Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord. The earliest symptom of ALS is often fasciculations, which are small, local, involuntary muscle twitches visible under the skin. This leads many to wonder – do fasciculations come first in ALS?
What are fasciculations?
Fasciculations are brief, spontaneous contractions of small bundles of muscle fibers innervated by a single motor neuron. They appear as flickering or twitching under the skin and can occur in any skeletal muscle in the body. Fasciculations themselves are harmless and can be common in healthy individuals after exercise or with caffeine use. However, when fasciculations are widespread and persistent, they can be a symptom of an underlying neurological disorder like ALS.
In ALS, fasciculations occur due to dysfunction and degeneration of upper and lower motor neurons in the brain and spinal cord. As these motor neurons die off, the surviving neurons sprout extra branches to try to reconnect and compensate for the lost neurons. This results in overexcitation and abnormal firing of the muscle fibers, leading to fasciculations.
Are fasciculations an early symptom of ALS?
For many people with ALS, fasciculations are one of the earliest noticeable symptoms of the disease. According to population-based studies, up to 94% of ALS patients report experiencing fasciculations at some point during the course of their illness. Importantly, 30-60% of ALS patients state that fasciculations were their first symptom that led to seeking medical evaluation.
Fasciculations classically start in a focal area such as the arms, legs, shoulders, tongue or throat. They may initially come and go, but become more widespread and persistent over time as motor neuron degeneration progresses. Other early symptoms of ALS often follow the onset of fasciculations within months, including muscle weakness, cramping, slurred speech and difficulty swallowing.
Where do fasciculations start in ALS?
The location where fasciculations first appear can provide clues as to where ALS has started in the body. Common initial sites of fasciculations include:
- Thumbs or fingers – Can indicate ALS starting in the arms
- Calves – Can indicate ALS starting in the legs
- Tongue – Can indicate bulbar-onset ALS, which starts in throat/mouth muscles
- Shoulders or upper back – Can indicate either arm or thoracic-onset ALS
Keeping track of where fasciculations start and how they spread over time can help neurologists diagnose suspected ALS cases.
How are ALS-related fasciculations diagnosed?
There is no specific test just for fasciculations. However, fasciculations in combination with other symptoms and test results can support an ALS diagnosis. Evaluation may include:
- Electromyography (EMG) – Measures muscle electrical activity at rest and during contraction. Can detect fasciculations and confirm they originate from motor nerves.
- Nerve conduction studies – Assess how well nerves transmit electrical signals. Used along with EMG.
- Blood tests – Rule out chemical or metabolic causes of fasciculations like thyroid disorders or mineral deficiencies.
- MRI – Provides images of the brain and spine to rule out structural abnormalities causing fasciculations.
- Clinical exam – Tests muscle strength, reflexes, speech and swallowing to assess for evolving upper and lower motor neuron signs.
There is no single diagnostic test for ALS. Doctors make a final ALS diagnosis based on a combination of fasciculation history, MRI/lab test results, clinical presentation, and by excluding other potential causes. Rarely, a muscle or nerve biopsy may be needed to confirm the diagnosis.
How are ALS-related fasciculations treated?
Unfortunately, there are no treatments specifically for fasciculations in ALS patients. Fasciculations themselves do not cause pain or muscle damage and will resolve once the affected muscles become completely paralyzed later in the disease. Thus, treating fasciculations directly is not a priority.
The main goals of ALS treatment involve:
- Slowing disease progression with medications like riluzole
- Managing symptoms – cramps, spasticity, fatigue, respiratory problems
- Maintaining function through rehab and assistive devices
- Providing nutritional support via feeding tube when needed
- Monitoring for cognitive/behavioral changes
While fasciculations are difficult to treat, properly managing the other aspects of ALS care can help maintain a good quality of life.
What is the life expectancy after fasciculations start?
Unfortunately, ALS is a rapidly progressive disease. After onset of symptoms, average life expectancy is:
- 2 to 5 years for bulbar-onset ALS
- 3 to 5 years for limb-onset ALS
However, about 10% of patients live longer than 10 years, especially if younger at symptom onset. Rarely, ALS can progress extremely slowly over decades.
Once fasciculations begin, duration until death depends on:
- Age at onset – younger patients tend to have slower progression
- Site of onset – bulbar onset affects breathing sooner
- Mutation status – some genetic mutations cause faster progression
- Rate of progression over first 6-12 months – rapid progression predicts shorter survival
Though fasciculation onset varies, average time until death after fasciculations start is estimated at:
- 1 year for bulbar-onset ALS
- 2 years for limb-onset ALS
However, with proactive symptom management and multidisciplinary care, quality of life can remain stable for some time before decline near end of life.
What are the stages of ALS after fasciculations?
ALS tends to progress through the following general stages after onset of fasciculations:
1. Focal muscle twitching
Isolated fasciculations start in one area, such as hand, arm, leg, shoulder, or tongue. May come and go at first.
2. Weakness and atrophy
Grip weakness, foot drop, slurred speech and other symptoms of upper and lower motor neuron loss appear. Muscle tissue starts to shrink from disuse.
3. Spreading paralysis
Weakness and atrophy spread to other limbs. Daily tasks become impaired. Paralysis may occur in some muscles.
4. Dysphagia and respiratory decline
Trouble swallowing and shortness of breath appear as weakness reaches bulbar muscles and diaphragm.
5. End stage
Profound generalized weakness leaves patient bedbound. Loss of speech and swallowing necessitates feeding tube. Respiratory failure is main cause of death.
However, this sequence can vary – some patients progress from fasciculations directly to dysphagia or respiratory impairment. Close monitoring and proactive care is key.
Fasciculation FAQs
Here are answers to some frequently asked questions about fasciculations in ALS:
Are fasciculations dangerous?
No, fasciculations themselves are harmless. They do not damage muscles or nerves and are not usually painful. However, fasciculations are a symptom of ALS progression.
Can fasciculations be constant?
In early ALS, fasciculations may come and go. But as ALS advances, they often become more constant over the affected muscles.
Do fasciculations spread?
Yes, in ALS fasciculations generally start in one region but later spread to other areas as motor neuron degeneration progresses.
Can fasciculations be the only sign of ALS?
Rarely, but most patients will develop muscle weakness close to the onset of fasciculations. Doctors look for both fasciculations and progressive upper and lower motor neuron signs to diagnose ALS.
Do fasciculations eventually stop?
Yes, when the motor neurons to a muscle die off completely, the muscle will become paralyzed and stop twitching. But often, fasciculations spread to new areas even as they stop in certain muscles.
Conclusion
Fasciculations are an early symptom for around 60% of ALS patients and can precede muscle weakness by months. They result from the hyperexcitability and degeneration of motor neurons in ALS. While fasciculations themselves are benign, their presence should prompt evaluation for ALS and other motor neuron diseases when persistent. Unfortunately average survival after fasciculation onset ranges from just 1-2 years for bulbar and limb-onset ALS. However, proactive monitoring and symptom management from the time of fasciculation onset can maintain quality of life for as long as possible.