35 Bacterial Meningitis Steinberg Flashcards
What is Meningitis?
Inflammation of the meninges (membranous coverings of the CNS). Stiff neck and pain with neck movement. Marked pleocytosis (increased in white cells and differential)
What is Encephalitis?
Inflammation of brain parenchyma. Altered mental status (confusion, obtundation –> coma). Headache and photophobia. Mild pleocytosis
What is Meningoencephalitis?
Inflammation of the brain parenchyma with meningeal involvement. Combination of both signs and symptoms. Mild to moderate pleocytosis
What are the layers of the meningies (from outer to inner)?
Dura mater. Arachnoid. Pia mater
What is the Dura Mater?
Parchment-like membrane directly beneath and adherent to the skull
What is the Pia Mater?
Lies directly over the brain tissue
What is the Arachnoid?
Middle layer between dura and pia mater
What is the Subarachnoid Space?
CSF formed by ependymal cells in the lateral ventricles (infection of this space = meningitis). Adults : 110-160 ml
What is Vasogenic Edema?
Cytokines damage endothelial cells and BBB
What is Cytotoxic Edema?
Damage to brain cells –> increase of intracellular water
What is Interstitial Edema?
Obstruction of CSF flow and uptake
What can happen with increased intracranial pressure?
Reduced cerebral perfusion secondary to edema, (-) autoregulation. Cerebral ischemia secondary to thrombosis of meningeal vessels. Vasculitis. Direct neuronal cell damage secondary to bacterial elements, activated leukocytes, cytokines, and other inflammatory mediators
What is Brain Herniation?
Can result from increased ICP. Can result from sudden pressure change during/after LP (lumbar puncture; inserted between 3rd and 4th lumbar vertebrae)
What are the Sequelae?
Seizures. Hearing impairment. Vascular complications. Learning impairment, mental retardation. Hemiparesis, hemiplegia, paralysis, focal neurologic sensory/motor deficits. Hydrocephalus
What are the signs/symptoms of Meningitis in adults and older children?
Fever > 104 F. HA. Vomiting. Stiff neck; Kernig’s or Brudzinski’s sign. Irritability and drowsiness. Photosensitivity. Altered mental status. Focal neurologic deficits. Seizures. Coma (rare)
What are the signs/symptoms of Meningitis in infants and young children?
Any from the adults. Whimpering and crying in a high-pitched tone. Difficulty walking; lethargic, moribund. Fussiness when being held or cuddled. Arching or retracting the neck. Staring blankly at their surroundings. Reduced feeding, vomiting. Appearing pale or mottled, jaundice. Bulging fontanelle
When should a lumbar puncture be avoided?
When patient has: Cerebral infarction, Cerebral edema, Brain abscess, Hydrocephalus
What are the WBC (/mm3) counts like for the different types of Meningitis?
Bacterial (> 200-5000). Viral (< 200). Fungal/TB (100-1000)
What are the Differentials (%) like for the different types of Meningitis?
Bacterial (> 80% PMNs). Viral (> 60% mono). Fungal/TB (> 60% mono/lymph)
What is Protein (mg/dL) like for the different types of Meningitis?
Bacterial (> 150). Viral (50-150). Fungal/TB (100-200/ > 200)
What is Glucose like for the different types of Meningitis?
Bacterial (0-30). Viral (low to norm). Fungal/TB (0-30)
Which bacteria primarily cause meningitis in < 2 months of age?
GBS
Which bacteria primarily cause meningitis in 2-23 months of age?
Primarily Step. pneumoniae, some GBS and Neisseria meningitidis
Which bacteria primarily cause meningitis in 2-34 years of age?
Even amounts of S. pneumonia and N. meningitidis
Which bacteria primarily cause meningitis in 35+ years of age?
S. pneumoniae
What are some general characteristics of Meningitis caused by S. pneumoniae?
