CNS Infections Flashcards by Magda Kazmierczak

Tuberculous meningitis - etiology

hematogenous spread from pulmonary source

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what area of meninges does TB have a predilection for

basal meninges (at base of brain)

presents with CN palsies
hydrocephalus
brain infarct from inflammation around cerebral vessels

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typical course of TB meningitis

subacute/chronic, insiduous presentation with prolonged prodrome of malaise and nonspecific constitutional symptoms

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CSF findings in TB meningitis

LYMPHOCYTE predominance
glucose very low
acid fast bacilli on gram stain (consider PCR stain)

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presentation of tuberculoma

headache
focal neuro signs
seizures
- can calcify, variable enhancing on imaging and can be assoc with hydrocephalus

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Pott disease

tuberculous infection of the spine

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CF of Pott disease

fever and back pain

- if it extends into epidural space, can lead to subacute spinal cord or cauda equina compression

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how can you differentiate Pott disease from metastatic cancer

Potts disease usually spread through disk spaces to adjacent vertebral bodies

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how can Lyme dz affect CNS? (3)

meningitis
cranial nerve palsies
polyradiculopathy

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how do you diagnose Lyme dz

serology tests of blood and CSF

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CSF profile in Lyme dz

lymphocytic pleocytosis with elevated protein and normal glucose

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early neurologic manifestations of Lyme dz

aseptic meningitis, facial nerve palsy or both, within weeks after infection

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later neurologic manifestations of Lyme dz

leukoencephalopathy, painful polyradiculopathy or both, months after infection

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tx of Lyme dz (CNS involvement)

isolated facial n. palsy w/ negative CSF –> oral antibiotics; if more disseminated, IV antibiotics

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MCC of viral meningitis

enteroviruses, i.e. Coxsackie virus, arboviruses (West Nile)

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CSF profile in viral meningitis

lymphocytic predominance
elevated protein w/o lower glucose
gram stain and culture unrevealing

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Tx. viral meningitis

supportive care, unless HSV1 is suspected

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presentation of encephalitis

headache
fever
altered LOC
seizures
focal neuro deficits

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where does HSV1 love in the brain?

base of the brain, esp. medial temporal lobes and orbitofrontal regions of cortex

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common clinical presentation of HSV1 encephalitis

limbic dysfunction - complex partial seizures, olfactory hallucinations and memory disturbances (profound anterograde amnesia)

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CSF in HSV1 encephalitis

elevated RBC count and leukocytosis

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EEG findings in HSV1 encephalitis

periodic epileptiform discharges over one or both temporal regions

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Tx. HSV encephalitis

IV acyclovir

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definitive dx of HSV1 encephalitis

PCR of CSF - takes few days to get back so start acyclovir if you have high clinical suspicion

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MCC of fungal meningitis

cryptococcus

how does one get cryptococcal meningitis?

more likely if you have HIV/AIDs but maybe if you are healthy and if you inhale soil and pigeon droppings, it can disseminate hematogenously

CSF profile in fungal meningitis

lymphocytic predominance of WBCs elevated protein low glucose

Dx. of cryptococcal meningitis

India ink stain of CSF | now --> rapid latex agglutination assay for cryptococcal antigen

where do toxoplasmosis lesions love to go?

basal ganglia or at gray-white matter junction

differential of toxoplasmosis like lesions

CNS lymphoma

management of suspected toxoplasmosis

empiric anti-toxo therapy --> if lesions dont improve with this, consider brain biopsy for definitive diagnosis

MC parasitic infection of the CNS

neurocysticercosis

neurocysticercosis on imaging

multiple cystic lesions which can be ring-enhancing or calcified with surrounding edema

tx of neurocysticercosis

albendazole IV steroids anticonvulsants

clinical presentation of HIV dementia

subcortical dementia with cognitive impairment and psychomotor slowing

MRI findings in HIV dementia

patchy T2 hyperintensity in white matter as well as cerebral atrophy

vacuolar myelopathy - what does it resemble?

vit B12 deficiency (subacute combined degeneration)

CF in vacuolar myelopathy

- posterior column signs with loss of vibration and proprioception with sensory ataxia - corticospinal tract dysfunction bilaterally (spasticity, hyperreflexia)

PML

demyelinating dz of CNS caused by infection oligodendrocytes with JC virus --> result of prolonged immunosuppression (HIV or medications)

MRI in PML

patchy non-enhancing foci of T2 hyperintensity within subcortical white matter

Fever and mental status changes equal...

CNS infection unless proven otherwise

What can bacteria cause in CNS?

Meningitis, empyema, abscess

What can viruses cause in CNS?

Meningitis, encephalitis

What can fungi cause in CNS?

Meningitis

MCC of bacterial meningitis in neonates and elderly

Group B strep E.coli Listeria

MCC of bacterial meningitis in toddlers

H.influenza (recently decreasing due to vaccination)

MCC of bacterial meningitis in teenagers

N.meningitidis

MCC of bacterial meningitis in adults

Strep pneumoniae

Clinical signs of bacterial meningitis

``` Headache Fever Neck stiffness Mental status changes - delirium - usually there's a prodrome flu-like feeling ```

Complications of acute bacterial meningitis

Cortical vein thrombosis and stroke Seizures Increased ICP and herniation

CSF profile in acute bacterial meningitis

``` High WBC (>1000, mostly PMNs) Decreased glucose (<40) Increased protein High opening pressure Positive gram stain or culture ```

When should you order a CT scan before performing LP in meningitis?

Papilledema on fundoscopic exam Focal neurologic signs Non communicating hydrocephalus

Tx of bacterial meningitis

IV antibiotics: vancomycin and ceftriaxone Ampicillin if concerned about Listeria Corticosteroids in children or strep pneumoniae in adults (given a few minutes before antibiotics)

MCC of viral meningitis

Enteroviruses - polio, coxsackie, echo Arbovirus Herpes simplex

Sx of viral meningitis

Fever Bad headache Mildly stiff neck - no mental status changes

CSF profile in viral meningitis

WBC < 1000: mainly lymphocytes Normal glucose Slightly elevated protein Pressure not as high

Tx of viral meningitis

Acetaminophen and other symptomatic treatment

Types of chronic (basilar) meningitis

Fungal - cryptococcus | Mycobacterium tuberculosis

Symptoms of chronic meningitis

Headache Low grade fever Confusion - last for few weeks and are non specific

CSF profile in chronic basilar meningitis

WBC < 1000: mainly monocytes Glucose very low Protein elevated

Tx of cryptococcal meningitis

Amphotericin

Tx of TB meningitis

Triple therapy

Complications of basilar meningitis

Visual and hearing complications (pooling of pus in base of brain)

CSF profile of HSV encephalitis

``` Lymphocytic pleocytosis Mildly elevated protein Normal glucose Negative gram stain and culture RBC present (hemorrhagic encephalitis) ```

What cells of CNS does HIV primarily infect

Macrophages and microglia