CNS Infections | Myndbook

CNS Infection

Meningitis

Encephalitis

Acute Pyogenic Meningitis

1. Neonatal meningitis; most commonly due to GBS > E. coli > Listeria

2. Meningitis in Young Children; most commonly due to Neisseria meningitidis (meningococcus), steptococcus pneumoniae (pneumococcus) & haemophilus influenzae (reduced due to HIB vaccine)

3. Meningitis in other age groups; Neisseria meningitidis (meningoccocus) & strep. pneumoniae (pneumococcus)

Aspetic Meningitis

1. Viral meningitis; commonest aetiological agent > causes mild disease

- Enteroviruses & mumps virus (if unvaccinated)

2. Tubercular meningitis; following lung infection, difficult to diagnose (no inflammation, lymphoctyic response (intracellular), detected with acid-fast bacilli

3. Cryptococcal meningitis; yeast infection, encapsulated, treated with anti fungals, usually following asymptomatic lung infection

Amoebic Meningo-Encephalitis

Rare form of meningitis, aetiology; Naegleria fowleri, sequale usually acute infection > fatality

Listeriosis

Aetiological agent; Listeria monocytogenes (deli food, loves cold storage)

Laboratory Diagnosis

Normal CSF = protein, glucose & immunological cells similar to blood

Bacterial infected CSF = high proteins, low glucose & high polymorphs

Viral/tubercular/cryptococcal = high protein, normal glucose, & high lymphocytes

Mumps Encephalitis

Commonest cause of encephalitis (prior to vaccine)

Results in mild condition

Herpes Simplex Encephalitis

Commonest cause of serious encephalitis

Sequelae involves; mental retardation, epilepsy, paralysis, deafness, blindness

Treated with; Acyclovir

Murray Valley Encephalitis

Aetiological agent; mosquitoes > water birds > serious encephalitis

Rabies

Rabid animal > bite/saliva > universally fatal encephalitis

Treatment; 1. wash wound thoroughly 2. observe animal for signs of rabies 3. receive vaccine or immunoglobulin

Polio - Paralysis

Aetiological agent; poliovirus or enterovirus > GIT infection > viraemia > CNS infection > paralysis

Treatment; "Iron lung/artificial respirator" allow for diaphragmatic breathing

Prion Disease

Infectious proteins