Chorea and Ballismus in Neurology

Chorea/Ballismus

• Chorea: irregular, rapid, non-stereotyped, random, involuntary movement
• May manifest as fidgetiness or restlessness in children
• Ballismus: proximal chorea resulting in large amplitude movements
• Usually seen with lesion of the subthalamic nucleus, but can occur from lesions along all its afferent or efferent paths
• Classified according to aetiology
• Therapy relates to aetiology and symptomatic therapy usually with butoryphenones (e.g. haloperidol)

Neuroanatomy and Neurophysiology of Chorea

• Chorea results from dysfunction within a complex neuronal network interconnecting motor cortical areas and the basal ganglia
• Basal ganglia includes the caudate nucleus, putamen, external and internal segments of the globus pallidus (GPe and GPi), subthalamic nucleus, and substantia nigra

Chorea: Disease

• Huntington's disease: AD, 10/100000, Chr 4, codes for huntingtin, neurotoxic gain of function, may have psychiatric or movement disorder, associated with caudate atrophy, depression is common
• Sydenham's chorea: usually in childhood, major criterion for rheumatic fever, increased Group A beta hemolytic streptococcus titer, usually remits within 15 weeks but can recur, treat symptomatically with haloperidol and provide prophylaxis for rheumatic fever

Dystonia

• Dystonia: involuntary sustained contraction of muscles or groups of muscles resulting in an abnormal posture
• Can be caused by trauma, altered blood supply, altered blood content, metabolic abnormal brain chemistry, acidosis, hypoglycemia, hypoxia, electrolyte abnormalities, toxins

Threats to the System

• Ischemia
• Tumours in the brain or spinal cord
• Metabolic abnormal brain chemistry
• Acidosis, hypoglycemia, hypoxia
• Electrolyte abnormalities
• Toxins
• Abnormal circuits resulting in epilepsy, movement disorders, psychosis
• Neurodegenerative disease

Parkinson's Disease

• Neurodegenerative disease characterized by Lewy body accumulation in areas of the body resulting in dysfunction
• Recent data suggest that abnormality also occurs outside the CNS (e.g. the myenteric plexus)
• Classical degeneration in Substantia nigra pars compacta

Diagnosis of Parkinsonism

• Bradykinesia and at least one of the following:
  • Muscular rigidity
  • 4-6 Hz resting tremor
  • Postural instability not caused by primary visual, vestibular, cerebellar or proprioceptive dysfunction

Cerebellar Ataxia

• Characterized by an incoordination of movement and unsteadiness due to cerebellar dysfunction
• Clinical examination reveals:
  • Gait disorder with imbalance, staggering
  • Difficulties with tandem walking
  • Upper-limb and lower-limb dysmetria, dysdiadochokinesia
  • Hypotonia, cerebellar dysarthria, and saccadic ocular pursuit

Ataxia: Management

• If etiology found, treat
• Otherwise, symptomatic therapy:
  • Difficult to treat
  • Physical measures such as walkers, weights, etc.
  • In MS patients, DBS has some benefit

UMN and LMN

• UMN:
  • Weakness
  • No wasting
  • Increased tone (spastic)
  • Brisk reflexes
  • Extensor plantar responses
• LMN:
  • Weakness
  • Reduced tone
  • Reduced or absent reflexes
  • Wasting of muscles

UMN & LMN Causes

• UMN:
  • Brain lesions (stroke, tumour, haemorrhage, demyelination, ADEM)
  • Spine (fracture with spine impression, tumour, demyelination, viral myelitis, B12 deficiency)
• LMN:
  • AHC (polio, SMA, AVM)
  • Root (disc disease, arachnoiditis, AIDP, CIDP)
  • Plexopathies
  • Peripheral neuropathy
  • Myopathies
  • Myoneural junction (myasthenia gravis)

Muscular Dystrophies

• Many causes of muscular dystrophy
• Pattern of weakness defines type
• Examples:
  • Duchenne's muscular dystrophy (dystrophinopathy)
  • Limb girdle muscular dystrophy (many types)
  • Congenital myopathy (many types)
  • Myotonic dystrophies (dystrophia myotonica, schwartz Jampel)
• Most are genetically determined
• Therapy usually supportive: OT, physiotherapy

Infections

• Polio
• GBS (AIDP)
• Abscess
• Meningitis
• Encephalitis

Polio

• Poliomyelitis is inflammation of the grey matter usually of the spinal cord where the AHC resides
• Caused by polio or other viruses (CMV, herpes, entero-viruses)
• Characterized by LMN features and no sensory abnormality
• Therapy supportive