Neuro - Altered Conscious Level and Neurological Disturbance

Question 1

Loss of consciousness spectrum and summary of causes

Answer 1

Spectrum:
Syncope/Blackout
Impaired conscious level
Coma

Causes: BBBMF
Brain
Beat (Heart)
Blood
Metabolic
"Failure" (organ)

Question 2

Loss of Consciousness - Brain

Presentation and DDx

Answer 2

Neurological - Impaired conscious level/coma

Diffuse intracranial:
SAH, Epilepsy, Meningitis, Encephalitis

Hemisphere lesion [Cerebral]:
Subdural, Extradural, Stroke/TIA

Brain stem [Brainstem/Cerebellar]:
Any of the above - Raised ICP pushes on brain stem

Peripheral Nervous system:
Peripheral (Autonomic) Neuropathy

Hyponatraemia
Hypocalcaemia

Question 3

“SHIT”

Answer 3

abscesS
Haemorrhage
Ischaemia/Infarct
Tumour (primary/secondary)

Question 4

Loss of Consciousness - Beat

Presentation and BP formula

Answer 4

Cardiac –> Blackouts
Syncope - Loss in consciousness due to a sudden drop in blood pressure

BP=HRxSVxTPR

Question 5

Components of BP formula

Answer 5

HR: Bradycardia + Arrhythmias

SV (inc. Outflow obstruction):
Tamponade, Cardiomyopathy
Left: HOCM/Aortic stenosis
Right: PE

TPR (inc. Neuropathy):
Vagal overactivity
Peripheral (autonomic) neuropathy

Question 6

Loss of Consciousness - Blood

Presentation

Answer 6

Blood/Vasculature –> Impaired consciousness/Blackout

Venous - Pooling
Arterial - Atherosclerosis e.g. Vertebrobasilar insufficiency (TIA, CVA), shock
Anaemia

Question 7

Metabolic causes of impaired conscious level/coma

Answer 7

Hypoglycaemia/Hyperglycaemia
Hyper/Hypocalcaemia
Hyper/Hyponatraemia
Drug overdose/poisoning/toxins
Addisonian Crisis, Myxoedema

Question 8

Organ failure causes of impaired conscious level/coma

Answer 8

Hepatic encephalopathy
Uraemic Encephalopathy
Hypoxia/CO2/Narcosis (COPD)

–>Liver/Kidneys/Lungs

Question 9

Blackout - COLLAPSED

Answer 9

Carotid Sinus Syncope
Orthostatic (Postural) Hypotension
refLex - Vasovagal (Neurocardiogenic) Syncope
Low Glucose (Diabetics)
Arrhythmia/Stroke's Adam's Attack
Panic (--> Anxiety --> Hyperventilation)
Situational Syncope
Epilepsy
Drop Attacks

Question 10

Brain Haemorrhages

Answer 10

Extradural: Classic ‘lucid interval’ before LOC = arterial bleed

Subdural: Hx of falls, progressive confusion = venous bleed between dura and arachnoid layers

Subarachnoid: sudden severe headache = bleeding into the subarachnoid space. Half of all patients lose consciousness and altered mental status is common.

Question 11

Brain - Raised ICP

Answer 11

Raised ICP –> Space occupying lesion –> Abscess/Haemorrhage/Infarction/Tumours (SHIT); Oedema; Head injury

Question 12

Raised ICP compressive signs

Answer 12

Headache
Nausea and Vomiting
Altered GCS
Papiloedema
Focal neurology
Pupil changes - dilatation; down and out.

Question 13

Raised ICP herniation

Answer 13

CN III (opthalmoplegia)
Ataxia
Apnoea

Question 14

Transient Loss of Consciousness

Answer 14

Either increased vagal or decreased sympathetic activity

Question 15

Carotid Sinus Syncope

Answer 15

Hypersensitive Baroreceptors –> Excessive reflex bradycardia +/- vasodilation on minimal stimulation, e.g. head turning/shaving

Question 16

refLex - vasovagal (neurocardiogenic syncope)

Answer 16

Reflex Bradycardia +/- vasodilation provoked by emotion/pain/fear/standing too long

Question 17

Transient Arrhythmias (Stroke’s Adam’s attack)

Answer 17

–> Decrease in Cardiac Output –> LOC.

