Lower extremity radicular pain after prophylactic intrathecal saline injection through a subarachnoid catheter following accidental dural puncture

We describe a case in which severe lower extremity radicular pain occurred after administration of 0.9% saline into the subarachnoid space through a catheter that had been left for 20 h following inadvertent dural puncture in an obstetric patient. A 42-year-old (G8P7) woman was admitted for repeat cesarean delivery. Accidental dural puncture occurred during epidural placement. Following a slow 10-mL intrathecal injection of 0.9% normal saline an epidural catheter was advanced into the subarachnoid space. Spinal anesthesia was used for cesarean delivery and the subarachnoid catheter was kept in place for 20 h. Before catheter removal, an additional 10 mL of 0.9% saline was slowly administered into the intrathecal space. Almost instantly, the patient complained of back pain that progressed to lower extremity radicular pain and paresthesia; symptoms began to resolve after 10 min. Subsequently, the patient developed a postdural puncture headache that persisted for three days. The patient's radiculitis and paresthesia likely resulted from an acute increase in intrathecal pressure after saline administration or from direct catheter irritation. Although both intrathecal saline administration and subarachnoid catheter placement have been previously proposed as ways to prevent postdural puncture headache, their efficacy remains controversial, and we advise caution with these techniques.

The genetics of asthma

The genetic approach to asthma has revealed a few candidate genes. Among them, special attention is given to the association between chromosome 5q and various cytokines and also to chromosome 11q and the IgE receptor. A mutation in chromosome 5 enhances interleukin-4 activity, which increases IgE synthesis by plasma cells. Polymorphism in the beta chain of the high-affinity IgE receptor (FC epsilonRI-beta) is considered to play a key role in the pathogenesis of asthma. Increased IgE, caused by both mutations, is responsible for inflammatory allergic reactions. A possible link between genetics and asthma has been suggested, although some studies could not confirm an association. Further study of the candidate genes may allow at-risk individuals to be tested and new treatments to be developed.