Autonomic Hyperreflexia/Dysautonomia Flashcards
Why does autonomic hyperreflexia occur?
Stimulation of the anterolateral column of the spinal cord below
the level of the lesion results in an increase in sympathetic
activity. Normally, these impulses are counteracted by
inhibitory impulses from higher centers of the nervous system.
Because of the spinal cord injury, however, the inhibitory
impulses are blocked, resulting in unimpeded sympathetic
outflow.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259.
In what patient population does autonomic
hyperreflexia occur?
It occurs in patients who have experienced spinal shock and
appears in conjunction with the return of spinal reflexes.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259.
What are the hallmark cardiovascular symptoms of
autonomic hyperreflexia?
Severe hypertension and reflex bradycardia. It may also be
accompanied by blurred vision, loss of consciousness, seizures,
cardiac dysrhythmias, and pulmonary edema.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259.
What factors can trigger autonomic hyperreflexia?
It can be triggered by cutaneous stimulation such as surgical
incision or visceral stimulation such as distention of the bladder
or rectum.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259.
What are methods of preventing autonomic
hyperreflexia?
The goal is to prevent the triggering event from initiating the
reflex by deep general anesthesia, neuraxial anesthesia, or
regional anesthesia.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259-260.
How is the incidence of autonomic hyperreflexia
related to the level of the spinal cord injury?
About 85% of patients with an injury above T6 will suffer from
autonomic hyperreflexia, but it is unlikely to occur at all in
patients with a lesion below T10.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259.
During anesthesia, when is autonomic hyperreflexia
most likely to occur?
With the initiation of surgical stimulation at the beginning of the
case, especially if the patient is not under a deep enough
anesthetic, and at the end of the case as the effects of the
anesthetic are wearing off.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 260.
What is the treatment for autonomic hyperreflexia if it
occurs?
Vasodilators with a short half-life (such as sodium nitroprusside)
should be available to treat the sudden onset of systemic
hypertension.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 260.
Will an epidural prevent autonomic hyperreflexia
from occurring in a laboring parturient with a T6
injury?
Epidural anesthesia has been reported to be effective in
preventing autonomic hyperreflexia from occurring due to
uterine contractions, but, because epidurals may spare the
sacral segments, spinal anesthesia is more protective.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 260.
What symptoms may be seen in a patient who is
awake and experiences autonomic hyperreflexia?
Severe headache and blurred vision may occur due to severe
hypertension and nasal stuffiness may occur due to reflexive
cutaneous vasodilation.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 260.
What is reflexive cutaneous vasodilation and how
does it relate to autonomic hyperreflexia?
When a patient experiences autonomic hyperreflexia, a reflex
dilation of the tissues ABOVE the level of the spinal cord injury
will occur to help offset the sudden increase in blood pressure.
Patients may experience nasal stuffiness as a result of this
effect.
Hines RL, Marschall KE. Anesthesia & Co-Existing Diseases.
6th ed. Philadelphia, PA: Elsevier-Saunders; 2012: 259-260.
