CHAPTER 5, CENTRAL NERVOUS SYSTEM

CENTRAL NERVOUS SYSTEM

PREPARED BY MR. ABHIJIT DAS

EPILEPSY

Definition
Epilepsy is a neurological disorder marked by recurrent, unprovoked seizures due to sudden abnormal electrical activity in the brain.

Etiopathogenesis

1.    Genetic factors: Genetic mutations may raise epilepsy risk.

2.    Structural abnormalities: Brain injuries or birth malformations can trigger seizures.

3.    Infections: Brain infections like meningitis can lead to epilepsy.

4.    Developmental disorders: Conditions like autism increase epilepsy risk.

5.    Metabolic disorders: Imbalances, like low blood sugar, can cause seizures.

6.    Environmental factors: Exposure to toxins or drugs may trigger seizures.

Clinical Manifestations

  • Convulsions (muscle contractions)
  • Loss of consciousness
  • Altered sensations (e.g., tingling, visual/auditory changes)
  • Abnormal movements (e.g., repetitive actions)
  • Cognitive/emotional changes (confusion, anxiety)

Non-Pharmacological Management

1.    Ketogenic diet: High-fat, low-carb diet may reduce seizures.

2.    Vagus nerve stimulation (VNS): Implanted device stimulates vagus nerve.

3.    Surgery: Option to remove seizure-causing brain area.

4.    Education: Learning about epilepsy for better self-management.

5.    Cognitive-behavioral therapy (CBT): Helps manage emotional impact.

6.    Relaxation techniques: Meditation, yoga, and deep breathing reduce stress.

7.    Avoiding triggers: Managing stress, sleep, and dietary triggers.

Pharmacological Management
Common anti-epileptic drugs (AEDs):

  • Carbamazepine
  • Valproic acid
  • Phenytoin
  • Lamotrigine
  • Topiramate
  • Levetiracetam
  • Oxcarbazepine
  • Gabapentin
  • Pregabalin

 

PARKINSON’S DISEASE

Definition
Parkinson's disease is a progressive neurological disorder that impairs movement due to degeneration of dopamine-producing cells in the brain, especially in the substantia nigra.

Etiopathogenesis

1.    Genetics: Around 10-15% of cases are due to genetic mutations.

2.    Environmental factors: Exposure to toxins (e.g., pesticides) may increase risk.

3.    Neuroinflammation: Chronic brain inflammation may contribute to neuron loss.

4.    Protein aggregation: Abnormal alpha-synuclein protein buildup damages brain cells.

Clinical Manifestations

  • Motor symptoms ("Cardinal signs"):
    • Tremors: Involuntary shaking, usually starting in one limb.
    • Rigidity: Muscle stiffness and resistance to movement.
    • Bradykinesia: Slowed movement, making daily tasks difficult.
  • Non-motor symptoms:
    • Cognitive changes: Ranging from mild memory issues to dementia.
    • Sleep problems: Insomnia, sleep apnea, restless leg syndrome.
    • Mood symptoms: Depression, anxiety, and apathy.

Non-Pharmacological Management

1.    Exercise: Improves mobility and reduces fall risk.

2.    Physical therapy: Enhances posture, gait, and balance.

3.    Speech therapy: Assists with speech and swallowing issues.

4.    Nutritional counseling: Ensures a nutrient-rich diet to support digestive health.

5.    Deep brain stimulation (DBS): Surgery to reduce motor symptoms.

Pharmacological Management

1.    Levodopa: Converts to dopamine, helping with motor symptoms.

2.    Dopamine agonists: Mimic dopamine action; used alone or with levodopa.

3.    MAO-B inhibitors: Prevent dopamine breakdown, raising its levels.

4.    COMT inhibitors: Prolong levodopa effects and reduce "off" periods.

5.    Anticholinergics: Block acetylcholine to reduce tremors and rigidity.

 

ALZHEIMER’S DISEASE

Definition
Alzheimer's disease is a progressive neurodegenerative disorder that leads to memory loss, cognitive decline, and changes in behavior. It is the most common cause of dementia, accounting for 60-80% of cases.

