In this article, we will discuss the Definition and Etiopathogenesis of Guillain-Barrè Syndrome. So, let’s get started.
Acute inflammatory demyelinating polyradiculouropathy (AIDP) is defined as an immune mediated demyelinating (autoimmune) disorder with an acute onset characterised by a syndrome of rapidly developing flaccid paralysis, areflexia, paraesthesias with minimal sensory loss and albuminocytological
dissociation in the CSF (cerebrospinal
fluid). It is also popularly known as Guillain-Barré syndrome after the name of French neurologist (1916).
A history of preceding viral infection such as Cytomegalovirus (CMV), Epstein-Barr virus (EBV), hepatitis virus (B and C), mumps and herpes virus is present in about 50–60% of cases. Other infections (Campylobacter jejuni, typhoid, Mycoplasma, filarial), vaccination (for rabies, smallpox, oral polio, tetanus toxoid) and events like bee sting, surgery, MI, idiopathic glomerulonephritis and bone marrow transplantation have been implicated.
Campylobacter jejuni shares an identical immunogenic region with the ganglioside GM-I in the human peripheral nerve, and causes more severe form of the disease with axonal degeneration with or without demyelination. Two axonal variants of GB syndrome are: (1) acute motor axonal neuropathy (AMAN) and (ii) acute motor sensory axonal neuropathy (AMSAN). The Miller-Fischer syndrome, has close association with anti-GQ-lb antibody and, is specifically associated with ophthalmoplegia, areflexia without weakness and pupillary changes.
Three important pathological changes in AIDP are (i) inflammation (ii) demyelination and (iii) remyelination. In a minority of cases, intense axonal damage and degeneration occurs which does not recover.
Both humoral and cellular immune mechanisms contibute to the tissue damage in AIDP. Macrophages, autoreactive T lymphocytes producing cytokines and interferon-gamma cause damage to myelin sheath by penetrating
the Schwann cells. The remaining Schwann cells divide and remyelinate the bare axons.