PANDAS - Proposed Mechanism

Proposed Mechanism

The PANDAS diagnosis and the hypothesis that symptoms in this subgroup of patients are caused by infection are controversial.

Whether the group of patients diagnosed with PANDAS have developed tics and OCD through a different mechanism (pathophysiology) than seen in other people diagnosed with Tourette syndrome is unclear. Researchers are pursuing the hypothesis that the mechanism is similar to that of rheumatic fever, an autoimmune disorder triggered by streptococcal infections, where antibodies attack the brain and cause neuropsychiatric conditions.

The molecular mimicry hypothesis is a proposed mechanism for PANDAS: this hypothesis is that antigens on the cell wall of the streptococcal bacteria are similar in some way to the proteins of the heart valve, joints, or brain. Because the antibodies set off an immune reaction which damages those tissues, the child with rheumatic fever can get heart disease (especially mitral valve regurgitation), arthritis, and/or abnormal movements known as Sydenham's chorea or "St. Vitus' Dance". In a typical bacterial infection, the body produces antibodies against the invading bacteria, and the antibodies help eliminate the bacteria from the body. In some rheumatic fever patients, autoantibodies may attack heart tissue, leading to carditis, or cross-react with joints, leading to arthritis. In PANDAS, it is believed that tics and OCD are produced in a similar manner. One part of the brain that may be affected in PANDAS is the basal ganglia, which is believed to be responsible for movement and behavior. It is thought that similar to Sydenham's chorea, the antibodies cross-react with neuronal brain tissue in the basal ganglia to cause the tics and OCD that characterize PANDAS. Studies neither disprove nor support this hypothesis: the strongest supportive evidence comes from a controlled study of 144 children (Mell et al, 2005), but prospective longitudinal studies have not produced conclusive results.

Read more about this topic:  PANDAS

Other articles related to "proposed mechanism, mechanism, proposed, mechanisms":

Bayliss Effect - Proposed Mechanism
... The mechanism is not yet completely understood, but studies have shown that volume regulated chloride channels and stretch sensitive non-selective cation channels lead to an increased probability in opening of L-typ ...
William Lipscomb - Scientific Studies - Boron Chemistry and The Nature of The Chemical Bond
... Lipscomb is perhaps best known for his group's proposed mechanism of the three-center two-electron bond ... the three-center two-electron bond, nor did they develop formulas that give the proposed mechanism ... Eberhardt, Crawford, and Lipscomb proposed the mechanism of the three-center two-electron bond, and Lipscomb's group achieved an understanding of it through electron orbital calculations using formulas by Edmiston ...
Dejerine–Roussy Syndrome - Causes and Pathophysiology - Proposed Mechanism
... When a stroke damages one hemisphere, it is proposed that the other hemisphere will cope with the discrepancies in a specific manner ... from inputs, eliciting either denial or rationalization defense mechanisms in order to stabilize said discrepancy ... or allodynia), while damage to the right hemisphere can cause denial as a defense mechanism (anosognosia and somatoparaphrenia) ...

Famous quotes containing the words mechanism and/or proposed:

    The two elements the traveler first captures in the big city are extrahuman architecture and furious rhythm. Geometry and anguish. At first glance, the rhythm may be confused with gaiety, but when you look more closely at the mechanism of social life and the painful slavery of both men and machines, you see that it is nothing but a kind of typical, empty anguish that makes even crime and gangs forgivable means of escape.
    Federico García Lorca (1898–1936)

    On the 31st of August, 1846, I left Concord in Massachusetts for Bangor and the backwoods of Maine,... I proposed to make excursions to Mount Ktaadn, the second highest mountain in New England, about thirty miles distant, and to some of the lakes of the Penobscot, either alone or with such company as I might pick up there.
    Henry David Thoreau (1817–1862)