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Idiopathic Orthostatic Hypotension and other Autonomic Failure Syndromes

Practice Essentials

Primary syndromes of generalized autonomic failure include the following:

Idiopathic orthostatic hypotension and other forms of pure autonomic failure (PAF)

Autoimmune autonomic neuropathy (AAN)

Multiple system atrophy (MSA)

Unlike the above disorders, which each affect sympathetic and parasympathetic function, the autonomic condition postural orthostatic tachycardia syndrome (POTS) affects only sympathetic function.

Signs and symptoms

Symptoms of decreased sympathetic function may include the following:

Orthostatic hypotension

Decreased sweating

Ejaculatory dysfunction

Ptosis associated with Horner syndrome

Symptoms of decreased parasympathetic function may include the following:



Urinary retention

Erectile dysfunction

Pure autonomic failure

More specifically, symptoms of PAF include the following:

Orthostatic hypotension: With an inappropriate lack of compensatory increase in heart rate with standing

Gastroparesis: Associated with nausea or constipation

Urinary retention: May cause bladder distention

Decreased sweating: Manifesting as heat or exercise intolerance

Ophthalmologic manifestations: Including ptosis, anisocoria, Horner syndrome, and tonic pupils

Failure of either erection or ejaculation

Autoimmune autonomic neuropathy

The overall physical findings are similar to those observed in PAF. Patients may have additional findings of sensory abnormalities, pain, or loss of deep tendon reflexes.

Multiple system atrophy

Autonomic manifestations are similar to those observed in AAN and PAF. The following neurologic features may also be present:

Pyramidal or cerebellar abnormalities: Weakness, ataxia, incoordination, and eye-movement abnormalities may precede the autonomic features by as long as 2 years

Variable parkinsonian findings: Found in MSA parkinsonian variant; are unresponsive to levodopa; include rigidity, bradykinesia, tremor, and truncal instability

Evidence of cerebellar dysfunction: Found in MSA cerebellar variant; includes ataxia, dysmetria, dysdiadochokinesia, and incoordination; eye-movement abnormalities are frequently present

Postural orthostatic tachycardia syndrome

A greater than 30-bpm increase in heart rate on standing, without a clinically significant decrease in blood pressure, is diagnostic.

See Clinical Presentation for more detail.


Lab studies

Evaluation for acute inflammatory demyelinating polyneuropathy (AIDP): Prompted by an acute onset of autonomic symptoms without other neurologic problems or with features such as subtle weakness or numbness

Measurement of ganglionic AChR antibody: A subacute onset without other neurologic or systemic findings may indicate AAN

Evaluation for Parkinson’s disease and MSA: Should be performed in patients with a chronic onset

Drug or toxin exposure may cause generalized or organ-specific acute autonomic dysfunction. The predominant abnormality (ie, increased or decreased sympathetic or parasympathetic activity) should be identified. The patient’s medications should be reviewed carefully.

Tests for systemic disorders causing secondary pandysautonomia, including the following, may be ordered according to clues from the patient’s history:

Glycosylated hemoglobin or glucose tolerance test: To test for diabetes

Anti-Hu antibody titers: If the patient has associated sensory neuropathy or cognitive changes.

Anti-calcium channel antibody titers: For Lambert-Eaton myasthenic syndrome (LEMS)

Stool screen for botulinum by culture and detection of toxin: In cases of suspected poisoning by food or wound contamination

Serum and urine protein electrophoresis: To evaluate myeloma with amyloidosis

Genetic testing: To evaluate for familial amyloidosis

Rapid plasma reagent (RPR) or Venereal Disease Research Laboratory test (VDRL): To test for syphilis

Human immunodeficiency virus (HIV) testing

Autoimmune screening: To evaluate for collagen-vascular disease; may include antinuclear antibody levels, erythrocyte sedimentation rate, and other autoimmune tests (eg, rheumatoid factor, SS-A and SS-B antibodies)

Assessment of the urinary porphyrins and erythrocyte porphobilinogen deaminase levels: If the clinical history suggests the possibility of porphyria

Imaging studies

Brain magnetic resonance imaging (MRI): Particularly in cases of centrally mediated dysautonomia

In MSA, brainstem or cerebellar atrophy may be seen, with T2 hyperintensity of the pons (the hot-crossed bun sign); these findings differentiate MSA from other types of primary autonomic dysfunction.

See Workup for more detail.


Treatment strategies for autonomic disorders include the following:

AAN: Treatment is based on anecdotal evidence

Chronic PAF syndromes: Treatment is symptomatic only

POTS: Can be treated with low doses of beta blockers, as patients are normally sensitive to their adverse effects

Nonpharmacologic measures are useful for all patients with autonomic dysfunction.
They include the following:

Antihypertensive medications and other medications known to lower blood pressure should be discontinued, if feasible

Fluid and salt intake should be increased

Equipment aids may be helpful; these include tight support stockings, abdominal binders, or antigravity suits for symptomatic hypotension and bladder catheterization for urinary retention

Dietary fiber and enemas may help to improve bowel motility and decrease straining during defecation

Patients with decreased sweating should limit their physical activity, particularly in hot weather; sponging with water during activity may help to prevent overheating

Large meals may exacerbate hypotension and should be avoided

Positional changes, such as standing up, should be performed slowly and gradually

The head of the bed should be elevated, and prolonged recumbency should be avoided

See Treatment and Medication for more detail.

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