Title: Coma
1Coma
- A state of unarousable psychologic
unresponsive-ness in which the subjects lies with
eyes closed - Coma vs. Consciousness
- Consciousness wakefulness and responsiveness
- The severity of coma is measured by comparing the
intensity of an external stimulus and the
complexity and purposefulness of the response
2- Hypersomnia
- excessive drowsiness and excessive sleep
- narcolepsy, hypothalamic disorders, drugs
- Akinetic mutism
- silent, alert, and awake appearance
- regular sleep-wake cycles
- no evidence of response to the environment,
mental activities, or spontaneous movements
3- Locked-in syndrome
- total paralysis of all somatic musculature
- preserved consciousness and most sensory
modalities - preserved vertical eye movements
- ventral pontine infarct
- Persistent vegetative state
- preserved brainstem function, including breathing
- spontaneous eye opening and regular sleep-wake
cycles - no recognizable cognitive function
4Three categories of Coma
- Diffuse brain dysfunction
- matabolic encephalopathy
- drug intoxication
- Primary brain stem disorders
- brainstem stroke
- brainstem neoplasm, absecess
- Supratentorial mass lesions
- causing secondary brain stem compression
5Systemic evaluation of Coma
- Is there systemic illness causing brain failure?
- Is there evidence of diffuse or focal brain
injury? - Is the patient improving or deteriorating?
6Neurological examination in Coma
- Response to external stimulation
- Motor response
- Size and reactivity of pupils
- Eye movements and ocular reflexes
- Pattern of breathing
7Response to external stimulation
- In order of verbal command, shouting, shaking,
and noxious stimulation - Localizing pain
- preserved brain stem function and intact
connections to the appropriate cerebral
hemisphere - Eye opening
- preserved function of RAS
8Motor responses
- Absence of any motor response
- severe brain stem damage
- severe sedative drug ingestion
- Decorticate, flexor posturing of the arms
- bilateral cerebral hemisphere damage
- toxic/metabolic encephalopathy
- Decerebrate, extensor posturing of the arms
- destructive lesions of the midbrain and upper
pons - hepatic and anoxic-ischemic encephalopathy
9Pupillary responses
- Small, reactive pupils
- metabolic
- IICP with hypothalamic dysfunction
- Very small pupils (pinpoint)
- pontine lesion
- narcotic (opioids) overdose
- Bilateral dilated fixed pupils
- seizure, anoxic encephalopathy
- exogenous catecholamimes
10Pupillary responses
- Midposition and fixed pupils
- midbrain dysfunction
- brain death
- Unilateral dilated pupil
- damage to IIIrd nerve from trnastentorial
herniation
11Eye movements
- Spontaneous roving, horizontal and conjugate eye
movements - intact brain stem
- diffuse or metabolic cortical dysfunction
- Conjugate lateral deviation
- massive hemispheric lesion (eyes toward lesion)
- pontine lesion (eyes away from lesion)
12Eye movements
- Dolls eyes reflex
- intact brainstem function with depressed cortical
influences - normal sleep, coma, persistent vegetative state
- Ice water caloric test
- eyes toward the side of cold water
- absence in brainstem lesion, inner ear disease,
deep drug coma, and anticonvulsants overdose
13Pattern of breathing
- Cheyne-Stokes respiration
- Central neurogenic hyperventilation
- Apneustic breathing
- Irregular periodic breathing
- Ataxic breathing
- Yawning
14Cheyne-Stokes respiration
- Periodic breathing, crescendo-decrescendo
- The result of the loss of frontal lobe controls
- Blood PCO2 drives brain stem respiratory center
- Posthyperventilation apnea
- Causes
- Frontal lobe damage, unilateral or bilateral
- Secondary to cardiac or respiratory failure
15Central neurogenic hyperventilation
- Sustained, rapid, deep hyperpnea
- Not secondary to hypoxemia and acidemia
- Causes
- Upper brain stem lesion
- Metabolic disorders, especially the early stages
of hepatic coma
16Apneustic breathing
- Prolonged inspiratory gasp
- Discrete lesions of the mid-to-lower pons
- Need early intubation and ventilation
- Causes
- pontine infarct
- hypoglycemia, anoxia, or severe meningitis
17Ataxic and irregular periodic breathing
- Completely irregular pattern
- Slow and progressed to apnea
- Respiratory center - dorsomedial medulla
- Terminal states
- Causes
- posterior fossa lesions
- medullary damage
- overdoses of opiate and sedatives
18Differential diagnosis of Coma
- Metabolic and toxic causes
- presence of pupillary light reflex
- confusion and stupor precedes
- symmetric motor signs
- asterixis, myoclonus, tremor, seizures
(generalized) - central hyperventilation
19Differential diagnosis of Coma
- Supratentorial mass lesions
- focal neurologic sings
- progresses in a rostral-caudal fasion
- Subtentorial masses or destructive lesions
- sudden onset of coma
- history of brain stem dysfunction (the 6 Ds)
- abnormal eye movements
- cranial palsies
- irregular respiration
20Diagnostic procedures
- Metabolic or toxic causes
- blood, urine, gastric aspirates testing
- EEG
- Intracranial mass lesions, head injury
- CT
- Acute subarachnoid or intracerebral hemorrhage
- CT
- lumbar punctures
- Meningitis or encephalitis
- lumbar punctures
21Treatment of Coma
- Immediate treatment, even when the diagnosis is
uncertain, to prevent further brain damage - Oxygenation and airway protection
- ET tube
- ventilation
- Blood pressures maintain
- volume replacement with isotonic solutions
- hemodynamic monitoring
- inotropic and vasopressor drugs
22Treatment of Coma
- Glucose (50 mL of 50 glucose)
- Thiame (100 mg, with the glucose)
- Seizures stop
- Intracranial hypertension lower
- Systemic infections control
- Acid-base and electrolytes imbalances correct
- Hyperthermia treat
23Prognosis Hypoxic-ischemic encephalopathy
- 1st day absence of pupillary responses predicts
poor outcome - 2nd day no patients lack corneal reflex regained
consciousness - After 3rd day lack or purposeful motor responses
predict poor outcome
24Persistent Vegetative State (PVS)
- A form of eyes-open permanent unconsciousness.
- Periods of wakefulness and physiologic sleep/wake
cycles. - Unaware of self or environment.
25Persistent Vegetative State (PVS)
- No voluntary action or behavior. Only primitive
reflexes and vegetative functions. - Careful and extended clinical observation,
supported by laboratory studies. - In cases of hypoxic-ischemic encephalopathy,
observation period of one to three months. - Prolonged survival.
- No pain or suffering.
26Neurological criteria for Death
- The Uniform Determination of Death Acts
- irreversible cessation of circulatory and
respiratory functions, or - irreversible cessation of all functions of the
entire brain, including the brain stem - The determination of death must be made in
accordance with accepted medical standards
27Diagnosis of Death by neurologic criteria
- A clinical diagnosis, with preconditions and
confirmatory tests - The core of the clinical diagnosis is to
establish unresponsiveness and brain stem
areflexia - The preconditions
- the cause of coma be known
- the cause be adequate to explain the coma
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