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Bacterial Meningitis TBL
Terms in this set (76)
Bacteria enter the CNS by (4)
Colonization of the nasopharynx, traveling to CNS by blood or nerve roots; bacteremia secondary to localized source via secondary seeding of CSF; Direct extension of infection from adjacent focus; Direct inoculation by penetrating trauma
Etiology - Newborns <2 months
Group B Streptococcus, enteric gram negative bacili such as E. coli and Listeria are most common
Etiology - children and young adults
Neisseria Meningitidis, Strep pneumoniae, Haemophilus influenzae
Etiology - Older adults
Strep pneumoniae, Neisseria meningitidis, Haemophilus, and Listeria
Predisposing Condition - Asplenia or Ig deficient
S. pneumoniae, H. influenzae, N. meningitidis
Predisposing Condition - Complement deficiency
Predisposing Condition - Alcoholism, pregnancy, >50 y.o., immune compromise
Listeria monocytogenes, S. pneumoniae
Predisposing Condition - Nosocomial meningitis
Staphylococci and nosocomial gram negative bacilli such as Pseudomonas
Symptom variation - neonates and the elderly
Fever and signs of meningeal irritation may not be prominent
Assessment for meningeal irritation, evaluation of parameningeal focus, examination of skin & lymph nodes, funduscopic exam for papilledema, complete neurological exam
History (subcategories of note)
IVDU, TB exposure, animal & insect exposiure, rash (history of bulls-eye or rash with meningococcal disease)
Are steroids useful in treatment?
Dexamethasome has been shown to improve outcomes in patients with bacterial meningitis secondary to Strep pneumoniae. Must be given before or concurrent with antibiotics
Treatment - Infants
cefotaxime (for Group B Strep and enteric Gram Negative Rods) and ampicillin (for Listeria)
Treatment - Children and Young Adults
ceftriaxone (Neisseria and S. Pneumonia), vancomycin (for PCN resistant S. pneumoniae)
Treatment - Older adults
ceftriaxone (Neisseria and S. Pneumonia), vancomycin (for PCN resistant S. pneumoniae), ampicillin (Listeria)
Treatment - Immune compromised
Ceftazidime (to cover nosocomial GNRs including pseudomonas), vancomycin (PCN resistant S. pneumoniae), and ampicillin (Listeria)
Treatment - nosocomial
Ceftazidime (to cover nosocomial GNRs including pseudomonas), vancomycin(for Staph aureus including MRSA)
Empiric therapy in patients with possible encephalitis
Acyclovir to cover for Herpes Simplex Virus pending CSF results
CT should be considered prior to LP in these cases:
immunocompromise, history of CNS disease (mass lesion, stroke, seizure), papilledema, focal neurologic deficit, altered level of consciousness upon presentation
Lumbar puncture tests
Cell count with differential, glucose, protein, gram stain, and routine culture
Bacterial meningitis CSF findings
Opening pressure >200, Cell count >1000, >80% neutrophils, <45 glucose, 100-500 protein, positive gram test in 60-90%, positive culture in 80-90%
Aseptic Meningitis/Encephalitis CSF
Opening pressure normal or slightly elevated, Cell count 50-500, Lymphocyte predominant (may be neutrophil dominant in first 48 hours), normal to slightly low glucose, <200 protein (slightly high), negative gram test, negative culture
CSF guideline for bloody spoinal tap
Subtract 1 WBC per 700 RBCs and 1 mg per 1000 RBCs
Account for 85-95% of cases of aseptic meningitis in which a pathogen is identified. Includes Echovirus, Coxsacki virus, and Enterovirus(including polio)
fecal oral route; more common in late summer/early fall; more common in children
Associated symptoms of diarrhea and pharyngitis common. Exanthems, myopericarditis, conjunctivitis, pleurodynia, and herpangina (painful vesicles in pharynx). Usually self-limited; can cause severe meniningoencephalitis in neonates and those with deficient humoral imunity.
Replicates in peritonsilar lymphatics, Peyer's patches, and lamina propria of intestine. Hematogenous dissemination to the CNS.
PCR of enterovirus on CSF has good sensitivity and specificity, is test of choice. Isolation of enterovirus from throat or rectum is not diagnostic.
West Nile Virus epidemiology
Arbovirus predominantly seen in summer months when vectors (mosquitoes) are active. Life cycle is between birds and msoquitoes with humans as dead end host. Incubation 2-14 days.
West Nile Virus General Symptoms
Usually asymptomatic. Symptomatic is characterized by headache, fever, fatigue, truncal rash, adeopathy, and ocular pain.
West Nile Virus Predisposing Factors
Age >60, chronic disease (diabetes, cancer, hypertension, chronic kidney disease, solid organ transplant, alcoholism)
West Nile Virus neuroinvasive disease symptoms
<1% of infections reuslt in neuroinvasive disease. Menifestations are meningitis (25-35%) and encephalitis (60-75%); Can casue asymmetric flaccid paralysis without sensory loss (similar to polio). Death in ~10% of patients.
West Nile Virus Diagnosis
Detection of IgM in serum or CSF.
Aseptic meningitis is more likely with primary genital HSV 2 than recurrences of HSV2 or HSV1. Diagnosis is made by PCR on CSF. Acyclovir may be beneficial (recommended for primary genital HSV anyways), but symptoms usually resolve.
