Clinicians should be aware that patients with a history of stroke are at a much higher risk of developing herpes zoster (HZ) than the general population, especially in the first year of recovery.
That’s according to a report in PLoS One, which calculates that patients with stroke had a 25.27 times higher risk of HZ compared to the general population over a 1-year follow-up period and a 3.44 times higher risk of HZ over a 5-year follow-up period.
Kaohsiung Medical University–led researchers say that the higher risk affected both male and female stroke patients compared with controls but varied by age.
Researchers also note that both hemorrhagic stroke and ischemic stroke were significantly associated with increased risk of HZ (hemorrhagic type [IRR = 2.31; 95% CI, 1.67-3.20]; ischemic type [IRR = 2.51; 95% CI, 2.09-3.02]). “Specifically, hemorrhagic stroke was associated with an increased risk of HZ ophthalmicus and ischemic stroke was associated with an increased risk of post-herpetic neuralgia,” they explain. “To our knowledge, this is the first cohort study to compare HZ risk between hemorrhagic stroke and ischemic stroke.”
As a result of their findings, the authors urge healthcare professionals to make sure stroke patients have been vaccinated against HZ.
To determine whether stroke increases HZ risk, the cohort study compared patients who had HZ with and without a first incident of stroke using the Taiwan National Health Insurance Research Database. Included were 20,551 stroke patients and 20,551 controls matched for age, gender, age categories, and Charlson Comorbidity Index score categories at a one-to-one ratio.
“Physicians should know about that adults with stroke have a higher than normal risk of herpes zoster,” the authors write. “Thus, physicians must be acquainted with proper antiviral therapy and pain control to bring down the morbidity that ensues from herpes zoster. Use of herpes zoster vaccine may be considered in stroke patients.”
Noting that risk factors for HZ include “female gender, mechanical trauma, genetic susceptibility, interleukin 10 gene polymorphism, as well as weakening of the immune system [due to the aging process], comorbidity [drug exposure], disease severity and nutritional deficiencies,” researchers posit that the casual pathway between stroke and HZ could have several causes.
Among them are:
• Stroke results in a localized depletion of oxygen and energy, which causes death of cells in the affected areas. The resulting inflammatory process could put stroke patients at risk for HZ in addition to fatal secondary infections.
• Depression is a common complication after stroke, and depression can have neuro-endocrine and immunological/inflammatory effects. In fact, past research has shown that depression and other mood disorders are associated with increased HZ risk.
• HZ is usually seen in elderly immunocompromised patients, which is consistent with this study’s result showing that the incidence of HZ increased with age in stroke patients. Older age is considered the most important attributable factor in stroke and HZ.
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