[Changes in plasma histamine and catecholamines levels after injection of chymopapain in chemonucleolysis]

Because pruritus, erythema and tachycardia are observed in some patients during chemonucleolysis, a prospective study was designed to investigate the plasma levels of histamine and catecholamines occurring after an injection of chymopapain. Thirteen patients (11 men and 2 women), mean age 38 +/- 11 years, were studied. They all had negative prick skin tests, human basophil degranulation tests (HBDT) and radio-absorbent tests (RAST) to chymopapain. The patients were premedicated with 100 mg hydroxyzine and 3 g tranexamic acid. Sedation was carried out using 0.1 mg.kg-1 droperidol and 0.02 mg.kg-1 phenoperidine. The nucleosus pulposus was visualized with 3 ml of contrast medium (lopamiron 300); 2 ml of chymopapain were then injected. Blood samples were obtained at T1 (after the contrast medium, but before the chymopapain), and then 5, 10, 15, 20 and 30 minutes after the chymopapain. The usual haemodynamic parameters were recorded at the same times. Four patients had clinical signs (group I), whereas the other nine (group II) did not. There was an increase in histamine levels in three patients from group 1, as well as in two in group II (up to 33 nmol.l-1). However, mean histamine and catecholamines levels were comparable in both groups at all times, and between times, of sampling. There therefore was no relationship between clinical signs and the release of histamine or catecholamines. The premedication with an antihistamine may have protected the patients, but the signs reported by four patients may also be due to the chymopapain itself.