MENINGITIS Flashcards
What are the different ways that infective agents reach the meninges resulting in meningitis?
Haematogenous (most common)
Direct - sinuses or inner ear
Fractures of skull
What are the most common bacterial agents that causes meningitis?
Haemophilus influenzae
Neisseria meningitidis - gram negative diplococci
Streptococcus Pneumoniae - gram positive pairs/short chains
What is are the triad of clinical features associated with meningitis?
Headache
Photophobia
Neck stiffness
What are the two signs that are used to look for neck stiffness in someone with suspected meningitis?
Kernig’s sign
Brudzinski’s sign
How do you test for Kernig’s sign?
Extend knee with hip flexed at 90˚
How do you test for Brudzinski’s sign?
With patient supine, the neck is flexed passively. You are looking for involuntary lifting of the legs.
What symptoms might be seen in someone with suspected meningitis where there is raised intracranial pressure?
Confusion
Fluctuating levels of consciousness
Seizures
Cranial nerve palsies
What additional symptom may be seen in a patient who is suspected of having meningococcal septicaemia?
Rapidly progressing petechial/purpuric non-blanching rash
What are the major causes of aseptic meningitis?
Viruses
What is the leading causes of viral meningitis?
Enteroviruses - including echoviruses and coxsackieviruses.
What organism is most likely to be responsible for a chronic meningitis, developing over weeks to months?
Tuberculosis
What is the organism associated with meningitis is those with advanced HIV?
Cryptococcal meningitis (fungal)
What is the main investigations that should be done with someone who has suspected meningitis?
LP
When should a CT be done before a lumbar puncture?
Immunocompromised patients
Those with a history of central neurological disease
Those with new-onset seizures
Those with papilloedema
Those with abnormal levels of consciousness
Those with a focal neurological deficit
Why is important to do a CT on a patient with suspected meningitis if they have symptoms associated with raised intracranial pressure?
To assess the risk of coning
Give a description of the appearance of the CSF in each of the following situations: Normal Bacterial meningitis Viral meningitis Tuberculous meningitis
Normal - clear
Bacterial - Turbid/pus
Viral - clear/turbid
Tuberculous - Turbid/viscous
What are the levels of neutrophils in the CSF in each of the following situations: Normal Bacterial meningitis Viral meningitis Tuberculous meningitis
Normal - none
Bacterial - 200-10,000/mm3
Viral - none
Tuberculous - 0-200/mm3
What are the levels of lymphocytes in the CSF in each of the following situations: Normal Bacterial meningitis Viral meningitis Tuberculous meningitis
Normal -
What are the levels of protein in the CSF in each of the following situations: Normal Bacterial meningitis Viral meningitis Tuberculous meningitis
Normal - 0.2-0.4g/L
Bacterial - 0.5-2.0g/L
Viral - 0.4-0.8g/L
Tuberculous - 0.5-3.0g/L
What are the levels of glucose in the CSF in each of the following situations: Normal Bacterial meningitis Viral meningitis Tuberculous meningitis
Normal - >1/2 blood glucose
Bacterial -
What are the normal pressures of the CSF?
10 to 18 mmHg
What are the complications associated with meningitis?
Hydrocephalus Cerebral oedema Venous sinus thrombosis Subdural empyema Cerebral abscess Arteritis
What is the treatment of bacterial meningitis?
Treatment should be started immediately after LP, unless there is going to be a 30 minute delay prior to LP.
Cefotaxime or ceftriaxone
Cover with ampicillin with or without gentamicin where Listeria is suspected.
When should steroids be used in the treatment of meningitis?
In all adults with suspected or proven pneumococcal meningitis.
In tuberculous meningitis
Must be given within 12 hours of start of antibiotics
How is viral meningitis managed?
Largely supportive
Acyclovir is controversial
What must a doctor do by law if bacterial meningitis is diagnosed?
It is a notifiable disease
What is the treatment plan for tuberculous meningitis?
At least 9 months standard TB therapy:
Isoniazid, Rifampicin and Pyrazinamide and possibly ethambutol.
What is encephalitis?
Inflammation of the brain parenchyma.
What type of pathogen is normally responsible for encephalitis?
Viruses
What are the viruses most commonly associated with encephalitis?
Echovirus
Coxsackie virus
Mumps virus
Herpes simplex
Which virus causes the most severe cases of viral encephalitis in the UK and is also the most common cause?
Herpes simplex 1 and 2
What are the most common clinical features of encephalitis?
Most common:
Headache
Drowsiness
Also:
Focal signs
Seizures
Severely depressed levels of consciousness
What are the clinical features of Herpes simplex encephalitis?
Headache Pyrexia Myalgia Malaise Meningism Confusion Dysphasia Hemiparesis Seizures Ataxia Cranial nerve palsies Autonomic dysfunction
What investigations should be ordered for someone with suspected encephalitis?
FBC CRP CT scan MRI EEG Viral serology
What would a CT scan of someone with encephalitis reveal?
Cerebral oedema
What would a MRI scan of someone with encephalitis reveal?
Very distinctive pattern of Herpes simplex virus in one or both temporal lobes.
What might an EEG of someone with encephalitis reveal?
Non-specific slow wave changes and/or periodic changes - if findings are restricted to temporofrontal regions very suggestive of herpes simplex.
What is the management of someone diagnosed with herpes simplex encephalitis?
Acyclovir
Anticonvulsants for seizures
Control of cerebral oedema
What is a cerebral abscess?
A focal encapsulated area of infection with the cerebrum. Also possible to have cerebellar abscesses.
What are the diseases that predispose someone to brain abscesses?
Chronic lung infection - bronchiectasis, chronic sinusitis
Congenital heart disease - shunts
Bacterial endocarditis
Immunocompromised patients with infection
What are the usual causative organisms of a cerebral abscess in non-immunodeficient patients?
Bacteria - mainly anaerobes
Streptococcus viridans and milleri
Bacteroides species
Enterobacteria - E coli, Proteus species
Staph aures
What are the usual causative organisms of a cerebral abscess in immunocompromised patients?
Toxoplasma Aspergillus Candida Listeria Strongyloides
What are the classic clinical features of cerebral abscess?
Short (less than 1 month) history Headache Vomiting Deterioration in consciousness level Papilloedema
