Basic Approach to Coma

1. COMA
Dr. Valmiki Salema,
Med Officer, Gen Medicine
Definitions and Approach to:

2. Normal Brain Anatomy
Cerebral Cortex
Reticular
Activating
System

3. Consciousness is defined as a state of
full awareness of the self and one’s
relationship to the environment.
It has 2 components:
• Arousal (RAS)
• Awareness (Cortex)
Consciousness

4. Anatomy of Consciousness
Ascending Reticular Activating System (RAS) is
a system of fibers which arises from the reticular
formation of the brainstem and projects to the
thalamus.
Neurons in the reticular formation
receive collaterals from the
ascending spinothalamic pathways
and then projects diffusely to the
entire cerebral cortex .

5. Sensory stimuli are involved not only with sensory perception
but also play role in the maintenance of consciousness through
their connections with the RAS.
Stimulation of RAS produces arousal and destruction of RAS
produces coma.
 Hypothalamus is an important component of consciousness,
Stimulation of posterior hypothalamic region causes arousal.
The degree of alteration in consciousness is roughly
proportional to the volume of brain tissue involved in the
process.

6. Few Loosely UsedTerms in
Medical Practice, and their
Definitions

7. • Mild form of altered mental status.
• Patient has reduced wakefulness or awareness.
• Include hyper- excitibility or irritability alternating
with drowsiness.
Clouding of Consciousness:
Confusional State:
More profound deficit including disorientation and
difficulty in following commands due to focal deficit
of cognitive function.

8. 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.

9. 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.

10. Minimally Conscious state:
Patients shows limited but clear evidence of
awareness of themselves or their environment by at
least following simple commands, gestural or verbal
yes/ no response. Further improvement is more likely
than patients in a vegetative state.
Akinetic Mutism:
Sub category of minimally conscious state in which
patient neither tend to move nor speak, lack motor
functions such as speech, facial expression, gestures
but demonstrate alertness. They can move their eyes
in response to auditory stimulus or move after
repeated commands.

11. Causes of COMA
Structural Non- Structural
(Focal) (Diffuse or metabolic)

12. Structural brain injuries causing Coma
Compressive lesions Destructive lesions

13. Non Structural (Diffuse, Metabolic or Multifocal
causes of Coma)
A. Deprivation of oxygen, substrate or metabolic
cofactors
1. Hypoxia
2. Ischaemia
3. Hypoglycemia
4. Cofactor deficiency (thiamine, niacin, pyridoxine)
B. Toxicity of Endogenous products
1. Due to organ failure (hepatic coma, uremic coma)
2. Due to hyper or hypofunction of endocrine organs

14. C. Toxicity of Exogenous poisoning
1. Sedative drugs
2. Acid poisons/ poisons with acid breakdown
3. Psychotropic drugs
D. Infections or inflammation of CNS:
1.Meningitis
2.Encephalitis
3.Vasculitis

15. Approach to An Unconscious Patient..
History.. (Whenever possible from relatives, friends, reliable attenders)
Make sure to ask:
• Onset: (abrupt, gradual)
• Recent complaints: (headache, weight gain/ loss, fever,
depression (suicidal ideas), focal weakness, trauma)
• Previous medical illness: (diabetes, hypertension, chronic lung
diseases, renal failure, thyroid disease, heart disease)
• Drug intake history: (prescription drugs, insulin, thyroxine,
recreational drugs)
• Family History: (similar complains, to r/o environmental toxicity/
food poisoning etc.)
• Travel History: (to malaria/ Japanese encephalitis etc. endemic
regions. or contact with STD’s)

16. Examination.. (Brief but thorough)
• Vital signs: Pulse, BP, Temperature, RR
• GPE:
• Habitus, Pallor, Icterus, Cyanosis, Clubbing, Lymphadenopathy,
Oedema, Thyroid swelling.
• Evidence of Trauma: bruises/ laverations/ fracures/ bleeding
from ear or nose/ abd distension
• Evidence of Drug use: Needle marks/ smell from breath/ pupils/
unkempt and poor hygiene/ parasympathetic symptoms
• Evidence of previous suicide attempts: cut marks
• Systemic Exam: Respiratory/ Cardiac/ Abdomen/ Neurological.
(Esp. look for Meningeal signs, Pupils, Fundus)

18. Changes in Pupils with lesions at different levels
of brain that can cause Coma
Diencephalon:
• Thalamus
• Hypothalamus
• Pituitary
Pretectum:
• Lies at the junction of
mid and fore brain.
• Made up of atleast 7
nuclei
• Main role: initiation of
optokinetic reflexes,
also nociception and
REM sleep.
Hippus:
Pupillary athetosis.
Irregular alternating
dilation and contraction
of the pupil in response
to light.

