CNS Infections Flashcards
Tuberculous meningitis - etiology
hematogenous spread from pulmonary source
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
typical course of TB meningitis
subacute/chronic, insiduous presentation with prolonged prodrome of malaise and nonspecific constitutional symptoms
CSF findings in TB meningitis
- LYMPHOCYTE predominance
- glucose very low
- acid fast bacilli on gram stain (consider PCR stain)
presentation of tuberculoma
headache
focal neuro signs
seizures
- can calcify, variable enhancing on imaging and can be assoc with hydrocephalus
Pott disease
tuberculous infection of the spine
CF of Pott disease
fever and back pain
- if it extends into epidural space, can lead to subacute spinal cord or cauda equina compression
how can you differentiate Pott disease from metastatic cancer
Potts disease usually spread through disk spaces to adjacent vertebral bodies
how can Lyme dz affect CNS? (3)
meningitis
cranial nerve palsies
polyradiculopathy
how do you diagnose Lyme dz
serology tests of blood and CSF
CSF profile in Lyme dz
lymphocytic pleocytosis with elevated protein and normal glucose
early neurologic manifestations of Lyme dz
aseptic meningitis, facial nerve palsy or both, within weeks after infection
later neurologic manifestations of Lyme dz
leukoencephalopathy, painful polyradiculopathy or both, months after infection
tx of Lyme dz (CNS involvement)
isolated facial n. palsy w/ negative CSF –> oral antibiotics; if more disseminated, IV antibiotics
MCC of viral meningitis
enteroviruses, i.e. Coxsackie virus, arboviruses (West Nile)
CSF profile in viral meningitis
lymphocytic predominance
elevated protein w/o lower glucose
gram stain and culture unrevealing
Tx. viral meningitis
supportive care, unless HSV1 is suspected
presentation of encephalitis
headache fever altered LOC seizures focal neuro deficits
where does HSV1 love in the brain?
base of the brain, esp. medial temporal lobes and orbitofrontal regions of cortex
common clinical presentation of HSV1 encephalitis
limbic dysfunction - complex partial seizures, olfactory hallucinations and memory disturbances (profound anterograde amnesia)
CSF in HSV1 encephalitis
elevated RBC count and leukocytosis
EEG findings in HSV1 encephalitis
periodic epileptiform discharges over one or both temporal regions
Tx. HSV encephalitis
IV acyclovir
definitive dx of HSV1 encephalitis
PCR of CSF - takes few days to get back so start acyclovir if you have high clinical suspicion
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
