Viral Encephalitis Caused by Herpes Zoster in the Waist and Abdomen: An Unusual Case Report

Jian-Xia Chen, Yan-Yan Feng?, Xiao-Jing Kang?

Department of Dermatology, People’s Hospital of Xinjiang Uygur Autonomous Region, Uygur, Xinjiang 830001, China.

Introduction

Viral encephalitis caused by varicella zoster virus (VZV)mainly occurs in immunocompromised individuals and patients with VZV infection in the brain or nerves of the cervical or upper thoracic spinal cord. However, viral encephalitis caused by VZV affecting distant body parts,such as herpes zoster of the waist and abdomen, is rare.How herpes zoster virus reaches the central nervous system (CNS) is unclear. We herein present an atypical case of waist and abdomen herpes zoster infection that progressed to the CNS in a 48-year-old healthy,immunocompetent patient without brain magnetic resonance imaging (MRI) abnormalities, and may enrich the knowledge of viral encephalitis caused by herpes zoster.

Case report

A 48-year-old man was admitted to the Department of Dermatology,People’s Hospital of Xinjiang Uygur Autonomous Region, with a 2-day history of fever, impaired recognition and attention, reduced spontaneous speech,inability to answer questions correctly, and abnormal behavior (eg, brushing teeth with the end of toothbrush handle and impaired handwriting). Two weeks before presentation, the patient had developed clusters of small erythematous vesicular lesions with acupuncture-like pain on the right side of the waist and abdomen. He had no fever or neurological symptoms at that time and his mental status, cranial nerve reflexes, and motor and sensory examination findings were normal. Five days after symptom onset, he was diagnosed with herpes zoster and treated for the first 48hours with oral acyclovir (800mg three times daily) followed by ganciclovir (intravenous 5mg/kg twice daily), mecobalamin (vitamin B12, 0.5mg three times daily), dexketoprofen trometamol (12.5mg three times daily), and prednisone acetate tablets (15mg oncedaily)for5days.Theblistersgraduallybecamedryand scarred. However, he suddenly developed lethargy,impaired recognition,reduced spontaneous speech,inability to answer questions correctly, and abnormal behavior(eg,brushing teeth with the end of toothbrush handle and impaired handwriting). The patient had no relevant medical history.

Upon presentation,physical examination revealed a body temperature of 38.5°C, blood pressure of 107/65 mmHg,pulse of 80beats/minute,and respiratory rate of 20breaths/minute. The next day, his treatment was changed to acyclovir (intravenous 10mg/kg three times daily), oxiracetam(intravenous 4g once daily),and compound musk injection(intravenous 20ml once daily)for 2 days.He was then admitted to our department, and neurological examination showed that his nervous system abnormalities were somewhat relieved(his cognitive function and ability to answer simple questions correctly had recovered).However,he still exhibited recall impairment and fatigue.Clinical examination revealed several positive pathological signs,which was consistent with the CNS lesions.Signs of meningeal irritation were absent. Deep tendon reflexes,strength, and sensation were normal. Routine blood analyses showed a white blood cell count of 6.31×109/L,red blood cell count of 4.6×1012/L,platelet count of 290×109/L,neutrophil count of 2.87×109/L,lymphocyte count of 2.99×109/L,monocyte count of 0.34×109/L,eosinophil count of 0.06×109/L,and basophil count of 0.05×109/L.The erythrocyte sedimentation rate was 16mm/hour.Head computed tomography and brain MRI and magnetic resonance angiography were negative. Cerebrospinal fluid(CSF) analysis showed a cell count of 9×106/L with an increased proportion of monocytes, a positive Pandy test result, total protein level of 0.6g/L, glucose level of 2.72mmol/L, lactic dehydrogenase level of 16.75U/L,and adenosine deaminase level of ＜2U/L.

He was diagnosed with VZV encephalitis and treated with acyclovir(intravenous 250mg three times a day),oxiracetam(intravenous 4g once daily),and compound musk injection(intravenous 20ml once daily)for 5 days.His nervous system symptoms were resolved,and at discharge he had achieved near full recovery of his cognitive function and communicated without difficulty. His body temperature decreased to 36.8°C.At the 6-month follow-up,he had developed no CNS recurrence or sequelae.

Discussion

Viral encephalitis refers to inflammation of the brain parenchyma caused by viral infections and often manifests as fever, headache, and disturbances in mental function (eg, confusion, delirium, behavior changes,dysphasia/aphasia, temporal lobe seizures, and focal neurological signs proceeding to coma).These symptoms distinguish viral encephalitis from meningitis, which is characterized by the absence of nervous parenchymal tissue involvement and which manifests as fever,headache, and accompanying signs of meningeal irritation(photophobia,neck stiffness,and Kernig sign).Viral encephalitis has a poor prognosis,high mortality rate,and often severe sequelae.1

Viral encephalitis caused by VZV mainly occurs in immunocompromised individuals, such as patients with AIDS, patients who have undergone organ transplantation, patients of advanced age, and patients undergoing immunomodulatory therapy. It also mostly occurs in patients with VZV infection in the brain or nerves of the cervical or upper thoracic spinal cord.2Viral encephalitis caused by VZV affecting distant body parts,such as herpes zoster of the waist and abdomen, is rare.

