Definition

Amyotrophic Lateral Sclerosis (ALS) is a progressive neurological disorder that attacks the nerves in the brain and spinal cord. The most characteristic symptom of ALS is the loss of muscle movement ability. Another name for ALS is Lou Gehrig's disease, named after an American baseball player who suffered from ALS. In some cases, ALS is inherited. ALS is a rare disorder. To date, no effective therapy or treatment to inhibit the symptoms of ALS has been found. The number of ALS cases in the United States is 30,000, with 5,000 new cases per year.

Causes

To date, the cause of ALS is still unknown. Nine out of ten cases have no known cause. The reason for the loss of muscle control is that nerve fibers become damaged and die. When nerve fibers die, there is no electrical transmission to the innervated area, so muscles gradually weaken, twitch, and eventually atrophy. Ultimately, ALS patients lose the ability to control all muscles. This can occur within 3-5 years of symptom onset, though 10% of ALS patients can live up to 10 years.

Besides genetic factors, environmental factors are known to cause ALS, such as exposure to toxic substances. Current research focuses on the cellular mechanisms that occur in ALS, identifying risk factors, and developing new treatments.

Risk factor

Several known risk factors make a person more susceptible to ALS:

• Age 40-70 years, although ALS can occur at any age.
• Male gender: more often affected than females.
• Family history: 5-10 per cent of ALS cases have a family history.

Symptoms

ALS initially manifests as muscle abnormalities or stiffness in certain areas, spreading to other muscles. Symptoms in ALS patients may include:

• Twitching in hands, feet, shoulders, and tongue.
• Muscle stiffness/cramps.
• Muscle weakness in hands, neck, and respiratory muscles (diaphragm).
• Difficulty speaking.
• Difficulty chewing and swallowing, leading to choking.
• Frequent falls or slips while walking.
• Limping while walking.
• Difficulty using the right hand or fingers.
• Early symptoms include difficulty buttoning clothes, unlocking, or performing routine activities. Eventually, a person will lose the ability to speak, eat, move, and breathe. The sequence of muscle control loss varies among individuals. Respiratory failure is one of the leading causes of death in ALS patients. Besides muscle control loss, nerve damage can cause persistent pain.

ALS patients may also experience depression due to the symptoms. Memory and understanding abilities are not lost, so realizing the gradual loss of movement ability can lead to depression and dementia.

Diagnosis

A definitive diagnosis of ALS is difficult to establish early in the disease course. A definitive diagnosis can be made when the disease progresses and shows clearer symptoms, ruling out other possible causes. ALS is diagnosed if there is weakness in at least three locations. During a physical exam, the doctor will assess reflexes, muscle strength, sensory function, coordination, and balance.

Other tests that can help diagnose ALS include:

1. Laboratory tests like blood, urine, or thyroid function tests.
2. Muscle or nerve biopsy.
3. Analysis of cerebrospinal fluid.
4. Imaging tests like X-rays and MRI.
5. EMG (Electromyography) tests: EMG can show a definitive ALS diagnosis, where there is normal impulse transmission for sensory functions like touch or temperature stimuli but no impulse transmission for movement.

Management

There is currently no cure for ALS, and current treatments aim to prevent nerve damage and delay muscle damage progression in ALS. The following treatments can make symptoms more comfortable:

• Medications to treat muscle cramps, excessive saliva production, and other symptoms.
• Hot water pool therapy for muscle cramps.
• Nutritional counselling to choose foods when patients have difficulty swallowing.
• Use of assistive devices like braces for difficulty performing daily activities.
• Use of a wheelchair to maximize independent ability.
• Physical rehabilitation therapy can treat pain complaints while walking, moving, and maintaining patient independence in activities. Occupational therapists can help patients continue using their hands and other limbs with assistive devices. ALS patients also need emotional support and therapy from family and their environment.

ALS patients are not prohibited from exercising but should avoid endurance sports or repetitive movements. The main goal of exercise in ALS patients is to reduce pain and maintain flexible joints.

Complications

Complications in ALS patients include:

1. Breathing difficulties: can occur within 3-5 years of symptom onset.
2. Speaking difficulties: initially difficulty pronouncing some words, then difficulty speaking, leading to swallowing difficulties.
3. Dementia: some ALS patients experience memory and thinking problems caused by dementia.

Prevention

There is currently no definite preventive measure for ALS. Regular physical activity and a nutritious diet can prevent cell aging and reduce inflammation, helping combat ALS complications. Known environmental factors that can cause ALS include smoking.

When to see a doctor?

Seek medical attention immediately if you have any of the following symptoms:

• Difficulty speaking/slurred speech when tired.
• Difficulty swallowing liquids/solid foods, frequent choking, and excessive saliva production.
• Loss of ability to use hands and weakness in certain body parts.
• Muscle twitching is accompanied by muscle atrophy.
• Difficulty breathing.
• Changes in behavior and emotional state.

If the above symptoms do not go away or worsen, they may indicate early signs of ALS.

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