Autonomic dysfunction, or dysautonomia, may be due to
generalized or segmental disorders of the central or peripheral nervous system.
Symptoms can be generalized, segmental, or focal. These disorders may be
congenital, familial, or acquired. Common manifestations include impotence;
bladder and gas-trointestinal dysfunction; abnormal regulation of body fluids;
decreased sweating, lacrimation, and salivation; and orthostatic hypotension.
The lat-ter can be the most serious manifestation of the disorder.
Acquired autonomic dysfunction can be iso-lated (pure autonomic
failure), part of a more gener-alized degenerative process (Shy–Drager
syndrome, PD, olivopontocerebellar atrophy), part of a seg-mental neurological
process (MS, syringomyelia, reflex sympathetic dystrophy, or spinal cord
injury), or a manifestation of disorders affecting peripheral nerves (GBS,
diabetes, chronic alcoholism, amyloi-dosis, or porphyria).
Congenital or familial dysautonomia
occurs most frequently in Ashkenazi Jewish children and is usu-ally referred to
as Riley–Day syndrome. Autonomic dysfunction is prominent and is associated
with gen-eralized diminished sensation and emotional lability. Moreover,
patients are predisposed to dysautonomic crises triggered by stress and
characterized by marked hypertension, tachycardia, abdominal pain, diaphoresis,
and vomiting. Intravenous diazepam is effective in resolving such episodes.
Hereditary dysautonomia associated with a deficiency of dopa-mine β-hydroxylase is
described. Administration of α-dihydroxyphenylserine improves symptoms
The major risk of anesthesia in patients
with autonomic dysfunction is severe hypotension,compromising cerebral and
coronary blood flow. Marked hypertension can be equally deleterious. Most
patients are chronically hypovolemic. The vasodilatory effects of spinal and
epidural anesthe-sia are poorly tolerated. Similarly, the vasodilatory and
cardiac depressant effects of most general anesthetic agents combined with
positive airway pressure can be equally problematic. Continuous intraarterial
blood pressure monitoring is use-ful. Hypotension should be treated with fluids
and direct-acting vasopressors (in preference to indirect-acting agents).
Enhanced sensitivity to vasopressors due to denervation sensitivity may be
observed. Blood loss also is usually poorly tol-erated. Body temperature should
be monitored closely. Patients with anhidrosis are particularly susceptible to