神經系統之生理病理與簡易神經學檢查

1. 神經系統之生理病理與簡易神經學檢查

2. 意識之成分 • 喚醒度(Arousal):意識之原動力 1.臨床現象：外表上呈醒的狀態 (能主動睜眼或對外界刺激有睜眼反應） 2.是腦幹之網狀系統活動的表現 3.主為腦幹之功能 • 覺察能力(Awareness)：意識之內容 1.綜合認知和情感之腦功能 2.臨床現象：有意義的動作和語言 3.主為大腦半球的功能

3. Consciousness Disturbance(意識障礙) • Arousal / Level: maintained wakefulness by intact ARAS and both cerebral hemispheres Confusion Lethargy, Drowsy, Obtundation, Stupor, and Coma • Cognitive content: sum of mental function, leading to awareness of self and environment and the expression of psychological functions of sensation, emotion and thought  Confusion, Delirium, Delusion, Illusion, Hallucination etc.

4. Altered Consciousness • Delirium or acute confusional state. mostly awake to easily aroused level of consciousness fluctuates • Stuporous. difficult to arouse medical emergency • Coma (unresponsive). no speech, no eye opening, no motor response

5. Delirium Acute onset Inattention Disorganized thinking Altered alertness Fluctuating course Metabolic or structural MMS test not useful Dementia Chronic Attentive (early) Progressive loss of cognitive abilities Little fluctuation Structural MMS test useful Encephalopathy

6. Goal of N.E. in Consciousness Disturbance • To establish the existence of clinical diagnosis of coma • To localize the neurologic lesion • To provide clues about underlying cause

7. Conscious level 意識狀況 • 網狀結構 (reticular formation) • 視丘 (thalamus) • 大腦半球 (hemispheres)

8. 意識狀況不好的原因 • 兩側腦幹 • 兩側視丘 • 兩側大腦半球 • 單側大區域大腦半球合併腦疝脫

9. 昏迷的原因 • 天幕上(supratentorial)病灶………………….. 20% • 天幕下(infratentorial)病灶…………………… 13% • 瀰漫性或新陳代謝(diffuse/metabolic)腦病 … 65% • 心因性(psychogenic)之無反應(假昏迷) ……. 2%  依據Plum and Posner (1980): （500例）

10. Causes of Acute or Subacute Mental Status Changes • Toxic or metabolic encephalopathies Drug or alcohol toxicity Withdrawal from alcohol or other sedatives Electrolyte abnormalities (esp Na, Ca, Mg) Hypoglycemia Diffuse anoxia Hypothyroidism, hyperthyroidism Hypoadrenalism Thiamine deficiency (Wernicke-Korsakoff encephalopathy) Hepatic failure Renal failure Pulmonary failure Sepsis Inborn errors of metabolism Paraneoplastic syndrome Hereditary endogenous BZD production

11. Causes of Acute or Subacute Mental Status Changes • Head trauma • Diffuse or focal cerebral ischemia or infarct • Intracranial hemorrhage • Migraine • Seizures or post-ictal state • Hydrocephalus • Elevated intracranial pressure • Diffuse cerebral edema • Meningitis, encephalitis, brain abscess • Vasculitis, diffuse subcortical demyelination (e.g. MS) • Intracranial neoplasm • Paraneoplastic syndrome • Mild insult (e.g., UTI) in setting of underlying impaired mental status • Psychiatric disorder (e.g., depression, mania, schizophrenia) • Sleep deprivation • Visual deprivation or more generalized sensory deprivation • Hypotension • Hypertensive crisis

12. Herniation Syndromes • Bad prognosis • Avoid if possible • Recognize possibility (strokes) • Treat edema (masses) • Evacuate blood • Hyperventilate • Raise head of bed • Osmotic agents (Mannitol) • Neurosurgical emergency • Craniotomy

13. 1. Cingulate (subfalcine) herniation 2. Transtentorial (central) herniation 3. Uncal herniation: uncus  edge of tentoriumIII & cerebral peduncle 4. Tonsillar herniation Supratentorial Mass with Brain Herniation

14. Neurologic Examination in Consciousness Disturbance • Vital sings (TPR) and Skin before N.E. • Level of consciousness: GCS • Respiratory patterns: Cheyne-Stokes, hyperventilation, apneustic , ataxic • Brainstem reflexes: pupils, corneal reflex, reflex eye movements • Motor and reflex signs • Meningism

15. Abnormal respiratory patterns associated with pathologic lesions at various levels of the brain

16. Glasgow Coma Scale Monitoring level of consciousness (score 3-15) • Eyes open • Never • To pain • To verbal stimuli • spontaneously • Best verbal response • No response • Incomprehensible sounds • Inappropriate words • Disoriented and converses • Oriented and converses • Best motor response • No response • Extension (decerebrate rigidity) • Abnormal flexion (decorticate rigidity) • Flexion-withdrawal to pain • Localizes pain • Obeys commands

17. GCS Motor response • 6: 遵照指令 • 5: 不遵照指令，但有自發性動作。 • 4: 對痛會有目的性地避開。 • 在屈曲側刺激，造成伸張反射。 • 在伸張側刺激，造成屈曲反射。 • 3: 對痛僅有反射性的屈曲。 • 2: 對痛僅有反射性的伸張。 • 1: 無反應。

18. More on Exam • Best verbal response • Don’t miss aphasia • Head and neck • Fractures • Stiffness • Otitis media • Eyelids • Ptosis • Facial weakness

19. More on Exam • Observe body position and movement of limbs. • Posturing • Decorticate (a) • Above red nucleus • Decerebrate (b) • Level of red nucleus • Hemiparesis • Hemiposturing • Myoclonus

20. Posturing Reflexes • Can be seen in patients with damage to the descending upper motor neuron pathways. • These reflexes depend on brainstem and spinal circuitry. • Often seen in coma.

