This document summarizes key aspects of coma and brain stem death. It discusses the neurological structures involved in consciousness and what is required to induce coma. Coma is defined as unarousable unresponsiveness, distinguished from an alert state. Assessing a comatose patient involves obtaining history, performing a general and neurological exam including the Glasgow Coma Scale, and considering appropriate investigations and management. Brain death is defined as the irreversible loss of all brain functions including the brainstem, determined by coma, absence of brainstem reflexes, and apnea on testing.

1. “Coma and Brain Stem Death”
Osama Shukir Muhammed Amin
MBChB, MD, MRCP, FACP, FAHA, FCCP(USA),
FRCP(Edin), FRCP(Glasg), FRCP(Ire), FRCP(Lond)
Associate Professor of Neurology
School of Medicine, International Medical
University, Malaysia

3. Structures involved in consciousness?
Ascending Reticular
Activating System
(upper-pons and
midbrain)
Diencephalon
(mainly thalamus and
hypothalamus)
Cerebral Cortex
(diffuse)
Inducing and maintaining
alertness

4. What do we need in order to produce
coma?
Focal brain stem lesion (from
the tegmentum of the upper
pons to the upper end of the
midbrain).
Or, bilateral and diffuse
cerebral cortical
damage/dysfunction.
Or, large unilateral cerebral
hemispheric lesion which
compresses the contralateral
hemisphere and/or
underlying brain stem.
Toxic, metabolic,
and infectious
etiologies
and hypothermia

5. Alertness versus coma?
An alert patient
has a normal
state of arousal
Coma is defined
as unarousable
unresponsiveness

6. History, from?
Witnesses, friends or family
members, and emergency
medical technicians
Medical Alert bracelet or
necklace and/or a card in
the wallet
Old hospital chart/notes

7. Ask about what?
Onset and progression: acute (stroke?), gradual (brain tumor?), fluctuating
(metabolic encephalopathy?).
Features before coma: fever, hemiparesis, double vision, vertigo, etc.
Past history: stroke, epilepsy, depression, cirrhosis, diabetes, etc.
Medications, drugs, and substance misuse: alcohol, amphetamine, cocaine, etc.

8. Examination?
General Medical Neurological

9. General Medical Examination!
Vital Signs?
Hyperthermia
Hypothermia
Tachycardia
Bradycardia
Hypertension
Hypotension
Hyperventilation
Hypoventilation

10. General Examination?
Skin: pallor, cyanosis,
needle marks,
ecchymosis, jaundice, etc.
Lung, heart, and
abdomen.

11. Neurological Examination?
Level of
Consciousness
Motor
Examination
Brain stem
Reflexes

12. Assessing the level of consciousness?
Arousability is assessed by noise (e.g., shouting in
the ear) and somatosensory stimulation (e.g.,
pressing the supraorbital nerve).
Response to the above: vocalization, eye opening,
and/or limb movement.

13. Glasgow Coma Scale?
It grades coma severity and depth of consciousness.
Linked to prognosis (e.g., traumatic brain injury).
It does not diagnose coma.
Easy to use.
Good inter-observer reliability.
Intubation and use of sedating drugs interfere with the assessment.
Always obtain at the time of admission.

14. Glasgow Coma Scale (GCS), the three
categories of responsiveness: EMV?
Eye opening: 4 (spontaneous) to 1 (no eye opening).
Best motor response: 6 (obeys commands) to 1 (no motor response).
Best verbal response: 5 (oriented) to 1 (no verbal response).
The patient’s score is from 15 (the best) to 3 (the worst).
Record individually and totally: e.g., E2M4V4 resulting in GCS of 10/15.

15. Motor examination?
Tone, spontaneous and elicited movements, and reflexes.
Look for any asymmetry.
Response to elicited movements: no response, purposeful(less), towards the
stimulus, withdrawal, flexion/extension, midline/lateralized, etc.
Decorticate vs. decerebrate posturing.

16. Brain stem reflexes?
Pupillary size and
reactivity
Position of the eye
globe
Eye movement in
response to oculo-
cephalic maneuver and
oculo-vestibular reflex
NB: Bilateral conjugate roving eye movements that appear full indicate an intact
brainstem and further reflex testing is not required.

17. Investigations?
• CBC, ESR, blood film, blood sugar, blood urea and
electrolytes…to hormones, blood/urinary toxicology,
and cultures.
• Imaging: In general, brain CT is the test of choice for
initial evaluation. Follow-up MRI is recommended
when CT and other testing do not explain, or
incompletely explain, the clinical picture.
• CSF opening pressure and analysis.
• EEG.

18. Management?
An alteration in arousal represents an
acute, life threatening emergency,
requiring prompt intervention for
preservation of life and brain
function.

19. Brain Death
• Defined as the irreversible loss of all functions of the brain, including
the brainstem.
• Three essential elements: coma, absence of brainstem reflexes, and
apnea.
• Should be considered in all patients who have suffered a massive,
irreversible brain injury of identifiable cause.
• A patient determined to be brain dead is legally and clinically dead.
• The diagnosis of brain death is primarily clinical.

20. Determination of brain death?
• Identification of history or physical examination findings that
provide a clear etiology of brain dysfunction; irreversible vs
potentially reversible?
• Exclusion of any condition that might confound the
subsequent examination of cortical or brain stem function.
• Performance of a complete neurological examination,
including brain stem reflexes and apnea test.

21.  Shock/ hypotension.
 Hypothermia (core body temperature < 32°C).
 Drugs known to alter neurologic, neuromuscular function and
electroencephalographic testing, e.g., anesthetics, neuroparalytics,
barbiturates, benzodiazepines, alcohol, etc.
 Brain stem encephalitis.
 Guillain-Barre syndrome.
 Encephalopathy associated with hepatic failure, uremia and
hyperosmolar coma.
 Severe hypophosphatemia.
Exclusion of what?

22. Clinical observations compatible with the diagnosis of brain death?
These are occasionally seen and should not be misinterpreted as
evidence for brain stem function.
 Spontaneous movements of limbs other than pathologic flexion or
extension response.
 Respiratory-like movements (shoulder elevation and adduction, back
arching, intercostal expansion without significant tidal volumes)
 Sweating, flushing, tachycardia.
 Normal blood pressure without pharmacologic support or sudden
increases in blood pressure.
 Absence of diabetes insipidus.
 Deep tendon reflexes; superficial abdominal reflexes; triple flexion
response.
 Babinski sign.

23. Responsibilities of Physicians Determining Brain Death?
• Notify Next of Kin.
• Interval Observation Period (6 hours in adults).
• Repeat Clinical Assessment of Brain Stem Reflexes. Confirmatory
Testing as Indicated (e.g., in patients who all parts of the
examination cannot not be done safely, as in high cervical cord
trauma). For instance, angiography and nuclear brain scanning.

24. Other issues?
• Brain death can be certified by a single physician privileged
to make brain death determinations.
• Organ donation? In this case, two physicians are required to
certify the time of death.
• Withdrawal of cardio-respiratory support in accordance
with hospital policies, including those for organ donation.

25. Finally?
Wish you a very healthy and happy life!
Good luck!

26. Alabaster bas-relief from the North-West Palace of king Ashurnasirpal
II, 9th century BCE. From Nimrud, Mesopotamia, Iraq. Housed in the
National Museum of Scotland. Photo © Osama S. M. Amin.