Viral Infections of the CNS

Question 1

what are three ways you can access the CNS?

Answer 1

olfactory route, neuronal route, and hematogenous route

Question 2

meningitis

Answer 2

inflammation of the lining of the brain. aseptic meningitis is not caused by bacteria

Question 3

encephalitis

Answer 3

inflammation of the brain tissue

Question 4

meningoencephalitis

Answer 4

widespread infection of the meninges and brain

Question 5

aseptic (sterile) meningitis

Answer 5

caused by TB, viruses, fungi, and infections near CNS. 80% enteroviruses. symptoms: mental status remains normal! headache, fever, chills, stiff neck, malaise, sore throat, nausea and vomiting, ab pain, rash, muscle pain, photophobia. diagnosis: elevated WBC in CSF. treat with supportive care, some drugs. usually benign

Question 6

brudzinski’s sign

Answer 6

neck is so stiff that the knees flex when the neck is flexed

Question 7

encephalitis causes

Answer 7

caused by influx of immune cells in brain. cerebral edema destroys neurons. intracerebral hemorrhage is distinguishing feature from meningitis

Question 8

encephalitis symptoms

Answer 8

mental status is altered! fever, headache, vomiting, photophobia, stiff neck and back, confusion, sleepiness, irritability, stumbling. unresponsiveness/coma, seizures, neuro signs.

Question 9

encephalitis diagnosis

Answer 9

inflammation in CSF. PCR is gold standard for viruses in CSF. EEF is suggestive of seizures. brain MRI or CT scan may show foci of inflammation or hemorrhage

Question 10

encephalitis treatment

Answer 10

supportive care and symptom relief. antivirals for herpesviruses, antiseizure meds, anti-inflammatories to reduce edema, sedatives.

Question 11

pathogenesis of viral CNS disease

Answer 11

death of neurons: cytolytic viruses can directly kill tissues. host factors: infants and old are more susceptible. imunosuppressed = bad. exercise may increase dissemination of viruses into CNS.

Question 12

acute disseminated encephalomyelitis

Answer 12

ADEM. postinfectious encephalitis follows viral infection by 1-2 weeks. associated with measles, mumps, VZV, influenza, parainfluenza viruses. autoimmune disorder

Question 13

herpesviruses

Answer 13

HSV-2&raquo_space; HSV-1 primary infections often cause meningitis. recurrent HSV-1 infections can cause enceph. VZV, CMV, EBV meningitis in immunosuppressed. treat HSV and VZV aggressively with acyclovir

Question 14

HSV-1 encephalitis

Answer 14

most common cause of sporadic viral encephalitis. HSV-1 in oropharynx -> trigem nerve -> CNS. recurrent HSV-1 -> trigem -> CNS. Reactivation in situ HSV-1 -> CNS. altered mental states, focal cranial nerve deficits, hemiparesis, slurred speech, stumbling, seizures, fever. PCR of CSF for HSV. MRI shows unilateral temporal lobe abnormalities

Question 15

rabies disease mechanisms

Answer 15

transmitted through saliva by bite of rabid animal or aerosols in caves populated by infected bats. replicates in muscles at bite site. incubation period of weeks to months depending on inoculum and distance of bite from central nervouse system. infects peripheral nerve and travels to brain. replication in brain causes seizures, hallucinations, hydrophobia, coma, death. spreads to salivary glands where it is transmitted.

Question 16

picornaviruses

Answer 16

enteroviruses: fecal-oral. young and old are at risk for polio. newborns at risk for coxsackievirus and enterovirus. enterovirus is more common in summer. vaccine for polio, no for other entero/rhino viruses.

Question 17

arboviruses

Answer 17

VEE, EEE, WEE

Question 18

flaviviruses that cause encephalitis

Answer 18

japanese enceph, west nile, st. louis enceph, russian spring-summer enceph, powassan virus

Question 19

WNV meningoencephalitis

Answer 19

occurs in