Meningitis Flashcards
Define
inflammation of the leptomeningeal (pia and arachnoid mater) coverings of the brain, most commonly due to infection
Meningitis
BACTERIAL
Neonates
- Group B streptococci
- Escherichia coli
- Listeria monocytogenes
Children
- Haemophilus influenzae
- Neisseria meningitidis
- Streptococcus pneumoniae
Adults
- Neisseria meningitidis
- Streptococcus pneumoniae
- Tuberculosis
Elderly
- Streptococcus pneumoniae
- Listeria monocytogenes
VIRAL
- Enteroviruses
- Mumps
- HSV
- VZV
- HIV
Fungal
- Cryptococcus (common cause of meningitis in HIV patients)
Others
- Aseptic meningitis (not due to microbes)
- Mollaret’s meningitis (recurrent benign lymphocytic meningitis)
Risk factors
- Close communities (e.g. college halls)
- Basal skull fractures
- Mastoiditis
- Sinusitis
- Inner ear infections
- Alcoholism
- Immunodeficiency
- Splenectomy
- Sickle cell anaemia
- CSF shunts
- Intracranial surgery
Epidemiology
Variation by: geography, age, social factors UK ~2500 per year
Epidemics occur in the ‘meningitis belt’ of Africa (meningococcal serogroup A)
→’Meningitis belt’ is a region in sub-Saharan Africa where the rate of incidence of meningitis is very high
Symptoms
Severe headache
Photophobia
Neck or backache
Irritability
Drowsiness
Vomiting
High-pitched crying or fits (common in children)
Reduced consciousness
Fever
IMPORTANT: take a good travel history and exposure history and take not of exposure to any of the following
- Rodents (lymphocytic choriomeningitis virus)
- Ticks (Lyme borrelia, Rocky Mountain spotted fever)
- Mosquitoes (West Nile virus)
- Sexual activity (HSV-2, HIV, syphilis)
- Travel
Signs
Signs of MENINGISM
- Photophobia
- Neck stiffness
- Kernig’s Sign - with the hips flexed, there is pain/resistance on passive knee extension
- Brudzinski’s Sign - flexion of the hips when the neck is flexed
Signs of INFECTION
- Fever
- Tachycardia
- Hypotension
- Skin rash
- Altered mental state
Investigations
Bloods
- Two sets of blood cultures
Imaging
- CT scan - exclude mass lesion or raised ICP before LP
Lumbar Puncture
- MC&S
- Bacterial meningitis:
- Cloudy CSF
- High neutrophils
- High protein
- Low glucose
- Viral meningitis:
- High lymphocytes
- High protein
- Normal glucose
- TB meningitis:
- Fibrinous CSF
- High lymphocytes
- High protein
- Low glucose
Management
IMMEDIATE IV Antibiotics (before LP)
- First choice: 3rd generation cephalosporin (e.g. cefotaxime or ceftriaxone)
- Benzylpenicillin may be used as an initial blind therapy
Dexamethasone IV
- Given shortly before or with the first dose of antibiotics
- Associated with a reduced risk of complications
Resuscitation
- Manage in ITU
- Notify public health services
Complications
Septicaemia
Shock
DIC
Renal failure
Seizures
Peripheral gangrene
Cerebral oedema
Cranial nerve lesions
Cerebral venous thrombosis
Hydrocephalus
Waterhouse-Friderichsen Syndrome (bilateral adrenal haemorrhage caused by severe meningococcal infection)
Prognosis
Mortality rate from bacterial meningitis: 10-40% with meningococcal sepsis
Viral meningitis is self-limiting H
