This is a condition resulting in progressive weakness of muscles due to degeneration (dying) of neurons involved in motor control within the brain and the spinal cord.  Use of both terms ALS and MND can be a bit confusing. In U. S. A. it is also known as Lou Gehrig’s disease, named after the famous baseball player who suffered from this condition.

What is a motor neuron?

Neurons are the cells that make different parts of nervous system, like bricks for a building. Largest collection of neurons is in the brain, making its complicated circuitry. Some neurons act as nerves, like wires, transmitting messages towards or away from the brain. Sensory nerves transmit towards the brain, and motor nerves in opposite direction. Each neuron has a cell body with a central nucleus and surrounding cytoplasm. From that body comes out an extension, like a wire, sometimes delivering messages far away from its body.

Motor neurons are classified as of two types, upper motor and the lower motor neurons. Cell bodies of the upper motor neurons are in the brain, and of the lower in the spinal cord. The cell body and the nuclei of lower motor neurons reside in the spinal cord with an extension coming out in the form of short or long nerves. A material called myelin, like an insulation, covers this extension. Unlike a conventional wire that is uniformly coated with plastic, the myelin coating of nerves has gaps at regular intervals. These gaps are called nodes of Ranvier, which help to speed up the process of signal transmission. Some motor nerves are more than a meter long, starting in the back and traveling down to the foot.  

 

What exactly is the problem in ALS and MND?

ALS is an old term implying degeneration of upper motor neurons in the brain and spinal cord. The term Motor Neuron Disease include degeneration of the lower motor neurons with their cell bodies in the spinal cord. Loss of motor neurons leads to muscle weakness and shrinkage. In a classical case of ALS, there is evidence of both upper and lower motor neuron disease. The term MND is also used to describe all cases involving both upper and lower motor pathology, including ALS.

 

Are there different kind of MND?

There are some variations, but that subject is beyond the scope of this writing.

 

How common is ALS or MND?

It affects about 20-30 people in a million. It is little bit more common in men, and its incidence increases with age. In most cases, there is no prior family history of similar illness.

 

Are there any risk factors for ALS or MND?

. Men are more affected than women.

. Aging is a risk factor, but it can happen to young people too, including children.

. Genetics plays a part in a small percentage of patients.

. Higher level of physical activity or professional athletic sport with risk of concussion, especially American football, and soccer, seem to have higher risk.

. Military service.

. Exposure to heavy metals.

. Exposure to electromagnetic fields.

. Exposures to pesticides.

It is important to mention that exact relationship of many of these risk factors and exposures is not clear. Exact nature of the causative agent or the trigger is not known in any of these conditions.

 

What are symptoms of ALS?

Main symptom of ALS is weakness that may start in one or the following ways:

1. Weakness of arm or leg muscles: Most ALS patients present with relatively painless weakness of a foot or a leg, or difficulty walking, which progresses in weeks to months.
2. Weakness of face or swallowing muscles: In some patients, weakness starts in muscles around the mouth and throat, presenting as difficulty speaking and swallowing, the so-called bulbar form of ALS.
3. Weakness of breathing muscles: Weakness of diaphragm and respiratory muscles may cause difficulty breathing.

Other than weakness, about half of the patients may also have cognitive problems, about 15%v develop fronto-temporal dementia. Cramping and pain may also be a part of this condition.

 

How is ALS diagnosed?

It can be diagnosed by taking history, and a careful examination. In a typical case, one may find evidence of bilateral upper and lower motor neuron pathology. Upper motor pathology presents as spasticity, brisk reflexes, and extensor plantar reflexes. Lower motor pathology presents as muscle atrophy, weakness, and fasciculations. It is not uncommon to see lower motor pathology in a neurology office, the most common from peripheral neuropathy. In patients with ALS, one may find evidence of lower motor pathology with spasticity and hyperreflexia. 

