Nervous System Disorders

Nervous System Disorders

1. Trauma

   • Pattern of injury (e.g.coup/contrecoup), signs & symptoms depend on region and between which meninges
     • Bleeding/swelling may increase intracranial pressure (if brainstem damaged/coning - coma)
       • Concussion (brief LOC, full recovery)
       • Contusion (bruising, full recovery may not occur)
       • Laceration (tear of axons & blood vessels)
       • Signs of increased intracranial pressure?

2. Degeneration

   • Alzheimer's
     • Degeneration of cholinergic neurons in hippocampus, amygdala, frontal lobe
       • Pathophys: plaques & tangles
         • Affects: Memory, reasoning, personality, ADL
   • Parkinson's
     • Degeneration of dopaminergic neurons in substantia nigra
       • Pathophys? Lewy bodies?
         • Affects basal ganglia function: Tremor, rigidity, bradykinesia etc.

3. Environmental/Chemical Insult

   • Lead poisoning
   • Kernicterus
     • Elevated unconjugated bilirubin crosses BBB
       • Premature babies have immature liver & BBB
         • Brain toxicity

4. Genetic

   • Huntington's
     • Autosomal dominant
       • Loss of basal ganglia neurons
         • Choreiform movements, later cognition (presents 20-50y)

5. Auto-Immune

   • Multiple Sclerosis
     • Progressive demyelination
       • Affects: motor, sensory, visual, cognitive

6. Altered neurotransmitter activity

   • Unipolar depression
     • Causes: biological, psychological, social, neurotransmitter
       • Low serotonin/adrenaline activity?
   • Bipolar
     • Cycling of depression then mania
       • Dopamine or glutamate dysfunction?
   • Schizophrenia
     • Psychosis - positive & negative symptoms
       • Dopamine dysfunction mesolimbic & mesocortical paths
   • Epilepsy
     • Types: tonic/clonic, petit mal, temporal lobe
       • Uncontrolled firing of group of neurons
         • Due to hypersensitivity of neurons/low GABA?

7. Cerebrovascular accident

   • Ischemic stroke
     • Interruption in blood supply (e.g. thrombus, embolus, air, tumour), most strokes
       • underlying cause often atherosclerotic disease, so same risk factors
         • Signs - depend on area of brain affected
   • Haemorrhagic stroke
     • Bleeding in the brain or between meninges
       • underlying cause may be trauma, aneurysm or tumor
         • Signs & symptoms same as ischemic but also signs of increased intracranial pressure
         • Aneurysm
           • abnormal dilation and weakening of blood vessel wall
             • Cause? Atheroma, high BP, genetic