INFECTIOUS DISEASES: Neuro infections Flashcards
Define meningitis
Inflammation of the meninges
Gram stain of Neisseria meningitidis?
Gram negative diplococci
PURPLE
Symptoms of meningitis?
Signs of meningitis?
Symptoms: fever, headaches, photophobia, nausea and vomiting, seizures, drowsiness,
Signs: purpuric rash (non-blanching), neck stiffness
Common bacterial causes of meningitis in 6 years - 60 years?
Neisseria meningitidis
Streptococcus pneumoniae
Causes of meningitis? (i.e which pathogen groups?)
Viral
Bacterial
Fungal
Parasitic (v rare)
Bacterial meningitis is most clinically significant form because of its high mortality and morbidity
Most common bacterial cause of meningitis in neonates (0-3m)?
Group B Streptococcus (usually contracted during birth Group B strep that live harmlessly in the vagina).
Name of special tests to look for meningeal irritation?
Kernigs test
Brudzinki’s test
Describe Kernig’s test
Lying pt on back
Flex one hip and knee to 90deg
Slowly straighten knee while keeping hip flexed at 90deg
This creates stretch in meninges. If meningitis is present = spinal pain, or resistance to movement
Describe Brudzinki’s test
Pt lays flat on back
Examiner lifts pt’s head and neck off the bed and flex pt’s chin to chest
If meningitis is present = cause involuntary flex of hips and knees.
Most common cause of meningitis in older people ?
Listeria monocytogenes
Viral causes of meningitis?
Herpes simplex virus
Enterovirus
Varicella zoster virus
Causes of non-infective meningitis?
Malignancy (leukaemia, lymphoma and other tumours)
Chemical meningitis
Drugs (NSAIDs, trimethoprim)
Sarcoidosis
Systemic Lupus Erythematosus
Behcet’s disease
Investigations for meningitis?
Nice guidelines:
- FBC
- CRP
- Coag screen
- Blood culture
- Whole-blood PCR
- Blood glucose
- ABG/VBG
- Lumbar puncture - CSF analysis (if no signs of raised ICP)
Initial management of bacterial meningitis?
2g of IV ceftriaxone (or cefotaxime) twice daily.
Add IV amoxicillin if neonate or older person
Also require dexamethasone with 1st dose
Management of meningococcal meningitis?
Management of pneumococcal meningitis?
MM: Intravenous benzylpenicillin or ceftriaxone (or cefotaxime)
PM: IV ceftriaxone
If penicillin allergic = chloramphenicol IV
Management of meningitis with non-blanching rash in community setting before hospital transfer?
IM benzylpenicillin
Complications of meningitis?
Septic shock
DIC
Coma
Subdural effusions
SIADH
Seizures
Delayed complications : Sensorineural Hearing loss (most common), cranial nerve dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
Death
Patient with TB has insidious onset of personality change and headache. Also has N&V. What is top differential?
TB meningitis
Why does pt with miliary TB need lumbar puncture?
Exclude TB meningitis
Characteristics of CSF with bacterial meningitis:
Appearance?
Protein level?
Glucose level?
WCC?
Culture?
Appearance - cloudy
Protein level - high >1g
Glucose level - low; less than half of plasma.
WCC - neutrophils, 1000+
Culture - bacteria - diplococci, Gram -ve
Characteristics of CSF with viral meningitis:
Appearance?
Protein level?
Glucose level?
WCC?
Culture?
Appearance - clear (sometimes cloudy)
Protein level - normal/slightly raised
Glucose level - 60-80% of plasma
WCC - lymphocytes, 1000+
Culture - no bacteria culture
Characteristics of CSF with TB meningitis:
Appearance?
Protein level?
Glucose level?
WCC?
Appearance - clear, slightly cloudy. Fibrin web may develop.
Protein level - high >1g
Glucose level - low
WCC - lymphocytes, 1000+
Encephalitis features?
Fever, headache, psychiatric symptoms, seizures, vomiting
Focal features e.g. aphasia
Causes of encephalitis?
HSV-1 responsible for 95% of cases in adults
Where does encephalitis typically affect?
Temporal and inferior frontal lobes
Investigations + results for encephalitis?
CSF: lymphocytosis, elevated protein
PCR for HSV
Imaging: MRI is best- medial temporal and inferior frontal changes
Imaging normal in 1/3 of pts
ECG pattern: lateralised periodic discharges at 2Hz
Managment of encephalitis?
IV aciclovir should be started in all cases of suspected encephalitis
Prognosis of encephalitis?
Prompt treatment: 10-20% mortality
Untreated: 80% mortality
Aciclovir side effects?
Generalised fatigue/malaise (common)
Gastrointestinal disturbance (common)
Photosensitivity and urticarial rash (common)
Acute renal failure
Haematological abnormalities
Hepatitis
Neurological reactions
When should you suspect encephalitis?
Sudden onset behaviour changes, new seizures and unexplained acute headache with meningism
What is Waterhouse-Friderichsen syndrome?
Complication of meningoccoal meningitis- it is adrenal insufficiency secondary to adrenal haemorrhage
What is discitis?
- infection in the intervertebral disc space.
- It can lead to serious complications such as sepsis or an epidural abscess.
Features of discitis?
Back pain
Pyrexia
Rigors
Sepsis
Neurological features: e.g. changing lower limb neurology
Causes of discitis?
Bacterial- staphyloccocus aureus
Viral
TB
Aseptic
Diagnosis of discitis?
MRI- highest sensitivity
CT guided biopsy may be required for
Treatment of discitis?
6-8 weeks of IV antibiotics (flucloxacillin for staph aureus )
Choose antibiotic based on cultures
Complications of discitis?
- sepsis
- epidural abscess
What else do you need to be aware of for discitis?
Usually due to haematogenous spread implying bacteriaemia and seeding has occured.
Consider doing an transthoracic echo as pt may have endocarditis
