CNS infections Flashcards
What is meningitis
Inflammation of the meninges
What is route of infection of meningitis
Blood borne
Parameningeal suppuration
Direct spread through deject in dura such as post surgery, trauma
Direct spread through the cribriform plate
Symptoms of meningitis
Headache Neck and back stiffness Nausea and vomiting Photophobia Fever sometimes Rash petechial/purpuric
What is a purple rash/ petechial a sign of
Meningococcal but also streptococcal.
Sepsis and enteroviral infection
How is meningeal irritation tested for
Kernig’s positive due to hamstring spasm
Neck stiffness
Brudzinskis sign- flexing the patient’s neck causes flexion of the patient’s hip and knees
Photophobia
Symptoms of meningitis in infants
flaccid Bulging fontanelle due to ICP fever and vomiting often only sign Strang cry Convulsions
How to diagnose meningitis
When are the contraindications of this
get sample of CSF (puncture in lumbar space) and see if there is a high white cell count
contraindications: risk of herniation. Do a CT instead if there is raised inter cranial pressure
- raised inter cranial pressure detected by::
- -> drowsy, fitting , focal neurology
- ->risk of bleeding (abnormal clotting)
Cause of high white cell count in CSF
Inflammatory cause. Usually infective
Which bacteria cause meningitis
Neisseria meningitis
Strep pneumonia
Haemophilus infulenzae type b
Group b streptococci
Scherichia coli
Listeria monocytogenes
Causes of lymphocytic/mononuclear CSF (aseptic meningitis)
TB
Partially treated bacterial infection
Intercranial abbess
Spirochaetes
- leptospirosis
- lyme borreliosis
- syphilis
viral meaning-encephalitis
Lymphocytic leukaemias
Rapid diagnostic test for meningitis
Gram stain
Zn (TB few organisms present)
PCR (meningococcal and pneumococcal. TB)
Antigen agglutination tests (crypto coccus)
What are predisposing factors for pneumococcal meningitis
Immunosuppression Alcohol Diabetes Hyposplenism (spleen taken out) Myeloma
who is likely to get listeriosis
> 50
Neonates
Pregnant women
What does listeriosis do and how can you treat it
Meningo-encephalitis, brainstem with ataxia and movement disorders
Amoxicillin and/or gentamicin
Complications of meningitis
Death Empyema cebebral vein thrombosis Hydrocephalus Deafness Convulsions Visual/motor/sensory deficit
How to treat meningitis
High dose Antibiotics which can cross BBB
Adequate oxygenation
Prevention of hypoglycaemia and hyponatraemia
Anticonvulsants
Decrease inter cranial pressure
What can be given prior to antibiotics to treat meningitis for beneficial effect
Dexamethasome
What is encephalitis
Inflammation of brain
What is myelitis
Inflammation of spinal cord
What is neuritis
Inflammation of peripheral nerves
What can cause neuritis
Post infectious GBS
- campylobacter
- mycoplasmna pneumonia
- herpes
toxins
- diptheria
- tetanus/botulism
Signs of encephalitis and its definition and its diagnostic criteria
altered level of consciousness, cognition, behaviour or personality persisting for more than 24h. more than 2 of the following:
- Fever or history of fever
- Seizures and or focal neurological findings
- > 4 WBC
- EEG findings compatible
- Abnormal results of neuro imaging (evidence of brain parenchyma involvement)
Irritibility,
Altered personality
Drowsiness
Ataxia (slurred speech, stumbling, incoordination, falling. It is caused by damage to cerebellum)
Excessively brisk tendon reflexes
Signs of cerebral/brainstem failure (sluggish pupil reflexes)
Signs of brain swelling e.g. focal neurological signs
How to treat HSV encephalitis
IC Aciclovir (high dose for 2-3 weeks)
