Type of test Microscopic
Normal findings
No peripheral synucleinopathy
Test explanation and related physiology
Synucleinopathy refers to any degenerative disease of the central nervous system in which there is an excessive accumulation of alpha-synuclein (a brain protein) in the neurons. The synucleinopathies include Parkinson disease (PD), dementia with Lewy bodies, and multiple system atrophy. This test is used to diagnose PD. Peripheral synucleinopathy is also being used by researchers who strive to enroll patients in treatment trials early in the course of the disease.
In PD, alpha-synuclein proteins are found not only in the brain but throughout the body. Brain tissue examinations will most accurately identify these proteins. The submandibular gland, however, is the easiest to reach and potentially the safest, posing the fewest risks. The tissue is stained for phosphorylated alpha-synuclein. Rich staining indicates PD. Unfortunately, this test in only about 75% sensitive in early PD subjects. False positives may occur but may represent prodromal PD.
The DaT scan (Ioflupane I-123) is a radiopharmaceutical that can visualize striatal dopamine transporters as an adjunct to other diagnostic tests for PD. After intravenous (IV) injection, Ioflupane I-123 reversibly binds to the presynaptic dopa mine transporter (DaT) in the striatum and is visualized using single photon emission computed tomography (SPECT). DaT is reduced 50% to 70% in patients with PD. When combined with olfactory testing such as the University of Pennsylvania Smell Identification Test (UPSIT-40) (because most patients with PD lose some sense of smell), the diagnosis of PD can be more strongly confirmed with fewer patients falsely diagnosed as having PD.
Potential complications
• Submandibular gland bleeding, swelling, and inflammation
Procedure and patient care
Before
* Explain the procedure to the patient.
• Tell the patient no fasting is required
During
• Local anesthesia is used to numb the area.
• An otolaryngologist inserts a needle through the skin into the submandibular gland. Three to six needle core biopsies are obtained.
After
• A dressing is applied to the neck area.
• Check the site for bleeding.
Abnormal findings
- PD
