Can frequent fasciculations indicate benign fasciculation syndrome?

Question

Hi doctor,

I am a 42-year-old right-handed internist and hospital administrator. Around seven months ago, I developed fasciculations. I underwent an MRI (magnetic resonance imaging) brain, cervical spine examination, and EMG (electromyography) twice, and all were negative except for some spondylosis at C7 (cervical vertebrae 7) with cervical and neuroforaminal stenosis, both of which were insignificant. The physical exam was completely normal. Fasciculations have been intermittent, and I have been satisfied that these were benign twitches. As an administrator, I spend excessive time in front of my computer and using my phone. I have recently noticed that when I use a mouse and, to a much lesser extent, a keyboard, I can see fasciculations in the first dorsal interosseous muscles and the hypothenar muscles on the most lateral aspect of my hand. Fasculation stops when I lift my hand off the mouse or keyboard. Occasionally, they will continue, but when I completely relax my hand, they stop. Symptoms are much more pronounced in my right hand. The fasciculations are almost vermiform at times. There is no weakness at all, though sometimes my right-hand feels uncoordinated. Objectively, however, it is not, and I can type 100 words per minute. I wake up frequently with numbness or tingling along the lateral aspects of my arm, from the elbow down. I feel pain in my forearm with wrist dorsiflexion or typing and using my phone. It can occasionally occur at rest as well. The pain is mostly burning type. Do I have the beginning of a compressive ulnar neuropathy? I do not practice any outpatient medicine, so this sort of thing is not something that I have any experience in. Symptoms seem consistent, but I cannot find much about these fasciculations occurring as they do. As I said, they almost exclusively occur while using a mouse or keyboard. I continue to have twitches in my hands, forearms, and shoulders, which are much less pronounced than when they started six or seven months ago. The BFS (benign fasciculation syndrome) feels different from the fasciculations I am describing using a mouse. I am currently taking Trazodone, Famotidine, and Myrbetriq. I underwent laboratory tests conducted by a neuromuscular physician for fasciculations, and the reports were normal.

I hope this will help you.

Thank you.

Answer 1

Hello,

Welcome to icliniq.com.

I have read the query, and I can understand your concern.

I am so sorry that you are experiencing a combination of neurological problems. Meanwhile, I am glad your widespread fasciculations are compatible with BFS (benign fasciculation syndrome) clinically and electrodiagnostically. I read the radiologist report and studied the EMG (electromyography)-NCS (nerve conduction study) report (attachment removed to protect the patient’s identity). Fortunately, there was no evidence of myelopathy in your MRI (magnetic resonance imaging) report. Your EMG is nearly normal, except for some abnormal findings in the right upper limb muscles innervated from C6 (cervical vertebrae 6) and C7 myotome or roots. The neurologist did not record any muscle fasciculation in his report and its tables. Unfortunately, you did not mention whether the numbness and tingling sensation you are experiencing are in your right or left upper limb. However, as you described their location at the lateral aspect of your forearm, they cannot be attributable to the ulnar nerve because the ulnar nerve's dermatome is in the medial aspect of the forearm, hand, and the fifth finger and medial aspect of the fourth finger. As EMG-NCS is very sensitive to detect neuropathies, and regarding your recent normal report, I think that your paraesthesia is not due to neuropathy. There is a high possibility that your sensory problem is resulting from your cervical problem. Kindly provide me a more detailed location of numbness and tingling, especially if any side of the hand or fingers is also involved. Then I can give you better advice.

I hope this will help you.

Thank you.

Answer 2

Hello,

Welcome back to icliniq.com.

I have read the query, and I can understand your concern.

Decreased dexterity in fine hand movements might result from involuntary movements of the hand and finger muscles, which is undoubtedly uncomfortable. Here, possible clinical scenarios are:

Underlying BFS (benign fasciculation syndrome) is a superimposed ulnar neuropathy.
Underlying BFS and cervical C8 (cervical vertebrae 8) or T1 (first thoracic vertebrae) radiculopathy.

So, I suggest you repeat your right upper limb EMG (electromyography) - NCS (nerve conduction study). Repeat the cervical MRI (magnetic resonance imaging) if it does not confirm ulnar nerve neuropathy. In that case, get an STIR (short inversion recovery pulse) sequence with the common MRI sequences. STIR sequence increases the sensitivity of MRI to detect possible tiny abnormal signals in the spinal cord.

I hope this will help you.

Thank you.

Answer 3

Dear Dr Hayes, Thank you for the additional information and medical history. I saw the MRI and read your second EMG. The canal stenosis in your cervical MRI is not severe and there is no evidence of myelopathy. Moreover, I did not see any discopathy to explain cervical root compression at C8 or T1 root level (at sagittal plane) to be regarded as a possible cause of your newly formed paraesthesia in the medial aspect of hand and the first dorsal interoseous muscles. Interestingly, there is no record of any fasciculation in your second EMG, even in small muscles. Obviously, your second EMG is more thorough than the first one and the examiner has checked the thoracic and facial muscles in search of any evidence of a possible motor neuron disease. I completely understand how stressful it is for a physician to experience fasciculation, considering the possibility of a motor neuron disease. However, ‌please look on the bright side. You don't have any weakness up to now and your newly evolved symptoms of paraesthesia are not in favor of a progression of a possible MND. Because motor neuron disease does not cause sensory signs. So, regarding your MRI, at present, the only remaining possible diagnosis is an Ulnar neuropathy. Entrapment of the Ulnar nerve at elbow is a common cause of Ulnar neuropathy. Therefore, it would be beneficial if you pay attention to your elbow, especially during typing or studying or any position that may put pressure on elbows. Entrapment at the wrist is the second common cause of Ulnar neuropathy that especially may occur during activities such as cycling. Please try to avoid such positions. If the above recommendation is not helpful, it would be necessary to repeat the EMG study, as the examiner of the second EMG has proposed. You asked if a video of your hand abnormal movement is useful? yes, it may help. Best regards neuropathy.