Coma

Question 1

What is a coma?

Answer 1

Unrousable and unresponsive

Quantified using the GCS

Question 2

What are some metabolic causes of coma?

Answer 2

Drugs/poisoning - CO, alcohol, tricyclics

Hypoglycaemia/hyperglycaemia

Hypoxia/CO2 narcosis (COPD)

Septicaemia

Hypothermia

Myxoedema/Addisonian Crisis

Hepatic/uraemic encephalopathy

Question 3

What are some neurological causes of coma?

Answer 3

Trauma

Infection - encephalitis, malaria, typhoid, typhus, rabies, trypanosomiasis

Tumour

Vascular - stroke, haemorrhage, hypertensive encephalopathy

Epilepsy

Question 4

What is the immediate management for a patient with a reduced GCS?

Answer 4

ABC

• consider intubation if GCS <8
• treat seizures
• give o2 as req.
• protect c-spine

Check BM - give 200ml 10% dextrose IV stat if hypoglycaemia

IV thiamine if wernicke’s encephalopathy suspected

IV naloxone - opiate tox
IV flumazenil - benzodiazepine tox

Question 5

What is key on examination for a patient with reduced GCS?

Answer 5

Vital signs - full set + temperature
Signs of trauma
Stigmata of other illness - liver disease/alcoholism etc.
Skin
Smell breath - alcohol, hepatic fetter, ketosis, uraemia
Opisthotonus
Meningism
Pupils - size, reactivity, gaze
Heart/lung
Abdo/rectal
Foci of infection - abscess, bites, middle ear infection
Absence of signs

Question 6

What signs of trauma may you assess for in a patient with reduced GCS?

Answer 6

Haematoma
Laceration
Bruising
CSF or blood in nose/ear
Fracture of skull - step deformity
Subcutaneous emphysema
Panda eyes

Question 7

What signs may you see on the skin in a patient with reduced GCS?

Answer 7

Cyanosis
Pallor
Rash
Poor turgor

Question 8

What is opisthotonus and what is it indicative of?

Answer 8

Spasm of the muscles causing backwards arching of the head neck and spine.

Indicative of meningitis or tetanus

Question 9

What would you look for on examination of the heart and lungs in a patient with reduced GCS?

Answer 9

BP
Murmurs
Rubs
Wheeze
Consolidation
Collapse

Question 10

What would you look for on abdo/rectal exam in a patient with reduced GCS?

Answer 10

Organomegaly
Ascites
Bruising
Peritonism
Melaena

Question 11

What things would you ask in a quick collateral history for a patient with reduced GCS?

Answer 11

Onset - abrupt or gradual?

How found - suicide note? seizure?

Injury? - C-Spine immobilisation

Recent complaints - headache, fever, vertigo, depression

Recent medical hx - sinusitis, otitis, neurosurgery, ENT operation

PMH - diabetes, asthma, hypertension, cancer, epilepsy, psychiatric illness

Drug/toxin exposure? Travel?

Question 12

If the diagnosis is unclear in a patient in a coma, what is your management plan?

Answer 12

Treat the treatable - BM, O2 etc.

Routine biochemistry, haematology, thick films, blood cultures, blood ethanol and drug screens

Arrange CT head and LP if req.

Question 13

Outline the flowchart for managing a coma

Answer 13

ABC of life support
             v
Gain IV access
             v
Stabilise the C Spine
             v
Take blood glucose
             v
Control seizures
             v
Treat potential causes - O2, glucose, drugs etc.
             v
Brief collateral hx and examination
             v
Investigations
             v
Reassess

Question 14

What investigations may you do if unclear why a patient is in a coma?

Answer 14

ABG, FBC, U&E, LFT, CRP, Ethanol, Tox screen, drug levels

Blood culture, urine culture, consider malaria

CXR, CT head

Question 15

What are the parts of the GCS?

Answer 15

Motor Response
Verbal Response
Eye Movement

Question 16

Define how motor response is rated in the GCS?

Answer 16

6 - Obeys commands
5 - Localise to pain
4 - Withdraw from pain
3 - Flex to pain
2 - Extend to pain
1 - No response to pain

Question 17

Define how the verbal response is rated in the GCS

Answer 17

5 - Oriented to time, place and person
4 - Confused conversation
3 - Inappropriate speech
2 - Incomprehensible sounds
1 - None

Question 18

Define how eye opening is rated in the GCS

Answer 18

4 - Spontaneous
3 - In response to speech
2 - In response to pain
1 - None

Question 19

How can you categorise GCS scores?

Answer 19

<8 - severe injury - consider airway protection
9-12 - moderate injury
13-15 - minor injury

Question 20

Describe what happens in flexion to pain and what is the name of the posture?

Answer 20

Decorticate posture

Arms bent inwards on chest
Thumbs tucked in a clenched fist
Legs extended

Question 21

What does flexion to pain indicate about the injury?

Answer 21

It is above the level of the red nucleus in the midbrain

Question 22

What is the posture for extension from pain and describe it?

Answer 22

Decerebrate posture

Adduction and internal rotation of the shoulder
Pronation of the forearm

Question 23

What does extension from pain indicate about the injury?

Answer 23

Midbrain damage below the level of the red nucleus

Question 24

Pathology in which 2 locations may lead to altered consciousness?

Answer 24

1 Diffuse bilateral cortical dysfunction

2 Damage to ascending reticular activating system (located throughout brainstem) - this can be direct or indirect

Question 25

Give an example of direct and indirect causes of brainstem damage

Answer 25

Direct - pontine haemorrhage Indirect - compression from transtentorial or cerebellar herniation due to a mass or oedema

Question 26

What are some examples of pathological breathing patterns?

Answer 26

Cheyne Stokes - brainstem lesions or compression Hyperventilation - acidosis, hypoxia or (rarely) neurogenic Ataxic/Apneustic (breath holding) - severe brainstem lesion

Question 27

What are the parts of the eye examination for a patient in a coma?

Answer 27

Visual fields Pupils Extraocular movements Fundi

Question 28

What may be seen on examination of visual fields in a patient in a light coma?

Answer 28

No blink in one field - indicate hemianopia and contralateral hemisphere lesion

Question 29

What may be seen on pupil examination in a patient in a coma?

Answer 29

Normal direct and consensual reflexes - intact midbrain Midposition non reactive ± irregular = midbrain lesion Unilateral dilated and unreactive = 3rd nerve compression Small reactive - pontine Horners syndrome - ipsilateral medulla or hypothalamus lesion, may precede uncle herniation

Question 30

What do you look for on examination of the funds in a patient in a coma?

Answer 30

Papilloedema Subhyaloid haemorrhage Hypertensive retinopathy Signs of other disease

Question 31

How do you test extra ocular movements in a patient in a coma?

Answer 31

Observe resting position and spontaneous movement Test vestibule-ocular reflex with dolls head manoeuvre or ice water calorics If VOR is normal, most of the brainstem is likely unaffected

Question 32

What is dolls head manoeuvre?

Answer 32

Eyes should look at same point in space when head move quickly laterally or vertically

Question 33

What is ice water calorics?

Answer 33

Normal if eyes deviate to cold ear with nystagmus to the other side

Question 34

How do you assess for CNS asymmetry in a patient in a coma?

Answer 34

Assess tone, spontaneous movements and reflexes Test for hemiplegia - raise both arms and compare how they fall under gravity: - if one falls faster than the other, indicate cortical dysfunction