Meningitis/encephalitis Flashcards
Presentation of meningitis?
Symptoms:
- headache
- fever
- nausea/vomiting
- photophobia
- drowsiness
- seizures
Signs:
- neck stiffness
- purpuric rash
Investigations/examinations for meningitis?
Examination:
Kernig’s and Brudinski sign - these are insensitive but specific for meningitis
Investigation:
full blood count
CRP
coagulation screen
blood culture
whole-blood PCR
blood glucose
ABG
LP if no signs of raised ICP
Management for meningitis?
If in community setting = IM benzylpenicilin
Abx: in table.
Also need prophyalxis for close contacts - oral ciprofloxacin or rifampicin
Complications for meningitis?
- Septic shock
- DIC
- Coma
- Subdural effusions
- SIADH
- Seizures
- Delayed: Hearing loss, cranial nerve dysfunction, hydrocephalus, intellectual deficits, ataxia, blindness
- Death
CSF findings for viral meningitis?
Clear
Normal glucose
Mildly raised protein
Lymphocytes present
CSF findings for Fungal/ TB meningitis?
Fibrin web
Low glucose
High protein
High lymphocytes
CSF findings for bacterial meningitis?
Cloudy
Low glucose
High protein
High polymorphs - i.e neutrophils present
Positive for culture growth
Risk factors for meningitis?
Extremeties of age
Crowding
Exposure to pathogens
Immunocompromised - renal disease, DM
Sickle cell disease
IV drug users
Bacterial causes of meningitis?
Streptococcus pneumoniae (pneumococcus)
Neisseria meningitidis (meningococcus)
Haemophilus influenzae
Listeria monocytogenes (often in patients at extremes of age)
Viral causes of meningitis?
Most common = Enteroviruses such as Echoviruses, Coxsackie viruses A and B, poliovirus
Other viruses include herpes viruses:
- HSV2 (more associated with meningitis)
- HSV1 (more associated with meningoencephalitis/encephalitis, particularly affecting the temporal lobes).
- Paramyxovirus: can be a complication of mumps infection
- Measles and rubella viruses: can cause meningoencephalitis
- Varicella Zoster Virus: can be a complication of chicken pox
- Arboviruses - arthropod-borne viruses, cause meningoencephalitis
- Rabies virus - can cause meningo-encephalitis
Causes of non-infective meningitis?
Malignancy (leukaemia, lymphoma and other tumours)
Chemical meningitis
Drugs (NSAIDs, trimethoprim)
Sarcoidosis
Systemic Lupus Erythematosus
Behcet’s disease
When is IV dexamethasone not given to patients with meningitis?
When there is evidence of:
- septic shock
- meningococcal septicaemia
- immunocompromised
- meningitis following surgery
Presentation of encephalitis?
fever
headache
psychiatric symptoms
seizures
vomiting
focal features e.g. aphasia
Pathophysiology of encephalitis?
HSV-1 responsible for 95% of cases in adults
Typically affects temporal and inferior frontal lobes
Investigations for encephalitis?
CSF: lymphocytosis, elevated protein
PCR for HSV
Neuroimaging
- Medial temporal and inferior frontal changes (e.g. petechial haemorrhages)
- Normal in one-third of patients
MRI is better !
EEG - pattern shows lateralised periodic discharges at 2 Hz
Always test for HIV
