Coma

Question 1

Differentials for coma:

Answer 1

Lateralising signs
- Space-occupying lesion (tumour, abscess, AVM etc.)
- Haemorrhage
- CVA
- Trauma

Nil lateralising, but meningism
- Meningoencephalitis (infectious)
- SAH

Nither lateralising nor meningism (global)
- Organ failure (uraemia, ammonia)
- Toxins (alcohol, CO, sedatives, opioids, ++)
- Post-ichtal
- Endocrine (Addison’s, hypothyroidism, hypopit)
- Autoimmune encephalitis (post-infectious, paraneoplastic, antiNMDA)
- Metabolic (hypo/hyperglycaemia, hypo/hyperthermia, hypoxia, hypercarbia, hypoNa, hypo/erosmolarity)

NON-COMA:
- Functional
- Catatonia
- Locked-in
- Non-convulsive status epilepticus

Question 2

What IMMEDIATE threats need addressing when a coma patient arrives in ED?

Answer 2

Hypoxia
Herniation
Hypoglycaemia
Seizure

Question 3

PHYSICAL EXAMINATION in coma:

Answer 3

GENERAL
- Posturing
- Abnormal movements
- Stigmata (CLD, track marks etc.)

GCS

MENINGISM

EYES
1- Pupils
- Size
- Reactivity
2- Gaze
- Weirdly DYNAMIC eyes (Roving, PingPong) = GLOBAL (metabolic, toxic)
- Weirdly STATIC eyes (conjugate or skew deviation) = STRUCTURAL
3- Fundus
- ICP

Brainstem Reflexes
1- Corneal reflex
2- OC reflex (‘Dolls Eye’)
- Eyes follow head = bad brainstem
3- Gag/cough
Caloric VO reflex not in ED
–> Eyes should turn towards cold flush
–> Abscence means brainstem issue, or very deep global coma

Lateralising motor signs
- Tone/ reflexes/ clonus

Breathing
- ?hypovent (opioids)
- ?Kausmaul (metabolic)
- ?Cheyne stokes (structural brain)
- ?Hiccups/ sighing

Question 4

Differentials for abnormal pupils in coma:

Answer 4

Fixed and dilated
- Deep coma
- Brain death

Dilated and reactive
- Amphetamine
- Anticholinergics

Unilateral ‘blown’
- CN III compression
–> ICH + uncal herniation
–> PCOM
–> Cav sinus thrombosis

Pinpoint
–> Toxic: Opioids, clonidine, GHB, Organophosphates
–> Pons

Fixed in mid
–> Midbrain (lesion, or central herniation)

Question 5

Testing for meningism in comatose patient:

Answer 5

Patient lying flat and extended

1- Nuchal Rigidity
- Resistance to chin-to-chest

2- Kernig
- Flex to 90degr at hip and knee
- Attempt to straighten knee
- Positive if won’t let you (or brings other leg up)

3- Brudinski
- Attempt chin-to-chest
- Positive if brings legs up

___________
Other:
- Photophobia
- Opisthotonos

Question 6

What 3 investigations should ALL coma patients get?

Answer 6

GLUCOSE
GAS
CTB (almost all)

Other:
- Thyroid function
- UDS, serum drug levels
- LP (after CTB)
- EEG
- BHCG

Question 7

What is the ‘coma cocktail’:

Answer 7

Elements to be considered:

Naloxone 400microg IV + repeat
Flumazenil 0.1-0.2 mg/kg + repeat
Thiamine 100mg IV
Glucose 50ml 50%