5.10.5 Degenerative Disorders of the CNS

• Many diseases cause degeneration in different part of the nervous system without an identifiable external cause.
• Genetic factors are known to be involved.
• Example of such diseases is Alzheimer's disease.

Alzheimer's Disease

• Alzheimer's disease is a slowly progressive disease of the brain that is characterized by impairment of memory and eventually by disturbances in reasoning, planning, language, and perception.
• Although onset of this disease occurs in aged peoples but it is not particularly associated with aging.

Cause: - There is genetic predisposition, so tends to run in families.

Symptoms: - Most prominent symptom is short-term memory loss.

Treatment: - There is no effective treatment for this disease.

Summary Table of Nervous System Disorders

Intermediate Level

Classification of Nervous System Disorders

Detailed Description of Each Disorder

Types of Headaches

Formula / Mathematical Form

Not applicable to this topic.

Solved Example

Not applicable to this topic (descriptive topic).

Important Points

• 1. Nervous system disorders are classified into five categories.
• 2. Vascular disorders are due to abnormality in blood circulation.
• 3. Stroke is a vascular disorder.
• 4. Stroke occurs due to rupture of small cerebral arteries.
• 5. Stroke causes weakness, paralysis, and aphasia.
• 6. Infectious disorders are caused by infectious agents.
• 7. Meningitis is an infectious disorder.
• 8. Meningitis is an inflammation of the meninges.
• 9. Meningitis causes stiff neck, headache, and fever.
• 10. Structural disorders disturb the structure of the brain.
• 11. Tumour is a structural disorder.
• 12. Tumour is an abnormal mass of neurological cells.
• 13. Tumour is caused by mutation.
• 14. Functional disorders include headache.
• 15. Headache is pain in the head or neck.
• 16. Primary headaches are due to the headache condition itself.
• 17. Secondary headaches are due to an underlying structural problem.
• 18. Degenerative disorders cause degeneration of the nervous system.
• 19. Alzheimer's disease is a degenerative disorder.
• 20. Alzheimer's disease causes memory loss.

Remember

• - Vascular disorders = abnormality in blood circulation
• - Infectious disorders = caused by infectious agents
• - Structural disorders = abnormal mass of neurological cells
• - Functional disorders = pain without structural cause
• - Degenerative disorders = degeneration of nervous system
• - Stroke = vascular disorder
• - Meningitis = infectious disorder
• - Tumour = structural disorder
• - Headache = functional disorder
• - Alzheimer's disease = degenerative disorder

Common Mistakes

• 1. Confusing the categories of disorders — Vascular, infectious, structural, functional, degenerative.
• 2. Mixing up the examples — Stroke (vascular), meningitis (infectious), tumour (structural), headache (functional), Alzheimer's (degenerative).
• 3. Forgetting the causes — Stroke: rupture of arteries; meningitis: infection; tumour: mutation; Alzheimer's: genetic.
• 4. Confusing the symptoms — Stroke: weakness/paralysis; meningitis: stiff neck/fever; tumour: headaches/nerve pain; Alzheimer's: memory loss.
• 5. Mixing up the treatments — Stroke: prevent further attacks; meningitis: antibiotics/steroids; tumour: surgery; Alzheimer's: no effective treatment.
• 6. Thinking all headaches are the same — Primary and secondary headaches.
• 7. Forgetting the role of genetic predisposition — Alzheimer's tends to run in families.
• 8. Believing Alzheimer's is a normal part of aging — It is not particularly associated with aging.
• 9. Confusing meningitis and encephalitis — Meningitis = inflammation of meninges.
• 10. Thinking tumours are always cancerous — Tumours can be benign or malignant.

Quick Revision

The disorders of the nervous system may be classified as vascular, infectious, structural, functional and degenerative. While classifying, the site of involvement is also considered. Any disorder of nervous system which occurs due to abnormality in blood circulation is called vascular disorder of the nervous system e.g., strokes, brain haemorrhage. Stroke occurs due to rupture of small cerebral arteries. Infections of the central nervous system can be caused by almost any infectious agent, including viruses, bacteria, fungi, protozoa and Platyhelminthes. Meningitis is an inflammation of the meninges. Several disorders disturb the structure of brain are referred as structural disorders, such as tumours. Tumour is an abnormal mass of neurological cells produced as a result of uncontrolled cell division. Headache is the pain anywhere in the region of the head or neck. There are two major categories of headaches i.e., primary headaches and secondary headaches. Many diseases cause degeneration in different part of the nervous system without an identifiable external cause. Example of such diseases is Alzheimer's disease. Alzheimer's disease is a slowly progressive disease of the brain that is characterized by impairment of memory and eventually by disturbances in reasoning, planning, language, and perception.

60-Second Revision

• Vascular disorders = abnormality in blood circulation
• Infectious disorders = caused by infectious agents
• Structural disorders = abnormal mass of neurological cells
• Functional disorders = pain without structural cause
• Degenerative disorders = degeneration of nervous system
• Stroke = vascular disorder
• Meningitis = infectious disorder
• Tumour = structural disorder
• Headache = functional disorder
• Alzheimer's disease = degenerative disorder
• Warning: Alzheimer's disease causes memory loss; there is no effective treatment

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• Chapter:
• 5. Nervous System of Man

• Topic:
• 5.11 PRINCIPLES OF DIAGNOSTIC TESTS FOR NERVOUS DISORDERS

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