Diagnosis of Familial Amyloid Polyneuropathy
Bladder Function Tests
Bladder function tests, also called urodynamics testing, help to determine the functioning of the urinary bladder. The tests focus on the ability of the bladder to hold urine and release it steadily.
Electromyogram is a diagnostic test that assesses the interaction between muscle and nerve cells in terms of their ability to communicate with one another and respond to electrical signals.
Gastric Emptying Tests
The gastric emptying test is used to diagnose the underlying issues causing gastrointestinal symptoms. However, this test alone cannot be used to confirm a FAP diagnosis.
Genetic testing can determine whether you have changes in your genes or chromosomes that could cause disease. This type of testing helps to identify diseases before symptoms appear and can be key to slowing the progression of FAP.
Imaging Studies of the Heart
When a doctor suspects cardiac involvement, he or she may order heart imaging to confirm the diagnosis, visualize the extent of damage, and plan further treatment. Non-invasive imaging techniques such as echocardiography, electrocardiogram, and MRI are used to determine heart involvement in FAP.
Thermoregulatory Sweat Test
A thermoregulatory sweat test can help physicians determine a FAP diagnosis. Patients have an area of skin dusted with a powder that responds to moisture by changing color. The degree of color change at the end of the test is proportional to the amount of sweat produced, which is proportional to nerve activity.
Tilt Table Test
A tilt table test is one method physicians can use to help diagnose FAP. Patients are secured to a horizontal, motorized table for several minutes before the table is tilted vertically for up to an hour. Fainting or dizziness, along with a slow change in heart rate and blood pressure recovery, could be symptoms of FAP or another autonomic neuropathy disorder.
To aid in the diagnosis of FAP, biopsies of affected tissues can be surgically removed and analyzed for the presence of amyloid deposits. A biopsy is a surgical procedure in which a small piece of tissue is removed and retained for testing. Amyloid deposits can occur in multiple tissues in FAP, and a biopsy can be taken from these different areas.