Clinical Manifestations:

• ANS disorders: due to--

  • Central nervous system (CNS) causes

  • Peripheral nervous system (PNS) causes

• Signs/Symptoms: due to interruption of reflex arc

  • Site of interruption:

    • Afferent limb

    • CNS processing center

    • Efferent limb

  • Examples:

    •  Posterior fossa tumors: medullary lesions may cause --

      • Impaired blood-pressure responses to postural change (orthostatic hypotension)

    • Lesions of vasomotor nerve fibers to blood vessels (e.g. diabetes or spinal cord disease)

    • Lesions to afferent connections (e.g. Guillain-Barre syndrome)

    •  Segmental disorders (focal deficits):

      • In spinal cord disease

      • Reflex sympathetic dystrophy

      • Horner's syndrome

Autonomic Dysfunction: symptoms-- Organ dependent

• Impotence-- first sign of autonomic failure-- sequence

  1. Lost of spontaneous early morning erection

  2. Loss of nocturnal penile tumescence

  3. Total impotence

• Bladder dysfunction:

  • Occurs early both in men and women (especially with CNS involvement)

  • Brain/spinal cord disease: above the level of the lumbar spine(upper motor neuron) disease:

    1. Urinary frequency/small bladder volumes

    2. Incontinence

  •  Autonomic fiber disease to the bladder (lower motor neuron disease) or sensory denervation:

    • Large bladder volumes

    • Urinary frequency

    • Overflow incontinence

• Gastrointestinal Dysfunction:

  • Severe constipation typically

    • Exception -- diabetes diarrhea-- cause

      1. Rapid transit of contents

      2. Uncoordinated small bowel activity

    • Osmotic diarrhea (bacterial overgrowth -- small bowel stasis

  • Decreased salvation (glandular effects)

• Eye irritation: -- reduced lacrimation

•  Orthostatic Hypotension: most disabling feature of autonomic dysfunction

  • Definition: postural decrease of at least 20 mm Hg in systolic or 10 mm Hg in diastolic blood pressure sustained for least 3 minutes (to differentiate between autonomic dysfunction and sluggish baroreceptor reflex response {common in the elderly})

  •  Symptoms of postural hypotension:

    • Dimming or loss of vision

    • Light headedness

    • diaphoresis

    • Impaired hearing

    • Pallor/weakness

    • Syncope