Beta-2-transferrin and cerebrospinal fluid rhinorrhoea.

Beta-2-transferrin is a protein produced by neuraminidase activity in the brain which is uniquely found in the cerebrospinal fluid (CSF) and perilymph. Its absence in other body secretions makes its detection invaluable in diagnosing a CSF leak. In this series samples were analysed from 25 patients with suspected CSF rhinorrhoea. The presence of beta-2-transferrin was determined by immuno-fixation electrophoresis. Out of 25 patients 16 were positive for beta-2-transferrin. A dural defect and CSF leak were confirmed during surgery in 13 of the 16 patients. In three patients the rhinorrhoea stopped spontaneously. Out of nine patients who were negative for beta-2-transferrin in the nasal fluids, two underwent a craniotomy and neither had evidence of CSF leak or dural effect. Two of the eight patients had a normal computerized coronal tomography (CT) despite a CSF leak. Seventeen patients underwent CT cisternography (six in the beta-2-transferrin negative group and 11 in the positive group). A leak was shown by CT cisternography in seven patients in the positive beta-2-transferrin group, but a leak could not be confirmed in the other four patients. No leak was demonstrated in the six patients in the negative beta-2-transferrin group. Beta-2-transferrin is a valuable and sensitive means of confirming the diagnosis of CSF leaks. Patients with a suspected CSF leak but no beta-2-transferrin in their nasal discharge can avoid unnecessary invasive investigations.