Evaluation of Patients inComa
Definitions„ Coma: “Unarousable unresponsiveness in  which the subjects lie with eyes closed”
Consciousness„ Two components of conscious behavior  ƒ content- the sum of cognitive and affective    function  ƒ arousal-...
Really SimpleNeuroanatomy„ Arousal: where is it localized?  ƒ Ascending Reticular Activating System (ARAS)    ‘core of the...
ARAS„ ARAS acts as a gating system, increasing  or decreasing thalamic inhibitory influence  on the cortex  ƒ alters effec...
Demands of Arousal„ Function of ARAS-Thalamic-Cortical  system depends on:  ƒ anatomic integrity of structures  ƒ metaboli...
Coma Fact Number One„ Coma implies dysfunction of:  ƒ ARAS or  ƒ Both hemi-cortices„ Anatomically, this means  ƒ central b...
Clues from History„ Onset of symptoms  ƒ sudden onset  ƒ fluctuations„ Associated neurologic symptoms„ Medications
Breathing„ Abnormalities of respiration can help  localize but almost always in the context  of other signs  ƒ Central-ref...
Cranial Nerve Exam„ Systematic assessment of brainstem  function via reflexes„ Cranial Nerve Exam  ƒ   Pupillary light res...
.Pupillary Light Responses„ Afferent Limb: Optic Nerve„ Efferent Limb: Parasympathetics via  occulomotor„ Midbrain integri...
Pupillary Light Responses„ Be aware of drug effects  ƒ Systemic and Local„ Avoid ‘PERLA’  ƒ State size, before and after l...
Pupils: Localizing Value„ Pons-pinpoint pupils  ƒ Symp. Dysfinction plus parasymp.irritation„ Midbrain-Large fixed pupils ...
Ciliospinal Reflex„ 1-2 mm pupillary dilatation evoked by  noxious cutaneous stimulation„ More prominent in sleep or coma ...
Corneal Reflex„ Afferent: Trigeminal Nerve„ Efferent: Third Nerve (Bell’s Phenomenon and Facial Nerve (Eye closure)„ Tests...
Eye Movements„ Before maneuvers attempted note resting  position  ƒ Midline    ‚ Deviation suggests frontal/pontine damage...
Occulocephalic/ Calorics„   Same reflex elicited differently„   Afferent: Eighth nerve„   Efferent: 3,4,6 via MLF and PPRF...
Occulcephalic Reflex„ Brisk rotation of head with eyes held open„ Watch for contraversive movements„ Next:  ƒ Flexion: eye...
Caloric reflex„ Ensure TM integrity„ Elevation of head to 30 degrees (so that  lateral semicircular canal is vertical)„ In...
Calorics„ Watch for conjugance of deviation„ To test vertical eye movements  ƒ Both ears, cold water-downward gaze  ƒ Both...
Gag Reflex„ Afferent: Glossopharyngeal„ Efferent: Vagus„ Taken in context of other findings
Motor Exam„ Assess tone, presence of asterixis„ Response to painful stimuli  ƒ   none  ƒ   abnormal flexor  ƒ   abnormal e...
Reflexes„ Brainstem„ Deep tendon  ƒ Biceps, brachioradialis, triceps  ƒ Patellar, Achilles  ƒ Plantar Responses„ Superfici...
Uncal herniaiton„ Expanding lesions in lateral middle fossa„ Compression of hippocampal gyrus over  free edge of tentorium...
Goals in Emergency„ Primary Neurological Process?  ƒ evidence of raised ICP  ƒ focal findings, especially that implicate  ...
Coma Mimics„   Akinetic mutism„   ‘Locked-in’ syndrome„   Catatonia„   Conversion reactions
Akinetic Mutism„ Silent, immobile but alert appearing„ Usually due to lesion in bilateral mesial  frontal lobes, bilateral...
“Locked-In’ Syndrome„ Infarction of basis pontis (all descending  motor fibers to body and face)„ May spare eye-movements„...
Catatonia„ Symptom complex associated with severe  psychiatric disease with:  ƒ stupor, excitement, mutism, posturing  ƒ c...
Conversion reactions„ Fairly rare„ Occulocephalics may or may not be  present„ The presence of nystagmus with cold  water ...