Collapses with no warning, pale, slow/absent pulse; Recovery in seconds, patient flushes, pulse recovers

Question 18

Situational Syncope

Answer 18

Cough, Effort (e.g. exercise; cardiac origin), Micturition (mostly men)

Question 19

Postural Hypotension

Definition, Presentation, Diagnosis

Answer 19

Drop in systolic BP > 20 mmHg or diastolic BP > 10 mmHg after standing for 3 mins vs lying

Elderly
Hypovolaemia
Drugs (Nitrates, Diuretics, Antihypertensives, Antipsychotics)
Peripheral Neuropathy –> Inadequate Vasomotor reflex (insufficient sympathetic increase in HR/vasoconstrution) = DM, Parkinson’s disease, MSA, Autonomic Neuropathy
Endocrine = Addison’s, Hypopituitarism (decreased ACTH)

Good history and Lying/Standing BP should be enough to diagnose. Confirm with Tilt test

Question 20

Aortic Stenosis

Definition, Presentation, Clinical signs

Answer 20

Narrowed valve orifice
20% due to congenital bicuspid valve
Most common cause in adults is calcification of normal trileaflet valves

Presents with…
Dyspnoea
Chest Pain
Syncope

Clinical signs…
Harsh ejection systolic murmur heard loudest at the right upper sternal edge at end expiration, which radiates up towards the carotids.
Narrow pulse pressure
Slow rising pulse

Question 21

Hypoglycaemia presentation

Answer 21

Symptoms present when glucose <3mmol/L:
Mainly Diabetic on NEW insulin/Oral hypoglycaemic + exercise
Alcohol, Liver Failure = risk factor –> Decreased hepatic glucose production.

Symptoms;
Sweating
Weakness
Decreased GCS: Drowsiness --> LOC
Palpitations and anxiety

Question 22

Blackout Investigations

Answer 22

Depends on suspected cause

Bedside: Examination - Cardio, Neuro, Lying/Standing BP
Fluids: FBC, UandE, Glucose, ABG
Imaging:
ECG/Cardiac Monitor/24 hr tape
Echocardiogram
EEG, CT/MRI

Question 23

GCS Summary

Answer 23

Glasgow Coma Scal eis the most commonly used scoring system for initial assessment and monitoring of a patient’s level of consciousness.

Assessment of…
Eye opening (4)
Best Verbal Response (5)
Best Motor response (6)

Question 24

AVPU

Answer 24

Primary survey

Alert
responds to Vocal stimuli
responds to Pain
Unresponsive

Question 25

GCS Detailed

Answer 25

Motor 1-6:
No response to pain
Extensor response to pain
Flexor response to pain
Withdrawing to pain
Localising to pain
Obeying commands

Verbal 1-5:
None
Incomprehensive sounds
Inappropriate speech
Confused (disoriented)
Oriented (time/place/person)

Eyes 1-4:
None
In response to pain
In response to voice
Spontaneous

Question 26

GCS score ranges and implications

Answer 26

3: Globally no response
8 or less: Coma, Severe injury, Consider airway
9-12: Moderate injury
13-15: Minor injury

Question 27

Stroke Definition

Answer 27

Rapidly developing clinical signs of focal or global disturbance of cerebral function, with symptoms lasting 24 hrs or more, with no apparent cause other than that of a vascular origin.

Question 28

TIA Definition

Answer 28

Transient ischaemic attacks are acute episodes of focal loss of cerebral function lasting less than 24 hrs, which are attributed to an inadequate blood supply.

Question 29

UMN lesion clinical features

Answer 29

Contralateral Signs – motor and sensory
NO fasciculations
NO muscle wasting
Spasticity
Weakness – Extensors-Arms; Flexors-Legs
Hyperreflexia
Upgoing Plantar response
Pronator Drift

Question 30

Anterior Cerebral Artery

anatomy and pathophysiology

Answer 30

Frontal and parietal lobes

Disturbance of judgement
Loss of social behaviour
Contralateral hemiparesis leg > arm
Mild sensory deficit

Question 31

Middle Cerebral Artery

anatomy and pathophysiology

Answer 31

Frontal, Parietal, Temporal Lobe, Subcortical Structures (e.g. Basal Ganglia) Internal Capsule

Contralateral hemiplegia arm/face/thorax > leg
Aphasia (Broca & Wernicke’s areas)
Hemisensory deficits

Question 32

Posterior Cerebral Artery

anatomy and pathophysiology

Answer 32

Occipital and Lower Temporal Lobe

Visual Defects:
Homonymou hemianopia
Visual agnosia
Prosopagnosia

Question 33

TIA Clinical Features

Answer 33

(Common in SBAs is a description of) Focal neurological deficit unilaterally, e.g. Amaurosis Fugax
(Transient and painless loss of vision in one eye due to the passage of an embolus into the central retinal artery).

Question 34

TIA Ix/Rx

Answer 34

CT Head to exclude a haemorrhagic aetiology immediately.

