Human herpesvirus 7 meningitis in an adolescent with normal immune function: A case report

Abstract

BACKGROUND

Human herpesvirus type 7 (HHV-7) is a less common herpes virus that usually causes mild, self-limiting illnesses. However, in recent years, there have been increasing reports of HHV-7 causing serious central nervous system infections, especially meningitis. The pathogenesis and clinical features of HHV-7 meningitis, particularly in adolescents with normal immune function, remain incompletely studied. Therefore, the purpose of this report is to share a case of HHV-7 meningitis in an immunocompetent adolescent with a view to deepening our understanding of the disease.

CASE SUMMARY

A 12-year-old female was admitted with fever, headache, and vomiting. 4 d before admission, the patient developed a fever without obvious induction, with a temperature up to 39.5 °C, no convulsions, accompanied by chills, headaches, fatigue, and no muscle aches. The patient was treated with fever reduction, which could be reduced to 38 °C; repeated high fever, accompanied by vomiting 7-8 times; and no abdominal pain or diarrhea. The patient was diagnosed with "acute suppurative tonsillitis" in a local hospital, and the blood routine was generally normal. The patient was given symptomatic support treatment such as "ceftriaxone sodium" and antiemetic rehydration for 2 d, and his condition did not improve. The patient's physical examination showed pharyngeal congestion, bilateral tonsil grade I hypertrophy, regression of purulent secretions, and cervical resistance. Ocular B-ultrasound: Opacity of the vitreous body and edema of the optic disc in both eyes. Optical coherence tomography examination showed that the macular fovea was generally normal in both eyes, with edema of the optic disc. DNA virus monitoring results: HHV-7. We gave ganciclovir antiviral therapy, dexamethasone anti-inflammatory treatment, mannitol to reduce cranial pressure, omeprazole to protect gastrointestinal mucosa, and calcium and potassium supplementation.

CONCLUSION

This study reports a case of HHV-7 meningitis in an adolescent with normal immune function. Through comprehensive analysis of the clinical manifestations, laboratory tests, and treatment methods of the patient, it is found that early identification and antiviral treatment are essential for the outcome of the disease. This case suggests that despite normal immune function, adolescents may still suffer from herpes virus type 7 meningitis, so clinicians should be vigilant and take effective treatment measures in time.

Key Words: Human herpesvirus 7 meningitis, Immune function, Immune deficiency, Central system infection, Case report

Core Tip: This study reports an immunologically normal adolescent case of human herpesvirus 7 meningitis. The pathogenesis and clinical manifestations of the virus in healthy individuals were discussed by describing the clinical manifestations, laboratory findings, and imaging features of the patients in detail. The case reminds doctors to be alert to rare infections that may occur in individuals with normal immune function and to enhance awareness of the disease for timely diagnosis and treatment.

INTRODUCTION

Human herpesvirus type 7 (HHV-7) is a human herpesvirus that mainly infects infants and young children, causing mild infant rash[1-3]. However, in recent years, the cases of HHV-7 infection and meningitis in adolescents with normal immune function have gradually increased, causing widespread concern in the medical community[4-6]. The purpose of this study was to investigate the pathogenesis, clinical manifestations, diagnostic methods, and therapeutic effects of herpesvirus 7 meningitis in adolescents with normal immune function and to provide a scientific basis for clinical diagnosis and treatment[7]. At present, the diagnosis of herpesvirus-7 meningitis in adolescents with normal immune function mainly depends on cerebrospinal fluid examination, virus isolation, and serological detection[8-10]. In terms of treatment, although antiviral drugs can alleviate the disease to a certain extent, the therapeutic effect is not ideal due to the characteristics of the virus and individual differences, and some patients may have relapse or residual nervous system sequelae. Therefore, this study's significance lies in its deep exploration of the pathogenesis of HHV-7-induced meningitis, providing theoretical support for the development of more effective treatment and prevention strategies. At the same time, this study will also provide clinicians with a more accurate diagnostic basis and treatment recommendations, improve the diagnosis and treatment level of adolescent HHV-7 meningitis, and ensure the health of adolescents.

CASE PRESENTATION

Chief complaints

A 12-year-old was admitted to the hospital with a fever, headache, and vomiting for 4 d. 4 d before admission, the patient developed a fever without obvious inductions, with a temperature up to 39.5 °C, no convulsions, accompanied by chills, headaches, fatigue, and no muscle sores. The patient was treated with fever reduction, which could be reduced to 38 °C; repeated high fever, accompanied by vomiting 7-8 times; and no abdominal pain or diarrhea. The patient was diagnosed with "acute suppurative tonsillitis" in a local hospital, and his blood routine was generally normal. The patient was given symptomatic support treatment such as "ceftriaxone sodium" and antiemetic rehydration for 2 d, and his condition did not improve.

