Neuroscience (Approach to Loss of Consciousness)

Question 1

State the 4 levels of impariment of consciousness

Answer 1

Level 1 - Lethargy
- difficultu maintaining aroused state

Level 2 - Obtunded
- responsive to non-pain stimuli

Level 3 - Stupor
- responsive only to pain

Level 4 - Comatose
- no clinical repsonse to external stimuli
- only occurs if large areas of brain are affected

Question 2

SYNCOPE
- ____ cerebral ____
- Loss of ____ and ____ ____
- ____ reduction of energy substrates to ____ ____ due to (1) or (2)
- Presentation =
- Pre-syncope presentation =
- Risk factors =
- Types of syncope =

Answer 2

SYNCOPE
- TRANSIENT cerebral HYPOPERFUSION
- Loss of CONSCIOUSNESS and POSTURAL TONE
- ABRUPT reduction of energy substrates to CEREBRAL CORTEX due to (1) CEREBRAL PERFUSION or (2) OXYGENATION IN BLOOD
- Presentation = pallor, sweating, brief stiffening, few irregular myoclonic jerks (episode <30s)
- Pre-syncope presentation = dizziness, nausea, feeling of warmth, sweating, vision greying, hearing muffled
- Risk factors = peripheral vasodilation
- Types of syncope = neurally-mediated OR cardiogenic

Question 3

State the presentation of SYNCOPE and PRE-SYNCOPE

Answer 3

SYNCOPE
- loss of consciousness and postural tone
- pallor and sweating
- brief extesnor stiffening or spasms
- few irregular myoclonic jerks
- whole episode lasts less than 30 seconds

PRE-SYNCOPE
- lightheadedness, dizziness, nausea
- feeling of warmth
- sweating
- vision greying
- hearing muffled

Question 4

State everything you know about acute seizures

Answer 4

ACUTE SEIZURES = seizures resulting from acute systemic metabolic disturbace or from acute disturbance of brain strucure or metabolism

Causes:
1. hypoglycaemia or electrolyte distubrance
2. head trauma
3. stroke
4. alcohol or alcohol withdrawal
5. drugs or drug withdrawal

Question 5

State the causes of acute seizures

Answer 5

ACUTE SEIZURES
- hypoglycaemia or electrolyte disturbance
- head trauma
- stroke
- alcohol or alcohol withdrawal
- drugs or drug withdrawal

Question 6

State everything you know about epilepsy

Answer 6

EPILEPSY = chronic condition characterised by predisposition to recurrent, usually spontaneous seizures
- Reflex epilepsies occur in response to specific sensory stimulus and are hence not spontaneous

(1) Pathophysiology
- Increased excitatory neuronal discharges which spread to adjacent areas → spread across corpus callosum to opposite hemisphere
- Fewer inhibitory neurotransmitters

(2) Differentials
- Breath holding spell - precipitated by noxious, painful stimuli or suprise
- Cyanosed, limp, unresponsiveness
- Crying and cessation of breathing in expiration
- Rapid recovery

Question 7

State the pathophysiology of epilepsy

Answer 7

• Increased excitatory neuronal discharges which spread to adjacent areas → spread across corpus callosum to opposite hemisphere
• Fewer inhibitory neurotransmitters

Question 8

State the features of epileptic seizures

Answer 8

EPILEPTIC SEIZURES
- sudden stiffening followed by repetitive shakes or jerks
- sudden fall or drop of head
- blank spells and reptitive eye blinks
- loss of awareness with semi-purposeful movements
- brief involuntary purposeful movements
- spasms