Disturbances of Consciousness Flashcards
(36 cards)
Define consciousness
is the state of being aware of self and the environment
Describe an “alert” patient
full wakefulness and immediate and appropriate responsiveness
Describe a “confused” patient
inability to think with the usual speed and clarity
What is obtundation?
the patient is drowsy and indifferent to the environment, but responsive to verbal stimuli
What is stupor?
the patient is unconscious but rousable when stimulated
When would a patient be described as being in a coma?
the patient is unaware of self and the environment and is not rousable
What is important for forming a Dx relating to impaired consciousness?
the duration of impaired consciousness
- can be transient or ongoing
What does the normal conscious state depend on?
the integrity of the brainstem reticular activating system and the cerebral hemispheres
What are the most common causes of transient loss of consciousness (LOC) ?
- Syncope
- Seizures
- Psychogenic/’non-epileptic’ attacks
What are uncommon causes of transient LOC?
- Hypoglycaemia
- Narcolepsy/cataplexy
- Hyperventilation
- Vertebrobasilar ischaemia
- Vertebrobasilar migraine
What is syncope?
transient LOC and posture that results from a global reduction in blood flow to the brain
What are the main symptoms of syncope?
- usually when standing
- hypotensive symptoms: light-headed, faint, blurred/dim vision, sounds seem distant, nausea, hot/cold, sweating
- pale skin colour
- shallow respiration
- floppy tone
What are the features of recovery from syncope?
- Recovery is usually rapid with no confusion
- Pallor may persist
- No focal neurological signs
What are the 5 main causes of syncope?
- Vasovagal syncope
- Situational syncope; micturition/cough
- Postural hypotension
- Primary cardiac dysfunction
- Carotid Sinus disease
What causes vasovagal syncope?
caused by a sudden drop in BP due to peripheral vasodilation (systolic drops to <60mmHg)
Describe micturition syncope
Men who get up to urinate in the middle of the night. it is a combination of vasodilation (from emptying of the bladder), postural hypotension (from standing) and bradycardia
Describe cough syncope?
sustained coughing can increase intrathroacic pressure, which impairs venous return to the heart (valsalva). Increase in CSF pressure, reduction in pCO2 and resultant vasoconstriction may be contributory
What is postural hypotension
upright posture is accompanied by an uncompensated fall in BP
Who is postural hypotension likely to occur in?
- Normal individuals
- Drugs (antihypertensives)
- Autonomic neuropathy (diabetes, Guillian-Barre)
- Hypovolemia (blood loss, sepsis, hypoadrenalism)
- Neurodegenerative disease (Parkinsons, mutlisystem atrophy)
What conditions are likely to cause primary cardiac dysfunction syncope?
- arrhythmias
- LV outflow obstruction (aortic stenosis, hypertrophic obstructive cardiomyopathy)
- RV outflow obstruction (pulmonary stenosis, pulmonary hypertension, PE)
- Ventricular failure (acute anterior MI, dilated cardiomyopathy)
How does carotid sinus disease cause syncope?
Hypertensive - less stretch needed for reflex bradycardia/decreased BP
What are the prodromal symptoms for syncope caused by hypoglycaemia?
- feeling tremulous and sweaty
- palpitations
- confusion
What are the main causes of syncope caused by hypoglycaemia?
- over treatment of diabetes
- liver failure
- hypopituitarism
- Addison’s disease
- insulinsomas
What is narcolepsy?
excessive sleepiness and sleep attacks at inappropriate times