21. Posturing Reflexes

22. Posturing Reflexes • Flexor (decorticate) posturing – tends to occur with lesions at midbrain or above. • Extensor (decerebrate) posturing – tends to occur with more severelesionsextending lower down in the brainstem – slightly worse prognosis.

23. Posturing Reflexes • Depend on brainstem function. • Suggests damage to descending motor pathways, with some brainstem function left intact. • Can occur unilaterally or bilaterally. • Can be different on two sides.

24. Posturing Reflexes Must distinguish from purposeful withdrawal • By pinching the skin on the extensor and flexor sides of the limbs. For example : • In flexor posturing, the arm flexes even when been pinched, moving toward the stimulus. • In purposeful withdrawal, it always moves away from the painful stimulus.

25. Babinski sign • 首先使病人放輕鬆，膝關節打直，以稍尖的物體，慢慢地輕刮足板外側至第二拇趾下方。 • 檢查時，必須注意病人的膝關節是否彎曲，以免造成 false extension。

26. Babinski sign (plantar reflex) • 經由對 Sciatic nerve (tibial n. + peroneal n) 的刺激，引發大拇趾的反應。 • 正常的plantar reflex應是大拇趾往下flexion，也就是說刺激tibial n.的感覺區，則tibial n.使大拇趾往下 flexion。 • 如果病人有上運動神經元疾病 (upper motor neuron disease)，或意識不清的情形，則出現大拇趾往上 extension，即刺激tibial n.的感覺區，卻造成 peroneal n. 使大拇趾往上 extension。

27. Motor responses to noxious stimulation in acute cerebral dysfunction. A = Rt hemisphere B = Diencephalon C = Mibrain/Pons D = Medulla

28. Triple Flexion • Flexion at the thigh and knee, and dorsifelxion at the ankle. • Dose not require brainstem function and depends only spinal cord circuitry. • Distinguish from purposeful withdrawal by pinching the dorsal and ventral aspects of the leg or foot.

29. Major brainstem reflexes used in the coma

31. 瞳孔光反射 • 瞳孔大小：正常2-3mm，不對稱差1mm以上 • 沒有開刀的病史，如有不對稱，則考慮CrN3問題。 • 直接光反射：２入３出 • 如沒有反應，代表同側CrN2或3有問題，即代表同側視神經，或動眼神經或中腦有問題。 • 大面積中腦動脈栓塞病人，常因uncal herniation擠壓CrN3，造成同側瞳孔放大，直接光反射消失。

32. Pupils in comtose patients

33. More on Exam • Pupils equal • Pinpoint…………………opiates or pontine lesion • Small and reactive…….metabolic encephalopathy • Mid-sized fixed…………midbrain lesion • Mid-sized reactive……..metabolic lesion • Pupils unequal • Dilated and unreactive...3rd nerve palsy • Small and reactive……..Horner syndrome

34. More on Exam • Examine the fundi, eye position and eye movements. • Papilloedema: • Absence does not exclude raised ICP • Hypertension • Masses • Hydrocephalus • CVT • Meningitis • Hemorrhage

36. 眼球運動 • CrN3: 內直肌，上直肌，下直肌，下斜肌 • CrN4: 上斜肌 • CrN6: 外直肌 • 水平運動：由CrN3. 6負責。 • 垂直運動：由CrN3. 4負責。

37. 眼球運動 • 如果病人的意識狀況清楚，則可要求自主性水平及垂直運動。 • 如果病人的意識狀況不清楚，則做Doll eye sign，（水平及垂直運動）。 • 如果眼球運動有障礙，代表同側的CrN8. 6.或對側的CrN3有問題，可能是同側內耳或腦幹的問題。

38. 眼球自主運動是由額葉將命令傳至對側腦幹的CrN6及同側CrN3，而反射性運動(Doll eye sign)，則是由前庭神經傳至同側CrN6及對側CrN3。

40. More on Exam • Doll’s eye maneuver (oculocephalic testing) • Not to done unless cervical injury is excluded. • Both eyes move (normal). • One eye moves (unilateral lesion). • Eyes fail to move any direction (bilateral brainstem lesions). • Caloric testing • Corneal reflex • Gag reflex

41. 眨眼反射

42. 眨眼反射 • 是5進7出的反射路徑，代表Pons的功能。 • 眨眼反射包括撥眼刺激及睫毛刺激，意識較好的病人對撥眼刺激就有反應(2+)，如有病人對撥眼刺激沒有眨眼反應，則進行睫毛刺激(1+)，如果沒有反應(-)，表示腦幹功能有問 • 抽痰或病人咳嗽時亦可觀察有無皺眉

47. Brainstem pathways mediating conjugate horizontal eye movements

48. Caloric Test for Vestibular Function (30-100 cc ice water for oculovestibular reflexes in comatose patients)

49. Oculocephalic and Oculovestiblar reflexes in comatose patients with: (1) brainstem intact (doll’ head eye phenomenon) (2) bil. MLF involvement (3) and low brainstem lesion

50. 咳嗽反射 • 經由對咽喉的刺激，傳入Trigeminal spinal nucleus，再傳入延腦的Ambiguus nucleus (CrN9. 10) • 咳嗽反射代表medulla的功能。