Case-based discussion: 1 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 2
Question: 1 3
Case-based discussion: 1 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 4
Introduction Definition Inflammation of the meninges due to infective (bacterial, viral, or fungal) or non-infective causes S. pneumoniae and N.meningitidis are the most common • bacterial causes Enteroviruses are the most common viral cause • Epidemiology 5 per 100,000 population (NICE) • Bacterial meningitis mortality: 25% in adults • Viral meningitis mortality: <1% • 5
Introduction Risk factors Age • Immunocompromised • Non-immunised • Smoking • Crowded environment • 6
Pathophysiology Bacteria Haematogenous spread (most common) • Direct extension from a contiguous site • Release of inflammatory mediators in the CSF • Inflammation • Cerebral oedema • Raised ICP • Virus Enteroviruses spread via faecal-oral route • Enter the CNS through haematogenous spread • See above for the inflammatory response • 7
Aetiology Bacterial meningitis Viral meningitis Fungal meningitis Rare, but potentially fatal More common, but self-limiting Rarely affects immunocompetent patients Neonatal Enteroviruses : • • Children Coxsackievirus Cryptococcus neoformans • • • Adults Echovirus Candida • • • Elderly Herpes simplex virus (HSV ): • • HSV-2 • HSV-1 • Varicella-zoster virus (VZV) • 8
Question: 2 9
Aetiology by age Age Organism Group B streptococcus • E. Coli • 0 to 3 months Streptococcus pneumoniae • Listeria monocytogenes • Streptococcus pneumoniae • Neisseria meningitides • 3 months to 6 years Haemophilus influenzae b • Neisseria meningitidis • 6 months to 60 years Streptococcus pneumoniae • Streptococcus pneumoniae • Neisseria meningitidis • > 60 years Listeria monocytogenes • 10
Aetiology Neisseria meningitidis (Meningococcal meningitis) Colonises the nasopharynx – asymptomatic carriers • Droplet spread of respiratory secretions • Vaccination: • Men B and Men C • Men ACWY • Mortality: 10% • Typically causes a non-blanching purpuric rash • 11
Aetiology S. pneumoniae (Pneumococcal meningitis) Droplet spread • Poorer outcomes compared to N.meningitidis • Vaccination: PCV • Mortality: 25% • 12
Aetiology Group B streptococcus ( Streptococcus agalactiae) Most common cause of neonatal meningitis, • pneumonia, and sepsis Colonises the vagina and transmitted during birth • Currently not routinely screened for • Intrapartum antibiotics • Risk factors Prolonged membrane rupture • Low birthweight • 13
Streptococci Classified according to pattern of haemolysis on blood agar Alpha-haemolytic (partial haemolysis) • Beta-haemolytic (complete haemolysis) • Gamma-haemolytic (no haemolysis) • Beta-haemolytic Alpha-haemolytic Gamma-haemolytic Group A streptococcus S.pneumoniae Group D S.pyogenes streptococcus • S.viridans Enterococcus • Group B streptococcus S.agalactiae • 14
Question: 3 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 15
Question: 3 16
Clinical features Symptoms Signs Meningism Kernig’s sign Headache When the hip is flexed and the knee is • • Photophobia at 90°, extension of the knee results • Neck stiffness in pain • Fever Brudzinski sign Severe neck stiffness causes the hips • and knees to flex when the neck is flexed Nausea and vomiting Purpuric non-blanching rash Meningococcal disease • Seizures Pyrexia Reduced GCS 17
Clinical features 18
Clinical features 19
20
Differentials Tuberculous Viral meningitis Bacterial meningitis Encephalitis meningitis Acute onset Acute onset Chronic onset Abnormal cerebral • • • • Meningism Meningism Prodromal malaise function • • • Usually self limiting May be fatal and fever +/- meningism • • • CSF interpretation CSF interpretation CSF interpretation CSF profile may be • • • • PCR and Ziehl- similar to viral • Neelsen stain meningitis CXR • 21
Question: 4 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 22
Question: 4 23
Investigations Bedside Blood glucose: required to compare to CSF glucose • Bloods FBC: leukocytosis • CRP: raised inflammatory markers • Coagulation profile : sepsis and DIC • Blood culture • PCR for N. meningitidis • Imaging CT head: meningeal enhancement. May be conducted prior to an LP • Specialist tests Lumbar puncture (LP): MCS and PCR • 24
Investigations 25
Question: 5
CSF interpretation Viral Bacterial Fungal/TB Pressure Normal/elevated Elevated Elevated Appearance Clear Cloudy Cloudy Fibrin web WCC 3 3 3 <1000/mm 10-5000/mm <1000/mm Lymphocytes Neutrophils Lymphocytes Glucose >60% serum glucose <50% serum glucose <50% serum glucose Protein <1g/L >1g/L >1g/L 27
Question: 6 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 28
Question: 6
Management Antibiotics Secondary care: IV cephalosporin (cefotaxime or ceftriaxone) +/- amoxicillin • Primary care: IV or IM benzylpenicillin if there is evidence of a non-blanching rash • Steroids Dexamethasone: administered before or at the same time as antibiotics • Should be given within 12 hours of antibiotics • If pneumococcal meningitis is confirmed, continue steroid • Anti-viral Aciclovir: if viral meningitis is suspected. Used to treat HSV and VZV • Adjunct IVF • Analgesia and anti-pyretic • 30
Question: 7 History A 20-year-old medical student presents to the Emergency Department feeling generally unwell. He is wearing sunglasses and complains of a stiff neck with a ‘pounding headache’. He has vomited twice. On examination, he is Kernig's sign positive. Observations HR 121, BP 101/77, RR 20, SpO2 98%, Temp 38.3 31
Question: 7
Contact tracing Meningitis is a notifiable disease Meningococcal meningitis Prolonged close contact in a household setting in the preceding 7 days before onset of • illness Exposure to respiratory droplets • Ciprofloxacin 500mg one off dose to anyone who meets the above criteria • Rifampicin is an alternative • Pneumococcal meningitis Prophylaxis is not usually required • 33
Complications System Complication Neurological Sensorineural hearing loss • Seizures • Cerebral oedema • Long-term cognitive and behaviour • deficit Abscess • Hydrocephalus • Endocrine Waterhouse-Friderichsen syndrome • Other • Sepsis 34
Top-decile question 35
Top-decile question 36
Recap Meningitis is relatively rare but carries a high mortality • The most common cause are enteroviruses • S.pneumoniae and N.meningitidis is the most common bacterial cause • The definitive investigation is with CSF analysis • Management depends on the aetiology and involves: • Antibiotics • Antivirals • Corticosteroids • Ciprofloxacin prophylaxis is indicated for contacts of patients with meningococcal disease • 37
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