1 Pokfulam, Hong Kong
EditorAn epidural catheter was sited using an 18G Tuohy needle at the L4/5 interspace for labour analgesia in a 25-year-old parturient. The lady made some sudden movements during needle insertion, but there were no signs of a cerebrospinal fluid (CSF) leak. Unfortunately, she developed a headache of moderate severity 25 h (day 1) later. Treatment comprised bed rest, oral fluids and acetaminophen/propoxyphene (Dologesic). By day 3, the headache remained the same and she started complaining of tinnitus in her right ear when sitting up. She revealed that she had not been drinking much for the past day and the symptoms made it difficult to breast-feed her baby. An epidural blood patch was performed with 20 ml of autologous blood. During the procedure, the patient received 500 ml of i.v. Lactated Ringers solution and hydration was continued for 24 h with 0.9% normal saline at a rate of 90 ml h1. The headache resolved over the next 5 h but the tinnitus was the same. The tinnitus was slightly improved the next morning (about 19 h later) and resolved completely on the third day after the blood patch. The patient was discharged home 2 days later. On follow-up at 1 week, she had had no more headaches or tinnitus since discharge, although she did have some backache that subsequently settled.
Headache is a common complication following dural puncture in pregnancy, although associated auditory symptoms are infrequently reported. This may be because either the incidence is low or because it is overshadowed by the headache, and by the nausea and vomiting. The aetiology of the auditory symptoms is unclear, but is likely to be related to CSF loss decreasing intracranial pressure (ICP), creating a pressure imbalance and traction on cranial nerves. The predominantly affected cranial nerves are the abducens, facial and vestibulocochlear nerves. The vestibulocochlear nerve enters the tight internal acoustic meatus after crossing the posterior cranial fossa, which can predispose it to traction injury during intracranial hypotension. In this case, the onset of tinnitus lagged behind the headache by 2 days. This may have signified persisting or even worsening intracranial hypotension. There could have been continuing CSF leak through the dural tear and the patient might have been dehydrated causing a delay in the restoration of a normal ICP. The tinnitus might simply have taken a longer time to manifest than the headache.
We feel it is important to ask about this symptom and to treat it urgently. Bilateral tinnitus has been reported to last for as long as 4 yr as a complication of dural puncture, indicating neural injury possibly related to unrelieved traction.1 Fortunately, epidural blood patch is an effective treatment for both postdural puncture headache and auditory symptoms, and should not be unduly delayed.13 It would be devastating for the injury to the vestibulocochlear nerve to progress to persistent hearing loss.4
In this patient, the headache disappeared a few hours after the blood patch whereas the tinnitus took another 14 h to improve, and was only completely resolved on the third day after the blood patch. It is likely that vestibulocochlear neuropraxia would have taken a longer time to recover.
A. Y. C. Wong
M. G. Irwin
Pokfulam, Hong Kong
References
1 Narchi P, Veyrac P, Viale M. Long-term postdural puncture auditory symptoms: effective relief after epidural blood patch. Anesth Analg 1996; 82: 1303
2 Broome IJ. Hearing loss and dural puncture. Lancet 1993; 341: 6678[CrossRef][ISI][Medline]
3 Lybecker H, Andersen T. Repetitive hearing loss following dural puncture treated with autologous blood patch. Acta Anaesthesiol Scand 1995; 39: 9879[ISI][Medline]
4 Mak PHK, Tumber PS. Postoperative sudden sensorineural hearing loss after posterior lumbar decompression: a case report. Can J Anaesth 2003; 50: 51921