meningitis Flashcards
definition
Inflammation of the membranous coverings of the brain and S.C. (dura, arachnoid and pia)
causes [depending on age]
🍓 bacterial - positive CSF Gram stain and positive CSF bacterial with an increased polymorphonuclear leucocytes in the CSF
🍓 aseptic - no evidence of pyogenic bacterial infection on Gram’s stain or culture and usually accompanied by a mononuclear leucocytes in CSF
1. nonbacterial
- viral
- non viral - fungal, partially treated bacterial, meningial inflammation caused by adjacent pyogenic infections, TB, syphilis, Lyme disease
2. noninfectious
- common systemic disease e.g. - sarcoidosis
- neoplastic
- drugs
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0 - 3 months
- Group B Streptococcus (most common cause in neonates)
- E. coli
- Listeria monocytogenes
3 months - 6 years
- Neisseria meningitidis
- Streptococcus pneumoniae
- Haemophilus influenzae
6 years - 60 years
- Neisseria meningitidis
- Streptococcus pneumoniae
> 60 years
- Streptococcus pneumoniae
- Neisseria meningitidis
- Listeria monocytogenes
Immunosuppressed
- Listeria monocytogenes
Risk Factors
- Infectious spread in institution: dormitories, prisons
- 2O: Head injuries, Mastoiditis, Sinusitis, inner ear infections, cholesteatoma
- - Immunocompromised: HIV, organ transplant, malignancy, diabetes
s/s in kids
some children and young people may present with non specific symptoms and signs:
- fever - not seen always especially in neonates
- nausea and vomiting
- lethargy
- children are likely to be poorly responsive, staring, difficult to wake
- there can be drowsiness or poor eye contact
- irritable or unsettled mood
- babies are often irritable with a high-pitched cry, and may be stiff and jerky or else floppy and lifeless
- adolescents and adults may be aggressive or combative
- babies are often irritable with a high-pitched cry, and may be stiff and jerky or else floppy and lifeless
- ill appearance
- refusing food/drink
- headache
- muscle ache or joint pain
- respiratory symptoms and signs, or difficulty inbreathing
children and young people with more specific signs and symptoms are likely to have bacterial meningitis or meningococcal septicaemia. Symptoms and signs may become more severe and more specific as the disease progress.
- non-blanching rash – keep in mind that the rash may be less visible in people with darker skin tones, in these patients check the soles of the feet, palms of the hand and conjunctivae
- stiff neck
- absent in septicaemia
- not common in young children (2)
- altered mental state – which includes confusion, delirium, drowsiness, and impaired consciousness
- shock
- back rigidity
- bulging fontanelle - in children younger than 2 years
- photophobia
- Kernig’s sign is positive
- Brudzinski’s sign is positive
- unconsciousness
- toxic or moribund state
- paresis
- focal neurological deficit, including cranial nerve involvement and abnormal pupils
- seizures (1)
s/s in adults
Adults presenting with community-acquired acute bacterial meningitis, present with at least two of the following four symptoms (3):
- headache
- fever
- neck stiffness
- altered mental status (as defined by a score below 14 on the Glasgow Coma Scale
- There may rarely be focal neurological signs such as gait disturbances.
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- Early features:
- headache, leg pain, cold hands/feet, abnormal skin colour
- Later signs:
-
Meningism:
- headache and neck stiffness
- Kernig’s sign and Brudzinski’s signs: flexion of hips on neck flexion
-
Neurological
- ↑ICP = ↓ GCS → coma
- Seizures (20%)
- Focal neuro (20%): e.g. CN palsies
-
Sepsis:
- Fever
- ↓BP, ↑HR (or ↔)
- ↑CRT
- Purpuric rash: non blanching
- DIC
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must establish cause in pts suspected with meningitis- pyogenic meningitis has a high mortality without treatment.
The following clinical signs should be recorded in all patients with suspected bacterial meningitis or meningococcal disease:
- heart rate.
- respiratory rate.
- blood pressure.
- temperature.
- capillary refill time.
- oxygen saturation measurement
Perform a neurological assessment using the AVPU:
- Alert? (even an alert child may be very ill with septicaemia)
- Responds to Voice?
- Responds to Pain?
- Unresponsive?
