Testing of autonomic nervous system function; sudomotor, including 1 or more of the following: quantitative sudomotor axon reflex test (QSART), silastic sweat imprint, thermoregulatory sweat test, and changes in sympathetic skin potential
CPT4 code
Name of the Procedure:
Testing of autonomic nervous system function; sudomotor, including Quantitative Sudomotor Axon Reflex Test (QSART), silastic sweat imprint, thermoregulatory sweat test, and changes in sympathetic skin potential.
Summary
This procedure involves various tests designed to assess the function of the autonomic nervous system, specifically the sweat-producing (sudomotor) function. These tests measure how your sweat glands respond to stimuli and can help diagnose disorders related to nerve function.
Purpose
This procedure is used to diagnose conditions that affect the autonomic nervous system. The goals are to identify abnormalities in sweat production and autonomic function, aiding in the diagnosis and management of conditions such as neuropathies, dysautonomias, and other disorders affecting nerve function.
Indications
- Unexplained sweating or lack of sweating
- Signs of autonomic neuropathy
- Conditions like diabetes, Parkinson's disease, or multiple system atrophy
- Patient history suggesting autonomic dysfunction
Preparation
- Avoid caffeine, alcohol, and nicotine for 24 hours before the test.
- Fast for 2-4 hours prior to the procedure.
- Continue taking medications unless instructed otherwise by your healthcare provider.
- Wear loose, comfortable clothing.
Procedure Description
- Quantitative Sudomotor Axon Reflex Test (QSART): A mild electrical stimulus is applied to the skin to induce sweating, which is then measured using electrodes.
- Silastic Sweat Imprint: A silastic layer is applied to the skin to collect and measure sweat.
- Thermoregulatory Sweat Test: A special powder is applied to the body, which changes color with sweat production. The patient is then placed in a controlled environment to induce sweating, and the extent and distribution are observed.
- Sympathetic Skin Potential: Electrodes are applied to the skin to measure changes in voltage as the sympathetic nervous system responds to stimuli.
No anesthesia is typically required.
Duration
The procedure typically takes between 60-120 minutes, depending on the specific tests being performed.
Setting
The procedure is usually performed in a hospital or outpatient clinic specialized in autonomic testing.
Personnel
- Neurologist
- Trained technicians
- Nursing staff
Risks and Complications
- Mild discomfort from electrical stimulation
- Minor skin irritation or redness
- Rare risk of allergic reaction to materials used, such as the powder for the thermoregulatory sweat test
Benefits
- Helps diagnose autonomic nervous system disorders
- Provides valuable information for the treatment plan
- Non-invasive with relatively quick results
Recovery
- No significant recovery time is needed.
- Patients can typically resume normal activities immediately after the procedure.
- Follow any specific post-procedure instructions provided by the healthcare provider.
Alternatives
- Skin biopsy for nerve fiber density
- Tilt-table test for autonomic function
- Cardiovagal function tests
Each alternative has its own pros and cons, but the described procedure offers a comprehensive, non-invasive assessment specifically for sudomotor function.
Patient Experience
During the procedure, you may feel mild electrical tingling or warmth on your skin. The sweat tests might cause slight discomfort due to temperature changes. Post-procedure, you may experience mild redness or irritation on the test sites, which typically resolves quickly. Pain management and comfort measures will be provided as needed.