• -> Depressed consciousness (GCS < 13)
• -> Suspected haemorrhage (drugs etc) or Raised ICP

Consider thrombolysis with tPA if within the 4.5 hour window and there are no contraindications.
–> Thrombolysis is done with Alteplase (tPA) at 10% bolus, 90% infusion at a dose of 0.9mg/kg

Presentation after the 4.5 hr window is managed with aspirin.
All people presenting with acute ischaemic stroke should be given aspirin.

Question 35

Seizures/Epilepsy

Definition and Pathophysiology

Answer 35

Seizure - A paradoxical discharge of cerebral neurons –> External manifestations
Epilepsy - A recurring tendency to have seizures.

Before: epileptic aura (marks onset), triggers (flashing lights)
During: stiffness, jerking, incontinence, side tongue-biting, sweating, palpitations, mouth frothing, pallor, cyanosis
After: muscle ache, post-ictal confusion/drowsiness

Seizures may be partial (focal) or generalised (involving both hemispheres)

Question 36

Partial seizures

Categorization and complications

Answer 36

Simple Partial
[Focal motor/sensory/autonomic/psychic]
Awareness unimpaired
No post-ictal confusion

Complex Partial
[Deja-vu, depersonalisation, altered emotion, epigastric fullness; can start as simple partial (=aura)]
Most commonly arise form the temporal lobe
Awareness/consciousness is impaired
Post-ictal confusion common

Question 37

Partial seizures Localising Features

Frontal lobe

Answer 37

Behaviour
Motor – posturing, peddling
Dysphasia/speech arrest
Motor arrest, subtle behaviour disturbances
Jacksonian March

Question 38

Partial seizures Localising Features

Temporal Lobe

Answer 38

Complex
Emotional disturbance 
Hallucinates
(smell/taste)
Depersonalisation
Automatisms

Question 39

Partial seizures Localising Features

Parietal Lobe

Answer 39

Sensory disturbance – tingling, numbness

Motor symptoms – abnormal movement/rhythmic muscle contractions

Question 40

Partial seizures Localising Features

Occipital Lobe

Answer 40

Visual phenomena - spots, lines, flashes

Question 41

Primary Generalised Seizures

Pathophysiology

Answer 41

Convulsive vs Non-Convulsive

Convulsive:
Tonic - limb stiffening
Clonic - limb jerking
Tonic-Clonic - LOC followed by a stiff body with flexed elbows and extended legs followed by violent shaking with eyes rolling (grand mal), incontinence, post-ictal and drowsiness
Myoclonic - sudden isolated jerk of limb, face or trunk; disobedient limb –> thrown to the ground

Non-Convulsive:
Absence - 10s or fewer of vacancy, sometimes myoclonic jerks (petit mal), presents in childhood - no post ictal.
Atonic (Akinetic) - Sudden loss of muscle tone, ‘Drop Attacks’. No LOC

Question 42

Status Epilepticus

Definition and Rx

Answer 42

Continuous seizure or serial (at least 2) discrete seizures between which there is incomplete recovery of consciousness of at least 30 min duration.

–> Medical Emergency

Rx:
ABC - open and maintain airway, recovery position
Oxygen 100%
Stop seizures –> Slow IV Bolus Lorazepam (1) 204mg
–> Lorazepam (2) if no response in 10 mins
Continuing seizures –> IV Phenytoin/Diazepam

Question 43

Encephalitis

Definition, Causes, Signs, Ix

Answer 43

Brain parenchyma inflammation - may be focal symptoms

Causes
Viral - HSV, CMV, EBV, VZV
Non-viral - Any bacterial meningitis, TB, cryptocossus, etc

Bizarre Encephalopathic behaviour
Decreased GCS/Coma
Focal signs
Seizures

CT - cerebral oedema - compressive symptoms (Medical Emergency

Question 44

Meningitis

Answer 44

Meningeal Inflammation

Causes:
Meningococcus
Pneumococcus

Headache
Meningism
Decreased GCS/Coma
Focal signs
Seizures
Fever
Rash
Kernig's sign +
Brudzinski +

Question 45

Encephalitis vs Meningitis

Answer 45

Encephalitis:
Compressive symptoms/focal YES
Seizures YES
Altered Mental State YES

Meningitis:
Meningism YES
Seizures < encephalitis
Altered mental state < encephalitis

Question 46

Metabolic LOC/Seizures

Presentations and Causes

Answer 46

Hyponatraemia (<135)
Headaches, comiting, drowsiness, seizures
Thiazide Diuretics (Hypo/Eu/Hypervolaemic)

Hypocalcaemia
e.g. complicatoin of thyroid surgery (loss of parathyroids)
4 CATS - Consulvsions, Arrhythmia, Tetany, Spasms
Chvostek’s and Trousseau’s signs (Face and hand)