James Parkinson's original 1817 description of the “shaking palsy” remains a remarkably accurate account of the disease now bearing his name.1 Although the cardinal manifestations of Parkinson's disease (PD) are no different today, our understanding of the full array of parkinsonian signs and symptoms continues to grow. In addition to motor symptoms, the nonmotor symptoms of PD are now recognized as a significant source of disability.2 Given continuing advances in therapy, it is increasingly important that clinicians recognize PD in its earliest stages. Equally critical, PD must be distinguished from less common forms of parkinsonism because prognosis and treatment may differ. In this chapter, we discuss the motor and nonmotor clinical manifestations of PD, followed by a discussion of clinical signs that can distinguish PD from other parkinsonian syndromes.
In order to better recognize, understand, and distinguish PD, it is important to define and clarify the terminology used when assessing a patient with signs and/or symptoms of this hypokinetic movement disorder.
Parkinsonism is a clinical syndrome characterized by specific motor deficits, referred to as the cardinal motor features of PD: akinesia/bradykinesia, rigidity, tremor, and postural instability. A wide variety of unrelated disease states can result in parkinsonism. The common thread linking these disorders is an underlying disruption of the dopaminergic nigrostriatal pathways that play a central role in controlling voluntary movements. This disruption can take one of many forms, and depending on the etiology, other brain structures may be involved. For example, it may be chemical, as is seen with drugs that deplete dopamine from intraneuronal storage sites or block striatal dopamine receptors. Acute and chronic metabolic insults, structural causes, and some inherited neurodegenerative disorders can also cause parkinsonism by direct or indirect disruption of the substantia nigra or striatum and their respective connections. The many causes of parkinsonism can be grouped into primary (or idiopathic), secondary (or symptomatic), the parkinsonism-plus syndromes, and hereditary neurodegenerative diseases (Table 13–1). They are covered in detail in their respective chapters in this text.
Table 13–1. Classification of Parkinsonism ||Download (.pdf)
Table 13–1. Classification of Parkinsonism
- Primary (idiopathic)
- Secondary (symptomatic)
- Drug-induced (phenothiazines, butyrophenones, metoclopramide, reserpine, alpha-methyldopa)
- Infectious/post-infectious (postencephalitic, syphilis)
- Metabolic (hepatocerebral degeneration, hypoxia, parathyroid dysfunction)
- Structural (brain tumor, hydrocephalus, trauma)
- Toxin (carbon monoxide, carbon disulphide, cyanide, manganese, MPTP)
- Vascular (stroke)
- Parkinsonism-plus syndromes
- Corticobasal degeneration
- Dementia syndromes
- Alzheimer's disease with parkinsonism
- Dementia with Lewy bodies
- Multisystem atrophy
- Parkinsonism-dementia-ALS complex of Guam
- Progressive supranuclear palsy
- Hereditary degenerative diseases
- Genetic forms of PD
- Autosomal dominant (PARK1,3,5,8: including alpha-synuclein and LRRK2 mutations)
- Autosomal recessive (PARK2,6,7: including parkin mutations)
- Spinocerebellar ataxias (especially Machado–Joseph disease, type 3)
- Neurodegeneration with brain iron accumulation (PKAN; HSD)
- Juvenile Huntington's disease
- Mitochondrial disorders
- Wilson's disease
In contrast to parkinsonism, idiopathic Parkinson's disease is a distinct clinical and pathological ...