Autonomic Dysfunction Page 3

Specific syndromes:
- Pure Autonomic Failure:--
  - Symptoms
    - postural (orthostatic) hypotension
    - impotence
    - bladder dysfunction
    - defective sweating
  - reduction in sympathetic ganglia neuronal density
  - low supine plasma norepinephrine levels
  - reduced norepinephrine response to tyramine
  - decreased neuronal norepinephrine uptake
  - noradrenergic supersensitivity- consistent with peripheral sympathetic dysfunction
- Multiple System Atrophy -- several, overlapping syndromes including:
  1. striatonigral degeneration
  2. Shy-Drager syndrome
  3. olivopontocerebellar atrophy
  4. General/common --Clinical Symptoms include
    - postural hypotension
    - impotence
    - bladder/bowel dysfunction
    - defective sweating
  5. Death may occur or 7-10 years after onset
- Peripheral Nerve Disorders: most common cause of chronic autonomic insufficiency
  - Neuropathies -- affecting small myelinated and unmyelinated fibers of sympathetic/parasympathetic nerves occur in:
    1. diabetes mellitus
    2. amyloidosis
    3. chronic alcoholism
    4. porphyria
    5. Guillain-Barre syndrome
  - Diabetes Mellitus:
    - initial finding: often asymptomatic abnormal vagal function (reduced heart rate variation with deep breathing)
      - Loss of myelinated and non-myelinated small nerve fibers in splanchnic distribution, carotid sinus, and vagus nerve
    - Enteric neuropathy:
      - disturbances and gut motility
      - nausea/vomiting
      - achlorhydria
      - bowel incontinence
    - Other Symptoms:
      - impotence
      - urinary incontinence
      - pupillary abnormalities
      - postural hypotension
      - symptoms of hypoglycemia -- blunted or detectable because damage to sympathetic adrenal gland innervation prevents epinephrine release
      - Autonomic dysfunction may lengthen Q-T interval -- associated with sudden cardiac death
  - Amyloid polyneuropathy
    - distal painful neuropathy on presentation
    - sensory loss
    - cardiac/renal impairment: usual causes of death
    - autonomic dysfunction manicured because of:
      1. amyloid deposits at intraneural blood vessels and neurons in autonomic ganglia
      2. loss of unmyelinated and myelinated nerve fibers
  - Alcoholic neuropathy:
    - Associated with abnormal vagal and efferent sympathetic function
    - Pathologic changes found in:
      - vagus nerves
      - sympathetic fibers/ganglia
  - Porphyria
    - Acute intermittent porphyria: -- autonomic symptoms
      1. tachycardia
      2. sweating
      3. urinary retention
      4. hypertension
      5. anxiety
      6. catecholamines elevated during acute attack but abnormal autonomic functions may occur even in remission
  - Guillain-Barre syndrome:
    - Acute Inflammatory Demyelinating Polyradiculopathy-- associated with:
      - BP fluctuation
      - arrhythmias
      - abnormal sweating
      - pupillary dysfunction
      - sphincter disturbance
    - Demyelination occurs in:
      - vagus
      - glossopharyngeal
      - sympathetic chain
      - white rami communicantes