Treating a weakened virus

A case study published in the Qatar Medical Journal reports that it’s important for primary healthcare and emergency physicians to be aware that renal patients could suffer from complications arising from the reactivation of varicella-zoster virus and from toxicity caused by the drug that treats it.

Varicella-zoster is the virus that causes the all-too-well-known chickenpox in children. Once the symptoms of chickenpox have resolved, the virus becomes dormant and can reactivate later in life — often in people whose immunity system is compromised or the elderly — in the form of painful skin eruptions around nerves called “shingles”. Its reactivation can also result in a variety of inflammations and complications in the central nervous system.

Nephrologist Yasser Abed from Oman’s Sultan Qaboos University Hospital was presented with the case of a 70-year-old renal dialysis patient who developed a rash around his eye typical of varicella-zoster reactivation¹. The patient was prescribed with the drug acyclovir in an oral dose that was modified to be appropriate for the kidney disease he was originally being treated for. Acyclovir is excreted by the kidneys, so it is important to adjust its dose in patients with impaired kidney functions. But, a few days later, the patient returned, presenting with confusion and difficulty speaking.

Clinical examination and tests did not reveal anything additional (except for later confirmation of varicella-zoster infection), leading Abed to conclude that the patient could be suffering from neurological complications of his varicella-zoster infection, toxicity resulting from the impaired ability of the patient’s kidneys to excrete acyclovir, or he was suffering from an acute stroke. Based on the clinical presentation, Abed suspected the first and prescribed intravenous acyclovir together with an oral steroid to counteract the suspected central nervous inflammation. The patient recovered and was returned home after two full weeks of treatment.

A single-dose varicella-zoster vaccine is now available in a few developed countries with a good efficacy and safety profile, writes Abed. “We do believe that there is a need for consensus policies for zoster vaccination in dialysis patients,” he concludes.

1. Abed, Y. W. A. Varicella-zoster virus associated encephalitis in a patient undergoing haemodialysis. Qatar Med. J.2015, 9 (2016). | article