Dextrans, glucose polymers, are used as plasma expanders, thromboembolic prevention and as distention and irrigating fluids for various endoscopic procedures. They are produced by Leuconostoc mesenteroides.
1/2000 grade III /IV without hapten inhibition ; 1/70000 grade III/IV with hapten inhibition.
Atopy (grade I and II reactions).
High levels of dextran-reactive antibodies (grade III and IV reactions).
General: anaphylactic shock, fever.
Cutaneous: general itching, macular rash, urticaria, flushing, angioedema.
Respiratory: dyspnea, tightness of chest, wheezing, coughing, pulmonary edema.
Other: nausea, vomiting, joint pains, oliguria, convulsions, increased clotting time.
Classification of dextran-induced adverse reactions.
Grade I: skin manifestations (urticaria, flush, erythema), back pain, mild fever.
Grade II: mild to moderate hypotension, gastrointestinal disturbances.
Grade III: severe hypotension, shock, bronchospasm.
Grade IV: cardiac and/or respiratory arrest.
Grade V: death.
Cutaneous testing (usually negative).
Dextran reactive antibodies (passive hemagglutination).
Dextran specific IgG and IgM (ELISA): the presence of a high level of specific IgG antibodies is a major risk factor.
The majority of adverse reactions are mild anaphylactoid, non-immunogenic reactions.
The severe reactions are immunogenic (immune-complex mediated) anaphylactic reactions, caused by naturally occurring IgG class dextran-reactive antibodies. When dextran is infused into a patient with high titer of dextran-reactive antibodies, immune-complexes are generated and lead to the release of mediators.
20 ml of Promit (dextran 1 (15%)) must be injected prior to infusion of clinical dextrans. If more than 15 minutes have passed following the injection before starting the infusion, another dose of dextran 1 should be given. This leads to a 35-fold reduction of severe (grade III/IV/V) reactions to clinical dextran.
Concerning preloading in pregnant women prior to epidural analgesia, dextrans should be avoided and replaced by gelatins or crystalloid solutions due to the risk to the fetus of anaphylactic shock in the mother (antidextran IgG cross the placental membrane). 18 neonatal deaths and 7 cases of neurological impairment have been reported in France.