History of present illness

Nothing special.

History of past illness

Nothing special.

Personal and family history

Nothing special.

Physical examination

Nothing special.

Laboratory examinations

Photographic fundus examination: Fundus photographic examination provides us with more intuitive visual data. The photo clearly shows edema in the patient's optic discs in both eyes, resulting in blurred boundaries. This is typical of a meningitis virus infection. At the same time, the posterior polar retina was present, indicating that the virus did not cause serious structural damage to the retina.

After a period of active treatment, the patient's eye condition has significantly improved. Although the boundary of the optic disc in both eyes remained slightly blurred, the fundus photography revealed a significant reduction in the edema of the optic disc compared to the previous examination. This change shows that the treatment is effective and the patient's condition is gradually improving. However, because the effects of HHV-7 on the eyes can be long-term, patients still need regular follow-up to ensure eye health. In summary, through the analysis of the ocular B-ultrasound and optical coherence tomography (OCT) examination of this patient, we have an in-depth understanding of the influence of HHV-7 meningitis on the ocular structure and provide an important reference for follow-up treatment (Figure 1).

Figure 1 Fundus photographic examination results. A: Pretreatment; B: Posttreatment.

Biochemical index monitoring: Respiratory pathogen antibody test: Influenza virus type A IgM antibody: Weak positive. Mycoplasma pneumoniae antibody: Mycoplasma pneumoniae IgM: 0.59 COI, Mycoplasma pneumoniae IgG: 73.07 AU/mL. DNA virus monitoring results: HHV-7. Blood routine, anti-O, thyroid function, biochemical set, abnormal cell morphology, urine and stool routine, erythrocyte sedimentation rate, procalcitonin, Epstein-Barr virus nucleic acid test showed no abnormality. Biochemical examination of cerebrospinal fluid: leukocyte 410x10^6/L; Monocyte accounted for 99.5%; Cerebrospinal fluid pressure 320 mmH₂0.

Imaging examinations

In the chest imaging examination, we found increased lung texture, manifested by increased small blood vessels and bronchial shadows in the lung field. This abnormal appearance suggests that there may be mild interstitial changes or inflammation in the lungs. Because HHV-7 mainly invents the central nervous system, lung changes may be related to the systemic immune response triggered by the virus. Although the patient's immune function is normal, the viral infection may induce a certain inflammatory response in the lungs, resulting in increased lung texture (Figure 2). Craniocerebral magnetic resonance imaging (MRI): No obvious abnormality was found in the brain parenchyma; a circular liquid signal shadow was seen in the left middle cranial fossa; and the boundary was clear. The ventricular system was symmetrical, the sulci fissure did not increase in depth or width, and the midline structure did not shift. The examination results suggested the possibility of an arachnoid cyst in the left middle cranial fossa. Re-examination of cerebral MRI: The left anterior temporal pole arachnoid cyst is possible, similar to the previous (Figure 3).

Figure 2  Analysis of chest X-ray results.

Figure 3 Results of craniocerebral magnetic examination. A: T1-weighted imaging; B: T2-weighted imaging; C: Fluid-attenuated inversion recovery; D: Diffusion-weighted imaging.

Eye-B ultrasound examination: During a B-ultrasound examination of the patient's eye, we found a significant anomaly. The vitreous bodies of both eyes appear cloudy, which is one of the inflammatory responses caused by herpes virus type 7 infection. In addition, the examination results also showed that the patient's binocular optic disc appeared to have an to have an obvious edema phenomenon, which further confirmed the virus's effect on the patient's eye structure. Optic disc edema is a common ocular complication of meningitis virus infection that can lead to vision loss or other visual impairment (Figure 4).

Figure 4 Ocular B ultrasonography results. A: Left eye; B: Right eye.

OCT analysis: With further examination by OCT, we were able to more precisely observe the microscopic changes in the patient's eye. Despite the macular fovea's generally normal shape in both eyes, the presence of optic disc edema remained a significant problem. The fovea of the macula, the most significant area of visual function in the retina, maintains its normal shape, indicating no significant impact on the patient's central vision. However, the presence of optic disc edema may affect patients' visual field and color vision to some extent (Figure 5).

Figure 5  Optical coherence tomography examination.

