Crash course: CNS infections + STIs Flashcards
What is meningitis?
Inflammation of the meninges
Can be bacterial, viral or fungal (or TB)
Presents with meningism
What are the signs of meningism?
Stiff neck (nuchal rigidity)
Kernig’s sign
Brudzinski’s sign
List 5 symptoms of meningitis
Headache
Photophobia
Fever
N+V
Drowsiness
Give 4 signs of meningococcal disease
Non-blanching petechial rash
Altered mental status
Skin mottling
Cold + painful extremities
What is encephalitis?
Inflammation of brain parenchyma
Usually viral, rarely AI
Presents systemically unwell, altered mental state- personality change
What is a brain abscess?
Infective collection in the brain parenchyma
Presents with swinging fevers + SOL
What are the most common causes of meningitis in neonates?
Group B Strep
Listeria monocytogenes
E. coli
What are the most common causes of meningitis in adults?
Neisseria meningitidis
Streptococcus pneumoniae
What are the other causes of meningitis in the elderly in addition to Neiserria and Steptococcus?
Group B Strep
Listeria monocytogenes
What can cause meningitis in the
immunocompromised?
TB
What are the three classifications of meningitis? What are the usual causative organisms?
Acute: bacterial
Chronic: TB, Spherocytes, Cryptococcus
Aseptic: acute viral
Which organism causes meningococcal meningitis?
Neiserria Meningitidis
What are the 3 most common causes of meningitis in children/ young adults?
Neiserria Meningitidis
Haemophilus influenzae (rare in vaccinated countries)
Streptococcus pneumoniae
What are the viral causes of meningitis?
Enterovirus: Adenovirus, Cocksackie
HSV-2
HIV seroconversion (rarely)
Name 2 fungal causes of meningitis. In which patients?
Cryptococcus neoformans: HIV
Cryptococcus gattii: immunocompetent
How is meningitis diagnosed?
LP
Ideally LP before abx, but like with cultures, don’t delay abx
If any Sx consistent with raised ICP or SOL, need brain imaging first
Give 4 signs of raised ICP
Focal neurology
Papiloedema
Reduced GCS
Seizures
What analytics are used on CSF in meningitis?
Biochemical analysis
Gram stain for bacteria
PCR for viruses
Ziehl-Neelson stain forTB
India ink stain for Cryptococcus
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in BACTERIAL meningitis?
Cloudy + turbid
↑↑↑ WCC
Massive neutrophilia
↑↑ Protein
↓ glucose (<40% plasma glucose, as bacteria consuming)
↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in VIRAL meningitis?
Clear
↑ WCC
Lymphocytosis
N/ ↑ protein
N glucose (>60% plasma glucose)
N/ ↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in FUNGAL meningitis?
Fibrin web
N/ ↑ WCC
Lymphocytosis
N/ ↑ protein
N/ ↓ glucose (<40% plasma glucose)
↑ / ↑↑ opening pressure
Describe the appearance, white cells, protein, glucose of CSF and opening pressure on LP in TB meningitis?
Cloudy + viscous
↑ WCC
Lymphocytosis
↑↑ protein
↓↓ glucose (<30% plasma glucose)
↑ opening pressure
What is normal opening CSF pressure?
10-20
Describe management of meningitis
In community: IM Benzylpenicillin
In hospital:
IV Ceftriaxone/ Cefotaxime
(+ Amoxcillin/ Ampicillin if baby or >50y)
+ Acyclovir if can’t exclude encephalitis
When should steroids be used for meningitis ?
Give dexamethasone as if caused by strep pneumoniae or haemophilus influenzae, 5d dex reduces the incidence of sensorineural hearing loss
Give dex with the 1st dose of cef, once LP done + organism confirmed, if S. pneumoniae or H. influenzae continue for 5d.
If neither, stop dex
When should meningitis prophylaxis be given?
If meningococcal meningitis + exposure within 7d before onset
Oral ciprofloxacin or Rifampicin
What is the most common cause of encephalitis in the UK?
HSV 1
Name 2 rare causes of encephalitis
Previous hx of measles: subacute sclerosing panencephalitis (SSPE)
HIV/ on monoclonals: Progressive multifocal leukoencephalopathy
What is the treatment for encephalitis?
Empirically treat with Acyclovir
MRI + CSF PCR can help identify precise organism
What usually causes brain abscesses?
Typically mixed organisms
Staphylococcus/ Streptococcus + anaerobes is common
If patient with HIV: suspect toxoplasmosis
In HIV patients, what organisms are associated with what pathology?
