Superficial Siderosis, Traumatic Tap, and Xanthochromia—Reply

In reply

We thank Sellal and Ahle for their accurate comment on our article about idiopathic superficial siderosis.¹ We stated that “xanthochromia or the presence of red blood cells (RBC) in the cerebrospinal fluid (CSF) is a common finding and may be due to damage to a small blood vessel during the procedure (known as ‘traumatic tap’).” We were trying to emphasize that the observed bleeding was not secondary to the lumbar puncture, but the term xanthochromia was used incorrectly. By definition, xanthochromia is the yellow discoloration indicating the presence of bilirubin in the CSF and a previous bleeding. In clinical practice, it is used to differentiate hemorrhage from a traumatic lumbar puncture. A traumatic tap introduces RBCs into the CSF, which can hemolyze, forming oxyhemoglobin that is not promptly converted into bilirubin.² We agree with their point of view that the presence of xanthochromia is a good sign to differentiate subarachnoid hemorrhage from traumatic tap.