Clinical assessment of peripheral neuropathy in primary care

Clinical evaluation of peripheral neuropathy

Points in the history:

• sensory symptoms are usually the presenting features of neuropathy and include
  • numbness, tingling, pins and needles in the hands and feet,
  • burning sensations,
  • pain in the extremities,
  • sensations of walking on cotton wool,
  • band like sensations around the wrists or ankles,
  • unsteadiness on the feet, or stumbling
    
    
• motor symptoms
  • usually those of weakness and patients may find it difficult to turn keys in locks, unfasten buttons, and remove the tops of bottles and jars
    
    
• in the early stages of peripheral neuropathy, weakness is usually distal
  
  • early proximal weakness is a feature of inflammatory neuropathies and porphyric neuropathy
    
    
• autonomic symptoms, particularly postural hypotension, impotence, sphincter disturbances, diarrhoea, constipation, and dryness or excessive sweating of the extremities point to damage of small myelinated and unmyelinated fibres
  
  
• in the history, attention should be paid to recent upper respiratory tract or other infections, alcohol and drug intake, diet, possible exposure to industrial and environmental toxins, family history, and symptoms of systemic diseases
  
  
• important to note the tempo of the disease-acute, subacute or insidious onset; rapid or slow progression; progressive, stepwise or relapsing and remitting course.

Points on examination:

• signs are usually those of distal muscle wasting and weakness, and sensory impairment
  • predominantly over distal regions and often in a glove and stocking distribution
    
    
• in distal axonopathies, particularly in diabetes, there may be loss of sensation over the ventral regions of the trunk due to distal degeneration of the intercostal nerves
  
  
• a truncal neuropathy, with a dermatomal distribution of dysaesthesia and sensory loss, may also be seen in diabetes as well as in Lyme disease and Sjogren's syndrome
  
  
• in conditions that affect predominantly small fibres (amyloid neuropathy, Tangier disease, and some cases of diabetic neuropathy) there may be dissociated loss of sensation with loss of pain and temperature sensation and preservation of tactile sensation
  
  
• reflexes are usually depressed or absent but in mild cases, in small fibre neuropathies, and when peripheral neuropathy is associated with pyramidal tract lesions, reflexes may be preserved
  
  
• careful general examination
  • look for of pes cavus or other skeletal deformities, enlarged nerves, skin lesions, arthritis, dry mucous membranes, and enlargement of liver, spleen, and lymph glands.

The clinical features of the neuropathy may indicate the underlying cause (see notes)

• mononeuropathy is usually due to direct compression or entrapment but may be the first manifestation of diabetic or vasculitic neuropathy
• mononeuritis multiplex (multiple mononeuropathy) is caused by vasculitis, leprosy, sarcoidosis, and some other conditions

Notes:

• classification of different type of peripheral neuropathy based on clinical/pathological features:
  
  
• Acute onset:
  • Guillain-Barre syndrome
  • Porphyria
  • Toxic (for example, arsenic, nitrofurantoin)
  • Serum sickness (postimmunisation)
  • Diphtheria
  • Malignancy
  • Critical illness polyneuropathy
  • Diabetes, uraemia (rarely)
    
    
• Predominantly motor:
  • Guillain-Barre syndrome
  • Porphyria
  • Diphtheria
  • Lead
  • Charcot-Marie-Tooth disease
  • Diabetes (diabetic amyotrophy)
    
    
• Predominantly sensory:
  • Leprosy Diabetes (distal sensory polyneuropathy)
  • Vitamin B12 or thiamine deficiency
  • Malignancy
  • Hereditary sensory and autonomic neuropathy
  • Primary of familial amyloidosis
  • Uraemia
  • Lyme disease
  • Sjogren's syndrome
    
    
• Radicular:
  • Diabetic truncal neuropathy
  • Lyme disease
  • Sjogren's syndrome
    
    
• Painful neuropathies:
  • Alcohol, nutritional deficiencies
  • Diabetes (acute painful neuropathy)
  • Hereditary sensory and autonomic neuropathy (HSAN type 1)
  • Arsenic
  • Cryoglobulinaemia
  • Lyme disease
  • Paraneoplastic sensory neuropathy
  • Vasculitic neuropathies

Reference:

• McLeod JG. Investigation of peripheral neuropathy. Journal of Neurology, Neurosurgery, and Psychiatry 1995;58:274-28