Viral infection of CNS - DONE Flashcards
Encephalitis def:
Encephalitis is defined by the presence of an inflammatory process of the brain in association with clinical evidence of neurologic dysfunction
Viral encephalitis - symptoms:
- fever
- altered level of consciousness (confusion, behavioral abnormalities)
- depressed level of consciousness (lethargy, coma)
- focal or diffuse neurologic signs and symptoms
- seizures
Viral encephalitis - etiology:
Majority of cases are unknown (32%-75%)
Viral encephalitis - etiology - What are the common causes of sporadic cases?
- Herpesviruses:
- HSV-1
- VZV
- EBV
What are endemic encephalitis caused by?
arthropod-borne viruses
Viral encephalitis - diagnosis:
- MRI : is the most sensitive neuroimaging test to evaluate patients with encephalitis
- CT : with or without contrast enhancement, should be used to evaluate patients with encephalitis if MRI is unavailable or cannot be performed because of its low sensitivity
- CSF analysis is essential and should be performed (unless contraindicated) in all patients with encephalitis.
What is the most sensitive neuroimaging test to evaluate patients with encephalitis?
MRI
Viral encephalitis - diagnosis - findings:
- Focal findings in a patient with encephalitis should always raise the possibility of HSV encephalitis:
- 80% will have abnormalitis in the temporal lobe.
- Normal MRI does not exclude the HSV etiology:
- 10% of patients will have no abnormalitis on MRI
Viral encephalitis - diagnosis - Electroencephalography (EEG)
- rarely helpful in establishing an etiology in patients with encephalitis
- has a role in identifying patients with non-convulsive seizure activity who are confused, obtunded, or comatose
- should be performed in all patients with encephalitis
persistent neutrophilic pleocytosis has been observed in…..
patients with West Nile virus encephalitis.
Nucleic acid amplification tests example:
PCR
Viral encephalitis - empirical treatment:
acyclovir should be initiated in all patients with suspected viral encephalitis, especially if focal features are present
Viral encephalitis -treatment - Empirical therapy
- acyclovir should be initiated in all patients with suspected viral encephalitis, especially if focal features are present
Viral encephalitis -treatment - Supportive therapy:
- careful monitoring of ICP
- antipiretics
- anticonvulsant drugs
- prophylaxis of aspiration pneumonia, stasis ulcers, decubiti, deep venous thrombosis
What is the treatment of choice for patients with herpes simplex encephalitis?
acyclovir
Acute viral meningitides:
Inflammation caused by infection is limited to meninges.
Patients with Acute viral meningitides have:
- no signs of altered consciousness
- no seizures
- no focal neurologic symptoms
Acute viral meningitides - symptoms:
- headache- often in frontal or retro-orbital area
- photophobi
- pain on moving the eyes
- signs of meningeal irritation, mostly neck stiffness
- fever
- malase, mialgia
- nausea and vomiting
Acute viral meningitides - etiology:
Enteroviruses (including echoviruses and coxsackieviruses) are the most common cause, more than 85%
What is probably the 2nd cause of viral meningitides?
HSV-2
- about 5% of cases
Most cases of recurrent viral/aseptic meningitis (Mollaret’s meninigitis) are due to…..
HSV
When should VZV be suspected?
VZV should be suspected in the presence of concurrent chickenpox or shingles
EBV:
- may be accompanied by symptoms of infectious mononucleosis
- presence of atypical lymphocytes in peripheral blood and CSF should suggest this etiology
HIV:
- should always be suspected in patients with meningitis
- may follow primary infection in 5-15% of cases
MUMS:
- may be accompanied by symptoms of infectious mononucleosis presence of atypical lymphocytes in peripheral blood and CSF should suggest this etiology
- documented history of previous infection excludes this diagnosis
Viruses with high seroprevalence rate:
- HSV
- VZV
When is neuroimaging studies (MRI) not necessary?
In patients with uncomplicated viral meningitidis neuroimaging studies (MRI) are not necessery
Viral meningitis - treatment:
- Symptomatic:
- analgesics
- antipyretics
- antiemetics
- Acyclovir in HSV or VZV meningitis
- Antyretroviral treatment in HIV meningitis