Central Nervous System Infections in Denmark
Central Nervous System Infections in Denmark
The Danish Study Group of Infections of the Brain is a collaboration between all departments
 of infectious diseases in Denmark. The investigators aim to monitor epidemiological trends in
 central nervous system (CNS) infections by a prospective registration of clinical
 characteristics and outcome of all adult (>17 years of age) patients with community-acquired
 CNS infections diagnosed and/or treated at departments of infectious diseases in Denmark
 since 1st of January 2015.
The investigators include data on diagnosis at admission, symptoms and signs on admission,
 character and timing of diagnostic work-up and treatment and outcome assessed by the Glasgow
 Outcome Score (GOS).

 Diagnostic work-up and treatment is left at the discretion of the local physician and
 therefore not standardised

 In general any symptoms/deficits should only be listed if they are 'new' to the patient, e.g.
 a known palsy of the facial nerve should not be listed as a new relevant finding at
 admission. On the other hand, worsening of a known neurological deficit should be listed
 under signs in the given instrument (bacterial meningitis, encephalitis, neuroborreliosis
 etc). Likewise, for outcome only changes in pre-morbid conditions should be listed including
 place of residence, functional status, neurological deficits etc.

 Time of admission is obtained in prioritized order from the ambulance charts or notifications
 of arrival by secretaries or nurses in the emergency departments. Timing of lumbar puncture
 and cranial imaging is extracted from the electronic records at the departments of
 biochemistry or radiology while timing of antibiotic therapy for meningitis is identified in
 electronic medication systems. Time to lumbar puncture, cranial imaging and antibiotic
 therapy is calculated as time from arrival at hospital to each of the above events.

 Quality control of case enrollment is ensured by ad hoc case-to-case discussions and at study
 group meetings 2-3 times a year

 To ensure completeness of reported CNS infections annual searches of selected International
 Classification of Diseases version 10 (ICD-10) codes are performed in local administrative
 databases at each department:

 A17 A32.1 A32.7 A39.0 A52.1-52.3 A69.2 (neuroborreliosis) A83 A84 A85 A87 A89 B00.3-00.4
 B01.0-01.1 B02.0-02.0 B582 B451 B375 G00 G01 G02 G03 G04 G05 G06 G07
Definitions of central nervous system infections:

 For all cases with unproven aetiologies no alternative diagnosis than CNS infection is
 thought more likely after completed multidisciplinary diagnostic work-up.

 Viral meningitis inclusion criteria

 - All patients have to have a clinical presentation consistent with non-bacterial
 meningitis (e.g. headache, neck stiffness, photo- or phonophobia, fever)

 and

 Cerebrospinal fluid leukocytes>10 cells/ml

 Patients with viral meningitis with undetermined pathogen have to have:

 -  CSF leukocytes> 10/mL and no other more probable diagnosis assessed by the local
 investigator.

 In case of doubt, patients are discussed with the DASGIB secretary and chair or at
 meetings.

 Bacterial meningitis inclusion criteria - All patients have to have a clinical presentation
 consistent with bacterial meningitis (e.g. headache, neck stiffness, fever, altered mental
 status)

 and

 Proven bacterial aetiology (CSF or blood culture/DNA based technology or antigen tests)

 Patients with bacterial meningitis in whom the bacteria cannot not be cultured or
 identified by DNA-based technologies have to have:

 - CSF leukocytes> 10/mL and no other more probable diagnosis assessed by the local
 investigator.

 In case of doubt, patients are discussed with the DASGIB secretary and chair or at
 meetings.

 Encephalitis inclusion criteria - All patients have to have a clinical presentation
 consistent with encephalitis (e.g. headache, fever, focal neurological deficit, altered
 mental status >24 hours) as defined by the International Encephalitis Consortium
 (Venkatesan A et al., Clin Infect Dis 2013; doi:10.1093/cid/cit458.).

 Encephalitis exclusion criteria

 - We exclude cases of proven or suspected autoimmune encephalitis.

 Primary brain abscess inclusion criteria

 - All patient have a clinical presentation consistent with brain abscess (e.g. headache,
 focal neurological deficit, mass lesion on cranial imaging)

 and

 - Proven microbiological aetiology by culture/DNA-based technology from pus from brain
 abscess or blood or CSF

 or

 - Aspiration of pus from the brain abscess

 or

 - Response to antimicrobial treatment

 or

 - Tumour ruled out

 or

 - Tumour thought less probable than abscess on MRI using diffusion weighted imaging (DWI)
 and apparent diffusion coefficient (ADC) sequences.

 Lyme neuroborreliosis inclusion criteria

 - A clinical presentation consistent with neuroborreliosis (e.g. radiculopathy)

 and

 - CSF pleocytosis>10 leukocytes/mL

 and

 - Positive intrathecal B.burgdorferi antibody production index.

 Neurosyphilis inclusion criteria - A clinical presentation consistent with neurosyphilis
 (e.g. 'encephalitis-like symptoms', dementia, ocular or otogenic syphilis)

 and either

 - Positive syphilis serology in serum combined with CSF leukocytes>10/mL

 or

 - CSF syphilis antibodies.