Associated w/ prior/simultaneous otitis, sinusitis, pneumoniae, bacteremia. PCV-13 will increase coverage and protection against expanding serotypes; herd immunity noted in adults. Higher rates of seizures w/ this pathogen. Associated w/ more severe sequelae than other organisms
What are some general characteristics of Meningococcal Disease caused by Neisseria meningitidis?
Usually occurs winter/spring. Five main serogroups in invasive infection (A, B (individual cases), C (epidemics), Y (pneumonia), W-135). Can be meningitis alone (good prognosis) or sepsis/septic shock (poor prognosis). No problems w/ PCN or CEPH resistance; vaccination
What is the primary serogroup of N. meningitidis in < 5 years old?
Serogroup B
What is the primary serogroup of N. meningitidis in 5-10 years old?
Serogroup B ~ Serogroups A, C, Y, W-135
What is the primary serogroup of N. meningitidis in 11+ years old?
Serogroups A, C, Y, W-135
Who has an increased risk for Meningococcal Disease?
People living in crowded conditions. Active/passive smoking teenagers. Anatomic or functional asplenia
What are the treatment options for Meningococcal Disease?
Rifampin (2 days). Ciprofloxacin (adults only; 2 days or single dose). Ceftriaxone (single dose)
What is Enteroviral Meningitis?
Estimated cause of 80% of all viral meningitis, summer prevalence. Broad range of serotypes (Coxsackievirus, Echoviruses are major causes). MAJOR cause of HA!!!
What are the principles of antibiotic treatment of meningitis?
Empiric choice dependent on age, underlying disease, or risk factors suggestive of a specific pathogen. Penetration past blood-brain barrier: lipid solubility, low MW, inflammation, pH differential, serum protein binding. Activity in purulent CSF
Which antibiotics are used when “Needs Inflammation”?
Penicillin, Ampicillin. Ciprofloxacin. 3rd-gen CEPHs. Imipenem, Meropenem. Aztreonam. Vancomycin, Daptomycin. Clindamycin. Acyclovir, Ganciclovir. Ethambutol
Which antibiotics are used “Without Inflammation”?
Chloramphenicol. Some FQs. INH, Rifampin, Pyrazinamide. Metronidazole. Trimethorpim/Sulfonamides. Linezolid. Fluconazole, Itraconazole, Voriconazole
What is always given when suspected bacterial meningitis is present, but no lab tests back yet?
Dexamethasone + Empirical therapy
What is the usual Empiric choice for meningitis?
Vancomycin + Cefotaxime/Ceftriaxone
What is the definitive choice of abx for Pneumococcus?
Pen G or Ampicillin (MIC < 0.1). Cefotaxime/Ceftriaxone (MIC 0.1-1). Vancomycin + Cefotaxime/Ceftriaxone (MIC > 2 or CEPH MIC > 1). 10-14 days
What is the definitive choice of abx for Meningococcus?
Cefotaxime or Ceftriaxone. 7-10 days
What is the definitive choice of abx for H. influenzae?
Cefotaxime/Ceftriaxone. 7-10 days
What is the definitive choice of abx for Group B Strep?
Penicillin G or Ampicillin +/- Aminoglycoside. 14-21 days
What is the definitive choice of abx for E. coli?
Cefotaxime or Ceftriaxone +/- Aminoglycoside. Minimum 21 days
What are some significant predictive factors for unfavorable outcomes of meningitis in adults?
HR > 120. CSF WBC < 100 or 100-999. Blood Cx +. Absence of petechial rash. CSF/blood glucose ratio. S. pneumoniae. Tachycardia. Lower admission GCS. Focal cerebral abnormality. ABx delay. Age. Presence of seizures. Malignancy/DM/EtOHism
What is the use of corticosteroids as adjunct to treatment like?
Used to reduce the inflammation seen in bacterial meningitis as a byproduct of increased inflammation cytokines and cell wall/membrane antigens after cell lysis. Should optimally be given prior to the first dose of the antibiotic. Absolute necessity in TB meningitis in reducing mortality
