Coma Flashcards by Isla Anderson

define coma?

A state of unrousable psychological unresponsiveness in which the subjects lie with eyes closed and show no psychologically understandable response to external stimulus or inner need

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what is the glasgow coma scale?

measures coma in patients

mild 13-15
moderate 9-12
severe - 3-8

3 = coma

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what 2 things is conciousness dependent upon?

an intact ascending reticular activating system to act as the alerting or awakening element of consciousness

a functioning cerebral cortex of both hemispheres which determines the content of that consciousness

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what is responsible for arousal in conciousness?

Reticular activating system

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what is responsible for awareness of environment in conciousness?

Cerebral hemispheres

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what are causes of reduced GCS?

Toxic/metabolic states
Hypoxia/hypercapnia/sepsis/hypotension
Drug intoxication/renal or liver failure
Hypoglycaemia, ketoacidosis

Seizures

Damage to reticular activating system

Causes of raised intracranial pressure
tumour, stroke, EDH, SDH, SAH, hydrocephalus

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what are examples of toxic/metabolic states?

Hypoxia/hypercapnia/sepsis/hypotension

Drug intoxication/renal or liver failure

Hypoglycaemia, ketoacidosis

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what are causes of raised intracranial pressure?

tumour, stroke, EDH, SDH, SAH, hydrocephalus

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what is first line management for resusitation?

Airway
Breathing
Circulation

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what does depressed respiration indicate?

drugs overdose
metabolic disturbance

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what does increased respiration indicate?

hypoxia
hypercapnia
acidosis

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what does fluctuating respiration indicate?

brainstem lesion

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following ABC what should be done further in a hospital setting?

blood samples

baseline bp, pulse, temp, IV acsess, neck stabalised

examine for evidence of meningitis

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what is a persistent vegetative state?

A state in which the brain stem recovers to a considerable extent but there is no evidence of recovery of cortical function

There is arousal and wakefulness but the patient does not regain awareness or purposeful behaviour of any kind

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what should be asked in the history of a patient experiencing coma?

? Predictable progression of underlying illness

? Unpredictable event in patient with previously known disease

? Totally unexpected event
? Head injury, sudden collapse, limb twitching, previous history of drug or alcohol abuse

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what should be monitored and examined in a coma patient?

Temperature
Heart rate, Blood Pressure, CVS
Respiration
Skin, breath
Abdomen
Meningism
Fundal examination

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what are neurological assessments of coma?

Glasgow Coma Scale

Brainstem Function

Motor Function + Reflexes

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how is eye opening measure in GCS?

Spontaneous 4
To speech 3
To pain 2
None 1

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how is best verbal response measured in GCS?

Orientated 5
Confused 4
Inappropriate words 3
Incomprehensible sounds 2
None 1

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how is best motor response measured in GCS?

Obeying Commands 6
Localising to pain 5
Withdrawing from pain 4
Flexing to pain 3
Extending to pain 2
None 1

what cranial nerves are responsible for pupillary reactions?

II + III

what cranial nerves are responsible for corneal responses?

V+VII

what cranial nerves are responsible for spontaneous eye movements?

III, IV, VI

what cranial nerves are responsible for oculocephalic responses (Doll’s eye)?

III, IV, VI, VIII

what cranial nerves are responsible for Oculovestibular responses?

III, IV, VI, VIII

what cranial nerves are responsible for Respiratory pattern?

Medullary centre

how is motor function tested?

Motor response Muscle tone Tendon reflexes Seizures (twitching posturing on limbs)

Coma without focal or lateralising signs and without meningism?

Anoxic/ ischaemic conditions Metabolic disturbances Intoxications Systemic infections Hyperthermia/ Hypothermia Epilepsy

what are investigations for Coma without focal or lateralising signs and without meningism?

Toxicology screen including alcohol level Measure blood sugar and electrolytes Assess hepatic and renal function Acid - base assessment and blood gases Measure blood pressure Consider carbon monoxide poisoning

Coma without focal or lateralising signs but with meningism?

Subarachnoid Haemorrhage Meningitis Encephalitis

investigations for Coma without focal or lateralising signs but with meningism?

CT head scan Lumbar puncture Appearance Cell count Glucose level Capsular antigen tests

Coma with focal brainstem or lateralising cerebral signs?

Cerebral tumour Cerebral haemorrhage Cerebral infarction Cerebral abscess

Investigations for Coma with focal brainstem or lateralising cerebral signs?

CT or MRI obligatory If CT/MRI not diagnostic, then investigate as for other causes of coma e.g. including metabolic screens lumbar puncture EEG

“Medical” causes of coma lasting more than 5 hours?

40% due to drug ingestion ± alcohol 25% due to hypoxia e.g. secondary to MI 20% due to cerebrovascular event, either haemorrhage or infarction 15% metabolic e.g. diabetes, hepatic failure, renal failure, sepsis, hypercapnia/hypoxia

what is locked in syndrome?

patient has total paralysis below level of nthird nerve nuclei and although able to open elevate and depress eyes has no horizontal eye movement and no other voluntary eye movement diagnosis depends on recognising that patient can open eyes voluntarily and signal numerically by eye closure

what factors affect prediction of outcome in coma?

Age Cause of coma Depth of coma Duration of coma Certain clinical signs, the most important of which are the brain stem reflexes

Prediction of Outcome in Coma in non traumatic coma?

Overall, only 15% of patients in non-traumatic coma for more than 6 hours will make a good or moderate recovery, the other 85% will die, remain vegetative or reach a state of severe disability in which they remain dependent

how is recovery in non traumatic cober > 6 H?

In non-traumatic coma >six hours, good recovery is seen in 35% of those with underlying metabolic cause 11% of those with hypoxic ischaemic insult 7% of those with cerebrovascular disease

how should care be continued for coma patients?

Maintenance of vital functions Care of skin, avoidance of pressure sores Attention to bladder and bowel function Control of seizures Prophylaxis of DVT, peptic ulceration Prevention of contractures Consider the “Locked - in” Syndrome

how can head injury leas to focal neurological signs/ epilepsy?

Diffuse axonal injury Contusion Intracerebral haematoma Extra-cerebral haematoma Extra-dural haematoma Sub-dural haematoma

how does subdural haematoma present on CT?

Subdural haematoma ellipse convex/convex

how does extradural haematoma present on CT?

Extradural haematoma concave/convex (lens)

how should a head injury be managed?

Stabilise cervical spine Airway/Breathing/Circulation If GCS≤8 - intubation+ventilation Treat raised ICP Cranial imaging - may need decompressive surgery or removal of haematoma Neuro observation

how is raised intracrainial presssure treated?

Surgery to relieve pressure heamatoma, ventricular shunt Osmotic agents e.g. mannitol Nurse with head at 30-45% (Venous return) Reduce pain Maintain good PO2, reduce PCO2 Reduce metabolism (reduce temperature, barbiturates)

what are clinical features of non epileptc attacks?

sinusoidal tremour not jerking pelvic thrusting side to dide head movements eyes closed and resist openong partial responsivness

what is the rosier scale used for?

It was created to aid first-line ER providers in determining which patients were likely experiencing a stroke, thus expediting referral to an acute stroke team. When compared to similar scales, such as the FAST, the ROSIER scale had greater sensitivity in acute stroke recognition.

what is a hemicraniectomy

decompressive surgeryf for severe cerebral swelling post stroke GCS fails 24-72 hour post stroke