Viral CNS Infections Flashcards
Two primary ways that viruses get into the CNS?
Blood and Neurons
What is meningitis?
Inflammation of the lining of the brain
What is Encephalitis?
Inflammation of the brain tissue
What is Meningoencephalitis?
Widespread infection of the meninges and brain
What is encephalopathy? Common cause?
Damage to brain tissues: Prions
What is aseptic meningitis?
Meninges are inflamed and pyogenic bacterial source is not to blame; Infectious bug cannot be determined.
What are typical causes of aseptic meningitis? What is the most common type of viral infection?
Virus, fungi, TB; Enterovirus (90%)
Describe lumbar puncture findings of aseptic meningitis
Increased WBCs but no CSF
What Tx is used for aseptic meningitis?
Not many options but few options for herpes, fungal, and mycobacterial infections
What is Brudzinski’s sign?
Lift patient’s head upward when in the supine position and knees will bend up indicating meningitis
Describe the general progression of encephalitis
Virus (generally) -> influx of immune cells in brain -> Cerebral edema destroys neurons -> Hemorrhage
What are some urgent Syx of encephalitis?
Unresponsive/Coma, Seizures/Weakness/Paralysis, Memory Loss/Flat Affect/Withdrawal/Poor Judgement
How do you diagnose encephalitis?
Spinal tap indicates inflammation in CSF, blood (possibly), PCR for viruses; EEG/MRI/CT
What is the treatment for encephalitis? If herpes?
Supportive care/Syx relief, sedate (phenytoin), anti-inflamm/reduce edema (dexamethasone); Acyclovir
What are typical complications of meningitis? Encephalitis?
Generally benign, resolve in 2 wks; Permanent neurologic ipairments to memory, speech, vision, hearing, muscle control, or sensation
What are risk factors for viral CNS infection?
- Age (older)
- Immune status (Immunoincompetent)
- Genetics (Innate resistance of viruses)
- Exercise (may increase dissemination of virus)
What is Acute Disseminated Encephalomyelitis (ADEM)?
Postinfectious encephalitis following viral infection by 1-2 wks; possibly autoimmune etiology
What are the Alphaherpesviruses?
HSV-1/2, VZV;
When can herpetic meningitis occur?
In both primary and recurrent infections
What is the most common herpes virus that causes meningitis? What are other less frequent offenders?
HSV-1/2; VZV, CMV, EBV;
Tx for herpesvirus meningitis?
Acyclovir, valaciclovir, famciclovir
Describe the dessemination of Rabies Virus. Why is this relatively easy to treat?
Inoculated within an injured site -> Replicated w/i muscle -> Travel up nerve (slowly) -> Brain; It is so slow!
How is rabies spread? What does the virus have a tropism for?
Through salivary glands! or organ transplants!
What is the transmission of picornaviruses? Who does it affect? What are two to major Picornaviruses and which one are we currently worried about? What do we have a vaccine for?
Fecal-oral; Young children (mild disease), Old children, adult (asymp - paralytic); Polio and entero; Only to Polio