Autonomic Neuropathies

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Chapter 607 Autonomic Neuropathies

Involvement of small, lightly, or unmyelinated autonomic nerve fibers may be seen in many peripheral neuropathies; the autonomic manifestations are usually mild or subclinical. Certain autonomic neuropathies are more symptomatic and demonstrate varying degrees of involvement of the autonomic nervous system regulation of the cardiovascular, gastrointestinal (GI), genitourinary, thermoregulatory, sudomotor, and pupillomotor systems.

The differential diagnosis is noted in Table 607-1. Autonomic nervous system functional tests are noted in Table 607-2. The general treatment of acquired autonomic dysfunction includes treating the primary disorder (systemic lupus erythematosus, diabetes) and long-term management of specific organ system manifestations (Table 607-3). Acute fluctuations of autonomic symptoms may be seen in Guillain-Barré syndrome. Rapid fluctuations of hypertension or tachycardia changing to hypotension or bradycardia should be managed carefully and with very short-acting medications.

Table 607-1 AUTONOMIC NEUROPATHIES

Guillain-Barré syndrome (Chapter 608)

Non–Guillain-Barré syndrome autoimmunity

• Paraneoplastic (type I antineuronal nuclear antibody)

• Lambert-Eaton syndrome

• Antibodies to neuronal nicotinc acetylcholine receptors

• Antibodies to P/Q type calcium channels

• Other autoantibodies

• Systemic lupus erythematosus

Hereditary

• Type I autosomal dominant

• Type II autosomal recessive (Morvan disease)

• Type III autosomal recessive (Riley-Day)

• Type IV autosomal recessive (congenital insensitivity to pain with anhidrosis)

• Type V absence of pain

• Triple A (Allgrove) syndrome

• Navajo Indian neuropathy

• Multiple endocrine neoplasia type 2b

Toxins (see Table 606-1)

Table 607-2 AUTONOMIC FUNCTION TESTING

Sympathetic and parasympathetic divisions of the autonomic nervous system are involved in all tests of autonomic function

CARDIAC PARASYMPATHETIC NERVOUS SYSTEM FUNCTION

Heart rate variability with deep respiration (respiratory sinus arrhythmia); time-domain and frequency-domain assessments

Heart rate response to Valsalva maneuver

Heart rate response to standing

SYMPATHETIC ADRENERGIC FUNCTION

Blood pressure response to upright posture (standing or tilt table)

Blood pressure response to Valsalva maneuver

Microneurography

SYMPATHETIC CHOLINERGIC FUNCTION

Thermoregulatory sweat testing

Quantitative sudomotor-axon reflex test

Sweat imprint methods

Sympathetic skin response

From Freeman R: Autonomic peripheral neuropathy, Lancet 365:1259–1270, 2005.

Table 607-3 MANAGEMENT OF AUTONOMIC NEUROPATHIES

PROBLEM	TREATMENT
Orthostatic hypotension	Volume and salt supplements Fluorohydrocortisone (mineralocorticoid) Midodrine (α agonist)
Gastroparesis	Prokinetic agents (metaclopramide, domperidone, erythromycin)
Hypomotility	Fiber, laxatives
Urinary dysfunction	Timed voiding; bladder catheterization
Hyperhidrosis	Anticholinergic agents (glycopyrrolate, propanthdine) Intracutaneous botulism toxin