Meningitis Flashcards
what are the features of meningism?
headache
stiff neck
photophobia
vomiting
what are the causes of meningism?
meningitis
SAH
infection accompanied by bacteraemia
severe viral infections i.e. influenza can also cause meningitism
what is characteristic of the neck stiffness in meningism?
stiffness on passive flexion (looking down to the feet)
what is neck stiffness with lateral or rotational movements indicate?
local cause in the cervical joints
by what mechanism does molecules pass through the blood brain barrier?
active transport
lipid solubility
what are the 5 steps of the pathogenesis of meningitis?
attachment to mucosal epithelial cells transgression of the mucosal barrier survival in the blood stream entry into CSF production of infection in the meninges with or without brain infection (encephalitis)
what are the bacterial causes of meningitis?
neisseseria meningitidis
streptococcus pneumoniae
e.coli
group B strep
what are the common organisms responsible for meningitis in neonates?
e.coli
group B streptococci
listeria monocytogenes
what are the viral causes of meningitis?
enteroviruses;
- cocksackie A and B
- polio
- echoviruses
- parechoviruses
mumps
HSV
what is aseptic meningitis?
non-infective meningitis
usually caused by tumour cells in the CSF which cause an elevated lymphocyte and protein count
no organism is cultures or detected
what cranial nerves palsies may occur with meningitis?
VI, VII, VIII
what are risk factors for meningitis?
recent skull trauma
alcoholism
diabetes
if the presentation of meningitis is acute and rapidly progressive what is the most likely cause?
meningococcal
what is Kernig’s sign?
with the hip flexed, the patient leg cannot be straightened due to hamstring spasm in meningism
if FBC shows a low white cell count (leucopenia) what does this indicate?
septicaemia or disseminated intravascular coagulation
= poor prognosis
(the infection should cause it to rise)
what is the predominant cell types in bacterial and viral meningitis in the CSF?
bacterial - neutrophils
viral - lymphocytes
what antibiotics are used to treat meningitis?
benzylpenicillin given 4 hourly
or ceftriaxone
what strain of meningococcal meningitis is most common?
groups B and C
ratio 3:2
what strain of meningococcal meningitis is there a vaccine for?
group C
what are the features of fulminant meningococcal septicaemia?
sudden onset of symptoms with rapid deterioration of consciousness, renal failure, disseminated intravascular coagulation, fever and septicaemic shock
what is the mortality rate for fulminant meningococcal septicaemia?
50% die within first 24 hours of illness
what are bad prognostic markers of meningitis?
DIC metabolic acidosis absence of polymorph leukocytosis delay in instigation of therapy extremities of age purpuric lesions shock with absence of signs of meningism hyperpyrexia
what is the most common organism that causes meningitis in adults?
streptococcus pneumoniae
what are predisposing factors for pneumococcal meningitis?
alcoholism splenomegaly head trauma endocarditis sinusitis pneumonia
what is the treatment for pneumococcal meningitis?
ceftrixone
(or benzylpenicillin but there are now resistant strains)
dexamethasone to minimise risk of complications
what are complications of pneumococcal meningitis?
loss of hearing hydrocephalus seizures hemiparesis cranial nerve defects
a patient 5 years old presents with a mild upper respiratory tract infection followed by a rapidly deteriorating meningitis. what is the most likely causative organism?
haemophillus influenzae
what is the treatment for haemophilias influenzae (type B) meningitis?
cefotaxime
name 2 spirochetes that can cause aseptic meningitis?
leptospirosis and lyme disease
what is the most common cause of meningitis in HIV patients?
cryptococcal meningitis (fungal)
what investigations should be carried out to diagnose cryptococcal meningitis?
LP for measurement of CSF
serum cryptococcal polyssacharide antigen
what is the treatment for cryptococcal meningitis?
parenteral amphotericin + flucytosine
or high dose fluconazole as an alternative to this combination
how is cryotoccal meningitis prevented in HIV patients?
chemoprophylaxis with fluconazole
what are predisposing factors for neonatal meningitis?
low birth weight
maternal diabetes
prolonged rupture of membranes
what is the treatment for neonatal meningitis caused by E.coli?
cefotaxime
what is the treatment for neonatal meningitis caused by listeria monocytogenes ?
ampicillin + gentamicin for 3 weeks or longer
what is the treatment for group B strep meningitis in neonates?
benzoyl penicillin and amoxicillin
