# Disorders of the Nervous System The nervous system can be affected by various disorders, which are classified based on their underlying cause into five main categories: vascular, infectious, structural, functional, and degenerative. Understanding these classifications is essential for diagnosis and treatment. ## Vascular Disorders of the CNS Vascular disorders occur due to abnormal blood circulation within the central nervous system. ### Stroke **Definition:** A stroke occurs when a cerebral artery ruptures, leading to sudden loss of function in a specific brain region. This can cause cerebral infarction, where brain tissue dies due to lack of blood supply. **Causes and Risk Factors:** - Hypertension (high blood pressure) - Cigarette smoking - Diabetes mellitus - High alcohol intake - Thrombosis (blood clot formation) - Blood embolism (a blockage-causing particle in the bloodstream) - Cocaine abuse **Symptoms:** - Sudden loss of function in one region of the brain - Weakness and heaviness in an arm, leg, or the face - Paralysis on the side of the body opposite to the cerebral infarction - Aphasia (inability to express through words) **Treatment:** - Administration of anticoagulants and platelet aggregation inhibitors (e.g., aspirin) - Management of blood pressure - Essential nursing care - Aimed at preventing further attacks ## Infectious Disorders of the CNS Infectious disorders are caused by pathogens such as viruses, bacteria, fungi, protozoa, and Platyhelminthes. ### Meningitis **Definition:** An inflammation of the meninges, the protective membranes covering the brain and spinal cord. **Cause:** Bacterial or viral infection of the meninges. **Symptoms:** - Stiffness in the neck - Headache - Fever - In severe cases: paralysis, coma, or death **Treatment:** - Viral meningitis: No specific treatment - Bacterial meningitis: Treated with antibiotics and steroids ## Structural Disorders of the CNS Structural disorders disturb the physical structure of the brain or spinal cord. ### Tumour **Definition:** An abnormal mass of neuroglial cells (supporting cells of the nervous system) produced by uncontrolled cell division. **Cause:** Mutations in the brain or spinal cord, which can occur at any age. **Symptoms:** Vary depending on the tumour location but may include: - Headaches - Severe nerve pain - Paralysis - Seizures - Coma and death **Treatment:** Surgical removal of the tumour ## Functional Disorders of the CNS Functional disorders relate to nervous system function without an obvious structural or infectious cause. ### Headache **Definition:** Pain located anywhere in the region of the head or neck. The brain tissue itself lacks pain receptors; the pain originates from disturbance of pain-sensitive structures around the brain. **Categories:** - Primary headaches: Due to the headache condition itself (e.g., migraine, tension headache) - Secondary headaches: Due to an underlying structural problem (e.g., brain bleeding, tumour, meningitis) **Treatment:** Analgesic drugs are available for various types of headaches ### Epilepsy Epilepsy is a functional disorder characterized by recurrent seizures due to abnormal electrical activity in the brain. ## Degenerative Disorders of the CNS Degenerative disorders cause progressive breakdown of parts of the nervous system, often with a genetic link. ### Alzheimer's Disease **Definition:** A slowly progressive brain disease characterized by impairment of memory, followed by disturbances in reasoning, planning, language, and perception. It is not considered a normal part of aging. **Cause:** Genetic predisposition; the disease tends to run in families. It is often associated with a deficiency of Acetylcholine. ### Parkinson's Disease A progressive disorder of the nervous system that affects movement. It is caused by the death of dopamine-generating cells in the substantia nigra, a region of the midbrain. ### Multiple Sclerosis (MS) A chronic disease involving the damage of the myelin sheath (demyelination) in the CNS. | Disorder Category | Example | Core Cause | | :--- | :--- | :--- | | Vascular | Stroke | Disruption of blood supply (artery rupture) | | Infectious | Meningitis | Infection by pathogens (bacteria, viruses) | | Structural | Tumour | Uncontrolled cell division forming a mass | | Functional | Headache / Epilepsy | Disturbance of pain-sensitive structures / Abnormal electrical activity | | Degenerative | Alzheimer's / Parkinson's | Progressive breakdown of nervous tissue |

5.10 Disorders Of The Nervous System | Nervous System Of Man | Biology 12