Parkinson Disease PDF

Parkinson Disease Pathophysiology Parkinson Disease and Parkinsonism  Parkinson Disease early 1800s as “shaking palsy” by Dr. James Parkinson chronic, progressive neurodegenerative condition degeneration of neurons is associated with impaired motor function idiopathic ons...

Parkinson Disease Pathophysiology Parkinson Disease and Parkinsonism  Parkinson Disease early 1800s as “shaking palsy” by Dr. James Parkinson chronic, progressive neurodegenerative condition degeneration of neurons is associated with impaired motor function idiopathic onset occurs predominantly in individuals of middle to old age the condition still has no cure  Parkinsonism broad term encompass all the conditions that have a similar pathology but have different aetiologies and clinical presentations Parkinson disease is the most common cause can develop as a consequence of brain damage from a variety of causes head trauma the presence of a tumour growing in a particular brain region after exposure to certain neurotoxic chemicals Parkinson Disease: Pathophysiology  Basal ganglia: control of movement through Neurons of the substantia nigra regulation of inhibitory and excitatory stimuli and the locus ceruleus are heavily pigmented with neuromelanin.  Basal ganglia and functionally associated structures: striatum (caudate nucleus and putamen) globus pallidus interna subthalamic nucleus (diencephalon) substantia nigra (midbrain)  Substantia nigra: black appearance of cells caused by the pigment melanin https://medlineplus.gov/ency/imagepages/19515.htm  SN cells secrete neurotransmitter dopamine Parkinson Disease: Pathophysiology Bullock S, Hales M. Principles of pathophysiology. 1st ed. Frenchs Forest, Pearson Australia; 2012. Parkinson Disease: Pathophysiology Bullock S, Hales M. Principles of pathophysiology. 3rd ed. Pearson Australia. Lewy body: protein aggregations in the cells of Substantia Nigra McCance KL, Huether S. Pathophysiology. 7th ed. N.S.W, Mosby; 2015 Parkinson Disease: Clinical Manifestations  Most neural degeneration in PD occurs before the onset of the manifestations of the disease (preclinical period)  The four cardinal (primary) manifestations of overt PD: 1. Tremor 2. Rigidity (resistance to movement) 3. Akinesia (absence of spontaneous) or Bradykinesia (slow movement) 4. Postural instability Sudden halting of movement Shuffling gait Stooped posture Parkinson Disease: Clinical Manifestations Bullock S, Hales M. Principles of pathophysiology. 3rd ed. Pearson Australia. Parkinson Disease: Clinical Manifestations Speech problems Feeding difficulties Swallowing difficulties, choking Aspiration pneumonia (food/liquid enter lungs - leading cause of death) Facial features of Parkinson disease: Blunted expression Decreased blinking Stare Bickley LS, Szilagyl P. Bates’ Guide to Physical Examination and History Taking. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2003. Parkinson Disease: Clinical Manifestations Indirect manifestations: Result of influence of basal ganglia in autonomic nervous system responses Increased sebaceous, sweat, and saliva secretions are common Other autonomic dysfunctions altered blood pressure altered thermal regulation constipation incontinence impotence Cognitive and personality changes Dementia Parkinson Disease: Diagnosis  No single, definitive test  Diagnosis is based on: Clinical picture Assessment of neurological and psychological signs and symptoms Hoehn and Yahr rating scale for progression and severity Parkinson Disease: Treatment Pharmacologic management is the first line of treatment Provide symptomatic control To slow deterioration by increasing the amount of dopamine available 1. Dopamine (DA) prodrug/precursor: L-dopa, converted into DA in the brain 2. DA agonists: stimulate DA receptors DA prodrugs + DA agonists: synergistic effect, can reduce dose of DA prodrug L-dopa 3. Decarboxylase inhibitors: decrease the destruction of L-dopa peripherally 4. MAO-B inhibitors: reduce destruction of DA in synaptic cleft, increase amount of DA for binding 5. Anticholinergic agents (Cholinergic antagonist - muscarinic): correct imbalance between dopaminergic and cholinergic pathways reduce the stimulating action of acetylcholine Parkinson Disease: Treatment Surgical intervention for advanced disease  Irreversible: Pallidotomy: destruction of globus pallidus to decrease nerve firing in damaged tissue  Reversible: Deep Brain Stimulation: to alter abnormal function of brain tissue 1. Insertion of neurostimulator 2. Electric signal delivery 3. Blocks abnormal signals that result in tremor and other PD symptoms Location for DBS is identified by MRI, CT https://www.nni.com.sg/AboutUs/Newsroom/news-releases/2016/Pages/NNI- establishes-Centre-of-Excellence-on-World-Parkinsons-Day-to-provide- innovative-care-for-patients.aspx