From the Guidelines
Testing for anti-GQ1b antibodies in cerebrospinal fluid (CSF) is not typically recommended as a primary diagnostic tool, but may be considered in certain situations where additional diagnostic confirmation is needed, particularly in cases of suspected Miller Fisher syndrome. The diagnostic value of measuring serum levels of anti-ganglioside antibodies is limited and assay-dependent, and a positive test result can be helpful, especially when the diagnosis is in doubt, but a negative test result does not rule out GBS 1.
Key Points to Consider
- Anti-GQ1b antibodies are found in up to 90% of patients with Miller Fisher syndrome (MFS) and therefore have greater diagnostic value in patients with suspected MFS than in patients with classic GBS or other variants 1.
- CSF examination is mainly used to rule out causes of weakness other than GBS and should be performed during the initial evaluation of the patient, with the classic finding in GBS being the combination of an elevated CSF protein level and a normal CSF cell count (known as albumino-cytological dissociation) 1.
- The presence of anti-GQ1b antibodies in serum is more commonly used for diagnosis, and CSF testing may not always detect these antibodies even when they are present in serum.
- Testing should be performed early in the disease course as antibody levels decrease over time, and results should be interpreted alongside clinical presentation and other diagnostic tests.
Clinical Implications
- The diagnosis of GBS and its variants, including MFS, relies on a combination of clinical presentation, laboratory tests, and CSF examination.
- The decision to test for anti-GQ1b antibodies in CSF should be made on a case-by-case basis, taking into account the clinical presentation and the need for additional diagnostic confirmation.
- Clinicians should be aware of the limitations of antibody testing and interpret results in the context of the overall clinical picture, as recommended in the diagnosis and management of GBS 1.
From the Research
Antigq1b Ab Tested in CSF
- The presence of anti-GQ1b antibodies in cerebrospinal fluid (CSF) is not directly mentioned in the provided studies as a diagnostic criterion 2, 3, 4, 5, 6.
- However, one study mentions that albuminocytological dissociation in the CSF appears later in the course of Miller Fisher syndrome, and the presence of anti-GQ1b IgG antibody in the serum can be identified in over 80% of patients, peaking in the first week 6.
- Another study found that increased CSF protein content was present in 24% of patients with acute anti-GQ1b antibody syndrome 5.
- The clinical features and outcomes of patients with anti-GQ1b antibody syndrome are diverse, and the presence of anti-GQ1b antibodies in CSF is not explicitly stated as a diagnostic or prognostic factor 2, 3, 4, 5.
Clinical Features and Outcomes
- The clinical features of anti-GQ1b antibody syndrome include ophthalmoplegia, ataxia, areflexia, central or peripheral vestibulopathy, and optic neuropathy 2.
- The prognosis is mostly favorable, with approximately 14% of patients experiencing relapse 2.
- A study of 166 patients with acute anti-GQ1b antibody syndrome found that the most frequent clinical features were areflexia, distal upper and lower limbs sensory symptoms, ophthalmoplegia, sensory ataxia, limb muscle weakness, and bulbar weakness 5.
- The outcome of patients with anti-GQ1b antibody syndrome is usually good, with complete recovery in 69% of cases at 1-year follow-up 5.