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Movement Disorder

Movement Disorder 
  • Hypokinetic: (as in PD - see below): 
    • Bradykinetic,  
    • Rigid, 
    • Akinetic-Rigid, 
    • Stiff-muscles, 
    • psychomotor depression
  • Hyperkinetic: 2A2D2TCM 
    • Tremors, 
    • Tic, 
    • Dystonia, 
    • Chorea, 
    • Dyskinesia, 
    • Myoclonus, 
    • Asterixis, 
    • Akathisia

TREMOR: Clinical diagnosis based entirely on history and neurological examination
    • Resting Tremor: 
      • Best assessed with the patient in a quiet, supine position with the mouth slightly opened and asking patient to perform a mental task (PD increases, ET decreases)
      • Present in a body part that is fully supported against gravity and not associated with any voluntary muscle contraction): eg. PD, PDSynd (Li, Valproate, Dopamine blocker i.e atypical and typical neuroleptics), Wilson's Ds, Severe Essential Tremor, Midbrain (Rubral) Tremor
    • Action Tremor (tremor with any voluntary movement of a body part)
      • Postural Tremor (patient asked to hold their hands either outstretched or just below the chin for 20 - 30 sec) eg. Essential Tremor, PD
      • Kinetic Tremor (assessed by finger-nose-test, writing, feeding, drinking)
      • Intention Tremor
      • Task-specific Tremor eg. writing, music playing, occupational activities.
      • Isometric Tremor (including Orthostatic tremor)
    • DDx of  Common Tremors: Also, distinguish from other hyperkinetic movement disorder (listed below in syllabus)
    • What to look for: 
      • Hx: Onset (associated events, a/symmetry), Age, Review of Medications, 
      • PE: Distribution (Body part involved), Resting vs.Action (which type if action), Frequency and amplitude, Neurologic Examination (handwriting, face, voice, gait, reflex to look for other signs of PD or structural brain lesions)
    • Mnt: 
      • PT/OT for compensatory strategies, 
      • Medical Rx for PD and ET (Table 2 of JAMA paper), 
      • Surgical approach
    • Ref: Up-to-date and an JAMA article
TARDIVE DYSKINESIA: ( chorea, athetosis, dystonia, akathisia, stereotyped behaviors, and rarely, tremor). This is different from acute dyskinesia, akathisia, parkinsonism)
    • Rx and Prevention:
      • Avoid / Stop dopamine receptor blocker
      • Change to second generation anti-psychotic  preferably with slower onset of action (i.e Clozapine, Quetiapine)
      • BZD or Botulinum toxin or Tetrabenazine, or Anti-cholinergics
      • Paradoxically by restarting antipsychotics
  • Extrapyramidal Symptoms of Dopamine blockage:
    • Tardive Dyskinesia
    • Akathesia
    • Parkinsonism
    • Acute Dyskinesia
  • DOPAMINE PATHWAYS (8 pathways, 4 major ones are)
    • Mesolimbic(VTA to limbic system via Nucleus accumbens; disorder leads to Schizophrenia, ADHD)
    • Mesocortical (VTA to cortex; disorder leads to Schizophrenia, ADHD; VTA are located near midline of midbrain i.e mesencephalon)
    • Nigrostriatal (Motor control; Disorder leads to Parkinsonism, Chorea)
    • Tubuloinfundibular (dopamine from Hypothalamus to Pituitary; inhibits prolactin; Disorder leads toHyperprolactinoma)

PARKINSONISM:

  • PD
  • Atypical P (MSA-c, MSA-p, PSP, CBGD, FTLD)
  • Secondary P (DDx: VITAMIN C)
  • Other Neuro Degenerative Disease

Reference:
Table 372-2 DDx of Parkinsonism (Harrison's Principles of Internal Medicine, 18e)
    • PARKINSON DISEASE
      • Clinical Features: 
        • Cardinal: Tremor, Bradykinesia, Rigidity, Postural Instability
        • Motor: See Below in Movement D/O in PD
        • Non-motor:  Anxiety (Even Panic), Inner Restlessness (Akathasia), Extreme Apathy, Depression, Insomnia, 
        • Pathophysiologically
          • Dopaminergic Clinical Features 
          • Non-Dopaminergic Clinical Features 
      • Diagnosis: Clinical
        • Rest Tremor, Asymmetry, Good Response to Levodopa (99% Correct Pathologically)
        • 2 of the 3 (Tremor, Rigidity, Bradykinesia; 22% error on autopsy)
      • Rx:
        • Dopaminergic Agents (for Tremor, Bradykinesia, Rigidity):
          • Carbidopa-Levodopa (is still the best)
            • Anti-PD effect occurs in 2 patterns
              • Long-Duration Response (First several years on treatment)
              • Short-Duration Response (SDR) (Response mirror the LD concentration in circulation; occurs after several years of treatment)
                • SDR Dose adjustment based on TWO concepts (Similar to Furosemide and Morphine)
                  • Is does enough to capture the optimum peak effect? (Larger dose does not last much longer)
                  • Assess duration of response (Do not worry about number of doses per day; there is no cumulative toxicity)
                    • Watch for "wearing off"
            • Always check orthostatics BP before and after starting
              • BP fluctuates with different times of the day (as much as 90/60)
            • Space from meal (1 hr before or 2 hr after)

