Demyelination disease
- Central Demyelination :
Multiple sclerosis, Central pontine myelinolysis (CPM)
- Peripheral Demyelination : GBS
Guillain-Barre syndrome
Acute polyneuropathy
Immune-mediated peripheral nerve myelin sheath or axon destruction
Antibodies directed against myelin sheath and axons of peripheral nerves
Antibodies are formed in response to a preceding viral or bacterial illness.
侵犯運動,感覺,自主神經系統
- 前驅感染激發自體免疫反應所造成 :
- Campylobacter jejuni
- Haemophilus influenzae
- EBV, CMV
- Mycoplasma pneumoniae
免疫系統製造多種 ganglioside 抗體
抗體對抗周邊神經的髓鞘或軸索
造成急性局部多發性神經的發炎反應
導致脫髓鞘病變
Preceded by a viral illness,
followed by ascending symmetric weakness or paralysis
and areflexia or hyporeflexia.
Respiratory function and requiring mechanical ventilation in 1/3 patients.
Autonomic dysfunction may be present as well.
前驅感染症狀
發病前三週內有上呼吸道感染 or 腸胃炎症狀
包括發燒, 咳嗽, 喉嚨痛, 流鼻水, 腹瀉
雙側對稱性漸進式遠端到近端 : Motor 為主
- 肢體下肢到上肢無力 (Ascending symmetric paralysis)
- 肢體疼痛
- 手足部刺痛感, 輕微感覺異常
- DTR 消失
通常是由 : 遠端往近端 !!!
但亦有少數是由近端肌肉或頭頸部肌肉無力為初始表現
肌肉的無力可由輕微的走路困難至四肢癱瘓, 吞嚥, 呼吸困難
80% 病人會有四肢或背部肌肉的刺痛感
但神經理學檢查感覺神經大多正常
70% 的病患會有 自主神經功能失調
常見的自主神經功能障礙包括
心搏過速, 心律不整, 心博過慢, 尿液滯留, 高血壓,
姿態性低血壓, 嚴重的自主神經功能失調會造成猝死
90% 病患在 發病後第四週臨床症狀最嚴重
症狀停止惡化後2-4週, 接下來是穩定期與恢復期
Symptoms are at their worst in 2 - 4 weeks,
and recovery can vary from weeks to a year.
GBS consists of two major subtypes,
acute inflammatory demyelinating polyneuropathy (AIDP),
and acute motor axonal neuropathy (AMAN)
Demyelinating form (lymphocytic infiltration of the myelin sheath of peripheral nerves)
is common in the US
and the axonal form (motor paralysis with sensory function intact) in Asia
The Miller-Fisher syndrome variant is characterized by
ophthalmoplegia, ataxia, and areflexia.
AIDP : Acute inflammatory demyelinating polyneuropathy
Sensory symptoms and muscle weakness,
often with cranial nerve weakness and autonomic involvement
Most common in Europe and North America
Demyelinating polyneuropathy
最常見的 GBS, 約占85~90%的個案
典型表現為雙側對稱、漸進性的肌肉無力, 合併 DTR ↓
病程：脫髓鞘從 nerve roots 開始 → 傳導速度下降或阻斷
肌肉無力, 脫髓鞘範圍越來越大, 肌肉癱瘓
Acute motor axonal neuropathy (AMAN)
Isolated muscle weakness without sensory symptoms in less than 10%
cranial nerve involvement uncommon
Rare in Europe and North America, substantial proportion (30-65%)
in Asia and Central and South America
sometimes called "Chinese paralytic syndrome"
Axonal polyneuropathy, normal sensory action potential
以中國、日本的個案較多，夏天為主
只有影響到運動神經元, 感覺通常會保留, DTR 有些會正常
除了髓鞘外, AMAN患者的軸突也會受損, 可由EMG和AIDP區分
Acute motor and sensory axonal neuropathy (AMSAN)
→ 是AMAN中更嚴重的一個類型，感覺和運動都會影響到
→ 除了髓鞘外，軸突也會受損 → 恢復的時間較慢
Miller Fisher syndrome
→ 典型表現：Ophthalmoplegia、ataxia 和 areflexia
→ 大約有1/4的患者會出現四肢無力, 和GBS非常類似
→ 85~90%的患者有GQ1b的抗體 → 導致眼肌無力的症狀出現
CSF : Cytoalbumin dissociation
high protein and low white cell count
high protein levels (> 45 mg/dL) and WBC counts typically <10 cells/mm3
with predominantly mononuclear cells.
When there are >100 cells/mm3, other considerations include
HIV, Lyme disease, syphilis, sarcoidosis, tuberculous or bacterial meningitis,
leukemic infiltration, or CNS vasculitis.
神經傳導及肌電圖檢查 : 多發性脫髓鞘神經病變
電生理學變化包括多發性局部神經傳導阻斷 (multifocal conduction block)
和傳導速度減緩
Electrodiagnostic testing demonstrates demyelination.
Nerve biopsy reveals a mononuclear inflammatory infiltrate.
If MRI is performed to rule out alternative diagnoses,
it will show enhancement of affected nerves.
* 診斷必備的特徵 :
至少有一肢出現 漸進性肌肉無力
由輕微的下肢無力至吞嚥, 顏面, 眼肌, 驅幹
四肢無力, DTR 消失
* 支持診斷的特徵 :
● 疾病進行時間由數日至四週
● 對稱性症狀
● 輕微感覺症狀
● 顱神經侵犯, 尤其兩側顏面神經無力
● 症狀停止惡化後二至四週, 臨床開始康復
● 自主神經功能異常
● 疾病發生時無發燒現象
● 腦脊髓液中蛋白質增加, 細胞數 < 10 ∕ mm3
● 電生理檢查出現傳導速度減緩或傳導阻斷現象
* 不支持診斷的特徵 :
● 出現脊髓感覺位階 ( Spinal cord sensory level )
● 持續不對稱性的肌無力
● 持續嚴重性的排尿及排便功能障礙
● 腦脊髓液中細胞數 > 50 ∕ mm3
Treatment :
Assessment of respiratory function
Avoid depolarizing neuromuscular blockers like succinylcholine
for intubation in Guillain-Barré syndrome
due to the risk of a hyperkalemic response.
A simple bedside assessment of respiratory status is obtained by trending values reached
when the patient counts from 1 to 25 with a single breath
評估病人呼吸, 咳嗽能力很重要 !!!!!
Both IV immunoglobulin and plasma exchange shorten the time to recovery
Corticosteroids are of no benefit and may be harmful
80%的病人的神經功能會完全恢復
- Supportive : Ventilator for respiratory failure, Moniotr BP, HR
- Immunomodulatory : Plasma exchange, IVIG
http://www.tma.tw/ltk/99530505.pdf
CIDP :
依舊是 Motor predominant !!
Progressive bilateral weakness of proximal and distal ( Upper + lower )
DTR 下降
太久的會 Muscle atrophy
Muscle tone can be normal or decreased.
Hypotonia, atrophy, and fasciculations may be present.
Sensory symptoms are common !!
tingling and numbness of hands and feet
Sensory loss typically stocking & Gloving
也可 ANS
和 AIDP 差別就在
Chronic !!
Motor 比較是遠端近端都有 ( 比較不是遠端到近端 )
Sensory common !!
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