Small fiber neuropathyの鑑別

Small fiber neuropathyは神経診察で異常がでないため非常に軽視されがちです。問診が重要であり、起立性低血圧、動悸、発汗異常、口腔・眼・皮膚乾燥、腹痛や下痢・便秘、勃起障害を聞いておきましょう

 

Lancet Neurol 2017; 16: 934–44

 

Small fiber neuropathy SFN

 

Length dependent SFNでは足趾や足底から症状が出現し(陽性症状・陰性症状)、神経障害が膝まで出現すると上肢に症状が出始める

 

Non length-dependent SFNではどこから症状が始まってもよい

Non length-dependent SFNは大まかに3つに病態が分かれ
・Paraneoplastic
・Immune-mediated
・Ideopathic

単神経障害や神経節障害では下肢より前に顔面や舌、頭皮、上肢、体幹などに症状が出現する
神経節障害Ganglionopathyでは顔面や体幹、上肢に症状が出現するが下肢にはでにくい
GanglionopathyはParaneoplastic conditionやSjSでみられる

 

Causes of small fibre neuropathy
Metabolic causes
• Diabetes, impaired glucose tolerance, and rapid glycaemic control in the setting of
chronic hyperglycaemia (treatment-induced neuropathy of diabetes)
• Hypothyroidism
• Hypertriglyceridaemia
• Uraemia
Vitamin deficiency
• Vitamin B12
Neurotoxic exposure or vitamin intoxication
• Alcohol
• Antiretroviral agents
• Chemotherapeutic agents
• Organic solvents
• Pyridoxine B6 intoxication
• Statins
• Anecdotal cases: antiarrhythmic drugs (flecainide), antibiotics (metronidazole,
nitrofurantoin, linezolid, ciprofloxacin), ingestion of Clostridium botulinum toxin,
heavy metals (thallium, lead), and tumour necrosis factor α inhibitors
Infections
• Hepatitis C virus
• HIV
• Influenza
• Leprosy
• Severe sepsis, septic shock, and critical illness
• Anecdotal cases: Epstein-Barr virus, herpes simplex infection, mycoplasma
pneumonia, rubella, syphilis, vaccination for rabies, varicella or Lyme disease, and
hepatitis B virus
Immunological causes
• Autoimmune autonomic ganglionopathy
• Coeliac disease
• Guillain-Barré syndrome, monoclonal gammopathies, and primary amyloidosis
(immunoglobulin light chain associated)
• Paraneoplastic syndrome
• Sarcoidosis
• Scleroderma
• Sjögren’s syndrome
• Systemic lupus erythematosus
• Vasculitis
Hereditary causes
• Familial amyloid polyneuropathy (transthyretin amyloidosis)
• Hereditary sensory and autonomic neuropathies
• Fabry disease
• Mutations in COL6A5 and genes encoding voltage-gated sodium channels
• Pompe’s disease
Idiopathic small fibre neuropathy