19. Coma Evaluation Scales
Glasgow Coma Scale
• Graham Teasdale and Bryan Jennet, Neurosurgery
professors, at the University of Glasgow, Developed this
scale in 1974
• 15 point scale, used to test best motor response (6), best
verbal response (5) and best eye response (4).
• Score ranges from 3 (deep coma or death) to 15 (fully
awake).
• Limitations:
• Failure to assess verbal score in intubated patients.
• Inability to test brainstem reflexes
• Person to person variation (a 2005 trial in the US, showed only 30% ER
docs, 38% Neurosurgeons Concur)
• Does not take physical debility into account ( eg. eyes swollen shut after
head injury, broken bones causing painful movements)

20. Newer Scales for Prognosis of Coma:
• FOUR (Full Outline of UnResponsiveness) SCALE
New Coma Scale is devised in 2005, Four components (Eye,
Motor, Brainstem, Respiration)
Each component has maximum of score of Four.
• AVPU
 Alertness, response to Verbal stimuli, response to Painful
stimuli, or Unresponsive
• ACDU
 Alertness, Confusion, Drowsiness, and Unresponsiveness
• Grady Scale:
 Scale of I toV along a scale of Confusion, Stupor, Deep
stupor, abnormal Posturing, and Coma.
Wijdicks E, BamletWR et al.Validation of New Coma Scale:The Four Scale.Ann Neurol 2005;
58: 585 – 593.

21. Investigations.. (But don’t wait to start stabilising the patient)
• Laboratory:
• Routine: CBC, LFT, RFT, U/E, CRP, ESR
• Specific: ABG’s, Amylase, TFT, Calcium, Lactate, Cultures,
CSF, Toxicology screen
• Radiological:
• X- Rays: Chest/ Abdomen/ Skull/ Bones
• Ultrasound: Abdomen
• CT Brain: Plain/ With Contrast
• MRI: If CT inconclusive

22. 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 II - The person lapses into sleep when undisturbed and is
aroused only when a pin is tapped gently over the chest wall.
Grade III - 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.

23. Consisting of High Flow Oxygen, dextrose,
flumazenil, naloxone , thiamine, activated
charcoal is sometimes used in the
management of an orphan comatose patient.
Coma cocktail

24. TO RECAP...

26. TAKE HOME MESSAGES....
Even before detailed history & examination, it is
important to start emergency measures such as
correction of possible deficiencies in glucose,
oxygenation and blood pressure.
After determination of vital signs, attention should
be towards ensuring an adequate airway, oxygenation
and intravenous access.
Immediately after obtaining blood samples, 50 cc of
50% glucose followed by 100 mg of thiamine should
be given.

27. Naloxone and flumazenil may be given if there is
suspicion of opiate or benzodiazepine overdose.
Preparation for intubation, respiratory support, and
for use of pressor agents should be made, as it may
become necessary.
Always assume a cervical spine injury may be
present, and immobilise the neck until a fracture can
be ruled out.
Never forget to check ECG/RBS/ TFT’s in an
unconscious patient.

30. Eye response ( Score – 4)
4 - eyelids open , 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

31. Motor response (Score – 4)
4 - thumbs-up, fist, or peace sign
3 - localizing to pain
2 - flexion response to pain
1 - extension response to pain
0 - no response to pain

32. Brainstem reflexes ( Score – 4)
4 - pupil and corneal reflexes present
3 - one pupil wide and fixed
2 - pupil or corneal reflexes absent
1 - pupil and corneal reflexes both absent
0 - absent pupil, corneal, and cough reflex

33. Respiration (Score – 4)
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 apnea