Parkinson’s Disease

Parkinson’s Disease

Joanne V. Hickey

Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease (AD). PD is characterized by a loss of dopaminergic neurons in the substantia nigra of the basal ganglia. The major signs and symptoms include tremors

(at rest), rigidity, bradykinesia, and gait and balance disorders. PD causes significant disability and decreased quality of life.1 There are also many nonmotor features of PD which will be discussed. The etiology of PD is unknown, and there is no cure.

PD can occur from 10 to 20 years of age (juvenile onset) through 21 to 40 years of age (young onset), through the 90s years of age. The most frequent time of diagnosis is between 60 and 70 years although the disease often begins between 45 and 70 years of age. Approximately 1% to 2% of people over the age of 65 years have PD.1, 2 Over one million people live with PD in the United States, and with current demographic trends of increased older persons, the number is expected to increase significantly in the next three decades.3 Early-onset PD affecting persons as early as in their 20s is being recognized with greater frequency. More than ten autosomal dominant and recessive genes or gene loci have been linked to PD.4 PD is a progressive degenerative disorder of multifactorial etiology. A small proportion of patients have a direct inherited causative mutation for PD; multiple genetic predisposing factors and environmental factors are more commonly involved.5


The basal ganglia is a collective term for the subcortical motor nuclei of the cerebrum. The structures that compose the basal ganglia include the substantia nigra, striatum, globus pallidus, subthalamic

nucleus, and red nucleus. Symptoms of PD are caused by loss of nerve cells in the pigmented substantia nigra pars compacta, including the locus ceruleus in the midbrain. Cell loss also occurs in the globus pallidus and putamen.3 Depletion of the dopaminergic neurons (pars compacta) of the substantia nigra results in reduction of dopamine, the main biochemical abnormality in PD. Normally, the pars compacta neurons of the substantia nigra provide dopaminergic input to the striatum, a part of the basal ganglia. In PD, loss of pars compacta neurons leads to striatal dopamine depletion and reduced thalamic excitation of the motor cortex.3 Although the central problem in PD is dopaminergic loss in the basal ganglia, other neurotransmitters are also involved and the disease extends to other areas of the brain.5

Figure 31-1 ▪ Understanding Parkinson’s disease. Asset provided by Anatomical Chart Co.

Jul 14, 2016 | Posted by in NURSING | Comments Off on Parkinson’s Disease

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