Evaluation of Unconsciousness - FM Flashcards
What are the core components of managing an unconscious patient?
History, Examination (GCS/AVPU, pupil size), Investigations, Treatment/Management
How is coma defined in an unconscious patient?
A completely unaware patient unresponsive to external stimuli, with only eye opening to pain, no eye tracking or fixation, and limb withdrawal to a noxious stimulus at best
What are the two main pathophysiological causes of unconsciousness?
Diffuse cerebral hemisphere insult (e.g., hypoxia, ischaemia, trauma) and disruption of the ascending reticular activating system
What are the possible differential diagnoses of non-traumatic unconsciousness?
Metabolic disorders, infections, stroke, epilepsy, drug toxicity, organ failure, etc.
What does the Glasgow Coma Scale (GCS) assess?
Eye response, verbal response, and motor response
What is the AVPU scale used for?
A quick assessment of consciousness: Alert, Verbal response, Pain response, Unresponsive
What is the significance of small pupils (<2 mm) in an unconscious patient?
Opioid toxicity or a pontine lesion
What does midsize (4–6 mm) unresponsive pupils suggest?
A midbrain lesion
What are maximally dilated pupils (>8 mm) associated with?
Drug toxicity (e.g., anticholinergic overdose)
What condition is indicated by mixed and dilated pupils?
3rd cranial nerve (oculomotor) lesion from uncal herniation
What is Kussmaul respiration and what does it indicate?
Deep, laboured breathing indicating severe metabolic acidosis, often seen in diabetic ketoacidosis
What are the characteristics of ataxic (Biot’s) breathing, and what does it suggest?
Quick, shallow inspirations followed by apnoea, indicating a lesion in the lower pons
What does central neurogenic hyperventilation indicate?
Deep and rapid breathing (≥25 breaths per minute), indicating a lesion in the pons or midbrain
Why is Cheyne-Stokes breathing not useful for making a firm diagnosis?
It is associated with many conditions and does not point to a specific diagnosis
What is the first bedside investigation to perform in an unconscious patient?
Bedside capillary glucose
Why should blood glucose be checked even if capillary glucose is normal?
To confirm hypoglycaemia, as capillary glucose may be inaccurate
What are the key laboratory investigations for an unconscious patient?
FBC, electrolytes (E/U/Cr), calcium, phosphate, LFTs, clotting profile, toxicology screen
What imaging studies are useful in evaluating an unconscious patient?
ECG, CXR, blood cultures, arterial blood gases, brain CT, brain MRI, lumbar puncture
Why is EEG performed in unconscious patients?
To rule out non-convulsive status epilepticus
When should an unconscious patient be intubated?
If GCS < 8, airway protection is lost, or ineffective respiratory drive is present
What is the recommended initial treatment for a patient with hypotension?
IV fluids or vasopressors if MAP < 70 mmHg
What is the antidote for opioid toxicity?
Naloxone
How should a patient with raised intracranial pressure (ICP) be positioned?
30-degree head tilt position, consider mannitol
When should specialist or critical care be involved in management?
Early, when cause is unclear or condition deteriorates
