Sudoscan / QSART test

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QSART/Sudoscan test

Quantitative Sudomotor Axon Reflex Test (QSART) is a test for the examination of peripheral autonomic fibres, which enables the precise assessment of sebaceous gland function.

 QSART/Sudoscan test

Quantitative Sudomotor Axon Reflex Test (QSART) – a test for the examination of peripheral autonomic fibres, which enables the precise assessment of sebaceous gland function, is available in Latvia for the first time. During the test, attention is paid to the fine autonomic nerve tissues of the peripheral nervous system that innervate the sebaceous glands. The test is performed with SUDOSCAN, which is an innovative device for early diagnostics of fine nerve tissue polyneuropathy and autonomic polyneuropathy.

Duration of the test

Approximately 5 minutes.

Preparation

Minor amount of preparation is required prior to the examination.

Sensations

The test is non-invasive and painless.

Limitations

There are no limitations.

Advantages

Quick, simple and precise.

Results

The physician provides an examination report.

Diagnostic principles

The capacity of the sebaceous glands to release chloride ions is measured during the test, in reaction to electrochemical stimulus in the hands and feet – the sites with the highest density of sebaceous glands. The results may be used to evaluate autonomic dysfunction of the patient, by measuring electrochemical skin conductance (ESC) and the degree of asymmetry observed between the left and the right side.

How the test is performed

You will be asked to remove footwear and socks; then you will be asked to stand on sensor plates with your feet and place your hands on them as well. You will have to stand motionless for approximately 3 minutes.

Preparation: minor amount of preparation is required prior to the examination

  • informing on the medicinal products you are using
  • avoiding the use of ointments, lotions or other cosmetics on the skin of the hands and feet

this examination needs to be performed on patients with suspected autonomic polyneuropathy of fine nerve fibres in the event of the following diseases:

  • diabetes mellitus
  • Parkinsonism
  • polyneuropathy caused by chemotherapy
  • familial amyloid polyneuropathy
  • Fabry disease
  • fibromyalgia
  • Sjogren’s syndrome
  • Lyme disease
  • HIV
  • for the assessment of therapy results
  • congenital polyneuropathies
  • autoimmune diseases

 

Symptoms of peripheral autonomic polyneuropathy

Gastrointestinal system

  • constipation
  • diarrhoea
  • nausea after meals
  • gastrointestinal tract motility disorders
  • abdominal bloating

Heart and lungs

  • pathological heart function or arrhythmia
  • fluctuations of blood pressure (orthostatic hypertension)
  • vertigo/instability, while changing body position
  • high blood pressure
  • disorders of physical load tolerance

Genitourinary system

  • difficulty commencing urination
  • sensation of insufficient emptying of the urinary bladder
  • urinary incontinence

Other symptoms

  • swearing disorders
  • disorders of heat tolerance during physical load
  • sexual disorders, including erection problems
  • pupillary light reflex disorders
  • weight loss (without the observation of a diet)

 

SUDOSCAN test in the event of different diseases and complications

Diabetes mellitus
Type 2 diabetes mellitus frequently progresses without developing clinically significant symptoms In some of the cases it remains undiagnosed until complications appear. At the same time, there is epidemiological evidence that complications occur at a much earlier stage of the disease than known earlier. A considerable number of patients have incurred irreversible tissue damage (diseases of peripheral blood vessel, nephropathy, retinopathy, neuropathy) at the moment of diagnosing diabetes. 60-70% of patients with diabetes mellitus are diagnosed with neuropathies.

Diabetic foot and cardiovascular complications
Diabetic autonomic neuropathy is a serious and common diabetic complication that may affect the entire autonomic nervous system. This frequently occurs before other complications and manifests as a dysfunction of one or several organ systems, for instance, cardiovascular, gastrointestinal, genitourinary, visual or sudomotor systems.

Diabetic foot
The loss of autonomic innervation affects peripheral microvascular perfusion. This eventually promotes skin dryness, impaired sweating and the development of microscopic cracks. In the latter phases, skin ulcer infection and gangrene develops. In the long term, leg ulcers and amputation of extremities become the most common consequence of peripheral diabetic neuropathy, as well as the most significant cause of disability. Every 30 seconds a lower extremity is lost to diabetes somewhere in the world and up to 70% of all leg amputations have the same cause. The most commonly available methods for the determining of distal peripheral neuropathy are based on the assessment of irreversible damage to myelinated nerve fibres. Common tests (feeling of pressure, sensation, vibration sensation) are subjective and poorly reproducible.

Cardiovascular complications
Diabetic autonomic neuropathy (DAN) is the clinically most critical form of diabetic autonomic neuropathy. It is caused by the loss of heart autonomic nervous system innervation, as a result of which, the heart rate variability (HRV) and blood vessel tone reduces. Early detection of autonomic cardiac and vascular neuropathy can help in preventing the risk of sudden death and myocardial infarction. Herat rate variability serves as a biological marker of increased mortality risk; however, the assessment thereof requires a lot of time and special diagnostic equipment. SUDOSCAN is an innovative device for the detection and observation of diabetic foot and autonomic heart neuropathy.

Specialists