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Chronic Autonomic Dysfunction in SCI

Chronic Autonomic Dysfunction in SCI. Aims of this Session. Describe autonomic dysfunction: physiology, pathophysiology in SCI Discuss lasting effects of autonomic dysfunction in SCI Describe severe autonomic dysreflexia, its recognition, treatment and prevention.

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Chronic Autonomic Dysfunction in SCI

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  1. Chronic Autonomic Dysfunction in SCI

  2. Aims of this Session • Describe autonomic dysfunction: physiology, pathophysiology in SCI • Discuss lasting effects of autonomic dysfunction in SCI • Describe severe autonomic dysreflexia, its recognition, treatment and prevention

  3. Autonomic Dysfunction: Physiology & Pathophysiology of SCI • SCI affects the somatic (i.e. the sensory and motor pathways we are aware of and can control) nervous system below the level of the injury • However the autonomic (i.e. ‘self-regulating’) nervous system is also affected, and, like the somatic central nervous system, the severity and extent of the damage is largely related to the level and neurological completeness of the injury

  4. What is the Autonomic Nervous System? • The ANS maintains many body systems that need to run constantly without conscious effort: for example breathing, digestion, secretion and storage of urine, thermoregulation, circulation of blood. • The ANS can be viewed as two systems, the sympathetic and parasympathetic, which respond to each other and the external environment in order to maintain an internal equilibrium while facilitating conscious response to challenges (‘flight or fight’)

  5. Parasympathetic

  6. Sympathetic

  7. What is the Autonomic Nervous System? • It is important to realise that the primary mode of action of the autonomic nervous system is the reflex: stimulus-response.

  8. Autonomic Dysfunction: Physiology & Pathophysiology of SCI • As we have seen the parasympathetic and sympathetic tend to involve distinct levels of the spinal cord • This means that the nature of the autonomic dysfunction in an individual is heavily influenced by the location and extent of the SCI

  9. Autonomic Dysfunction Landmarks UMN lesion Spasm Reflex NBD Reflex erection sympathetic cardioaccelerator supply T6 Profound spinal shock Risk of severe autonomic dysreflexia LMN lesion No spasm Areflexic NBD Severe erectile dysfunction

  10. Neurological Completeness of Injury: Risk of Severe Autonomic Episodes

  11. High Risk Group: AIS ‘A’ Tetraplegics

  12. Chronic Autonomic Dysfunction in SCI • After spinal shock has subsided, there will be a persistent autonomic dyssynergy, again relative to level and density of lesion • The parasympathetic and sympathetic systems will not be properly moderated or inhibited by each other, which will often result in hyperreflexia, particularly of the sympathetic system • This will often have evident functional physiological consequences

  13. Cardiovascular System

  14. Respiratory system

  15. Gastrointestinal System

  16. Skin

  17. Genitourinary System

  18. Chronic Autonomic Dysfunction in SCI • Autonomic symptoms can be many and various • Many of these can be distressing • In the absence of normal somatic sensation these can be a useful aid to diagnosis • Many SCI individuals ‘learn’ to interpret autonomic signs usefully

  19. Chronic Autonomic Dysfunction in SCI • Distressing autonomic symptoms can often be addressed rationally. For example: • Sweating often responds to sympatheticomimetics (oxybutynin etc) • Postural hypotension is treated by gradual mobilisation, and use of elastic stockings and abdominal binder. Sometimes ephedrine is used • However attention must be given to any underlying cause- particularly bladder and bowel management

  20. What is Autonomic Dysreflexia? • Severe autonomic dysflexia is a sudden rise in blood pressure in response to a harmful stimulus (usually the increase in pressure in a body cavity caused by the collection of fluid) • Untreated, this rise in blood pressure may continue and result in cerebrovascular events or even death

  21. What is Autonomic Dysreflexia? • The noxious stimulus triggers unmediated sympathetic reflex activity which causes massive vasoconstriction below the level of injury. • This in turn causes a rise in central blood pressure which causes an alarming headache • The area above the lesion tries to compensate with vasodilation, causing flushing and sweating

  22. What is Autonomic Dysreflexia? • In most cases the noxious stimulus is urine in the bladder (probably above 90% of new dysreflexia) • In practice (outside of SCI Centres) this is usually due to a blocked catheter

  23. What is Autonomic Dysreflexia? • Bowel triggers are constipation, anal fissure, bleeding haemorrhoids etc • Other (rarer) primary causes include infected pressure sores and abscesses, pus from an ingrowing toenail collecting behind the nail, and DVT

  24. Recognition of Severe Autonomic Dysreflexia • Non- drainage of urine • Severe headache • (raised BP) • (sweating and flushed above lesion)

  25. Treatment of Severe Autonomic Dysreflexia • Change catheter (do not attempt washout) • (Give chemical vasodilator eg: GTN) • Reassure • (Elevate head)

  26. Prevention of severe Autonomic Dysreflexia • Good bladder and bowel management: • Regular catheter change • Avoid constipation

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