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medicine.Coma.(dr.muhamad tahir)

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medicine.Coma.(dr.muhamad tahir)

  1. 1. Evaluation of Patients inComa
  2. 2. Definitions„ Coma: “Unarousable unresponsiveness in which the subjects lie with eyes closed”
  3. 3. Consciousness„ Two components of conscious behavior ƒ content- the sum of cognitive and affective function ƒ arousal- appearance of wakefulness„ Content depends on arousal but normal arousal does not guarantee normal content
  4. 4. Really SimpleNeuroanatomy„ Arousal: where is it localized? ƒ Ascending Reticular Activating System (ARAS) ‘core of the brainstem’ ƒ receives input from numerous somatic afferents ƒ projects to midline thalamic nuclei (which are in a circuit with cortical structures) and the limbic system
  5. 5. ARAS„ ARAS acts as a gating system, increasing or decreasing thalamic inhibitory influence on the cortex ƒ alters effect of sensory stimuli ascending ƒ alters descending cortical stimulation
  6. 6. Demands of Arousal„ Function of ARAS-Thalamic-Cortical system depends on: ƒ anatomic integrity of structures ƒ metabolic integrity (circulatory integrity) ƒ communicative integrity (neurotransmitter function)
  7. 7. Coma Fact Number One„ Coma implies dysfunction of: ƒ ARAS or ƒ Both hemi-cortices„ Anatomically, this means ƒ central brainstem structures (bilaterally) from caudal medulla to rostral midbrain ƒ both hemispheres
  8. 8. Clues from History„ Onset of symptoms ƒ sudden onset ƒ fluctuations„ Associated neurologic symptoms„ Medications
  9. 9. Breathing„ Abnormalities of respiration can help localize but almost always in the context of other signs ƒ Central-reflex Hyperpnea (midbrain- hypothalamus) ƒ Apneustic, cluster, Ataxic (Lower pons) ƒ Loss of automatic breathing (medulla)
  10. 10. Cranial Nerve Exam„ Systematic assessment of brainstem function via reflexes„ Cranial Nerve Exam ƒ Pupillary light response (CN 2-3) ƒ Occulocephalic/calorics (CN 3,4,6,8) ƒ Corneal reflex (CN 5,7) ƒ Gag refelx (CN 9,10)
  11. 11. .Pupillary Light Responses„ Afferent Limb: Optic Nerve„ Efferent Limb: Parasympathetics via occulomotor„ Midbrain integrity/ tectum„ Uncal Herniation (3rd nerve dysfunction)„ Pupillary resistance to insult
  12. 12. Pupillary Light Responses„ Be aware of drug effects ƒ Systemic and Local„ Avoid ‘PERLA’ ƒ State size, before and after light stimulation ƒ Specify right and left
  13. 13. Pupils: Localizing Value„ Pons-pinpoint pupils ƒ Symp. Dysfinction plus parasymp.irritation„ Midbrain-Large fixed pupils unresponsive to light, hippus„ Horner’s- symp.dysfunction„ Unilateral dilation- parasymp. Dysfunction usually due to 3rd nerve lesion
  14. 14. Ciliospinal Reflex„ 1-2 mm pupillary dilatation evoked by noxious cutaneous stimulation„ More prominent in sleep or coma than during wakefulness„ Test integrity of symp.pathways in comatose patients„ Not particularly useful in evaluating brainstem function
  15. 15. Corneal Reflex„ Afferent: Trigeminal Nerve„ Efferent: Third Nerve (Bell’s Phenomenon and Facial Nerve (Eye closure)„ Tests dorsal midbrain (Bell’s) and pontine integrity (Eye closure)
  16. 16. Eye Movements„ Before maneuvers attempted note resting position ƒ Midline ‚ Deviation suggests frontal/pontine damage ƒ Conjugate ‚ Dysconjugance suggests CN abn. ƒ Moving ‚ Roving, dipping, bobbing
  17. 17. Occulocephalic/ Calorics„ Same reflex elicited differently„ Afferent: Eighth nerve„ Efferent: 3,4,6 via MLF and PPRF„ Occulocephalics may also involve proprioceptive afferents from the neck
  18. 18. Occulcephalic Reflex„ Brisk rotation of head with eyes held open„ Watch for contraversive movements„ Next: ƒ Flexion: eyes deviate up and eyelids open (doll’s head phenomenon) ƒ Extension:eyes deviate downward
  19. 19. Caloric reflex„ Ensure TM integrity„ Elevation of head to 30 degrees (so that lateral semicircular canal is vertical)„ Instillation of up to 120 ml of ice water ƒ Awake: deviation toward,nystagmus away ƒ Comatose: deviation toward„ Wait 5 minutes, do other ear
  20. 20. Calorics„ Watch for conjugance of deviation„ To test vertical eye movements ƒ Both ears, cold water-downward gaze ƒ Both ears, warm water-upward gaze
  21. 21. Gag Reflex„ Afferent: Glossopharyngeal„ Efferent: Vagus„ Taken in context of other findings
  22. 22. Motor Exam„ Assess tone, presence of asterixis„ Response to painful stimuli ƒ none ƒ abnormal flexor ƒ abnormal extensor ƒ normal localization/withdrawal„ Avoid use of decerebrate/ decorticate
  23. 23. Reflexes„ Brainstem„ Deep tendon ƒ Biceps, brachioradialis, triceps ƒ Patellar, Achilles ƒ Plantar Responses„ Superficial skin ƒ Abdominal, cresmasteric
  24. 24. Uncal herniaiton„ Expanding lesions in lateral middle fossa„ Compression of hippocampal gyrus over free edge of tentorium„ Three stages described ƒ Early third nerve ƒ Late third nerve ƒ Midbrain-Upper pons stage
  25. 25. Goals in Emergency„ Primary Neurological Process? ƒ evidence of raised ICP ƒ focal findings, especially that implicate brainstem structures„ Secondary Processes ƒ signs of infection, toxic/metabolic processes ƒ relative lack of focality
  26. 26. Coma Mimics„ Akinetic mutism„ ‘Locked-in’ syndrome„ Catatonia„ Conversion reactions
  27. 27. Akinetic Mutism„ Silent, immobile but alert appearing„ Usually due to lesion in bilateral mesial frontal lobes, bilateral thalamic lesions or lesions in peri-aqueductal grey (brainstem)
  28. 28. “Locked-In’ Syndrome„ Infarction of basis pontis (all descending motor fibers to body and face)„ May spare eye-movements„ Often spares eye-opening„ EEG is normal or shows alpha activity
  29. 29. Catatonia„ Symptom complex associated with severe psychiatric disease with: ƒ stupor, excitement, mutism, posturing ƒ can also be seen in organic brain diease: encephalitis, toxic and drug-induced psychosis
  30. 30. Conversion reactions„ Fairly rare„ Occulocephalics may or may not be present„ The presence of nystagmus with cold water calorics indicates the patient is physiologically awake„ EEG used to confirm normal activity
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