Lecture 28: Coma, Persistent Vegetative State, Brain Death

Question 1

What is the definition of coma?

Answer 1

State of unrousable unresponsiveness with eyes closed and no purposeful response; GCS ≤ 8

Question 2

What two components are required for consciousness?

Answer 2

Ascending Reticular Activating System (RAS) for arousal and cerebral cortex for awareness

Question 3

What is a persistent vegetative state (PVS)?

Answer 3

Brainstem recovery with arousal present but no cortical recovery; no awareness or purposeful behaviour

Question 4

What is locked-in syndrome?

Answer 4

Pontine infarction causing paralysis below 3rd nerve nuclei; vertical eye movements preserved; awareness intact

Question 5

List toxic/metabolic causes of depressed consciousness.

Answer 5

Hypoxia, hypercapnia, sepsis, hypotension, hypoglycaemia, ketoacidosis, drug intoxication, renal/hepatic failure

Question 6

List structural causes of depressed consciousness.

Answer 6

Tumour, stroke, extradural/subdural/subarachnoid haemorrhage, hydrocephalus

Question 7

List seizure-related causes of depressed consciousness.

Answer 7

Post-ictal state, status epilepticus

Question 8

List head injury causes of depressed consciousness.

Answer 8

Diffuse axonal injury, contusion, intracerebral haematoma, extradural/subdural haematoma

Question 9

How can causes of depressed consciousness be grouped clinically?

Answer 9

By presence or absence of meningism and focal signs

Question 10

What history features are important in coma assessment?

Answer 10

Predictable progression (malignancy), sudden collapse (vascular, seizure, trauma), risk factors (alcohol, diabetes, cardiac disease)

Question 11

What vital signs should be assessed in coma?

Answer 11

Temperature, heart rate, blood pressure, respiration

Question 12

What general exam features should be checked in coma?

Answer 12

Skin, breath, abdomen, meningism, fundus

Question 13

What neurological exam features are key in coma?

Answer 13

GCS scoring, brainstem reflexes, respiratory pattern, motor tone/reflexes, seizures

Question 14

Which cranial nerves are tested in pupillary reflexes?

Answer 14

CN II and III

Question 15

Which cranial nerves are tested in corneal reflex?

Answer 15

CN V and VII

Question 16

Which cranial nerves are tested in oculocephalic reflex?

Answer 16

CN III, IV, VI, VIII

Question 17

Which cranial nerves are tested in oculovestibular reflex?

Answer 17

CN III, IV, VI, VIII

Question 18

What baseline investigations are needed in coma?

Answer 18

Blood glucose, electrolytes, renal/liver function, ABG, toxicology, FBC, ESR, infection screen

Question 19

What imaging is used in coma assessment?

Answer 19

CT/MRI brain to exclude haemorrhage, infarct, tumour, hydrocephalus

Question 20

When is lumbar puncture indicated in coma?

Answer 20

If meningism present and no raised ICP

Question 21

What other investigations may be useful in coma?

Answer 21

EEG for status epilepticus, carbon monoxide screen

Question 22

What factors predict coma outcome?

Answer 22

Age, cause, depth/duration, presence of brainstem reflexes

Question 23

What is the prognosis of non-traumatic coma >6h?

Answer 23

Only ~15% achieve good/moderate recovery

Question 24

Which coma cause has the best prognosis?

Answer 24

Metabolic (35% recovery)

Question 25

Which coma cause has the worst prognosis?

Answer 25

Vascular (7% recovery)

Question 26

What complications can occur in coma?

Answer 26

Pressure sores, contractures, DVT, seizures, infections, aspiration pneumonia

Question 27

What are immediate resuscitation steps in coma?

Answer 27

Airway, breathing, circulation; stabilise cervical spine if trauma; intubation if GCS ≤ 8

Question 28

How is raised ICP treated?

Answer 28

Surgery (haematoma evacuation, shunt), osmotic agents (mannitol), head elevation, oxygenation, CO₂ reduction, barbiturates

Question 29

What supportive care is needed in coma?

Answer 29

Skin care, bladder/bowel management, seizure control, DVT prophylaxis, nutrition, ICU/stroke unit care

Question 30

What head injury mechanisms can cause coma?

Answer 30

Diffuse axonal injury, contusion, haematomas (EDH, SDH, ICH)

Question 31

What CT features distinguish subdural vs extradural haematoma?

Answer 31

Subdural: crescent/banana shape; Extradural: lens/biconvex shape

Question 32

How are haematomas managed?

Answer 32

ABC, neuro observation, surgical evacuation if mass effect, prevent post-traumatic epilepsy

Question 33

What causes coma without meningism or focal signs?

Answer 33

Toxic/metabolic, systemic, intoxication

Question 34

What causes coma with meningism but no focal signs?

Answer 34

SAH, meningitis, encephalitis

Question 35

What causes coma with focal signs ± meningism?

Answer 35

Tumour, infarct, haemorrhage, abscess