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38 Cards in this Set
- Front
- Back
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Describe 4 factors that influence antibiotic transfer across BBB
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-Inflammed meninges
-Lipophilicity -Low molecular weight -Low protein binding -Nonionized at physiologic or pathologic pH |
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How can drugs with poor penetration into the CSF be given?
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All invasive procedures:
-intrathecally (spinal column) -intracisternally (subarachnoid space) -intraventricularly (ventricles)(requires placement of reservoir) |
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Symptoms of bacterial meningitis in adults
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-fever/chills
-photophobia -Severe HA -Nuchal rigidity -Decreased mental status -Stiff neck or back Other symptoms (less common) -Irritability -Delirium -Lethargy -Coma -Seizure (less likely in adults) |
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Kernig's sign
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When patient is supine and the thigh is flexed to a right angle, complete extension of the leg is impossible
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Brudzinski's sign
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-passive flexion of the leg on one side results in similar movement in the opposite leg
-involuntary flexion of the knees and higs following flexion of the neck while supine |
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Symptoms of bacterial meningitis in infants
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-Irritability
-Altered sleep patterns -Vomiting -Decreased oral intake -Seizures -Apnea -Purpuric rash -Seizures |
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Symptoms of bacterial meningitis in children
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-Change in activity level
-Somnolence -Confusion -Lethargy -Apnea -Purpric rash General symptoms = missed diagnosis |
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Describe the composition of normal CSF
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-Normally clear
-Protein content <50 mg/dL -[Glucose] is about 50-66% of the simultaneous peripheral serum [] -pH 7.4 -WBC <5 cells/mm3 (all types) Obtain from lumbar puncture |
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Composition of the CSF when the meninges are inflamed due to bacterial meningitis
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-Cloudy/turbid
-WBC 1000-5000 cells/mm3 (increased) -Differential: >80% PMNs -Protein: 100-500mg/dL (>100) -Glucose: <60% blood glc (decreased []) |
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Describe 4 factors that influence antibiotic transfer across BBB
|
-Inflammed meninges
-Lipophilicity -Low molecular weight -Low protein binding -Nonionized at physiologic or pathologic pH |
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How can drugs with poor penetration into the CSF be given?
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All invasive procedures:
-intrathecally (spinal column) -intracisternally (subarachnoid space) -intraventricularly (ventricles)(requires placement of reservoir) |
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Symptoms of bacterial meningitis in adults
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-fever/chills
-photophobia -Severe HA -Nuchal rigidity -Decreased mental status -Stiff neck or back Other symptoms (less common) -Irritability -Delirium -Lethargy -Coma -Seizure (less likely in adults) |
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Kernig's sign
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When patient is supine and the thigh is flexed to a right angle, complete extension of the leg on the thig is impossible
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Brudzinski's sign
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-passive flexion of the leg on one side results in similar movement in the opposite leg
-involuntary flexion of the knees and higs following flexion of the neck while supine |
|
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Symptoms of bacterial meningitis in infants
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-Irritability
-Altered sleep patterns -Vomiting -Decreased oral intake -Seizures -Apnea -Purpuric rash -Seizures |
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Symptoms of bacterial meningitis in children
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-Change in activity level
-Somnolence -Confusion -Lethargy -Apnea -Purpric rash General symptoms = missed diagnosis |
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Describe the composition of normal CSF
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-Normally clear
-Protein content <50 mg/dL -[Glucose] is about 50-66% of the simultaneous peripheral serum [] -pH 7.4 -WBC <5 cells/mm3 (all types) Obtain from lumbar puncture |
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Composition of the CSF when the meninges are inflamed due to bacterial meningitis
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-Cloudy/turbid
-WBC 1000-5000 cells/mm3 (increased) -Differential: >80% PMNs -Protein: 100-500mg/dL (>100) -Glucose: <60% blood glc (decreased []) |
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What 4 organisms are responsible for causing MOST cases of bacterial meningitis?