MULTIDISCIPLINARY EXPERT CONSULTATION

This case of HHV-7 meningitis in an immunologically normal adolescent has sparked interdisciplinary interest and discussion. Neurologists focus on neurological symptoms such as headache, meningeal irritation, and cerebrospinal fluid test results. The infectiology specialist provides treatment recommendations and preventive measures against the herpes virus, taking into account the pathogen. Imaging experts confirmed the structural abnormalities in the brain with an MRI. The Clinical Laboratory Section provided the results of relevant laboratory tests, including cerebrospinal fluid analysis and viral nucleic acid testing. Psychologists pay attention to the psychological state of patients and their families and provide support and psychological intervention. Finally, the treatment team worked together to develop a personalized treatment plan and continuously monitored the patient changes and treatment effects.

FINAL DIAGNOSIS

Immunologically normal adolescent herpesvirus 7 meningitis.

TREATMENT

We gave ganciclovir antiviral therapy, dexamethasone anti-inflammatory treatment, mannitol to reduce cranial pressure, omeprazole to protect gastrointestinal mucosa, and calcium and potassium supplementation.

OUTCOME AND FOLLOW-UP

The patient was treated with medication and recovered from the hospital.

DISCUSSION

This study reports a case of HHV-7 meningitis in an immunocompetent adolescent. The successful diagnosis and treatment of this case are of great significance for further understanding of the infection characteristics and clinical manifestations of HHV-7[11]. HHV-7, as a herpes virus, is generally considered to be mostly cryptic or with mild symptoms, but can lead to serious central nervous system infections such as meningitis in certain circumstances, such as when immune function is compromised or viral load is high[12-14]. Although the patient is a teenager with normal immune function, the virus replicates heavily in the body and eventually causes meningitis, which suggests that we should improve awareness of the possibility of HHV-7 infection in clinical practice, especially in the face of patients with meningitis of unknown cause[15]. The successful treatment of this patient has also provided us with valuable experience[16]. Timely virus detection, accurate diagnosis, and effective antiviral therapy are the keys to controlling the progression of the disease. At the same time, attention should also be paid to a comprehensive immune status assessment of patients in order to timely detect and deal with immune factors that may affect the course of the disease[17].

The primary infection of HHV-7 occurs within 3 years of age. The manifestations of primary HHV-7 infection are similar to those of primary HHV-6 infection, including fever, roseola, and febrile convulsions, which then enter the incubation period and are carried throughout life[18]. In adults with a seropositivity rate of over 90%, HHV-7 infection occasionally causes meningoencephalitis, mononucleosis, or hepatitis. HIV-7-related diseases are rarely reported and may be related to their biological characteristics[19]. The disease can occur in children of all ages, and reports of central nervous system HHV-7 infection in China are rare. There have been cases reported of deaths from meningitis in immune-functioning patients due to HHV-7. There have also been cases reported of patients with urinary retention, respiratory failure, and flactic paralysis of the limbs progressing to quadriplegia despite empiric antiviral therapy. There are no uniform diagnostic criteria for HHV-7 viral encephalitis or meningitis; metagenomic next-generation sequencing (mNGS) detection: Cerebrospinal fluid pathogen second-generation sequencing detected an HHV-7-specific sequence; autoimmune encephalitis and other related antibodies were negative. There is no standard treatment for HHV-7 viral encephalitis or meningitis; treatment can last from weeks to months[20]. Laboratory examination, imaging, cerebrospinal fluid mNGS, and other technologies are used to achieve accurate diagnosis, and neurobiology and other research methods are applied to explore the pathogenesis of diseases and treatment targets[21-23]. The clinical manifestations and prognosis of patients with HHV-7 infection in the central nervous system vary greatly from individual to individual. Based on the results of cerebrospinal fluid and other laboratory tests of patients, the infection status and antiviral treatment effect can be evaluated[24]. Due to the severity, lethality, and rarity of HHV-7 infection in the central nervous system, symptomatic and supportive treatment should be actively provided along with empirical and targeted treatment. Use safe, effective, and less-adverse drugs[25-27]. A better understanding of the clinical characteristics of HHV-7 neurological infection will be achieved through the identification, accumulation, and analysis of additional cases.

CONCLUSION

In summary, this case report of HHV-7 meningitis in an immunocompetent adolescent not only enriched our understanding of HHV-7 infection but also provided a useful reference for clinical diagnosis and treatment. In the future, we look forward to further revealing the infection mechanism and prevention and control strategies of HHV-7 through more studies.