Peripheral neuropathy with fasciculations

[Stephen-J-Clark]

    
      Re: Peripheral neuropathy with fasciculations
    


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Posted by CCF NEURO MD on June 10, 1997 at 16:43:02:

In Reply to: Peripheral neuropathy with fasciculations posted by Stephen J. Clark on June 02, 1997 at 22:46:26:

: Hello,
  I am a 48 yr. old male endodontist. In early 1996, I began to have a tingling in my right hand which gradually progressed over the next few weeks to be an electric shock which ran up my arm when I turned my head to the right or arched my head back. Over the next several weeks I developed tingling in both feet. In April 1996, I began having fasciculations and electric shocks in my lower legs and feet. At the same time, I began having a "quivering" feeling in my muscles occasionally. I had a neurological workup with EMG, nerve conduction studies, cervical MRI, extensive blood studies, upper limb and visual evoked potential studies, and cerebral MRI. All were negative or WNL. In 9/96 I discovered a large hole in the mixing bag for my nitrous oxide unit. I have used the gas with patients for 22 years, but I have never abused it. However after researching the subject, I believe that I have been exposed to higher trace amounts than is healthy. I have discontinued the use of this drug in my practice. I thought that I improved for a while, but my fasciculations are now in my hands forearms and torso. I have also had burning feet but that is some better. I dont have noticeable weakness at present and no symptoms seem to be terrible. But the symptoms seem to spread out and cause me to worry. Could you give me your thoughts?
  Thank you.
  Stephen Clark      P.S. My mother has pernicious anemia, but all my blood workups for B12, malalonic acid, etc. were normal. Thanks.
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What you first described sounded like a pinched nerve in the neck (cervical radiculopathy)with shooting electric shock like pain in the arms.  However, this would not produce symptoms in your feet.  Nitrous oxide is known to be toxic to the peripheral nerves.  It produces a peripheral neuropathy that affects mainly the axons.  It causes a vitamin B12 deficiency that produces what is referred to as a myeloneuropathy.  Symptoms of this are sensory complaints, Lhermitte's sign ( electric shocks down the arm and legs with neck flexion) loss of balance, leg weakness, and difficulty walking due to the loss of balance/sensory loss.  It is not unusual for Vitamin B 12 levels to be normal.  Examination shows signs of a sensory and motor peripheral neuropathy and EMG test are often abnormal pointing to involvement of the axons.  Patients improve when the exposure to nitrous oxide is stopped. Many cases have been due to abuse, but there are also reports from people exposed at work in a dental office which are poorly ventilated.  It is hard to tell if you were affected by the nitrous oxide without looking at your studies,  however if you are improving since the nitrous oxide was removed, I would say that that is a positive sign but there is no way for me to tell.  
The fasciculations are spontaneous irregular discharges/contractions of a motor unit.  This appears as a slight twitch under the skin.  Sometimes it appears as a rippling affect.  Usually they indicate motor fiber irritability which may be due to damage to the anterior horn cells in the spinal cord or to the nerve itself.    There are a number of conditions that produce fasciculations including anterior horn cell disease (amyotrophic lateral sclerosis polio or progressive spinal muscular atrophy), compression of a nerve root such as with a herniated disk in the neck, chronic nerve entrapments and some peripheral neuropathies.  It is not rare for normal individuals to experience fasciculations.  There is a syndrome of benign fasciculations which are widespread and lasts months to years.  The benign fasculations are not associated with motor weakness.  The easist way to settle the questions you have is to see a neurologist who specializes in neuromuscular diseases.  If you live close to the Cleveland clinic we would be happy to see you :  call 1-800-223-2273  ext 45559 to arrange an appointment. Your case is interesting.  This information is provided for general medical education purposes only.  Please consult your physician for diagnostic and treatment options of your specific medical condition.  

[sue0007]

A related discussion, Neuropathy was started.