Cryptococcus: meningitis
Toxoplasmosis: brain abscess
What investigations are used for brain abscesses?
MRI:
Classically shows a ring-enhancing lesion
(CT)
What is used for treatment of brain abscesses?
Abx: Gentamicin + metronidazole
Surgical drainage
Consider steroids + anti-seizure meds (load on Levateracitam)
What is the most common STI?
Chlamydia
caused by Chlamydia trachomatis
How does chlamydia present?
Asymptomatic: 70%
F: cervicitis (discharge, bleeding) + dysuria, PID
M: discharge, dysuria
Reactive arthritis
What are 5 symptoms of reactive arthritis?
Anterior uveitis
Dysuria
Oligoarthritis
Balanitis
Keratoderma blennorrhagicum
How do serovars L1-3 of chlamydia present? In which patient groups?
Lymphogranuloma venereum
Presents first with proctitis
Painful, swollen, enlarged inguinal LN = Bubos
Common in MSM
How does chlamydia present in neonates? When?
Ophthalmia neonatorum
1-2w after birth
How is chlamydia diagnosed? What treatment is used?
NAAT (can’t culture)
Tx: Doxycycline (7d) or Azithromycin (STAT)
How does gonorrhoea present?
Less commonly asymptomatic
Typical STI Sx: PID
Disseminated gonococcal infection
How does gonorrhoea present in neonates? When?
Ophthalmia neonatorum
First few DAYS after birth
How is gonorrhoea diagnosed?
Culture = GS
In practice NAAT
What is treatment for gonorrhoea?
IM ceftriaxone
What are 3 key symptoms of disseminated gonococcal infection?
Migratory poly/ oligoarthritis
Dermatitis: maculopapular or vesicular
Tenosynovitis
List 3 further complications of disseminated gonococcal infection
Septic arthritis
Endocarditis
Perihepatitis: Fitz-Hugh-Curtis syndrome
What s the most common cause of septic arthritis in young adults?
Neisseria gonorrhoea
What causes syphilis?
Treponema pallidum
What are the stages of syphilis?
Primary: painless CHANCRE
Secondary: Unwell, condyloma lata, lymphadenopathy, maculopapular rash
Latent phase: can last decades
Tertiary: gummatous disease, aortitis, neurosyphilis, tabes dorsalis
What is a chancre?
Painless ulcer on genitals
(occasionally oral)
What are condyloma lata?
greyish warty, painless lesions, on genitals or mouth
Describe the 4 features of tertiary syphilis
Gummatous disease: erodes through cartilaginous structures in mouth + face
Aortitis: inflammation + formation of aneurysms
Neurosyphillis: argyll robinson pupils
Tabes dorsalis: degeneration of spinal cord
What is treatment for syphilis?
IM Benzathine penicillin
What must you be aware of when treating syphilis?
Jarish Herxheimer reaction
When started on abx for a couple of days feel worse: fevers, rigors
When killing sphirocytes they release preformed toxin → inflammatory response
→ give paracetamol
Rarely can be more unwell → steroids
What is the investigation for primary syphilis?
Darkfield microscopy of chancre sample
If a chancre sample is not possible, what investigations should be used for syphilis?
Non-treponemal tests = VDRL, RPR tests
Treponemal tests =TPHA,TP-EIA
Give an advantage and disadvantage of non-treponemal tests and treponemal tests
NT: Titre reduces with Tx. NOT specific to syphilis +ve for HIV, lupus
T: Specific. But stay +ve even if treated
How should non treponemal and treponemal tests be interpreted?
If both +ve: active syphilis
If NT +ve, T -ve: probably cross reaction indicating something else
If NT -ve, T +ve: previous treated syphilis
What are the buzzwords/ phrases for Chancroid?
Caused by Haemophilus ducreyi
Painful ulcers +/- lymphadenopathy
Tropical regions
What are the buzzwords/ phrases for Donovanosis/ Granuloma inguinale?
Caused by Klebsiella granulomatis
Painless red ulcers “beefy”
Tropical regions
Donovan bodies on histology
What are the buzzwords/ phrases for Trichomoniasis?
Cause by Trichomonas vaginalis
Yellow-green discharge
Strawberry cervix
What are the buzzwords/ phrases for genital warts?
Human papillomavirus
What are the buzzwords/ phrases for HSV?
Painful ulcers
Fluid filled vesicles
