Infections of the Nervous System Flashcards
Define Meningitis
Inflammation/infection of meninges
What is the classic triad of meningitis
Fever
Neck stiffness
Altered mental status
What is the clinical features associated with meningitis
Short history of a
Progressive headache with fever and meningism
Cerebral dysfunction
Cranial nerve palsy
seizures
focal neurological deficits
Petechial skin rash
A tumbler test indicates a petechial skin rash, what does this usually indicate
Meningococcal meningitis
What is the differential diagnosis for meningitis
Infective
Inflammatory - sarcodosis
Drug induced (NSAIDs, IVIG)
Malignant
What bacterial cause meningitis
Neisseria meningitidis (meningococcus) Streptococcus pneumoniae (pneumococcus)
What virus cause meningitis
enteroviruses
Define encephalitis
Inflammation/ infection of brain substance
What is the clinical features of encephalitis
Flu like prodrome
Progressie headache with associated fever
Progressive cerebral dysfunction
seizures
focal symptoms
What is the similarities to encephalitis and meningitis
Both have classic triad of meningism symptoms but encephalitis has more brain problems and is a more prominent feature
What is the differential diagnosis of encephalitis
Infective - viral
Inflammatory
(limbic encephalits,
Acute disseminated encephalomyelitis)
Metabolic
(Hepatic, uraemic, hyperglycaemic)
malignant
(metastatic, paraneoplastic)
migraine
After seizure
What is the most common cause of encephalitis
Herpes simplex virus
What are two important antibodies causing autoimmune encephalitis
Anti VGKC (voltage gates potassium channel)
Anti NMDA receptor
What is the the investigation for meningitis
Blood cultures (bacteraemia)
Lumbar puncture (CSF culture/microscopy)
When would imaging be needed in investigating meningitis
If there was contradictions to lumbar puncture
What is the CSF finding in Bacterial meningitis
Increased opening pressusre
High cell count - mainly neutrophils
Reduced glucose
High protein
What is the CSF findings in viral meningitis
Opening pressure is normal or increased
High cell count- mainly lymphocytes
Normal glucose levels
Protein slightly increased
What occurs after CSF findings
Gram stain and culture
how is bacterial meningitis diagnosed from gram stain and culture (blood/CSF)
Gram stain shows - gram positive cocci in chains
= streptococci
Culture and check is allergic to penicillin
= streptococcus pneumonia
What is the first line treatment for suspected meningitis
IV ceftriaxone
What is the investigations for encephalitis
Blood culture
Imaging (CT scan +/- MRI)
Lumbar punture
EEG
What is first line treatment of suspected herpes simplex encephalitis
Aciclovir
How do you specifically diagnose herpes simplex encephalitis
Lab diagnosis by PCR of CSF for viral DNA
Where does herpes simplex virus lay dormant after primary infection
Trigeminal or sacral ganglion
then patients is always affected with virus becoming active again when patient is under immune pressure