The patient in the present case was diagnosed with VZV encephalitis based on the following five factors:fever and behavioral abnormalities as the main clinical manifestations, CSF analysis abnormalities (positive Pandy test result, elevated protein, and decreased glucose), a history of herpes zoster before neurological symptom onset,improvement of symptoms following antiviral treatment,and exclusion of alternative causes of the fever and abnormal behavior.

Most patients with encephalitis have nervous system symptoms and abnormalities on brain MRI or magnetic resonance angiography. Some patients may have normal MRI findings, although such cases are rarely reported.Riciglianoet al.2reported a 56-year-old immunocompetent man developed brainstem encephalitis as a complication of Ramsay Hunt syndrome with normal MRI findings,physical examination findings,chemistry parameters, and cell counts in the CSF. Finally, his diagnosis of herpes zoster virus encephalitis was made and confirmed by CSF VZV polymerase chain reaction.

The present case was a healthy,immunocompetent man,who developed neurological symptoms 5 days after being diagnosed as herpes zoster on the right side of the waist and abdomen.MRI,routine blood analyses,autoimmune screening, and HIV andTreponema pallidumserology yielded negative results.However,Pandy test was positive,and CSF analysis showed elevated protein and decreased glucose. After treatment with antiviral therapy, his nervous system symptoms were somewhat relieved.Finally, the diagnosis of herpes zoster viral encephalitis was made. Unfortunately, detection of VZV DNA in the CSF by reverse transcription polymerase chain reaction was not performed due to conditional restrictions.However,the patient had a favorable outcome in contrast to previously reported cases, most of which had a poor prognosis, high mortality, and often severe sequelae.Administration of glucocorticoids to reduce inflammation,adequate antiviral therapy, and nutritional neurotherapy in the early stage of the disease may lead to successful management of the condition.

How herpes zoster virus reaches the CNS is unclear.The virus is thought to be directly transmitted from the anterior and posterior roots of the spinal cord to the CNS or travel to the CNSviaimmune-mediated demyelination and vasculitis.Several paraclinical tools are used for early and accurate diagnosis and management of immune-mediated demyelinating disease. For example, MRI is the gold standard technique to determine the spatiotemporal pattern of demyelination,the diagnosis of viral encephalitis is based on the presence of focal lesions in the white matter of the CNS, long T1 and T2 signal changes, and hyperintense FLAIR images with a blurred lesion edge.Cranial enhanced MRI suggests that multiple white matter demyelinating lesions are present with no significant lesion enhancement.3Vasculitis/vasculopathy from VZV infection mainly causes cerebral and spinal infarction and rarely hemorrhage.4The use of corticosteroids and immunosuppressive agents in patients with immunologically mediated vasculitis and demyelinating lesions has a positive effect on the prognosis,whereas antiviral therapy is not effective.

In our case, the patient developed neurological symptoms and continued antiviral treatment, and we added neuroprotective treatment (oxiracetam and compound musk injection). The neurological symptoms gradually eased on the third day. Additionally, no obvious abnormality was present on head MRI. Therefore, we presume that the herpes zoster virus in this case was directly transported into the brain by retrograde axoplasmic flow. This is a viral immune evasion mechanism.Once inside the axon, the virus is invulnerable to immune control.Further clinical studies are needed to elucidate the access of herpes zoster virus to the CNS and its pathogenesis. For patients developing a sudden consciousness or behavioral disorder,we should carefully inquire about their medical history, closely observe the evolution of their condition, carefully perform a neurological examination,and select reasonable auxiliary examinations to avoid delayed treatment. Antiviral treatment should be started as soon as viral encephalitis is clinically suspected. Oral treatment (acyclovir or its prodrug valacyclovir, which has better oral absorption)should be given in benign cases and IV acyclovir should be given in severe cases such as those involving ocular and CNS complications,especially in immunosuppressed individuals. High-dose acyclovir should be used(10mg/kg IV every 8hours for 21 days). Strict attention must be given to the patient’s fluid balance because dehydration increases the likelihood of acyclovir-induced renal toxicity.Relapse occurs in up to 5%of patients and requires continuation of treatment for an additional 7 days.5-6

In conclusion, for patients developing a sudden consciousness or behavioral disorder,we should carefully inquire about their medical history, closely observe the evolution of their condition, carefully perform a neurological examination, and select reasonable auxiliary examinations to avoid delayed treatment. Antiviral treatment should be started as soon as viral encephalitis is clinically suspected. Oral acyclovir or its prodrug valacyclovir, which has better oral absorption, should be given in benign cases,and intravenous acyclovir should be given in severe cases such as those involving ocular and CNS complications, especially in immunosuppressed individuals.

Acknowledgements

ThisstudywassupportedbytheNationalNaturalScienceFoundation of China (No. 81660514) and the Xinjiang Uygur Autonomous Region Natural Science Foundation(No.2016D01C102).