        • Non-dopaminergic agents (solely or primarily for tremor reduction)
          • COMT Inhibitor (Entacapone): Blocks COMT outside the BB
            • Can Increase Levodopa Dyskinesia
            • Helps to amplify the potency of CP-LD
        • Insomnia: Common due to akathisia, stiffness, cannot turnover in bed
          • Bedtime LD-CD will help
          • If they wake up in middle of the night, LD-CD may need to be given
          • Insomnia also responds in ALL-or-NONE fashion, if under treated even potent sleep aid medications will be ineffective
        • Nausea: 
          • LD effect at Brain-Stem N/V Center will cause N
          • Avoid anti-dopaminergic anti-emetics (Metoclopramide, Prochlorperazine - Compazine); Ondansetron can be used.
        • Hallucinations and Delusions
          • Drugs for the treatment of PD can cause these symptoms especially Dopamine agonists than LD-CD (50% dose reduction is reasonable)
          • Avoid anti-psychotic agents (all most all will block Dopamine); Exception: Quetiapine (can be started at 25 mg)
          • Often they act out their dreams (REM Behavior). Do not confuse this with Hallucinations
        • Pain
          • Directly due to PD (painful leg cramps, toe curling, dystonic limbs): Highly responsive to treatment with LD
          • Pain from other source are worse in LD worn off state, and pain threshold reduced and severity enhanced if undertreated
        • Dyskinesia (Chorea like; LD Excess) and Dystonia (Low LD)
        • Anxiety: Is also ALL-OR-NONE phenomenon
    References
    Parkinson Disease Treatment in Hospitals and Nursing Facilities: Avoiding Pitfalls MCP 2014

    Movement Disorders in patient with PD (details in movement disorder: see below): 
    • Pre-diagnosis : 
      • Restless Leg Syndrome, 
      • Dystonia (Task-specific, Exertion-induced), 
      • Inner sense of Tremor
      • Akathisia
    • At Diagnosis: 
      • Resting / Action Tremor, 
      • Akinesia / Bradykinesia, 
      • Postural Instability
    • Post-Diagnosis:  Two Concepts
      • Levodopa Dyskinesia (Chorea, Choreo-Dystonia)
        • Excessive Levodopa Effect
        • Usually "short duration" effect
        • Related to individual dose and not cumulative dose
        • Decreasing the dose to the level that prevents dyskinesia is the simple strategy
        • AMANTADINE reduces dyskinesia. Usually added if dose reduction of LD-CD leads to Parkinsonism symptoms.
          • Amantadine can induce hallucinations esp in higher dose
      • Levodopa MOTOR FLUCTUATIONS Pure Dystonia (especially if painful), Akathisia(restlessness)
        • Due to Levodopa Insufficiency
        • Distinguish it from Levodopa excess effect as above
        • Somewhat similar to pre-diagnosis stage (which has dopa insufficiency)
      • Other Myoclonos

    Additional Resources on PD and Pharmacology
    Parkinson's Disease (Medical Letter)
    Myoclonic Jerk


    Anatomic-Physiologic Classification includes the following
      • Cortical: Due to insufficient inhibition from primary sensory cortex, primary motor cortex or both
      • Cortical-subcortical: as in primary generalized epileptic syndromes
      • Subcortical-nonsegmental:
        • reticular-reflex myoclonus and propriospinal myoclonus. In both of these examples, the abnormal activity begins in a focal area of the neuraxis and then spreads in both rostral and caudal directions, producing generalized myoclonus due to the bilateral pathways involved.
      • Segmental
        • generated at a particular segment or contiguous segments of the brainstem and/or spinal cord. The pathologic motor oscillations in this type of myoclonus occur at a lower frequency than what is usually seen in tremor.
      • Peripheral
        • peripheral nervous system lesion producing hyperactive motor discharges to its muscle (eg, hemifacial spasm). The possible role of central reorganization is not well defined
    Myoclonus: current concepts and recent advances. Lancet Neurology 2004
    • Clinical and etiological classification of Myoclonic Jerk
      • Physiologic
      • Essential
      • Epileptic
      • Secondary (symptomatic)
    • EVALUATION — Guidelines for the evaluation of a patient with myoclonus may be conceptualized into four parts
      • Syndrome identification based upon clinical features
        • distribution, temporal profile, and activation characteristics of the myoclonic movement
      • Ancillary laboratory testing
      • Clinical neurophysiology
      • Testing for rare causes of myoclonus


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