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-Neisseria Meningitidis (adult)
-Streptococcus Pneumoniae (highest mortality) -Hemophilus Influenzae -Gram (-) organisms |
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Factors affecting Lumbar Puncture
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-If patient has received multiple doses of Abx before LP, it may come back negative
-If patient has only received 1-2 doses, LP may show bacteria -Takes about 24-48 hours after Abx admin for LP to come back negative -Never hold Abx to obtain LP - begin emperic tx |
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Rationale for using adjunctive dexamethasone therapy
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-Inflammation is major factor contributing to morbidity and mortality
-Inflammation is poorly tolerated in the CNS -Dexamethasone controls the inflammatory response and inhibits cytokine production |
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Effect of decreased inflammation in meningitis
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Decreased neuronal consequences
-cerebral edema -intracranial pressure -change in cerebral blood flow -neuronal injury |
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Role of cytokines in neuronal injury
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-induce inflammation
-directly toxic to neurons -stimulate entry of WBC into subarachnoid space -Increase permeability of BBB -Increased [] = Increased severity |
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What patients should received the dexamethasone therapy
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*Adults - give for all types of bacterial meningitis
*Children > 1 month - give for all types of bacterial meningitis in high-income countries w/ good access to services *Neonates (<1 month) - Do NOT give b/c no available data |
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What are the doses for dexamethasone therapy
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*Adults - 10mg IV Q6 x 4 days or 0.6mg/kg/Qday divided Q6 x 4 days
*Children - 0.6mg/kg/Qday divided Q6 x 4 days |
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Dexamethasone therapy basics
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*Give before Abx or with b/c Abx kill cells and release inflammatory products
*Controls the inflammatory response *Inhibits cytokine production *Cant reverse any damage... can only prevent |
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Why might dexamethasone therapy be harmful in some pts with pneumococcal meningitis?
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*PCN or CPN-resistant penumococcal meningitis requires treatment with vancomycin
*Vanco is big fat molecule that requires inflammed meninges in order to cross BBB *Dexamethasone reduces inflammation and may delay CSF sterilization *Ceftriaxone is not affected |
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What additional therapy can be used for pneumococcal meningitis that is being treated with vancomycin?
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*Higher dose of vanco is 1st line
*If bacteria are susceptible to rifampin, add this to the tx with a 3rd gen cephalosporin |
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What is meropenum
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*Brand name = Merrem
*Broad spectrum carbapenem *B-lactam Abx *No MRSA/E or enterococcus coverage *PCN allergy cross sensitivity exists but can use if reaction was just a rash... CI if developed urticaria or anaphylaxis |
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What is the advantage of meropenum over imipenum
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-Imipenum can cause seizures especially if the dose has not been adjusted for renal function
-Seizures can occur in pts regardless (2-30%) |
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What form of meningitis may present with petechiae
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*Petechiae = purpuric rash
*Caused by N. meningitidis *~50% have purpuric lesions, petechiae or both *Can cause immune reaction manifested as fever and arthritis |
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What type of antibiotic is ceftriaxone?
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*3rd Gen CPN
*Cross sensitive with PCN and carbapenum allergies *Mod to good coverage of G(+) with expanded G(-) but no pseudomonas coverage *Unique elimination via the bile which does not require renal dose adjustments |
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What is the concern with ceftriaxone
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Biliary sludging
*precipitated calcium salt *leads to biliary obstruction *secondary to high dose or prolonged tx *usually reversible upon D/C *more common with children |
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Cefotaxime
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*acceptable for <1 month
*no problem with biliary sludging |
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Ceftriaxone and Calcium
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-cant be admin w/in 48 hours
-IV solutions -will cause biliary sludging and possible obstruction |
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Red Man Syndrome
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*Also known as Red Neck Syndrome
*sudden and/or profound hypotension *with or without a maculopapular skin rash on face, neck, chest, and extremities (will subside several hours after completion of infusion) *occurs within a few minute of starting the infusion or nears its completion *may be mistaken for an allergic or anaphylactoid reaction |
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Red Man Syndrome
Management |
*stop or slow vancomycin infusion
*IV diphenhydramine 50mg stat which can be given prophylactically to prevent syndrome *bolus IV fluid and/or vasopressor if needed |
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Red Man Syndrome
Prevention |
*must monitor BP while admin vancomycin
*slowly adminster dose over one hour *give prophylactic antihistamine |
