BIOS5130 Week 11 Part 1 Lecture Slides (1) Human anatomy ll

Disorders of the Nervous System

Overview

• Disorders of the nervous system include various categories of diseases affecting neural function.

Neurodegenerative Diseases

• Alzheimer's Disease

  • Most common cause of dementia; affects ~0.5-0.6% of the global population (approximately 50 million people).

  • Incidence increases with age: 7-10% for those over 65, 40% for those over 80.

  • Symptoms include cognitive impairment, memory loss, and disorientation.

  • Pathology includes neurofibrillary tangles and amyloid plaques leading to neuronal degeneration.

• Parkinson's Disease

  • Second most common neurodegenerative disease, affecting 0.2% of the world's population.

  • Characterized by tremors, rigidity, and motion difficulties due to dopaminergic neuron degeneration.

  • Age is the biggest risk factor; most cases arise after 50.

Demyelinating Diseases

• Multiple Sclerosis (MS)

  • Affects ~2.5 million people globally, with lesions in CNS myelin leading to motor and sensory defects.

  • Can be classified into four types:

    • Relapsing-Remitting (RRMS) - alternating periods of recovery and relapse.

    • Secondary Progressive (SPMS) - gradual deterioration post-RRMS.

    • Primary Progressive (PPMS) - steadily progressive without remissions.

    • Progressive Relapsing (PRMS) - progressive deterioration during relapse phases.

• Guillain-Barré Syndrome

  • Rare autoimmune condition triggered by infections, attacking Schwann cell myelin, leading to paralysis.

• Charcot-Marie-Tooth Disease

  • Inherited peripheral neuropathy, impacting motor and sensory nerves, with a prevalence of 1 in 2500.

Impact of Neurodegenerative Diseases

Mortality Rates

• Death rates from Alzheimer’s disease more than doubled between 2000 and 2019, becoming a leading cause of death in high-income countries.

• In the UK, Alzheimer’s and dementia are now the leading causes of death for females.

Measure of Disease Burden

Disability-Adjusted Life Years (DALYs)

• DALY Calculation = YLL (Years of Life Lost) + YLD (Years Lived with Disability)

  • 1 DALY represents 1 year of full health lost.

• Neurological conditions accounted for a significant DALYs burden, particularly Alzheimer's and other dementias.

Causes and Risk Factors

Alzheimer's Disease

• Major risk factors include age, genetic mutations (e.g., in APP and presenilin genes), and environmental factors (e.g., aluminum exposure).

• Late-onset and early-onset Alzheimer’s can be influenced by different genetic and environmental components.

Parkinson’s Disease

• Genetic factors play a significant role, including SNCA gene mutation related to alpha-synuclein.

• Environmental factors may exacerbate the condition.

Treatments

Current Treatments

• Alzheimer's Disease:

  • Acetylcholinesterase inhibitors (e.g., donepezil) to alleviate symptoms.

  • Memantine to regulate glutamate and protect neurons.

• Parkinson’s Disease:

  • L-DOPA to increase dopamine levels.

  • Surgical options like Deep Brain Stimulation and emerging therapies such as cell replacement.

MS Treatments

• Diagnosis includes neurological exams and MRI; treated with β-interferons and monoclonal antibodies to reduce inflammation.

Summary of Learning Outcomes

• Understand prevalence and burden of these diseases.

• Distinguish categories of diseases, symptoms, affected regions, and types of nervous systems involved (CNS or PNS).

• Identify current and possible future treatments and their mechanisms.