Laboratory investigations include:
1. Investigations suggested by NICE
- full blood count
- CRP
- coagulation screen
- blood culture
- whole-blood PCR
- blood glucose
- blood gas
Lumbar puncture if no signs of raised intracranial pressure
2. Lumbar puncture- mandatory in any patient w/ suspected bacterial meningitis
do this unless specifically CI’d
diagnosis of bacterial meningitis depends on CSF examination performed after lumbar puncture (3)
CSF should be sent for:
- gram stain, culture and sensitivity
- cell count
- glucose
- protein determination
- PCR- polymerase chain reaction
antibiotics should be given as a priority and should not be delayed because a lumbar puncture has not been performed.
in children and young people with suspected bacterial meningitis, perform a CRP and white blood cell count (4):
- if the CRP and/or white blood cell count is raised and there is a non specifically abnormal cerebrospinal fluid (CSF) (for example consistent with viral meningitis), treat as bacterial meningitis
- be aware that a normal CRP and white blood cell count does not rule out bacterial meningitis
- regardless of the CRP and white blood cell count, if no CSF is available for examination or if the CSF findings are uninterpretable, manage as if the diagnosis of meningitis is confirmed
if a child or young person has an unexplained petechial rash and fever (or history of fever) carry out the following investigations (4):
- full blood count
- C-reactive protein (CRP)
- coagulation screen
- blood culture
- whole-blood polymerase chain reaction (PCR) for N meningitidis
- blood glucose
- blood gas
3. CT scan: do if diagnosis is in doubt and there is raised intracranial pressure, or there are focal neurological signs, the presence or recurrence of pyrexia may suggest subdural empyema or cerebral abscess.
4. blood cultures, urinanalysis, blood glucose - to give relevance to CSF glucose levels, urea and electrolytes, syphilitic and viral serology
5. skull radiology is required if head injury is suspected
- others such as stool sample for virology, nasal swabs for culture
Notes:
<u><em><strong>indications for CT scan prior to lumbar puncture include</strong></em></u>
- immunocompromised state (AIDS, immunosuppressive therapy, or after transplantation)
- history of CNS disease (mass lesion, stroke, or focal infection)
- new onset seizure
- papilloedema
- abnormal level of consciousness
- focal neurologic deficit
CSF interpretation: Bacterial meningitis
Appearance: Cloudy and turbid
Opening pressure: Elevated (>25 cm H₂O)
WBC: Elevated >100 cell/µL (primarily polymorphonuclear leukocytes (>90%))
Glucose level: Low (<40% of serum glucose)
Protein level: Elevated (>50 mg/dL)
Causes:
- Newborns: Listeria monocytogenes, E. Coli, Group B Streptococci
- Older children: Neisseria meningitidis, Haemophilus influenzae Type B, Streptococcus pneumoniae
- Adults: Neisseria meningitidis, Streptococcus pneumoniae, Listeria monocytogenes
Symptoms:
- Headache
- Fever
- Neck stiffness
- Photophobia
- Meningococcal meningitis presents with a characteristic petechial rash
Further investigations:
- CSF gram stain and cultures
- CSF bacterial antigens
- CSF PCR
- Blood cultures
- Imaging to rule out other intracranial pathology – CT / MRI head
CSF interpretation: Viral (aseptic) meningitis
- Appearance: Clear
- Opening pressure: Normal or elevated
- WBC: Elevated (50 – 1000 cells/µL, primarily lymphocytes, can be PMN early on)
- Glucose level: Normal (>60% serum glucose however may be low in HSV infection)
- Protein level: Elevated (>50 mg/dL)
Causes:
- Herpes simplex virus (HSV 2 is more common than HSV 1)
- Enteroviruses
- Varicella zoster virus (VZV)
- Mumps
- HIV
- Adenovirus
Symptoms:
- Headache
- Fever
- Neck stiffness
- Photophobia
Further investigations:
- CSF PCR for viruses (e.g. Herpes simplex virus (HSV) / Varicella-zoster virus (VZV))
- Blood cultures
- Imaging to rule out other intracranial pathology – CT / MRI head
CSF interpretation: Fungal meningitis
- Appearance: Clear or cloudy
- Opening pressure: Elevated
- WBC: Elevated (10 – 500 cells/µL)
- Glucose level: Low
- Protein level: Elevated
Causes:
- Cryptococcus neoformans
- Candida
Symptoms:
- Patients are often immunocompromised
- Headache
- Confusion
- Nausea
- Vomiting
- Fever and neck stiffness are less common
Further investigations:
- CSF cultures
- CSF PCR
- CSF staining
- HIV test (with consent)
- Blood cultures
- Imaging to rule out other intracranial pathology – CT / MRI head
CSF interpretation: Tuberculosis meningitis
- Appearance: Opaque, if left to settle it forms a fibrin web
- Opening pressure: Elevated
- WBC: Elevated (10 – 1000 cells/µL, Early PMNs then mononuclears)
- Glucose level: Low
