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
References and Links
CCC Neurocritical Care Series
Emergencies: Brain Herniation, Eclampsia, Elevated ICP, Status Epilepticus, Status Epilepticus in Paeds
DDx: Acute Non-Traumatic Weakness, Bulbar Dysfunction, Coma, Coma-like Syndromes, Delayed Awakening, Hearing Loss in ICU, ICU acquired Weakness, Post-Op Confusion, Pseudocoma, Pupillary Abnormalities
Neurology: Anti-NMDA Encephalitis, Basilar Artery Occlusion, Central Diabetes Insipidus, Cerebral Oedema, Cerebral Venous Sinus Thrombosis, Cervical (Carotid / Vertebral) Artery Dissections, Delirium, GBS vs CIP, GBS vs MG vs MND, Guillain-Barre Syndrome, Horner’s Syndrome, Hypoxic Brain Injury, Intracerebral Haemorrhage (ICH), Myasthenia Gravis, Non-convulsive Status Epilepticus, Post-Hypoxic Myoclonus, PRES, Stroke Thrombolysis, Transverse Myelitis, Watershed Infarcts, Wernicke’s Encephalopathy
Neurosurgery: Cerebral Salt Wasting, Decompressive Craniectomy, Decompressive Craniectomy for Malignant MCA Syndrome, Intracerebral Haemorrhage (ICH)
— SCI: Anatomy and Syndromes, Acute Traumatic Spinal Cord Injury, C-Spine Assessment, C-Spine Fractures, Spinal Cord Infarction, Syndomes,
— SAH: Acute management, Coiling vs Clipping, Complications, Grading Systems, Literature Summaries, ICU Management, Monitoring, Overview, Prognostication, Vasospasm
— TBI: Assessment, Base of skull fracture, Brain Impact Apnoea, Cerebral Perfusion Pressure (CPP), DI in TBI, Elevated ICP, Limitations of CT, Lund Concept, Management, Moderate Head Injury, Monitoring, Overview, Paediatric TBI, Polyuria incl. CSW, Prognosis, Seizures, Temperature
ID in NeuroCrit. Care: Aseptic Meningitis, Bacterial Meningitis, Botulism, Cryptococcosis, Encephalitis, HSV Encephalitis, Meningococcaemia, Spinal Epidural Abscess
Equipment/Investigations: BIS Monitoring, Codman ICP Monitor, Continuous EEG, CSF Analysis, CT Head, CT Head Interpretation, EEG, Extradural ICP Monitors, External Ventricular Drain (EVD), Evoked Potentials, Jugular Bulb Oxygen Saturation, MRI Head, MRI and the Critically Ill, Train of Four (TOF), Transcranial Doppler
Pharmacology: Desmopressin, Hypertonic Saline, Levetiracetam (Keppra), Mannitol, Midazolam, Sedation in ICU, Thiopentone
MISC: Brainstem Rules of 4, Cognitive Impairment in Critically Ill, Eye Movements in Coma, Examination of the Unconscious Patient, Glasgow Coma Scale (GCS), Hiccoughs, Myopathy vs Neuropathy, Neurology Literature Summaries, NSx Literature Summaries, Occulocephalic and occulovestibular reflexes, Prognosis after Cardiac Arrest, SIADH vs Cerebral Salt Wasting, Sleep in ICU
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC