Aseptic Meningitis
OVERVIEW
- Aseptic Meningitis = meningeal inflammation with negative bacterial cultures.
CAUSES
- enteroviruses (most common)
- other infections (mycobacteria, fungi, spirochetes, viruses)
- parameningeal infections
- malignancy (lymphoma, leukaemia, metastatic disease)
- autoimmune (sarcoid, SLE, Behçet Disease)
- medications (NSAIDs, co-trimoxazole, anti-CD3 monoclonal antibody, azathioprine)
- -> either (1) delayed hypersensitivity or (2) direct meningeal irritation
HISTORY
There may be much overlap between aseptic meningitis, encephalitis and aseptic meningitis on presentation.
In encephalitis brain function abnormal:
- -> altered mental status (confused, agitated, obtunded)
- -> motor and sensory deficits
- -> altered behaviour
- -> personality changes
- -> speech disorders
- -> movement disorders
- -> seizures
- -> hemiparesis
- -> cranial nerve palsies
- -> exaggerated deep tendon reflexes
Meningitis:
- headache, uncomfortable and lethargic (but normal brain function)
- travel history
- exposure to rodents (lymphocytic choriomeningitis virus), ticks (Lyme) and Tb
- sexual activity (HSV 2, HIV, syphilis)
- contacts with viral exanthems (enteroviruses)
- drug history (NSAIDs, IV Ig, co-trimoxazole)
EXAMINATION
- diffuse maculopapular exanthem (enterovirus, HIV, syphilis)
- parotitis (mumps)
- vesicular and ulcerative genital lesions (HSV 2)
- oropharyngeal thrush and cervical lymphadenopathy (HIV)
- asymmetric flaccid paralysis (West Nile virus)
INVESTIGATIONS
CSF
- opening pressure
- PCR for HSV
- VDRL
- HIV antibody
- RNA testing
- Lyme serology
- fungal and mycobacterial culture
- bacterial meningitis: positive gram stain, WCC > 1000, glucose < 2.2
- viral meningitis: WCC < 500, >50% lymphocytes, low protein, normal glucose
Serum
- VDRL
- HIV antibody
- RNA testing
- Lyme serology
- acute and convalescent serology (LCMV, mumps, measles)
CT head
MRI
MANAGEMENT
- ceftriaxone 50mg/kg IV OD
- acyclovir 10mg/kg Q8hrly
- consider repeat LP
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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