Etiopathogenesis

1.    Genetics: Mutations in genes.

2.    Beta-amyloid accumulation: Beta-amyloid plaques disrupt brain cell communication, leading to cell death.

3.    Neuroinflammation: Chronic inflammation damages neurons and promotes plaque formation.

4.    Environmental factors: Head injuries, stress, and pollutants may raise the risk.

5.    Age: Risk significantly increases after age 65.

Clinical Manifestations

1.    Memory loss: Difficulty remembering recent events and learning new information.

2.    Language difficulties: Trouble finding words, following conversations, and expressing thoughts.

3.    Impaired judgment: Poor decision-making and vulnerability to scams.

4.    Mood changes: Depression, anxiety, irritability, and aggression.

5.    Loss of motivation: Reduced interest in activities and social interactions.

6.    Difficulty with daily tasks: Problems managing finances, cooking, and self-care.

Non-Pharmacological Management

1.    Cognitive stimulation: Puzzles and games to help maintain brain activity.

2.    Physical activity: Exercise improves mood, cognitive function, and overall health.

3.    Social engagement: Social activities prevent isolation and improve well-being.

4.    Nutritional support: A balanced diet supports cognitive health.

5.    Music and art therapy: Enhance mood and reduce behavioral symptoms.

6.    Caregiver support: Education and resources to reduce caregiver stress.

Pharmacological Management

1.    Cholinesterase inhibitors: Boost acetylcholine for memory (e.g., donepezil, rivastigmine).

2.    Antidepressants: Manage depression (e.g., sertraline, citalopram).

3.    Anxiolytics: Treat anxiety (e.g., lorazepam).

4.    Antipsychotics: For agitation and psychosis (e.g., risperidone).

5.    Sleep aids: Address sleep disturbances (e.g., zolpidem).

 

STROKE

Definition
A stroke in the CNS is a sudden disruption of blood flow to the brain or spinal cord, leading to neurological damage. It is caused by either a blockage (ischemic stroke) or bleeding (hemorrhagic stroke), resulting in the death of brain cells due to lack of oxygen.

Etiopathogenesis

1.    Atherosclerosis: Plaque buildup in brain vessels restricts blood flow.

2.    Hypertension: High blood pressure can damage vessels, increasing rupture risk.

3.    Cardiovascular disease: Conditions like atrial fibrillation create blood clots that may travel to the brain.

4.    Diabetes: High blood sugar damages vessels, raising stroke risk.

5.    Smoking: Promotes atherosclerosis and vessel damage.

6.    Genetics: Family history and clotting disorders can elevate stroke risk.

Clinical Manifestations

1.    Sudden weakness or numbness, often on one side.

2.    Difficulty speaking or understanding speech.

3.    Vision loss in one or both eyes.

4.    Severe headache with nausea or altered consciousness.

5.    Loss of balance, dizziness, or walking issues.

6.    Confusion, memory loss, or cognitive changes.

7.    Seizures or convulsions.

8.    Paralysis or impaired motor skills.

Non-Pharmacological Management

1.    Rehabilitation: Physical, occupational, and speech therapy aid recovery.

2.    Lifestyle changes: Healthy diet, exercise, and managing blood pressure.

3.    Emotional support: Psychological support to manage depression or anxiety.

4.    Assistive devices: Wheelchairs or communication aids if needed.

5.    Education: Training on prevention and self-management.

Pharmacological Management

1.    Thrombolytic therapy: tPA to dissolve clots in ischemic strokes, used within hours of symptom onset.

2.    Antiplatelet and anticoagulants: Prevent clot formation, like aspirin or warfarin.

3.    Blood pressure control: ACE inhibitors or calcium channel blockers to lower blood pressure.

4.    Neuroprotective agents: Drugs like citicoline and nimodipine to protect brain cells.

 

MIGRAINE

Definition
Migraine is a neurological disorder marked by recurring moderate to severe headaches, often accompanied by nausea, vomiting, and sensitivity to light, sound, or smells.

Etiopathogenesis

1.    Genetics: Certain genes increase susceptibility to migraines.

2.    Neurovascular dysfunction: Changes in blood flow and inflammation in brain vessels and nerves.

3.    Trigeminal nerve activation: Pain signals from the trigeminal nerve.

4.    Serotonin imbalance: Low serotonin levels affect blood vessel behavior.

5.    Environmental triggers: Stress, weather, hormones, or specific foods.

Clinical Manifestations

1.    Headache: Throbbing, often one-sided, lasting hours to days.

2.    Aura: Visual or sensory disturbances before the headache.

3.    Nausea and vomiting: Often severe.

4.    Sensitivity: Increased sensitivity to light and sound.

5.    Fatigue: Exhaustion during and after attacks.

6.    Cognitive issues: Difficulty concentrating and confusion.

Non-Pharmacological Management

1.    Identify triggers: Track and avoid triggers with a headache diary.

2.    Relaxation: Deep breathing, meditation, or yoga.

3.    Exercise: Regular, gradual physical activity.

4.    Sleep: Consistent, adequate sleep.

Pharmacological Management

1.    Triptans: Constrict vessels, block pain pathways.

2.    NSAIDs: Relieve pain and inflammation.

3.    Acetaminophen: Effective for mild to moderate migraines.

4.    Anti-nausea meds: Alleviate nausea and vomiting.


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