Coma

COMA

Objectives
To roughly understand the anatomical basis of Consciousness

To know the common causes of coma

To know the basic management of patients with coma.

Definition

Consciousness?

A state of awareness of self and environment and responsiveness to external stimulation and inner need.

- Adams -

Aetiology

Metabolic
-extrinsic: Alcohol
substance abuse
Drugs
heavy metals and poisons

Aetiology

Metabolic
-intrinsic: fluid (Shock) and electrolytes
Nutritional
Endocrine
Organ failure

Aetiology

Structural
- Supratentorial
Traumatic
Vascular
Inflammatory
Neoplastic
Degenerative


Aetiology
Structural
- Infratentorial
Traumatic
Vascular
Inflammatory
Neoplastic
Degenerative

Brain Herniation

Supratentorial herniation

• Uncal (transtentorial)
• Central
• Cingulate (subfalcine)
• Transcalvarial


Infratentorial herniation
• Upward (upward cerebellar or upward transtentorial)
• Tonsillar (downward cerebellar)

Workup

How bad it is?
Is it Coma?
Is it metabolic x Structural?
Supra x Infra _tentorial?


Workup
ABC
History
[Hypoglycemia, B1 def., Narcotic, Benzodiazipine]  immediate correction

Physical examination

Workup
Physical examination

Medical exam.

Neurological exam.

Neuro-exam

Goals

-functional assessment!

-Is there structural brain damage?


-Supra x Infra tentorial?

-Differential diagnosis of Coma

Neuro-exam

Consciousness:
Responses to painful stimuli?
R/O locked in state,
Vegetative state,
Minimally conscious state
Glasgow-Coma scale

Neuro-exam

Ocular:

Hutchison's pupil -uncal herniation

Miotic sluggishly reacting to light – pontine

Midsized or Mydriatic fixed to light – Midbrain

Neuro-exam

Oculo-cephalic

Vestibulo-ocular

Neuro-exam

Rest of Cranials:
-Fundoscopy
-V: blink
-VII: cheeks and Eyes: Eyelid release test
-Gag

Neuro-exam

Respiratory patterns: Poorly localizing
Cheyne-Stokes : Supra-tentorial /metabolic
Central neurogenic hyperventilation: Midbrain/pons
Apneustic (short-cycle Cheyne-Stokes): pons/medulla
Ataxic (Biot): medulla
Intermittent: medulla


Neuro-exam
Motor system
Signs of hemiplegia
-wrist-dropping test
Arm-dropping test
Legs-dropping test
Driven postures: Decorticate, Decerebrate.

Neuro-exam

Meningeal Irritation Signs
- Neck stiffness
-Kernig’s sign
-Brudzniski’

Further assessment

. Investigations
-Blood
-Bed side
-Imaging
-Toxicology

Management

Specific: Treat the cause

Non specific: ABC, Feeding, Positioning, physiotherapy, monitoring, nursing care, etc…