- Protein level: Elevated (1-5 g/L)
Symptoms:
- Headache
- Fever
- Neck stiffness
- Photophobia
- Delirium
- Cranial nerve palsies
Further investigations:
- CSF cultures
- CSF bacterial antigens
- CSF PCR
- HIV test (with consent)
- Blood cultures
- Imaging to rule out other intracranial pathology – CT / MRI head
- Chest X-ray
CSF interpretation: Subarachnoid haemorrhage
- Appearance: Blood stained initially, then xanthochromia (yellowish) >12 hours later
- Opening pressure: Elevated
- WBC: Elevated (WBC to RBC ratio of approx 1:1000)
- RBC: Elevated
- Glucose level: Normal
- Protein level: Elevated
Causes:
- Trauma
- Vascular malformations (e.g. aneurysms, arteriovenous malformations)
Symptoms:
- Sudden onset “thunderclap” headache (patients may describe it as the “worst headache ever”)
- Stiff neck
- Vomiting
- Seizures
- Confusion
- Neurological deficits (e.g. weakness / sensory disturbance)
Further investigations:
- Cerebral angiogram
- CT angiography
CSF interpretation: Guillain Barre syndrome
- Appearance: Clear or xanthochromia
- Opening pressure: Normal or elevated
- WBC: Normal
- Glucose level: Normal
- Protein level: Elevated (>5.5 g/L)
Causes:
- Campylobacter jejuni
- CMV
- EBV
- Mycoplasma pneumonia
- VZV
Symptoms:
- Often occurs after a recent bacterial / viral illness
- Symmetrical ascending muscle weakness primarily affecting proximal musculature (trunk/respiratory muscles)
Further investigations:
- Serologic studies
- Nerve conduction studies
- EMG
- Imaging to rule out other intracranial pathology – CT / MRI head
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All patients should be transferred to hospital urgently. If patients are in a pre-hospital setting (for example a GP surgery) and meningococcal disease is suspected then intramuscular benzylpenicillin may be given, as long as this doesn’t delay transit to hospital.
BNF recommendations on antibiotics see attachment
If the patient has a history of immediate hypersensitivity reaction to penicillin or to cephalosporins the BNF recommends using chloramphenicol.
Management of contacts
- prophylaxis needs to be offered to household and close contacts of patients affected with meningococcal meningitis
- oral ciprofloxacin or rifampicin or may be used. The Health Protection Agency (HPA) guidelines now state that whilst either may be used ciprofloxacin is the drug of choice as it is widely available and only requires one dose
- the risk is highest in the first 7 days but persists for at least 4 weeks
- meningococcal vaccination should be offered to close contacts when serotype results are available, including booster doses to those who had the vaccine in infancy
- for pneumococcal meninigitis no prophylaxis is generally needed. There are however exceptions to this. If a cluster of cases of pneumococcal meninigitis occur the HPA have a protocol for offering close contacts antibiotic prophylaxis. Please see the link for more details
General management of meningitis involves: Seek expert advice
- relief of pain - meningitis is a very painful disease
- sedation, plus or minus anticonvulsants
- position the patient head up
- hyperventilate in some cases
- cool the patient
- darken the room
- adequate nutrition and fluid replacement, not fluid restriction
- care of bedridden patient
- dexamethasone - reduces mortality in S. pneumonia and also in Haemophilus influenzae - may reduce meningeal inflammation and cerebral inflammation in the acute phase, and decrease incidence of sensorineural deafness
prophylaxis: Preventative measures for bacterial meningitis include:
- prophylactic antibiotics, for example, rifampicin for Haemophilus infections and N. meningitidis.
- This is recommended for close, usually household, contacts of patients with meningococcal infection, but only for families and other close contacts with children under 4 years of age in the case of Haemophilus infection.
- Pregnant women should not be given rifampicin prophylaxis. It is also recommended that there is prophylaxis for patients themselves.
drugs recommended for use in preventing secondary cases of meningococcal disease include
rifampicin
- the only antibacterial agent licensed for use as chemoprophylaxis.
- can be used in all age groups
ciprofloxacin
- can be used as an alternative to rifampicin for chemoprophylaxis
- can be used in adults and children above the age of two
- can be given as a single dose
ceftriaxone
- can only be given as an injection
vaccine - Hib, meningococcal Group C vaccine, S.pneumonia - for high risk patients
Complications
- Hydrocephalus
- Cerebral oedema
- Venous sinus thrombosis
- Subdural empyema
- Cerebral abscess
Arteritis and endarteritis: TB, meningitis à inflammation à ischemic stroke
