Meningititis Flashcards
What is meningitis?
Inflammation of the membranes lining brain and spinal cord.
How is meningitis caused?
Bacteria that cause meningitis live in the back of the nose and throat in 1/10 people.
They don’t usually cause disease. Kept in check by NS defences.
They can however invade the back of the throat, pass into blood stream and invade CSF. Thus inflammation of membranes lining brain and spinal cord and the presence of bacteria in CSF.
How is meningitis spread?
Not easily but can be transferred from one person to another through secretions from the nose or throat during close contact.
The infection is not acquired simply by being in the same room as an infected person, it is only those who have had close contact with a person who has either got bacterial meningitis or who is an asymptomatic carrier that are at a SMALL increased risk of contracting the disease.
How does meningitis present?
Symptoms occur suddenly after incubation period of 1-3 days.
Skin rash associated with septicaemia which is associated with meningitis caused by N. Meningitidis.
Not always present. Results from bleeding from capillaries close to surface. Bacteria release toxins into the blood which break down blood vessel walls causing blood to leak out into skin.
When does meningococcal septicaemia occur?
Blood poisoning: when the bacteria in the blood multiply uncontrollably.
Symptoms of meningitis include:
Severe headache High temp/fever Vomiting Stiff neck Pale, Blotchy skin Drowsiness/lethargy Joint pains Cold hands and feet Rash
What causes the skin rash?
Skin rash associated with septicaemia which is associated with meningitis caused by N. Meningitidis.
Not always present. Results from bleeding from capillaries close to surface. Bacteria release toxins into the blood which break down blood vessel walls causing blood to leak out into skin.
What initial therapy should be instigated immediately if suspected meningitis?
Blood cultures taken and then antibiotic treatment started immediately. Initial blind therapy.
1st line treatment: High dose 3rd gen cephalosporin: ceftriaxone IV/ cefotaxime IV.
2g twice daily.
If mild allergy to beta-lactams: Meropenem.
If severe allergy then use IV chloramphenicol 12.5mg/kg qds (max 1g qds).
Dexamethasone to reduce inflammatory response.
What is the 1st line treatment of suspected meningitis infection?
High dose 3rd gen cephalosporin:
ceftriaxone or cefotaxime.
Dose of 2g twice daily.
Skin rash associated with septicaemia which is associated with meningitis caused by:
N. Meningitidis.
What alternatives to 3rd gen cephalosporins are there for immediate treatment?
Meropenem if mild allergy to penicillins.
IV Chloramphenicol if severe:
12.5mg/kg/qds (Max. 1g qds)
Why is dexamethasone sometimes included in immediate treatment for suspected meningitis infections?
Reduce inflammatory response
What is the pharmacokinetic rationale for the use of IV beta-lactams?
Broad spectrum and fast acting.
Capably of rapid concentrations in the blood stream.
Non toxic.
Good penetration into CSF if meninges are inflamed.
What is the pharmacokinetic rationale behind the use of IV chloramphenicol?
Can cause aplastic anemia but benefits outweigh risk if severe allergy or penicillin resistance found.
Broad spectrum, well absorbed.
Good penetration into the brain and spinal cord.
What are the main bacterial causative agents of meningitis?
N. Meningitidis
S. Pneumoniae
H. Influenzae B.
Less common: S. Aureus Listeria. Monocytogenes. M.tuberculosis E.coli and S. Agalactiae.
