Infections of the CNS - Zlotnik

Question 1

What are the characteristics of normal CSF compared to bacterial and aseptic meningitis?

Answer 1

Question 2

What are the common etiologic organisms of bacterial meningitis in each age group?

Answer 2

Less than 3 months – S.agalactiae , E.Coli, L.monocytogenes
3 months – 8 years – N. meningitides, S.pneumoniae, H.Influenza
18-50 years – S.pneumoniae , N.meningitides
older than 50 – S.pneumoniae, L.monocytogenes , gram negative bacilli
impaired cellular immunity – L.monocytogenes , gram negative bacilli
head trauma, neurosurgery, or csf shunt – staphylococci, gram negative bacilli, s.pneumoniae.

Question 3

What are the signs and symptoms of meningitis?

Answer 3

• At presentation, most patients have had symptoms of meningitis for 1–7 days: fever, confusion, vomiting, headache, and neck stiffness, but the full syndrome is often not present.
• Physical examination may show fever and signs of systemic or parameningeal infection, such as skin abscess or otitis.
• A petechial rash is seen in 50–60% of patients with N. meningitidis meningitis.
• Signs of meningeal irritation are seen in approximately 80% of cases, but are often absent in the very young and very old, or with profoundly impaired consciousness.
• These signs include neck stiffness on passive flexion, thigh flexion upon flexion of the neck (Brudzinski sign;), and resistance to passive extension of the knee with the hip flexed (Kernig sign). -The level of consciousness, when altered, ranges from mild confusion to coma.
• Focal neurologic signs, seizures, and cranial nerve palsies may occur

Question 4

What is the treatment for meningitis and complications thereof?

Answer 4

Antibiotics (broad spectrum, immedately, empirically depending on age of patient)

Steroids (for edema, within an hour of admission)

AEDs (for seizures, via IV)

Other complications: hydrocephalus, SIADH, residual deafness (most common in children), coma/death.

Question 5

What are the most common etiologic pathogens in aseptic meningitis?

Answer 5

Enteroviral (80%) – echovirus & coxsackie
Mumps
HSV-2 (straight meningitis) , adenovirus , LCM , hepatitis, EBV , CMV , HSV-1 (#1 cause of US viral encephalitis-treat empirically with HSV), influenza, West Nile Virus (most common in Israel, also other Flaviviruses)

Can also be autoimmune postinfectious

Question 6

What are the 3 main findings to suspect brain abscess?

What other sequelae are there?

Answer 6

1. Progressive deterioration
2. Ring lesion
3. Fever

Do NOT perform a lumbar puncture, this will cause herniation

Sequelae: seizures, hemiparesis, cognitive decline

Question 7

What is the treatment for brain abscess?

Answer 7

1. Empirical IV antibiotic (in rare cases this is sufficient-cerebritis)
2. Drainage (CT guided stereotactic aspiration

Fatal without treatment!

30% fatality with CT

Question 8

What are the lab findings in toxoplasmosis?

Answer 8

CSF: May be normal or may have increased cells or proteins, maybe mild mononuclear pleoctosis

Give pyrimethamine and sulfadiazene empirically. Serology may or may not indicate toxoplasma infection. If patient is negative and does not respond to treatment evaluate for CNS lymphoma.