Parkinson disease (PD) and amyotrophic lateral sclerosis (ALS) are usually considered to be neurodegenerative disorders caused by the progressive death of specific neuronal populations within the gray matter of the central nervous system (CNS). The cause of cell death in PD and ALS is unknown.
Neurodegeneration in multiple sclerosis (MS) is the result of a chronic, inflammatory, autoimmune process with predominant targeting of the CNS white matter.

None of these conditions is considered to be curable. In each case, as the disease progresses the focus often shifts to symptom management with the eventual need for a palliative care plan.

Motor neuron disease (MND) is a family of progressive, neurodegenerative diseases characterized by loss of upper motor neurons (UMN) in the motor cortex and/or lower motor neurons (LMN) in the brainstem and spinal cord.
- UMN disease manifests as spasticity, slowed movements, poor dexterity, pseudobulbar affect, hyperreflexia, and pathologic reflexes.
- LMN disease manifests as weakness, atrophy, fasciculations, cramps, reduced tone, and hyporeflexia.

ALS, or Lou Gehrig’s disease, is the most common form of MND and includes both UMN and LMN pathology. Disease duration is quite variable but most patients will live for 3 to 5 years from disease onset.
Other much rarer forms of adult-onset MND include primary lateral sclerosis (which affects exclusively UMNs), progressive muscular atrophy (which affects exclusively LMNs), and progressive bulbar palsy (which is motor neuron disease limited to the cranial segment). There are also infectious forms of MND, such as polio, which can lead to long-term sequela.

MS is an immune-mediated disease characterized by multifocal plaques of demyelination within the central nervous system. Concepts regarding its pathophysiology are evolving, yet the etiology remains unclear. Also unclear are the factors underlying the transition from the more common relapsing-remitting form of disease (approximately 80% at diagnosis) to the secondary progressive form, to which over 50% of patients will progress in 10 years.
It is a chronic, often progressive disease with motor, sensory, autonomic, and diffuse symptoms.

PD, with or without dementia, produces progressive decline and disorders of progressive supranuclear palsy, multiple systems atrophy, and corticobasal degeneration.
As these patients reach levels of disability associated with end-stage disease, the primary goal becomes palliative management of motor and non-motor complications.
Motor complications arise from excessive hypokinesis (i.e., increasing off times, freezing, rigidity, dysarthria, dysphagia, and respiratory compromise) and excessive hyperkinesis (i.e., choreiform and dystonic dyskinesia from long-standing use of levodopa and other dopaminergic medications).
Non-motor complications include significant cognitive changes; psychiatric complications, such as visual hallucinations and delusions; dysautonomia of bowel, bladder, and blood pressure control; sleep disturbances; and pain.

Elman LB et al. Palliative care in amyotrophic lateral sclerosis, Parkinson’s disease, and multiple sclerosis. Journal of Palliative Medicine, 2007. 10(2): 433-457.