An EMG/NCS (electromyogram and nerve conduction study) can help to corroborate the diagnosis. There is no lab or imaging test for ALS. Part of diagnosing ALS is to make sure it is not one of ALS look-alike, which, unlike ALS, may be treatable. For example, some patients have severe spinal stenosis in the neck or cervical area, which can present as combination of upper and lower motor neuron findings. Careful examination and logical analysis of findings may help to make this distinction. In doubtful cases, a cervical spine MRI can help.

 

What conditions can look like ALS?

Many conditions can mimic ALS and need careful consideration before making its diagnosis. In most cases, history and examination can help rule out these conditions. Following is a list of possibilities:  

Benign fasciculations: Fasciculations alone do not make a diagnosis of ALS. They are more common due to nerve injury from other causes. Rarely, patient may have widespread fasciculations but otherwise no other clinical feature to suggest ALS.

Inclusion body myositis: This can present as hand and leg weakness, creating some confusion.

Multifocal motor neuropathy with conduction block: This is addressed in a separate section.

Monomelic amyotrophy or Hirayama disease

A form of Charcot-Marie-Tooth disease

Post-polio syndrome

Nutritional myeloneuropathies: such as severe B12 deficiency

Hereditary spastic paraparesis

Adrenomyelneuropathy

Human immunodeficiency virus (HIV) myelopathy

Multiple sclerosis

Cervical radiculomyelopathy

 

Is there a cure for ALS?

Not at this time.

 

Are there any medicines that can slow down ALS?

There are two medicines so far that may help:

1. Riluzole: It is a tablet taken twice a day. It may increase survival by about 12%, or for about 3 months.
2. Edaravone (Radicava): It is an intravenous infusion. Initial study indicated a survival benefit of about 33%. Later studies suggested less effective response.
3. Sodium phenylbutyrate/taurursodiol (Relyvrio): It is taken by mouth. Like edaravone, it provides some survival benefit somewhat delaying the devastating effects of ALS.

Benefit from both riluzole, edaravone, and sodium phenylbutyrate at best is modest, i.e., delaying disability and death by a few months.

Other than these, many other medicines may also be used for pain, spasticity, muscle cramps, excessive salivation, insomnia, anxiety, laryngospasm, pseudobulbar affect, and depression.

 

What is the solution if patient with ALS is not able to swallow?

In initial stages, some changes in meal consistency may help. Ultimately, swallowing may become too risky (risk of food going into lungs), and a feeding tube is needed for nutrition. A temporary feeding tube can be inserted through the nose, while a permanent is arranged. The permanent tube is placed directly in the stomach through the abdominal wall.

 

What is the solution if patient with ALS has difficulty breathing?

A pulmonary consultation is always recommended as soon as diagnosis is made to obtain baseline studies and formulate a plan of action in case breathing issues arise. A non-invasive machine can be used for pressure support or in more severe cases, the pulmonologist may recommend formal ventilator. This is done by putting a breathing tube in the trachea, the so-called endotracheal tube (ET tube). It is important to inform the patient and the family that once inserted, the possibility of ET tube coming out is almost zero.

 

What is the life expectancy in ALS?

In most cases, ALS is a rapidly progressive fatal disease, with life expectancy of 1-3 years. Patients gradually lose almost all, or all muscle functions. Technically, it is possible to keep a patient alive with artificial means, including artificial means of nutrition, breathing machine, and nursing care. Famous physicist Stephen Hawking lived for 55 years after he was diagnosed. Unfortunately, for most patients, the level of care required for long-term care is not a feasible option.

A doctor or a neurologist’s job is to help patients and their families make critical decisions about putting the feeding or the breathing tube or not. They should educate the patient and the family and answer their questions in straightforward and simple terms. Patient or his/her family or properly designated health-proxy make these difficult decisions. Once the diagnosis of ALS is made, I discuss these matters with my patients and encourage them to reflect and try to make these decisions in advance before an emergency appears.

 

Where can I find more information about ALS?

American Academy of Neurology

The ALS Association