Muscle Atrophy, Weakness, and Fasciculations: A Neurology Perspective

Muscle atrophy, twitching, weakness?

Hello, doctor.
I would like to ask you about something.
About two months ago, I suddenly noticed a depression on the right side of my thigh near the groin area.
Later, I found a similar depression on the left side, measuring approximately 5x5 cm.
Subsequently, I have experienced occasional weakness in my left leg, and numbness in my left buttock, thigh, perineum, and the soles of my feet when sitting down.
Additionally, I have noticed intermittent muscle twitching in my buttocks, thighs, and calves.
I am very worried that I might be in the early stages of amyotrophic lateral sclerosis (ALS).
I consulted a doctor and underwent an MRI, which showed that the compression was not significant.
I also had blood tests for cortisol, immunological analysis, CPK, and a complete blood count, all of which were normal.
Prior to noticing the depression, I had a nerve conduction study that was normal.
The doctor believes that the depression is likely due to fat atrophy, and the weakness and numbness may be related to prolonged sitting or piriformis muscle inflammation.
However, I feel that the area of the depression has increased, and I am now very concerned that I might be in the early stages of ALS.
Could you please share your thoughts, doctor? Thank you.

Chychy, 30~39 year old female. Ask Date: 2022/01/25

Dr. Jiang Junyi reply Neurology

Hello Ms.
Chychy,
You mentioned that "...but because I feel that the area of indentation has increased, I am now worried every day that I might be in the early stages of ALS..." The symptoms you describe are more indicative of localized muscle or peripheral nerve issues.
Generally speaking, motor neuron diseases do not typically present with sensory symptoms.
You noted that "the left side of my buttock to my thigh, perineum, and the soles of my feet feel numb when sitting." ALS primarily refers to problems with motor neurons, which control muscle movement.
In the brain, the motor neurons are referred to as upper motor neurons, while those in the brainstem and spinal cord are called lower motor neurons.
When motor neurons become dysfunctional, our muscles do not receive adequate nutrients and chemicals, which can lead to muscle death.
This is a chronic muscle-wasting disease that may cause muscle atrophy.
If upper motor neurons die, abnormal signal transmission may cause muscle twitching.
The presence of lower motor neuron signs (muscle atrophy, weakness, and fasciculations) can almost confirm a diagnosis of motor neuron disease, especially when upper motor neuron signs such as enhanced tendon reflexes, the Hoffmann sign, and the Babinski reflex are observed in the same limb.
However, clinical diagnosis requires electromyography and muscle biopsy, among other methods.
I recommend that you visit a neurology clinic for further evaluation (especially with a peripheral neurologist).
Please ensure to practice self-protection, maintain cleanliness and disinfection, and adhere to new pandemic prevention measures before and after your medical visits.
Thank you for your inquiry, and feel free to discuss any related questions further!
Wishing you good health and peace,
Dr.
Jiang Junyi, Department of Neurology, Taoyuan Medical Center

Reply Date: 2022/01/25

More Info

Understanding muscle atrophy, weakness, and fasciculations can indeed be a complex journey, especially when symptoms lead to anxiety about serious conditions like amyotrophic lateral sclerosis (ALS). Your concerns about the sudden appearance of muscle atrophy, weakness, and involuntary muscle twitching are valid and warrant a thorough understanding of the underlying mechanisms and potential causes.

Muscle atrophy refers to the wasting or loss of muscle tissue, which can occur due to a variety of reasons, including disuse, malnutrition, or neurological conditions. In your case, the observation of a 5x5 cm indentation on your thigh, along with feelings of weakness and fasciculations (involuntary muscle contractions), raises several considerations.

Firstly, it is important to note that muscle atrophy can occur without a neurological disease. Conditions such as prolonged inactivity, injury, or even certain metabolic disorders can lead to muscle wasting. The fact that you have undergone imaging studies like MRI and blood tests, which returned normal results, is reassuring. These tests help rule out significant structural or systemic issues that could contribute to your symptoms.

Fasciculations, or muscle twitching, can be benign and are often associated with stress, fatigue, or even caffeine intake. They can occur in healthy individuals and do not necessarily indicate a serious underlying condition. However, when combined with muscle weakness and atrophy, they can understandably cause concern about conditions like ALS, where motor neurons degenerate, leading to muscle weakness and atrophy.

The normal results from your nerve conduction studies suggest that your peripheral nerves are functioning properly, which is a positive sign. In ALS, one would typically expect to see abnormalities in these tests as the disease progresses. Furthermore, the mention of a possible "fatty infiltration" or "fatty atrophy" in the area of concern could indicate a benign process rather than a neurodegenerative disease. Fatty atrophy can occur when muscle fibers are replaced by fat tissue, often due to disuse or localized inflammation.

The symptoms of numbness and weakness in your left leg, particularly when sitting, could be related to positional factors or nerve compression, such as from the piriformis muscle, which can irritate the sciatic nerve. This could explain the localized weakness and tingling sensations you are experiencing.

Given your anxiety about ALS, it is crucial to maintain open communication with your healthcare provider. If your symptoms persist or worsen, further evaluation may be warranted. This could include a referral to a neurologist specializing in neuromuscular disorders for a more comprehensive assessment, including electromyography (EMG) to evaluate muscle function more closely.

In summary, while your symptoms are concerning, the normal diagnostic tests you have undergone provide a reassuring backdrop. Muscle atrophy and fasciculations can arise from various benign causes, and it is essential to consider these possibilities. Managing anxiety through education, reassurance, and possibly counseling can also be beneficial as you navigate this challenging experience. Regular follow-ups with your healthcare provider will help monitor your condition and address any new or worsening symptoms promptly.

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