Systemic varicella (chickenpox) is usually a benign infection of childhood. In some adults, however, herpes encephalitis or other central nervous system (CNS) pathology must be excluded by performing a diagnostic dural puncture which, in a significant number of patients, is complicated by headache (1). Some of these patients will subsequently require consideration of therapeutic epidural blood patch. Although epidural blood patch is effective in treating dural puncture headache (2), it does introduce blood into both the epidural and intrathecal spaces (3). In the context of varicella, introducing viremic blood to the neuraxis requires careful consideration of the potential risks and benefits.
A 38-yr-old woman presented to the emergency department for evaluation of malaise, stiff neck, and a papular rash. Her workup included overnight admission and a diagnostic lumbar puncture with a 20-gauge Quincke needle at L4-5. Upon confirmation of varicella and exclusion of meningitis, valacyclovir treatment was initiated, and she was discharged.
The patient returned the next day to the emergency department complaining of photophobia and a postural frontal headache that had been present for 18 h. Her examination was consistent with varicella, with diffuse skin lesions covering most of her body. The headache was attributed to her recent dural puncture.
Conservative therapies (i.e., rest, analgesics, and caffeinated beverages) were not effective, and 4 days after the initial lumbar puncture, the patient presented to the pain clinic for consideration of epidural blood patch therapy. She had been receiving valacyclovir for 96 h at this point and was afebrile. After a thorough discussion of the risks, benefits, and alternatives, she elected to undergo epidural blood patch.
Epidural blood patch was performed, with the patient in the right lateral decubitus position, with an 18-gauge Husted needle at L3-4, a site without varicella lesions. The epidural space was identified without complication on the first pass by using loss of resistance with saline. Blood was sterilely withdrawn from the right antecubital vein at a site unaffected by varicella lesions and was injected slowly into the epidural space. The patient reported a “full” sensation after 20 mL of blood had been deposited, and the injection was terminated. After 30 min in the supine position, she was allowed to sit and then stand. She reported complete resolution of her headache.
Nine days after the epidural blood patch, the patient returned to the pain clinic for evaluation of lower back and lower extremity pain that had persisted since the blood patch. She remained free of headache symptoms. Her neurologic examination was normal. A magnetic resonance image (MRI) revealed a residual clot in the epidural space (Fig. 1). There was no evidence of spinal cord or nerve root compression. Her symptoms were monitored conservatively. She was seen again 30 days later, at which time her back and leg pain had completely resolved. One year later, she remained free of all symptoms.
Dural puncture headache in the context of varicella infection is relatively rare. The incidence of systemic varicella in adulthood is 3 per 1000, but the incidence in this age group is increasing (4). Approximately 1% of these patients will require hospitalization, during which approximately 10% are likely to require a diagnostic dural puncture (5). The incidence of spinal headache after diagnostic dural puncture with a 20-gauge needle is approximately 11%–28% (1). Assuming that a third of the patients with headache will be considered for blood patch, this circumstance would occur in approximately 1:10,000,000 in the population. Treatment of such patients requires several important considerations.
An alternative to blood patch would have been epidural saline infusion. Although epidural saline can relieve postdural puncture headache symptoms in the short term, the effects are only transient (6). For patients who have persistent positional headache despite conservative measures, epidural blood patch is the most effective treatment (2,6). Risks associated with blood patch include back pain, bruising, and infection. Additionally, there is the risk of producing yet another dural tear, which could exacerbate the headache. In a patient with acute varicella, there is an additional theoretical risk of introducing infected blood into the epidural or intrathecal space (3). This may increase the risk of CNS complications of varicella—an argument analogous to performing the procedure in a patient with human immunodeficiency virus (7) or bacteremia (8).
However, effective antiviral drugs are available that inhibit replication of the varicella zoster virus (VZV). Viral activity cannot be detected in peripheral blood 24 hours after initiation of acyclovir therapy (9). Hence, it is possible to reduce the infectious risk by treating the patient with appropriate antiviral medication for at least one day. Furthermore, neuraxial infection may occur naturally and independently of blood patch therapy, because systemic varicella is characterized by infection of the sensory neurons. The virus characteristically remains latent within the sensory ganglia, forming a reservoir from which reactivation can occur, producing zoster.
Our patient experienced lower back and leg pain after the blood patch, and this has occasionally been reported by others (10–12). MRI evaluation was consistent with other reports of imaging after epidural blood patch (13,14). Back and leg pain have been associated independently with both VZV infection and epidural blood patch. Valacyclovir treatment has been weakly associated with weakness, myalgias, and arthralgias, although the causal relationship is uncertain (15). Given the juxtaposition of three possible causes, we consider the temporal association. Our patient’s back and leg symptoms seem best correlated with the epidural blood patch. It is interesting to speculate that her symptoms may have been precipitated by leptomeningeal irritation caused by varicella infection.
Epidural blood patch may be a safe therapeutic option for patients with postdural puncture headache in the context of acute varicella. In these circumstances, patients should first receive adequate antiviral coverage.
1. Morewood G. A rational approach to the cause, prevention and treatment of postdural puncture headache. Can Med Assoc J 1993;149:1087–93.
2. Taivainen T, Pitkanen M, Tuominen M, Rosenberg P. Efficacy of epidural blood patch for postdural puncture headache. Acta Anaesthesiol Scand 1993;37:702–5.
3. Griffiths A, Beards S, Jackson A. Visualization of extradural blood patch for post lumbar puncture headache by magnetic resonance imaging. Br J Anaesth 1993;70:223–5.
4. Fairley C, Miller E. Varicella-zoster virus epidemiology: a changing scene? J Infect Dis 1996;174:314–9.
5. Levin M, Weinberg A. Infections: viral & rickettsial. In: Hay W, Hayward A, Levin M, Sondheimer J, eds. Current pediatric diagnosis & treatment. 16th ed. New York: McGraw Hill, 2003: 1117–9.
6. Duffy P, Crosby E. The epidural blood patch: resolving the controversies. Can J Anaesth 1999;46:878–86.
7. Tom D, Gulevich S, Shapiro H, et al. Epidural blood patch in the HIV-positive patient: review of clinical experience. Anesthesiology 1992;76:943–7.
8. Anwari JS. Epidural blood patch (EBP) and septic complication. Can J Anaesth 2000;47:289–90.
9. Wolff MH, Schunemann S. Acyclovir treatment prevents varicella-zoster virus replication in PBMC during viremia. New Microbiol 1999;22:309–14.
10. Cornwall RD. Radicular back pain following lumbar epidural blood patch. Anesthesiology 1975;43:692–3.
11. Oh J, Camann W. Severe, acute meningeal irritative reaction after epidural blood patch for postdural puncture headache. Anesth Analg 1998;87:1139–40.
12. Tarkkila P, Miralles J, Palomaki E. The subjective complications and efficiency of the epidural blood patch in the treatment of postdural puncture headache. Reg Anesth 1989;14:247–50.
13. Beards S, Jackson A, Griffiths A, Horsman E. Magnetic resonance imaging of extradural blood patches: appearances from 30 min to 18 h. Br J Anaesth 1993;71:182–8.
14. Vakharia S, Thomas P, Rosenbaum A. Magnetic resonance imaging of cerebrospinal fluid leak and tamponade effect of blood patch in postdural puncture headache. Anesth Analg 1997;84:585–90.
15. Weller S, Blum MR, Doucette M, et al. Pharmacokinetics of the acyclovir pro-drug valaciclovir after escalating single- and multiple-dose administration to normal volunteers. Clin Pharmacol Ther 1993;54:595–605.