CNS Infections Flashcards
Encephalopathy
Altered brain function/change in consciousness
Encephalitis
Sudden onset brain inflammation
Brain Abcess (causes)
- contiguous spread (sinus–>brain)
- hematogenous seeding (bacteremia–>brain)
- post-traumatic (injury, surgery leaving brain accessible)
- cryptogenic (idk why)
Brain Abcess (locations)
frontal-temporal>frontal-parietal>cerebellar>occipital
-multiple regions = hematogenous spread
Brain abcess (pathogens)
- streptococci, anaerobes, fungi
- NOT s. pneumo, H. influenza (they do meningitis)
Brain abcess clinical signs
- headache
- slow progressive- weeks
- focal neurologic findings, seizures (since abcess presses on brain)
- nausea/vomiting
- fever+/- (unlike meningitis, +)
- no nuchal rigidity (unlike mengitis)
Cranial Epidural Abcess
- Usually related to frontal sinus disease/osteomyelitis
- Elliptical shape (Epidural–>”E”lliptical)
Cranial Subdural Abcess
- Emergency (like subdural hematoma, also crescent moon)
- Bacteremia related
- headache/seizure common
Paraspinal abcess
- Epi/subdural
- bacteremia origin, can be contiguous spread
- S. aureus most common (most common metastatic infection in general)
Spinal Subdural Abcess
- radicular pain (999/1000 sciatica, but with further symtoms diagnose SSA)
- urinary retention
- constipation
- leg weakness
- hyperreflexia
Spinal Epidural Abcess
- Thoracic>Lumbar>Cervical
- Cord compression symptoms (radicular pain, urinary retention, constipation, hyperreflexia, leg weakness)
- Vertebral osteomyelitis common
- CSF shows Polys, elevated protein, normal/low glucose (indicating bacterial infection), can be culture -
- Posterior>anterior but presents the same
Chronic Meningitis
Can be infectious/noninfectious
Chronic Meningitis (infectious)
- TB
- cryptococcus (in immunocompromised)
- coccidioidomycosis
- histoplasmosis (mississippi r. valley)
- Lyme Disease
- Syphilis
TB-caused chronic meningitis
- PPD -
- Need high index of suspicion (recent/past/current TB infection/TB endemic area)
- CSF: high protein, low glucose, lymphocytes (unlike bacterial meningitis- PMNs)
Cryptococcus chronic meningitis
- immunocompromised patients
- stain with india ink
- Presents similar to fungal meningitis but with india ink stain
Lyme Meningitis (chronic meningitis)
- Can occur at any stage of Lyme infection (unlike syphilis- just 2º/3º)
- CSF: Nonspecific lymphocyte (protein elevated, normal glucose, lymphocytes)
- Often see uni/bilateral Bell’s Palsy, headache, disrupted thoughts
Syphilitic Meningitis (chronic meningitis)
- Common in 3º>2º syphilis, most frequent manifestation of 3º syphilis
- So suspect with Sexual history
Meningovascular syphilis
- Endarteritis Obliterans causes small vessel stroke
- See stroke symptoms but no HTN or other indicators
- Seizures
Parenchymatous Neurosyphilis
- Destruction of neurons in cortex shows PARESIS and Tabes Dorsalis
- psychiatric/neurologic issues
- PARESIS: Personality, Affect, Reflexes, Eye, Sensorium, Intellect, Speech
Tabes Dorsalis
Less common
- shooting pains
- ataxia
- sphincter disturbance
- peripheral (decreased vibration) and cranial neuropathies
- uveitis, deafness, optic neuritis/atrophy
Neurocysticercosis
- Caused by infection of Taenia Solium (pork parasite) with neural involvement
- Brain cysts cause epileptic seizures
- CSF: lymphocyte pleiocytosis (abnormal lymphocyte increase, 1000+), low glucose
Non-Infectious Chronic Meningitis (causes)
- Neoplasms
- Sarcoidosis (looks like TB meningitis but more CN neuropathy)
- Vasculitis
- Drug-induced (bactrim, NSAIDs)
Meningitis vs. Encephalitis
-Differentiate by altered mental status (E), neck stiffness (M). See fever, CSF alterations, headache in both.
Viral Encephalitis CSF
Cell count <500
- Lymphocytes, though EES and other encephalopathies can have PMNs
- RBCs>500 in HSV, California Encephalitis, Colorado Tick Fever
- Glucose normal (since viral)- if low, consider alternative
- Diagnose with PCR, serology, MRI, brain biopsy (last resort)
Herpes Simplex Encephalitis
- Clinical suspicion (signs/Hx of HSV)
- lumbar puncture/PCR for HSV1
- MRI (show medial temporal lobe involvement), brain biopsy
- Treat with acyclovir
Viral Encephalitis Etiologies
HSV CEF, CTEF St Louis Encephalitis (SLE) EEE WEE West Nile E Varicella Zoster
Rare: EBV HIV HHV-6 CMV PML (progressive multifocal leukodystrophy- JC virus)
Eastern Equine Encephalitis (EEE)
Highest mortality encephalitis
- avian reservoir
- daytime mosquito feeder (unlike most night)
West Nile Encephalitis
-Greatest in elderly
-Fever + altered mental status
CSF: elevated protein, lymphocytes, normal glucose
-Can have muscle weakness/flaccid paralysis
Non-viral Encephalitis causes
Bacteria: Listeria, salmonella, nocardia (will culture + on lumbar puncture, glucose low)
- spirochetes
- rickettsia
- parasites
- mycoplasma
- drugs
- vasculitis
- carcinomatosis (cancer metastasis)
Naegleria Fowleri
- Freshwater amoeba
- causes acute hemmorrhagic encephalitis
- CSF: looks like bacterial (low glucose, PMNs, high protein), but becomes bloody in days (from hemorrhage)
- 99% mortality
Post Infectious Encephalitis
- kids>adults
- Acute Disseminated Encephalomyelitis (demyelination but no direct infection)
- multifocal neurologic symptoms
- CSF shows inflammation
- follows viral illness (MMR, mycoplasma, varicella, EBV, influenza..)
- treat with glucocorticoids. But need to diagnose prior encephalitis to properly treat
