Meningitis

Introduction

Meningitis is inflammation of the meninges as well as the CSF in the subarachnoid space. Meningitis can be bacterial or viral. Bacterial meningitis is a serious cause of morbidity and mortality in all age groups. The likely causative bacteria varies depending on age

  • Neonates = Group B Strep, E. coli, Listeria, Coag Neg Staph

  • Children = H. influenza B, N. meningitidis, S. pneumo

  • Adults = Neisseria meningitis (young), S. pneumo, Listeria (> 50yrs, Alcoholic)

Viral meningitis is usually benign and self-limiting in adults. May need admission for work up and symptomatic management

Clinical Features

 

Symptoms

Pain

  • Headache (severe, unrelenting), neck pain, generalised myalgia, Photophobia

GI Symptoms

  • Nausea, vomiting

Neurological symptoms

  • New confusion, drowsiness.

Signs

Signs of Sepsis

  • Fever, Tachycardia, hypotension

Neurological signs

  • Decreased GCS, Seizures (15-30%), focal neurological signs, papilloedema

Meningism

  • Neck stiffness in sagittal plane

  • Kernig’s sign (cannot fully extend knee with hip flexion) + Brudzinski’s sign (flexing the neck causes thighs and knees to flex also)

Rash

  •   Macular or non blanching petechial rash present in only 40%.

  • Seen in sepsis due to N. meningitidis or S. pneumo. Very sinister sign. Start antibiotics Immediately

Differential Diagnosis

 

Other Meningitis

  • Viral (HSV, EBV, Mumps, Coxsackie)

  • TB

  • Cryptococcus,

 

Other Sources of Sepsis

  • Respiratory

  • Renal

  • Intra-abdominal

  • Skin + Soft Tissue

  • Infective endocarditis

Other CNS Causes

  • Encephalitis

  • Brain abscess

  • SAH

 

Drug Overdose

  • Anticholinergics e.g. antipshychotics, TCAs, atropine

  • Sympathomimetic Syndrome e.g. cocaine, amphetamines

  • Seretonin Syndrome e.g. MDMA, SSRIs,

  • Neuroleptic Malignant Syndrome e.g. older antipsychotics

 

Clinical Investigations

 
Bedside.jpg

Bedside

  • VBG

    • ? high lactate, ? low pH in sepsis. ? Low BM accounting for GCS

  • Urinalysis

    • Seeking other causes for sepsis

  • Urine Toxicology screen

  • ECG

 
LP+equipment.jpg

Laboratory

  • General Investigations

    • FBC, U&E, CRP, LFT, CoAg

    • Assist in building the overall clinical picture e.g. presence of end organ dysfxn

  • Blood Cultures

    • Take prior to Empiric antibiotics especially if LP is delayed

  • Lumbar Puncture – Antibiotics should not be delayed for LP

    • CT before LP if decreased GCS, focal neurological abnormality, seizure, concern for SOL

    • If evidence of high ICP on CT there is a risk of brain herniation during LP so it should be delayed

    • CSF in bacterial meningitis = High opening pressure, High protein, Low glucose, High WCC mostly polymorphs, +ve Gram Stain

  • CSF or Blood for viral and meningococcus PCR

  • CSF or urine for rapid antigen tests for Strep, Listeria

    MSU - ? other cause of sepsis

CTB+work+station.jpg

Radiology

  • CT Brain occurs in most cases to out rule increased ICP/other causes of headache e.g. SOL, Haemorrhage etc

  • CXR – as part of work up

Management and Disposition

 
IMG_7688.jpg

Infection Control

Patient should be managed in an isolation room with contact and droplet precautions and staff in full PPE

Initial Resuscitation

  • Assessment and concurrent management of Airway, Breathing and Circulation

  • Low GCS -> Pt may need airway management

  • High Flow O2

  • Fluid resuscitation as clinically indicated

 

Specific Treatment

  • Urgent early broad spectrum antibiotics as per local guidelines is the priority

    • e.g. Cefotaxime 2g Every 4 hours IV + Vancomycin 25mg/kg BD IV

  • May be role for steroids (IV Dexamethasone) if meningitis is strongly suspected.

    • Do NOT give if steroids if meningococcal septicaemia is suspected

  • If High risk for Listeria e.g. Age > 50yrs, Alcoholic add IV Amoxicillin to the above regimen

Symptomatic Treatment

  • IV Analgesia and IV Antiemetic as clinically indicated

  • IV Benzodiazepine if actively seizing

 
 

Disposition

  • All patients with suspected meningitis should be admitted to hospital under the medical team until diagnosis is ruled in or out. They will need an isolation room

  • Consider chemoprophylaxis for household contacts if ? bacterial meningitis (liaise with Micro/Public Health)

  • Bacterial meningitis is a notifiable disease to Public Health. They arrange contact tracing

 

References

1.     Singer A, Carmeron P et al. Chapter 9.2 Meningitis from The Adult Textbook of Emergency Medicine 4th Edition

2.     Dunn et al. Chapter 44: Headaches. The Emergency Medicine Manual. Vol 1. 5th Edition

3.     SJH Prescriber capsule. Antimicrobial prescribing

4.     https://www.hpsc.ie/notifiablediseases/listofnotifiablediseases/Immediate%20preliminary%20notification%20to%20a%20MOH%2004032020.pdf

This blog post was written by Dr. Deirdre Glynn and was last updated in October 2020

 

Before you go have another look at the clinical case and see have your answers to any of the questions changed and if so how?