severe,
a deteriorating state of consciousness provides additional evidence for critical care admission.
23. Further management
History : When the immediately life-threatening conditions have been excluded or managed, a detailed and accurate history should
be obtained.
Timing : Most patients presenting to the ER present with acute changes (minutes to days) rather than gradual (months to years).
Associated symptoms:
• Any preceding illnesses, concurrent symptoms, or other associated symptoms should be determined. Any recent focal neurologic
symptoms, even if brief and resolved, should raise suspicion for stroke, as transient ischemic attacks are a major risk factor for the
development of a stroke.
• Fevers, chills, or general weakness should raise suspicion for infection.
• Headaches should raise suspicion for intracranial mass or encephalitis.
• A recent trauma involving facial fractures should raise suspicion for meningitis.
o Medication history
24. Prior CNS pathology, endocrine system disorders, and malignancies, among other causes, may make patients
susceptible to AMS secondary to exacerbation of their disease processes or related processes (paraneoplastic
syndromes).
Similarly, a surgical history is important, as postsurgical complications such as infections may result in AMS.
Physical examination (head to toe) should be done
25.
26. NEUROLOGICAL ASSESMENT SCORES
The Glasgow Coma Scale (GCS) remains the most widely used coma assessment scale. However,
it suffers from some limitations. First, GCS may not always be reliable in mechanically ventilated
patients, particularly with regard to the verbal component. Second, GCS lacks assessment of an
important component of coma assessment in ICU patients, i.e. testing of brainstem reflexes.
The Full Outline of Un-Responsiveness score (FOUR) is a recently proposed coma asessment
scale that includes brainstem reflexes. It tests four components of brain function (eye response,
motor response, brainstem reflexes, and respiration pattern) and it has been validated extensively
in mechanically ventilated ICU patients
27. • 4 = eyelids open or opened, tracking, or blinking
to command
• 3 = eyelids open but not tracking
• 2 = eyelids closed but open to loud voice
• 1 = eyelids closed but open to pain
• 0 = eyelids remain closed with pain
Eye response
• 4 = thumbs-up, fist, or peace sign
• 3 = localising to pain
• 2 = flexion response to pain
• 1 = extension response to pain
• 0 = no response to pain or generalised myoclonus
status
Motor response
FOUR SCORE
28. • 4 = pupil and corneal reflexes present
• 3 = one pupil wide and fixed
• 2 = pupil or corneal reflexes absent
• 1 = pupil and corneal reflexes absent
• 0 = absent pupil, corneal, and cough reflex
Brain-stem reflexes
• 4 = not intubated, regular breathing pattern
• 3 = not intubated, Cheyne–Stokes breathing
pattern
• 2 = not intubated, irregular breathing
• 1 = breathes above ventilator rate
• 0 = breathes at ventilator rate or apnoea
Respiration
29. Stages of Coma
Grade I - Individuals who respond with recognition when their name is called and do not lapse into
sleep when left undisturbed.
Grade Il - The person lapses into sleep when undisturbed and is aroused only when a pin is tapped
gently over the chest.
Grade Ill - Patient who winces in response to deep pain stimulus. Deep pain stimulus may result in
abnormal postural reflexes either unilateral or bilateral.
Grade IV - Deep pain stimulus may result in decorticate or decerebrate posturing
Grade V - The patient who maintains a state of flaccid unresponsiveness inspite of deep pain
stimulation
32. LUMBAR PUNCTURE
• A lumbar puncture is appropriate in any patient with a history of fever, neck stiffness or sudden
severe headache provided there is no contraindication.
• Examinations of cerebrospinal fluid (CSF) should include the CSF appearance, opening pressure,
red blood cell count, white blood cell count and differential, glucose, protein, Gram stain, cultures
and viral PCR. Some extra fluid should be taken for special studies as indicated.
• There is a high prevalence of autoimmune encephalitis, especially anti-NMDA-receptor
encephalitis, in patients admitted at emergency department with a suggestive presentation of
infectious encephalitis (
• These autoantibodies should thus be checked early if the patient presents with psychiatric
symptoms and delusions associated to abnormal movements. Mild orofacial dyskinesia are also
frequent in this condition.
33. Imaging
Radiography
A chest X-ray should be considered in undifferentiated patients with AMS to evaluate for an infectious
infiltrate. It may also identify a pneumothorax, neoplasm, pulmonary edema, or a pleural effusion.
In patients with abdominal pain, careful attention should be paid to the hemidiaphragms evaluating for free
air which can suggest a perforated viscous.
An abdominal Xray should also be considered in patients with abdominal pain, though they are much less
sensitive than abdominal CT. Plain abdominal films should be evaluated for free air, an obstructive bowel gas
pattern, presence of a volvulus, and pneumointestinalis.
Further imaging should be performed based on history, physical exam, and laboratory analysis.
34. Neuroimaging
1. Non-contrast CT: Older patients, those with seizures, those with signs/symptoms concerning for stroke or
trauma, or those with sudden onset of impaired consciousness should undergo a noncontrast head CT. The
most common neuroimaging test ordered in the ED is a noncontrast head CT due to its speed and
availability. It can rapidly evaluate for hemorrhage, infarction, cerebral edema, and bony injury
2. Computed Tomography Angiography: If concern for stroke, carotid artery dissection, or subarachnoid
hemorrhage exists, CT angiography of the head and neck should be considered.
3. Magnetic resonance imaging (MRI) is not available in all centers and is more time consuming, but is
superior at detecting ischemic change, visualizing the posterior fossa and visualizing intracranial masses.
An MRI can be considered if no other etiologies for the patient’s AMS are found, and is usually done as an
inpatient. If an MRI is unavailable or a contraindication to such exists, a contrast enhanced CT may be
indicated.
4. Electroencephalography (EEG) should be performed on all patients with AMS having seizures or if
suspicion for NCSE exists. NCSE should be considered in patients with a seizure history, thosewho seized
prior to arrival, and in those in which no etiology of AMS has been discovered, as the incidence of NCSE in
patients with AMS is as high as 8 to 30%
35.
36. Altered consciousness due to unnecessarily deep and prolonged sedation contributesto delayed
convalescence.
When ICU stay is prolonged by altered consciousness there may be a further decline in functional
status due to the effects of bed rest and lack of exercise, drug administration, a catabolic state and
nosocomial infections.
With regard to long-term survival and functional outcome, these patients will probably suffer a
variable degree of long-term disability.
Therefore, the physician’s expertise andexperience, nursing care, a complex physiotherapeutic and
rehabilitation programmeand family involvement are all important issues for maintaining and
improving cerebral and other organs functions, preventing further damage and improving clinical
outcome with a reasonable standard of quality of life.
In the sedated patient in ICU, whenever possible, sedative drugs should bediscontinued
every day and the patient should be neurologically assessed.
37.
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40.
41. REFERRENCES
PACT MODULE
“ Altered Mental Status in the Emergency Department”,.
Evaluation and treatment of altered mental status patients in the emergency department: Life in
the fast lane.
FINK text book-2017
