Meningitis **** Flashcards
What is it?
What is the difference between meningitis, meningococcal septicaemia and meningism?
Inflammation of the meninges, the membrane surrounding the brain.
Bacterial meningitis occurs when bacteria infect the lining of the brain (the meninges) and the spinal cord. Meningococcal septicaemia – or blood poisoning – occurs when the bacteria in the blood multiply uncontrollably.
Doctors call septicemia (a bloodstream infection) caused by Neisseria meningitidis meningococcal septicemia or meningococcemia. When someone has meningococcal septicemia, the bacteria enter the bloodstream and multiply, damaging the walls of the blood vessels. This causes bleeding into the skin and organs.
Meningism is the clinical syndrome of headache, neck stiffness, and photophobia, often with nausea and vomiting. 1. It is most often caused by inflammation of the meninges (see later), but other causes include raised intracranial pressure.
Commonest causes of bacterial meningitis by age:
< 3 months
3 months - 45 yrs
> 45 yrs
Why are causative agents such as staph. aureus, E. coli, TB etc. quite rare?
Group B strep - that is why it is screened for
Neisseria meningitidis ****
Streptococcus pneumoniae
Because of the vaccine
Viral meningitis:
How does this compare to bacterial meningitis?
What is it typically mistaken for?
Pathogens - name a few?
How may this present? - 2
Commoner
Milder
Usually mistaken for flu
Enteroviruses - coxsackie
Herpes simplex
Mumps
Measles
Prominent headache
Flu like syndrome
Other signs minimal or absent
Fungal meningitis:
Pathogen - 1
What sort of onset does it have?
Cryptococcus neoformans
Insidious
Non-infectious meningitis:
A type of cancer?
Drugs:
- Antibiotic - C
- Pain med
- Immunosuppressor - A
Carcinomatous meningitis
Co-amoxiclav
NSAIDs
Azathioprine
Meningococcal disease:
What is the difference between meningitis and meningococcemia?
When the bacteria infect the membranes that cover the brain and spinal cord, it’s called meningitis.
When the infection remains in the blood but doesn’t infect the brain or spinal cord, it’s called meningococcemia.
It’s also possible to have both meningitis and meningococcemia at the same time.
Meningococcal disease:
What vaccine is reducing the number of cases?
Where is it usually found?
How is Neisseria meningitidis transmitted?
What is the incubation period?
MenB
Nasopharynx
Droplets from the upper respiratory tract
3-7 days so most infectious before symptoms being.
Presentation:
What is the classic triad which is present in 50% of patients?
Other features:
- A symptom for any systemic infection
- What do patients not like?
- What happens to their skin? Where does it happen first?
- What else may the patient complain about with the above?
- Neurological signs - 2
Fever
Stiff neck (can’t place it on the chest)
Headache or altered mental state
Vomiting, rigors
Photophobia
Mottled skin - the legs - LOOK UP
Complain of cold hands and feet
Confusion
Seizures
Presentation:
Signs of meningism:
- What is Kernig’s sign?
- What is Brudzinki’s sign?
Signs of cerebral oedema - 3
Signs of meningococcaemia:
- Skin
- Signs of sepsis
- Another body-wide clotting issue
Hip and knee flexed, pain limits passive extension of the knee
Neck flexion leads to involuntary hip and knee flexion
Kenig’s sign:
- The patient lies supine.
- The hip and knee is flexed by the examiner up to 90 degrees..
- The examiner then attempts to passively straighten the leg at the knee.
- In a patient with a positive Kernig’s sign, the patient experiences pain along the spinal cord and the pain limits passive extension of the knee.
Brudzinki’s sign
- The patient lies supine in extension.
- The examiner gently grasps the patients head in the occipital lobe region and attempts flexion of the neck.
- Brudzinski’s sign occurs when flexion of the neck causes involuntary flexion of the knee and hip (an attempt by the patient to lessen the stretching of the inflamed meninges).
EXTRA INFORMATION:
Kernig’s Sign
- Occurs when the patient does not a the examiner to extend the knee of the elevated leg due to pain along the spinal cord.
- Bilateral Kernig’s sign is more likely to implicate meningitis.
Brudzinki’s Sign
- Neck stiffness upon test movement causes the involuntary flexion of the knee & hip.
- The patient experiences pain along the cervical spine and thoracic spine.
Reduced GCS
Papilloedema
Focal CNS signs
Non-blanching rash - petechiae and purpura
Low BP and cap refill
DIC
What may also be present with pneumococcal meningitis?
Pneumonia
Risk factors - 2
What about where a person lives?
Immunosuppression
Skull fractures or anatomical defects
Crowding - uni halls, military barracks
Investigations:
What should be given before investigations are done if you suspect meningitis?
SEPSIS 6???
What blood would you do and why? - 5
Antibiotics
3 IN - FLUIDS, ABs & OXYGEN
3 OUT - LACTATE, BLOOD CULTURE, URINE OUTPUT
WBC and CRP - raised in inflammation
U&Es and LFTs - baseline
Coag - DIC
Investigations - Lumbar puncture:
What should be done before this if raised ICP is suspected?
When should a lumbar puncture not be done?
Some patient develop post-LP headaches. How is this managed?
What do you look for in the CSF? - 4
Why is a throat swab done?
Why do you do an X-ray? - 2
CT and fundoscopy
If the patient is septic, they should be stabilised first?
Caffiene and fluids - tends to improve with lying down for some reason
Bacteria on culture
Protein
Glucose
Pre-dominant cell - Polymorphs and Lymphocytes
Looking for N. meningitidis
Pneumococcal pneumonia and TB
Investigations - Lumbar puncture:
Bacterial meningitis:
- What does it usually look like?
- What predominant cell is very high and used to distinguish between other types of meningitis?
- Protein
- Glucose
- What other tests can be used to identify the bacteria present-3
What predominant cells can you see in listeria CSF?
Turbid CSF
Very high polymorphs
High protein
Low glucose - bac using up the glucose
Smear
Gram stain
Culture
Mix of poly and lymphocytes
Investigations - Lumbar puncture:
TB CSF:
- What does it usually look like?
- What predominant cell is very high and used to distinguish between other types of meningitis?
- Protein
- Glucose
- What type of staining is used to find TB specifically?
Fibrin webs - google
Lymphocytes
High protein
Low glucose
ZN-staining = a bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria.
