Thursday, April 1, 2010

Anti sulfatide neuropathies

clinical presentation is that of chronic axonal distal sensory neuropathy,symmetric, slowly progressive,  with pain in half and much less having any weakness. The frequency in idiopathic PN is only 0.7 %, but may be as high as 25 % in certain subgroups.  High titers are relatively specific for distal sensory neuropathy, whereas low titers can be seen in other conditons, including ITP, HIV, and autoimmune hepatitis.  Monoclonal gammopathies occur in half. 


GALOP (gait disorder, antibody, late age onset neuropathy) is a subgroup of antisulfatide neuropathy have monoclonal IgM  and antibodies to sulfatide and GALOP. 

anti GM1 antibodies pearls

1.  MMN with conduction block presents as asymmetric, painless, slowly progressive weakness especially in distal upper limbs. 
2.  Sensory sparing resembles ALS, however, UMN signs are not seen in MMN
3.   Conduction block outside of normal compression sites differentiates MMN and ALS.  Patients without conducton block occassionally respond to immunotherapy (Neurology 1997 first author JS Katz).
4. High titer IgM anti GM1 are seen in 50-60 percent of patients with MMN, but sensitivity is increased to 80-90 percent by complexing GM1 to secondary antigens co GM1 antibody test (Pestronk, Neurology 1997)
5.  In GBS, anti GM1 antibodies closely correlate with Campylobacter jejuni infection and sometimes correlate with worse neuropathy and outcome
6.  Other antigens coexpressed sometimes in GBS are GD1a, GD1b and GM2; some have argued GM2 correlates with CMV neuropathy but this is not univerally accepted.  GD1a is often seen in AMAN, the Chinese GBS variant (60 %) v. only 4 % of traditional GBS patients

Antibody related neuropathies anti MAG pearls

1.  typical presentation is distal symmetric slowly progressive sensorimotor neuropathy
2.  Half of patients with PN and IgM gammopathy have an autoantibody to MAG, typically kappa chain
3.  Antibody may cross react with SGPG
4.  Prolonged distal motor latencies are the most reliable finding, seen in 90 %
5.  Patients with a positive anti MAG confirmed by Western blot sugggests immune related PN
6.  If patients fulfil criteria for CIDP they should be so treated
7.  Patients with significant deficit should have immune therapy attempted even though it is likely to disappoint.
8.  Relationship to myeloma exists
9.  MGUS beyond  hematology read here http://neurologyminutiae.blogspot.com/2009/10/mgus-significant-beyond-hematology.html ;  malignant transformation here http://neurologyminutiae.blogspot.com/2007/04/malignant-transformation-of-monoclonal.html  ;  http://neurologyminutiae.blogspot.com/2007/04/malignant-transformation-in-mgus.html ; miscellany on MGUS prevalence here http://neurologyminutiae.blogspot.com/2006/08/miscellany-on-neuropathy-tests.html