Parkinsonism

Parkinsonism is a syndrome consisting of akinasia and bradykinesia, rgidity and tremors.
  Usualyy associated with abnormalities in postural rightning reflexes

Pathology:
 - loss of pigmented cells in substantia nigra with      deposition le lewy bodyies
 - degeneration of nigro-striatal pathway
 - dopamine level in striatum gets depleted which is normally synthesised by pigmented cells

Clinical features:
 - both sexes equally affected
 - sixth decade
1) Tremors:
  
  - Tremors at rest which decreses with action
     - occures at wrist and fingers
     - may occure at head, jaw or lower limbs
     - tremors r charactoristically pill rolling
2) rigidity:
     - lead pipe hypertonia. Hypertonia is due to
       rigidity
3) hypkinesia/akinesia:
     - difficulty in initiating a motor act
4) bradykinesia:
     - pausity of movements
     - reduced movements
     - expressionless 'mask like face'
5) disturbed postural reflexes:
     - bent posture with tendancy to fall easily
     - difficulty in maintaining balance
     - glabellar tap becomes positive
     - may develop depression, dementia
     - autonomic symptoms like sweating, sebaceous
       secretions, urinary urgency and constipation
     - low volm, monotonus speech, stance is
       stooped, shuffling gait with absent arm
       swinging, turning about bcomes slow
     - with advancement pt assumes flexed posture,
       unable to move, death occures due to
        infections

Managment:
    If any offending drug was used, it shud b withdrawn

Drug therapy:
 (1) anticholinergic:
        Trihexyphenidyl, benzhexole r useful in controling tremors only. Cause urinary retension, worson glaucoma. Avoided if pts is above 65
 2) amantidine:
        Potentiates endogenous dopamine, hs mild antiparkinsonian effect.
 3) levodopa:
       - oraly afministerd Levodopa afr administration crosses bloodbrain barrier and gets metabolised to dopamine in the brain. Bt large amt gets metabolised peripheraly to dopamine. By combining peripheral decarboxylase inhibitor e.g. Carbidopa, bensarazide with Ldopa this can overcome.
      - Ldopa : carbidopa is 4:1
      - Ldopa : bensarazide 4:1
      - drug is started at low dose and increase  once in 2 wks
      - at higher doses A/E like dyskinasia and hallusination occures
 4) dopamine receptor agonist:
      - these r bromocriptine, lisuroid, pergolide used in addition or as alternative to Ldopa
      - bromocriptine 2.5 mg/day incresed slowly to 60 mg/day
 5) seligiline:
       MAO B inhibitor. Reduces metabolism of dopamine and reduces dose and frequency of Ldopa
 6) COMT inhibitors
      : tolcapone, and entacapone. Enhances Ldopa by reducing conversion of Ldopa to methyldopa

Surgery:
    Steriotactic thalamotomy and deep brain stimulation (subthalamic nucleus and globus pallidus) in sever diseases.