Infection Flashcards
causes of meningitis
infection
intrathecal drug
malignant cells
blood (following subarachnoid haemorrhage)
how do microorganisms reach the meninges in meningitis
ears
nasopharynx
cranial injury
blood stream
common bacterial organisms causing meningitis
neisseria meningitidis
streptococcus pneumoniae
clinical features bacterial meningitis
headache
neck stiffness
fever
all develop over minutes to hours
photophobia and vomiting
kernig’s sign - severe stiffness of the hamstrings = inability to straighten
in meningococcal septicaemia = non-blanching petechial & purpuric skin rash and signs of shock
clinical features viral meningitis
benign self-limiting condition lasting for about 4-10d
no serious sequelae
non blanching petechial or purpuric skin rash = what? what needs to happen asap?
meningococcal infection
immediate (before hosp transfer) rx w benzylpenicillin or cefotaxime
lumbar puncture should NOT be performed if meningococcal sepsis is suspected because coning of the cerebellar tonsils will follow
investigations meningitis
head CT
lumbar puncture - urgent CSF microscopy, WCC and analysis for protein and glucose
normal CSF appearance
clear
bacterial CSF appearance
turbid (cloudy) / purulent (pus)
viral CSF appearance
clear / turbid (cloudy)
TB CSF appearance
turbid / viscous
rx bacterial meningitis
cefotaxim initially
add ampicillin or co-trimoxazole if risk of listeria
subsequent Abx dependent on organism in CSF
IV fluids and inotropes are given if there is also septicaemia
what is given to ppl who were in contact w meningitis person
oral rifampicin or ciprofloxacin
encephalitis
inflammation of the brain parenchyma
unlike meningitis, cerebral function is abnormal w altered mental state
encephalitis caused by?
mainly viruses
encephalitis mainly affects
MSM
IVDU
HIV
where opportunistic organisms are causes
organisms that cause acute viral encephalitis
herpes simplex virus
ECHO - enteric cytopathic human orphan
Coxsackie and mumps
clinical features acute viral encephalitis
mild self limiting illness with fever, headache and drowsiness
less commonly it’s severe with focal signs eg hemiparesis, dysphagia, seizure and coma
investigations acute viral encephalitis
CT and MRI shows areas of oedema in temporal lobes
CSF analysis shows inc in mononuclear cells and protein
viral serology of blood and CSF
rx acute viral encephalitis
suspected herpes simplex encephalitis is immediately treated with iv aciclovir - antiviral
if pt in coma prognosis = poor
varicella zoster virus cuases
chicken pox primarily and shingles after primary infec
clinical features varicella
varicella = chickenpox
incubation 14-21d
fever, headache, malaise
rash on face, scalp, trunk = macules initially, develops to papules and vesicles which heal crusting
investigations varicella
diagnosis clinical
confirmed by detection of viral DNA in vesicular fluid by PCR
management varicella
healthy children = no rx
anyone >16yo = aciclovir
preg women = zoster-immune immunoglobulin and aciclovir
