Coma

Question 1

What is the first biochemical test you would do in an unconscious patient?

Answer 1

Glucose (quick to do)- might be hypo-coma (easily remediable) + will affect prognosis if untreated (irreversible brain damage)

Question 2

What examination is important in an unconscious patient?

Answer 2

GCS assessment

Airway - clear? Maintained spontaneously?
Breathing - RR, clear chest?
Circulation - HR, cap refill, temp

Neuro - PEARL? Tone? Reflexes? Fundoscopy?

Full body scan - injuries? Bleeding? Tongue bites? Track marks? Organomegaly? Breath smell?

Question 3

What are the components on the GCS?

Answer 3

Best response /15, lowest is 3,

(Report each component individually - as can have same score of 14 due to confusion or due to opening eyes on command)

Eyes - open, responsive = 4; open to voice = 3; open to pain = 2; closed, unresponsive = 1

Motor - active = 6 , localises to pain = 5 , flexes from pain = 4, abnormal flexion from pain (decorticate), abnormal extension from pain (decerebrate) = 2, unresponsive = 1

Verbal - Oriented to time/place/person = 5, confused = 4 , inappropriate words = 3 , groaning/incomprehensible sounds = 2 , unresponsive = 1

Question 4

What is decorticate posturing?

Answer 4

Patients with decorticate posturing present with the arms flexed, or bent inward on the chest, the hands are clenched into fists, and the legs extended and feet turned inward; The effects on these two tracts (corticospinal and rubrospinal) by lesions above the red nucleus is what leads to the characteristic flexion posturing of the upper extremities and extensor posturing of the lower extremities.

May be damage to areas including the cerebral hemispheres, the internal capsule, and the thalamus.It may also indicate damage to the midbrain.

While decorticate posturing is still an ominous sign of severe brain damage, decerebrate posturing is usually indicative of more severe damage at the rubrospinal tract, and hence, the red nucleus is also involved, indicating a lesion lower in the brainstem.

Question 5

What is decerebrate posturing?

Answer 5

In decerebrate posturing, the head is arched back, the arms are extended by the sides, and the legs are extended.

A hallmark of decerebrate posturing is extended elbows. The arms and legs are extended and rotated internally. The patient is rigid, with the teeth clenched.

The signs can be on just one side of the body or on both sides, and it may be just in the arms and may be intermittent.

Indicates brain stem damage, specifically damage below the level of the red nucleus (e.g. mid-collicular lesion). It is exhibited by people with lesions or compression in the midbrain and lesions in the cerebellum.

Decerebrate posturing is commonly seen in pontine strokes.

A patient with decorticate posturing may begin to show decerebrate posturing, or may go from one form of posturing to the other.

Progression from decorticate posturing to decerebrate posturing is often indicative of uncal (transtentorial) or tonsilar brain herniation.

Question 6

What is the AVPU score useful for?

Answer 6

Nonverbal patients e.g. Children, elderly, mental disability

Question 7

What methods can be used to apply painful stimuli?

Answer 7

Trapezius squeeze = central painful stimulus

Supraorbital pressure = central - especially useful to differentiate flexion and localisation to pain (should localise, picking up hand to pull painful stimulus away),

Mastoid pressure

Jaw thrust

Ear lobe pressure

Compression of nailbed with hard object e.g. pen = peripheral

Repeat stimulus elsewhere if unsure

Question 8

What are some common causes of decreased level of consciousness?

Answer 8

Traumatic - SDH, EDH

Metabolic - Hypoglycaemia, DKA, hepatic encephalopathy, hyponatraemia, hypcalcaemia, uraemia, hypoxia, hypercapnia

Drugs - alcohol intoxication or withdrawal, overdose - heroin; sedating medications

Vascular - CVA (simple uncomplicated ischemic stroke not in brain stem shouldn’t cause LoC, UNLESS infarct in speech or motor regions - will affect GCS so use with caution in these instances) , SAH; haemorrhage (hypovolaemic shock), cardiogenic shock
Infection - neuro, systemic (septic shock)

Neurological - space occupying lesion e.g. Ca (primary or secondary), seizure/post ictal?

Psychiatric - catatonia, fugue states, dementias

Question 9

What are some important investigations that may be guided by the presentation?

Answer 9

CT head - esp if injured from falling

ECG - arrythmias, MI

Bloods - FBC (WCC, Hb), LFT (encephalopathy), U+E (ureaemia, other metabolic disturbances), VBG/ABG, cultures

Urine drug screen (+ dip?)