Meningitis Flashcards
What is meningitis?
Inflammation of the meninges, usually due to infection.
What are the causes of bacterial meningitis?
- Neisseria meningitidis (most common cause)
- Streptococcus pneumoniae
- Haemophilus influenzae,
- Group B strep (most common cause in neonates neonates as bacteria colonises the vagina)
- Listeria monocytogenes (seen in immunosupressed)
What are the viral causes of meningitis
Viral meningitis is more common but less severe.
- Enterovirus (coxsackie)
- HSV
- VZV
- Investigated by PCR of sample and treated with aciclovir if you suspect HSV.
What are the fungal causes of meningitis?
Cryptococcus neoformans - mainly affects immunosupressed. Causes a SOL
What are the parasitic causes of Meningitis?
Amoebea or toxoplasma gondii (occurs in immunocompromised)
What are the non infective causes on meningitis?
- Malignancy
- Chemical meningitis
- Drugs such as NSAIDs or trimethorprim
- Systemic inflammatory diseases
What are the signs and symptoms of meningitis?
- Headache,
- Fever,
- Neck stiffness,
- Photophobia,
- Nausea and vomiting,
- Seziures (less common in viral),
- Reduced consciousness
- Features of meningocccocal septicaemia such as a non-blanching petechial rash
What are signs of meningeal irritation?
- Kernig’s sign - Knee and hip flexed at 90 degrees. Patient experiences pain with knee extension
- Brudzinski’s sign - Passive flexion of the neck causes involuntary flexion of hips and knees
What are the differential diagnosis of meningitis?
- Enchephalitis (headaches, fever, altered consciousness, seziures, focal neurological signs and behavioral changes)
- SAH
- Brain abscess (headache, fever, N&V, focal neuro deficites, seziures)
- Sinusitis
- Migraine
What are the investigations for meningitis?
- Bloods (FBC, U&Es, Clotting and Glucose)
- ABG
- Blood cultures,
- Head CT
- Lumbar puncture for bacterial culture, viral PCR, cell count, protein and glucose (with paired blood glucose) (within 1 hour of arriving at hospital)
What are the contraindications for doing a lumbar puncture?
- Brain shift on CT,
- Rapid GCS reduction,
- Respiratory or cardiac compromise
- Rapidly evolving rash,
- Infection at the LP sight
- Coagulopathy
When do you need to CT BEFORE LP?
Signs of raised ICP, however do not delay giving antibiotics:
- Focal neurological signs/ CNS signs,
- GCS < 12 (DO CT FIRST),
- Immunocompromised
- Papilloedema,
- Buldging of fontanelle (children)
- DIC
- Seziures
What are the differences in a LP in a bacterial and viral infection
Bacterial - Cloudy, raised proteins, reduced glucose and neutrophils.
Viral - Clear, raised protein (not as high as in bacterial), normal glucose and lymphocytes
What are the risk factors for pneumococcal and listeria
Pneumococcal - Middle ear disease, head injury, neurosurgery, alcohol and immunosupression.
Listeria - Immunosupression and pregnancy
What are signs of pneumococcal meningitis
Focal signs, seziures and VIII palsy.
May have signs of pneumococcal infection elsewhere such as endocarditis
Pneumococcal meningitis has a higher mortality than meningococcal
What is the treatment of suspected bacterial meningitis in the community/hospital
- If there will be a delay of more than 1 hour of transferring patient to hospital then give urgent Benzylpenicillin or ceftriaxone/cefotaxime
- In hospital give 2g IV of ceftriaxone very 12hours. If over 50years then add amoxicillin
- Can also give IV Dexamethasone especially in high ICP
What is the definitive antibiotic therapy for the different bacterial meningitis?
Meningococcal - IV ceftriaxone/benzyl penicillin for 5 days.
Pneumococcal - IV ceftriaxone/benzyl penicillin for 10-14 days.
Listeria - IV amocixillin for 21 days
Add IV dex especially in pneumococcal.
Explain the prophylaxis measures for contacts of bacterial meningitis?
- Anyone who has been in close contact with the patient 7 days before onset.
- Single dose of ciprofloxacin
What are the complications of meningitis?
- Septic shock,
- DIC,
- Coma,
- Subdural effusions,
- SIADH,
- Seizures,
- Intracerebral abscess
- Brain herniation
- Hydrocephalus
- Delayed complications eg, hearing loss, CN dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
- Death
- Waterhouse-Friderichsen syndrome
What is progressive focal multifocal leucoencephalopathy?
Progressive motor dysfunction that occurs due to JC virus. Seen in immunocompromised patients.
- No specific treatment but can give ARVs if HIV positive
What are the features of encephalitis, the investigations and treatment?
Presents with confusion, fever +/- seizures. Most common is HSV encephalitis
Investigations are LP which shows lymphocytic CSF, temporal lobe changes on EEG and MRI scanning can be done.
Treat with IV aciclovir for 2-3 weeks
What is Waterhouse-Friderichsen syndrome?
This is where severe bacterial infections causes the blood vessels in the adrenal glands to rupture. It causes an adrenal crisis due to acute adrenal insufficiency
