Coma Flashcards
What is the definition of a coma?
A state of unarousable phycological unresponsiveness in which subjects lie with eyes closed and show no psychological understandable response to external stimuli or inner need
What the scoring of a come on the GCS?
GCS<8
Eye opening is 2 or less
Verbal response is 2 or less
Motor response is 4 or less
What does consciousness depend on?
Intact ascending reticular activating system to act as alerting or awakening element of consciousness
Functioning cerebral cortex of both hemispheres which determines content of that consciousness
What does the reticular activating system in coma control?
Arousal
What does the cerebral hemispheres control in coma?
Awareness of environment
Determines lethargy, stupurous, obtunded and coma
What are other states of consciousness?
Coma and general anaesthetic are least amount of cerebral hemispheres and reticular activating system
Vegetative state is more reticular activating system
What is involved in resuscitation?
ABC - airway, breathing and circulation
Blood samples - glucose, biochemistry, haematology, blood gas
Establish BP, pulse, temp., IV access and stabilise neck
Examine for evidence of meningitis
What can cause a change in respiration?
Depressed - drug overdose or metabolic disturbance
Increased - hypoxia, hypercapnia and acidosis
Fluctuating respiration - brainstem lesion
What is involved in examination and monitoring?
Temp., HR, BP, CVS, resp., skin, breath for ketones, abdomen, meningism, and fundal exam
What is involved in the neurological assessment of coma?
GCS
Brainstem function
Motor function and reflexes
What is tested in brainstem function?
Pupillary reactions, corneal responses, spontaneous eye movements, oculocephalic responses (doll’s eye), oculovestibular responses, and respiratory pattern in medullary centre
What can show motor function?
Motor response
Muscle tone
Tendon response
Seizures
What could be the cause if patient in coma but no meningism or focal brainstem/ lateralising cerebral signs?
Toxic, metabolic or systemic problems
What could be the cause if patient in coma with meningism but no focal brainstem or lateralising cerebral signs?
Subarachnoid haemorrhage
Meningitis
Encephalitis
What could be the cause if patient in coma with focal brainstem or lateralising cerebral signs?
Focal cerebral - tumour or infarct
What are some causes of a coma without focal or lateralising signs or meningism?
Anoxic/ ischaemic conditions
Metabolic disturbances
Intoxications
Systemic infections
Hyperthermia/ hypothermia
Epilepsy
What investigations are done?
Toxicology screen - alcohol level
Measure blood sugar and electrolytes
Assess hepatic and renal function
Acid base assessment
Measure BP
Consider carbon monoxide poisoning
What imagining investigations are done?
CT head scan
Lumbar puncture
MRI
If CT/MRI not diagnostic then metabolic screen, LP and EEG
What are medical causes of a coma lasting more than 5 hours?
Mainly drug ingestion or alcohol
Hypoxia
Cerebrovascular event - haemorrhage or infarction
Metabolic - diabetes, hepatic failure, renal failure, sepsis and hypoxia
Describe locked in syndrome
Patient has total paralysis below level of third nerve nuclei so although eyes are open and can elevate/depress but there is no horizontal movement or or other voluntary eye movement
Patient can open eyes voluntary and signal numerically by eye closure
What is involved in continuing care of patients in coma?
Maintenance of vital functions
Care of skin
Attention to bladder and bowel function
Control of seizures
Prophylaxis of DVT and peptic ulceration
Prevention of contractures
How can head injury lead to focal neurological signs/ epilepsy?
Diffuse axonal injury, contusion, intracranial haematoma, extradural haematoma and subdural haematoma
Describe a SDH and EDH on CT
SDH is ellipse and convex
EDH is concave makes lens shape
How is head injury managed?
Stabilise cervical spine, ABCs, GCS under 8 then intubation and ventilation, treat raised ICP, cranial imaging and neuro observation
How is raised ICP treated?
Surgery to relieve pressure, osmotic agents (mannitol), reduce pain, maintain good PO2 and reduce PCO2, and reduce metabolism
What are the clinical features of non-epileptic attacks?
Sinusoidal tremor not jerking, pelvic thrusting, side to side head movements, eye closed and resist opening and partial responsiveness
What is the Rosier scale?
From -2 to +5
Assess stroke
If more than 0 then stroke
Seizure and LOC is -1 each
Describe hemicraniectomy
Decompressive surgery for severe cerebral swelling post stroke