HSV Encephalitis General
Most common cause of sproadic, fatal encephalitis. Most cases secondary to reactivated HSV1, but HSV 2 can cause encephalitis in neonates. All opatients with acute encephalitis should be treated for HSV.
HSV Encephalitis Symptoms
Frequently involves temporal lobes with personality change, hallucinations, seizures, or aphasia.
HSV Encephalitis Radiology
MRI reveals edema and enhancement in temporal lobes
HSV Encephalitis Diagnosis
PCR for HSV has sensitivity 91% and specificity 92%
Aseptic meningitis can be aprt of Acute Retroviral Syndrome (ARS) with primary HIV infection. Because primary, HIV antibody can be indeterminate, but PCR of plasma can detect virus.
HIV - symptoms of ARS
fever, rash (erythematous maculopapular rash involving trunk and face), lymphadenopathy, pharyngitis, myalgias, and headache.
Replication of virus at site of infection with retrograde transport to CNS. Incubation 1-3 months but can be >1 year. Flu-like illness => progressive encephalomyelitis.
CNS infections that often occur in immunocompromised hosts (toxoplasmosis, cryptococcusm, PML, Mucormycosis)
Lyme Disease General
Multisystem disease caused by infection with the spirochete Borrelia burgdoferi. Transmitted by the bite of the deer tick.
Lyme Disease Symptoms
Early: fatigue, myalgias, arthralgias, headache, and malaise. Classic rash (erythema migrans) seen in 50-70% cases. Cardiac involvement characterized by heart block or myopericarditis. CNS involvement (most common is lymphocuytic meningitis) occurs in 10-15% of cases. Cranial nerve neuropathies in 50% with facial palsy most common.
Lyme Disease Time Course
Early neurological sumptioms develop 2-10 weeks post-infection.
Lyme Disease Diagnosis
Often based on clinical findings. Serological studies (IgM and IgG immunoblots) can support.
Lyme Disease Treatment
Multisystem disease caused by spirochete Treponema pallidum.
Syphilis Time Course
Primary Syphilis (chancre) 10-90 days after sexual contact; Secondary usually presents 3-6 weeks after chancre.
Secondary Syphilis Symptoms
Charactreized by rash (palm and sole). Lymphadeopathy is common. Shallow, highly contagious ulcers (condyloma lata). Lymphocitic meningitis can be seen. Untreated patients can go on to develop variety of neurological symptoms.
Syphilis Diagnosis and Treatment
Diagnosed using combination of specific and non-specific tests. Penicillin is the drug of choice for all stages.
Tuberculosis Risk Factors
Primarily reactivation. Age >65, immunosuppression, gastrectomy, pregnancy, lymphoma, DM, alcoholism, malnutrition, HIV
TB infection can be diagnosed by PPD skin testing or blood testing(QuantiFERON Gold and T-Spot) The yield on AFB culture of CSF is low and the organism can take weeks to grow. PCR on CSF for M. tuberculosis can have variable sensitivity but excellent specificity.
Humoral Defects (B cells, antibodies) are risk facotrs for:
Viruses, encapsulated bacteria
Cellular Defects (T cells, B cell help) are risk factors
Bacteria(not encapsulated), parasites, viruses, fungi
Neutrophil or Phagocyte Defects are risk factors for:
Extracellular bacteria, fungi
Disease states which confer humoral deficiency
CLL, splenectomy, Hodgkin's disease, Hypogammaglobulinemia
Disease states which confer cell-mediated deficiency
HIV, bone marrow, stem cell, or organ transplant recipients, or patients using daily corticosteroid therapy
Fungi associated with bird droppings, but also milk, fruits, and vegetables. Inhaled, followed by hematogenous dissemination
Meningitis picture with fever and headache, but meningismus is not always prominent feature.
Cryptococcal antigen in serum or spinal fluid. CSF may show findings of aseptic meningitis.
Controlling immunosuppression. Antifungals also play a role.
Progressive Multifocal Leukoencephalopathy results from reactivated JC Polyoma virus.
Subacute degeenrative brain disease leading to cognitive decline and dementia. One or more focal deficits: hemiparesis, ataxia, visual disturbances, or seizures.
CSF often unremarkable. MRI asymmetric white matter lesions which lack contrast enhancement. Diagnosis is PCR of CSF plus MRI.
Reducing immune suppression. Death generally within one year of diagnosis.
Intracellular protozoan parasite. Infection from cat feces or eating undercooked meat.
Toxoplasmosis Symptoms - Immunocompetent
Immunocompetent: non-specific ranging from flue to asymptomatic.
highly active antiretroviral therapy. Makes CNS disease due to toxoplasmosis much less likely. Now it is uncommon and seen in those with CD4 counts below 200.
Toxoplasmosis Symptoms - Immunocompromised
Encephalitis, fever is often present.
Mildly increased WBC in CSF; Imaging shows one or more ring-enahncing lesions often localized to basal ganglia or hemispheric corticomedullary junction
Fungus which lives in decaying vegetation. Infection often seen in patients with compromised neutrophil function.
Sinus pain, purulent nasal discharge, palatal erosion, CNS infection - characterized by necrosis
Made by identification of the fungal elements from sinus contents
Debridement and antifungal therapy
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