From the Guidelines
Infectious optic neuritis diagnosis relies on a combination of blood tests, cerebrospinal fluid analysis, and specific pathogen testing, as outlined in the 2013 IDSA and ASM guidelines 1. When diagnosing infectious optic neuritis, the following laboratory tests are typically considered:
- Blood tests: complete blood count, erythrocyte sedimentation rate, C-reactive protein, and serological tests for specific pathogens like Bartonella henselae, Borrelia burgdorferi, syphilis, tuberculosis, HIV, and various viral infections such as herpes viruses, cytomegalovirus, and Epstein-Barr virus.
- Cerebrospinal fluid analysis: cell count, protein levels, glucose, oligoclonal bands, IgG index, and PCR testing for viral, bacterial, and fungal pathogens, as recommended for ocular infections 1. Some key tests for specific pathogens include:
- Herpes simplex virus (HSV): HSV 1 and 2 NAAT on cerebrospinal fluid 1
- Varicella-zoster virus (VZV): VZV NAAT on cerebrospinal fluid or plasma 1
- Epstein-Barr virus (EBV): EBV NAAT on cerebrospinal fluid or plasma 1
- Cytomegalovirus (CMV): CMV NAAT on cerebrospinal fluid or plasma 1
- Bartonella spp: Bartonella spp NAAT on cerebrospinal fluid or plasma 1 The selection of tests should be guided by the patient's clinical presentation, geographic location, and exposure history, with the goal of identifying the specific infectious agent causing optic neuritis and determining appropriate antimicrobial treatment 1.
From the Research
Laboratory Tests for Infectious Optic Neuritis
The following laboratory tests may be conducted to diagnose infectious optic neuritis:
- Serological tests to identify infectious agents such as herpes viruses (HSV-1, HSV-2, VZV, EBV, and HHV6) 2
- Polymerase chain reaction (PCR) to detect the presence of infectious agents 3
- Blood tests to check for inflammation and infection
- Cerebrospinal fluid (CSF) analysis to check for the presence of infectious agents or inflammation
- Imaging tests such as MRI to rule out other causes of optic neuritis and to assess the extent of inflammation
Specific Tests for Infectious Agents
Some specific tests that may be conducted to identify infectious agents include:
- HSV-1 and HSV-2 DNA testing in CSF and blood lymphocytes 2
- VZV DNA testing in CSF 2
- EBV DNA testing in blood samples 2
- HHV6 DNA testing in CSF and blood lymphocytes 2
Importance of Early Diagnosis
Early diagnosis of infectious optic neuritis is crucial to prevent irreversible vision loss and to initiate timely treatment 4, 3. A comprehensive diagnostic approach, including laboratory tests and imaging studies, can help identify the underlying cause of optic neuritis and guide treatment decisions 5, 6.