Amyotrophic lateral sclerosis (ALS) (synonyms: myatrophic lateral sclerosis; motor neuron disease; Lou Gehrig syndrome; ICD-10-GM G12.2: motor neuron disease) is a progressive (progressive), irreversible degeneration of the motor nervous system. The 1st and 2nd motoneurons (nerve cells responsible for muscle movements) are affected by the damage. Gradually, the connection between the brain and muscles is lost. This affects muscle movements (muscles of the extremities, muscle groups close to the trunk, bulbar supplied muscles). Ultimately, atrophic and spastic paralysis are characteristic of the clinical picture. ALS is among the most common motor neuron diseases in adults. A variation of the disease is the so-called “chronic juvenile ALS”. It progresses much more slowly. Meanwhile, molecular pathological work shows that amyotrophic lateral sclerosis is more than a pure motor neuron disease: ALS is a multisystem degeneration with a variety of non-motor symptoms. Four subtypes of ALS are distinguished:
- Progressive bulbar paralysis: combined damage from the 1st and 2nd motoneurons, which is confined to the bulbar muscles (muscles of the pharynx/larynx); incidence, approximately 20%; prognosis: unfavorable
- Primary lateral sclerosis (PLS): largely isolated damage to the 1st motoneuron; age of manifestation 50-55 years of age year; frequency about 2-4%; prognosis: favorable.
- Flail-arm syndrome or Flail-leg syndrome: predominant or exclusive damage to the 2nd motoneuron, which presents clinically as initially asymmetric peripheral paresis (paralysis) of the arms or legs; men are affected significantly more often (9:1); prognosis: relatively favorable
- Progressive muscular atrophy (PMA): exclusively damage to the 2nd motoneuron; prognosis: relatively favorable if isolated the 2nd motoneuron remains affected/relatively unfavorable if in the course it comes to damage the 1st motoneuron.
Sex ratio: males to females is 1.5-2: 1. In the context of familial ALS, both sexes are equally affected. Frequency peak: the disease occurs predominantly in the age around 60 years (median), in familial ALS around 45 years. The prevalence (disease frequency) is about 5-8 diseases per 100,000 population. The incidence (frequency of new cases) is about 2-2.5 cases per 100,000 inhabitants per year (worldwide; tendency increasing). Course
- The onset of the disease can take a wide variety of forms. Usually, painless, progressive muscular atrophy (muscle atrophy) of the hands occurs initially. Disturbances of fine motor skills as well as fasciculations (involuntary movements of very small muscle groups) are the result.
- Paraspasticity of the legs develops (spastic paralysis of both legs).
- The disease may also begin with atrophic or spastic paresis of the lower legs and feet. Subsequently, the arms are affected.
- In 20% of cases, bulbar paralysis with speech and swallowing disorders are the initial symptom.
- Fasciculations may also occur in non-paralyzed muscles.
- 2-5% of patients show symptoms of frontal dementia.
- A so-called “pseudobulbar paralysis” may occur. This may manifest itself in pathological (pathological) laughter or crying (about 50% of sufferers are affected).
- The autonomic nervous system may also be affected (gastrointestinal (affecting the gastrointestinal tract) disorders), but also other organs such as the heart muscle and liver.
- In the course of the disease, all muscle groups are ultimately affected, including the respiratory muscles.
The disease progresses rapidly and inexorably. Not affected by the disease are the intellectual abilities and consciousness. Prognosis: The median duration of the disease is 25 months (after diagnosis 12-24 months). Life expectancy is higher at younger ages of onset, with a mean of 3.5 years. One-third of those with the disease survive 5 years, and 5% survive longer than 10 years. Dysphagia (dysphagia of swallowing) ultimately leads to aspiration pneumonia (pneumonia caused by inhalation of foreign substances (often stomach contents)) and respiratory muscle involvement leads to respiratory failure. Both lead to patient death. Respiratory insufficiency is the most important cause of the limited life expectancy of ALS patients.
