Patho- CNS infections Flashcards
What are the three main infections of the CNS called?
Meningitis
Encephalitis
Abscess
What are the three forms of meningitis called?
Acute pyogenic
Acute aseptic
Chronic bacterial
What bacteria can cause acute pyogenic meningitis?
Strep Pneumonia- Pneumococcal meningitis
Neisseria meningitidis- Meningococcal meningitis
Listeria
Staph
Describe pneumococcal meningitis
Strep Pneumonia- gram +ive diplococci
Usually in >21
Who tends to get pneumococcal meningitis?
> 21YO
Describe meningococcal meningitis
Neisseria meningitidis- Gram -ive diplococci
10-21YO
Do NOT miss it!!!
Who tends to get meningococcal meningitis?
10-21YO
Do NOT miss it!!!
Describe listeria meningitis
Listeria- gram +ive bacilli
Neonates and immunosuppressed and >55
Who tends to get listeria meningitis?
Neonates and immunosuppressed and >55
Who tends to get staph meningitis?
Those with head injury
What are some symptoms of acute pyogenic meningitis?
Headache Stiff neck Fever and N+V Altered consciousness- GCS<12 Photophobia Purpuric rash
What is the pathology of acute pyogenic meningitis?
Thick layer of exudate on the surface of the brain- causes adhesions and palsy
Neutrophils in SA space
What do measurement of the CSF look like in acute pyogenic meningitis?
10-10,000 polymorphic neutrophil cells
Protein>220mg/dl
<70% blood glucose
WBC>2000 (Neutrophils>1180)
What are some complication of pyogenic meningitis?
Purulence- mats of pus round neurons causing palsy
Cerebral oedema
Hydrocephalus
How do you treat pyogenic meningitis?
Start IV Ceftriaxone 2g immediately (unless penicillin allergic or suspect listeria)
Give steroids with first does (or upto 4 days if pneumococcal)
Take bloods and CSF sample
What antibiotics should you give to someone with penicillin allergy?
Chloramphenicol and vancomycin
What antibiotic should you give to someone with suspected listeria?
Amoxicillin 2g bd or Co-trimoxazole if allergic
What can cause chronic bacterial meningitis?
TB
What are some symptoms of chronic bacterial meningitis?
Symptoms progress over 4-6 weeks Headache N+V Anorexia Neck stiffness Papilloedema Fever is uncommon
How do you investigate for TB caused meningitis?
CXR for granulomas
Tuberculin skin test
CT/MRI brain
CSF analysis
What will you see in the CSF of TB meningitis?
Raised WCC- all lymphocytes
Protein >1g/l
Low glucose
How do you treat TB meningitis?
Isoniazid + rifampicin
Add pyrazinamide
Avoid ethambutol
When should you admit someone with meningitis to the hospital?
Signs of meningeal irritation
Impaired conscious level
Petechial rash
Febrile/unwell/recent fit
What is acute aseptic meningitis?
Meningitis caused by anything other than bacteria
What can cause aseptic meningitis?
Virus
Bacteria
Tumor
Inflammation- sarcoidosis and vasculitis
What viruses can cause meningitis?
Enterovirus Herpes simplex Coxsackie HIV Epstein Barr
How do you diagnose viral meningitis?
Viral stool culture
Throat swab
CSF PCR
CSF analysis
What will you find in the CSF in viral meningitis?
Low WBC- Neutrophils then lymphocytes
Little protein- up to 0.8g/l
Normal glucose
How do you treat viral meningitis?
Support
What fungi can cause meningitis?
Cryptococcal neoformans- Cryptococcal meningitis
Who mainly suffers from fungal meningitis?
HIV sufferers
How do you treat Cryptococcal meningitis?
IV amphotericin B
What how do you test for Cryptococcal meningitis?
India ink
Antigen
CSF analysis
What will the CSF of Cryptococcal meningitis show?
High lymphocytes
Raised protein
Low glucose
How do you treat inflammatory aseptic meningitis?
Steroids
How will the CSF appear in tumor caused meningitis?
Raised Cell Count
High protein
Low glucose
What are some general symptoms of meningitis?
Fever Cold hands and feet Vomiting Drowsiness Confusion and irritability Severe muscle pain Rash Severe headache Stiff neck Photophobia Convulsions or seizures
How do you diagnose meningitis?
LP
Blood cultures- looking for cause of infection
Throat swab- looking for cause of infection
What are you looking for in the LP for meningitis?
Hematology- Cell count
Microbio
Chemistry- Glucose, proteins
When should you CT before LP in meningitis?
Immunocompramised History of CNS disease New onset siezures Papilloedema Altered conciousness Focal neurological deficit
Do you diagnose or treat meningitis first?
Treat
What tends to cause encephalitis?
Virus
What viruses can cause encephalitis?
HSV Echovirus Coxsackie Mumps EBV
What are some symptoms of encephalitis?
Headache Stupor/coma Speech and memory problems Seizures and partial paralysis Confusion and psychosis
Describe encephalitis
Acute onset of febrile illness with mental status abnormalities with or without fever
How do you diagnose encephalitis?
LP
CRP
CT/MRI to exclude other causes
What will you see in the CSF on LP of encephalitis?
Raised WCC
Protein normal
Glucose slightly raised
How do you treat encephalitis?
Support
IV acyclovir for 10d
Anticonvulsants for seizures
What is limbic encephalitis?
Antibodies against VCKC
How do you diagnose limbic encephalitis?
MRI
Antibodies for VCKC
What two places in the CNS can an abscess form?
Brain
SC
What organisms tend to cause a brain abscess?
Strep
Bacterioids
Staph
Where can bacteria causing brain abscesses come from?
Chronic ear infection (40%)
Throat infection
Blood born
What are some symptoms of a brain abscess?
Headache Focal signs Epilepsy Raised intracranial pressure Fever N+V
How do you diagnose a brain abscess?
CT
How do you treat a brain abscess?
Treat underlying cause Aspirate Strep- Cefuroxime and metronidazole Staph- Flucloxacillin and cefuroxime Surgery Do NOT LP!!!
What should you not do to a patient with a brain abscess?
LP
What is a complication of a brain abscess?
Epilepsy
What is the most common cause of a spinal abscess?
Staph A
What are some symptoms of a spinal abscess?
Fever
Back pain
Paraparesis and/or root lesions symptoms
How do you treat a spinal abscess?
Staph- Flucloxacillin and cefuroxime
Surgery
What is myelitis?
Spinal cord inflammation
What can cause myelitis?
Varicela virus
Polio virus
What are the normal CSF values?
WCC<5
RBC<5
Protein 150-450mg/l
Glucose 60-70% blood
