CNS Infections Flashcards
What is infected in meningitis?
Infection of pia mater and pus in subarachnoid space
What are the causes of meningitis in the elderly?
Listeria, TB and gram negatives
What are the causes of meningitis in neonates?
E-Coli
Beta Haemolytic Strep
Listeria
What are the viral causes of meningitis?
HIV
Mumps
Herpes
Coxsackie
What are non infectious causes of meningitis?
Tumours Cysts NSAIDs SLE Vasculitis Parameningeal infections
What is the presentation of meningitis?
Meningismus Headache Fever Kernigs sign Bradzinki's sign Photophobia Rash?
What is Bradzinki’s sign?
Neck flexion causes knee flexion
What is Kernig’s sign?
Hip flexion and knee extension causes pain
How do you investigate meningitis?
CT then LP
CSF culture
What is CSF like in viral meningitis?
Clear
Raised lymphocytes
Raised protein
Normal Glucose
What is CSF like in TB meningitis?
Fibrin web
Raised WCC
Raised Protein
Low Glucose
What is CSF like in bacterial meningitis?
Turbid
Raised Neutrophils (& polymorphs)
Very raised protein
Low Glucose
How is meningitis treated?
ABCD
IV fluid
IV Ceftriaxone (Amoxicillin if pregnant or immunocompromised) & Isolate
Dexamethasone if pneumococcal
What prophylaxis do you give close contacts and what is your other responsibilty?
Notifiable disease
Rifampicin or Cipro and meningococcal vaccine
How do you treat meningitis in primary care or if the patient is in shock?
IV Benzylpenecillin
How do you treat aseptic or viral meningitis?
No treatment its self limiting
ABC & maintain fluids
Where do brain abscesses from direct invasion come from & what organisms?
Middle ear- S. pyogenes or S milleri
Sinus
Tooth
Where do brain abscesses that occur after haematologous spread originate?
Endocarditis
Right to left Cardiac shunts
Bronchiectasis (anaerobes)
What investigations do you do for a brain abscess?
CT
MRI
WCC
ESR
What are the symptoms of a potential brain abscess?
Fever
Headache
Focal Neurological signs
Seizures
What treatment options are there for brain abscesses?
Surgical excision/drainage
Ceftriaxone and Flucloxacillin and Metronidazole
Reduce ICP with dexamethasone
What toxin mediated causes of CNS infection are there?
Tetanus
Botulinism
Is Encephalitis usually viral or bacterial?
Viral
What are the common causative agents in encephalitis?
Enteroviruses Mumps HSV VZV HIV Rabies Japanese encephalitis
Symptoms of encephalitis
Headache Fever Altered consciousness Hallucinations and delusions Focal signs Hemiparesis etc
How do you diagnose encephalitis?
High contrast CT Blood culture Viral ABs EEG LP
How do you treat encephalitis?
High dose IV Acyclovir
How is rabies spread?
Saliva
How do you treat rabies in vaccinated and non vaccinated individuals?
5 IM vaccine shots and Ig to bite site if not vaccinated
Ditto, but 2 shots if vaccinated
How is rabies diagnosed?
Nape of neck biospy
How does rabies affect the brain?
Spreads up peripheral nerves and forms Negri bodies.
Symptoms of rabies
Fever Heachache Malaise Hallucination and excitation with lucent periods Salivation
What symptoms are classic of Tetanus?
Trismus (lockjaw)
Sustained muscle contraction (bent back)
Facial muscle involvement and spasms
How is tetanus diagnosed?
Wound culture
How is Tetanus treated?
Benzlypenecillin and IVIg
How does botulinism present?
Descending paralysis starting with cranial neuropathy
How is Botulinism treated?
Antitoxin
How is Polio spread?
Faeco Oral
What kind of vaccine is the polio vaccine?
Live attenuated
How do polioenteroviruses cause disease?
They cross the BBB and cause encephalitis with motor nuclei destruction in the anterior horn or brainstem and spinal cord causing paralytic poliomyelitis
