1 / 39

CNS Infections

CNS Infections. 11-23-04 Chapter 235. Bacterial Meningitis. Epidemiology. 400 per 100,000 in neonates 1-2 per 100,000 in adults S pneumoniae & N meningitidis m/c HIB vaccine has been very effective Mortality 5% in children beyond infancy 25% in neonates and in adults. Pathophysiology.

issac
Download Presentation

CNS Infections

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CNS Infections 11-23-04 Chapter 235

  2. Bacterial Meningitis

  3. Epidemiology • 400 per 100,000 in neonates • 1-2 per 100,000 in adults • S pneumoniae & N meningitidis m/c • HIB vaccine has been very effective • Mortality • 5% in children beyond infancy • 25% in neonates and in adults

  4. Pathophysiology • S. pneumonia and N. meningitidis (and H. influenzae) are encapsulated which provides them with increased ability to invade BBB • Upper airway bloodstream subarachnoid space subcapsular constituents trigger inflammation fever, meningimus, change in MS brain/meningeal edema decreased CSF drainage hydrocephalus increased ICP ICP>CPP

  5. Clinical Features • 25% of adult cases “classic” • Rapid development of • Fever • HA • Stiff neck • Photophobia • Change in MS • Nonspecific signs/symptoms in very young/old • 25% will develop seizures

  6. Clinical Features • History • Living conditions • College dorm/barracksN meningitidis • Trauma • Recent neurosurgeryStaph/gram(-) rod • Immunocompetence • Immunization hx • NoneHiB • Antibiotic use

  7. Clinical Feratures • Physical Exam • Brudzinski • Passive neck flex hips & knees flex • Kernig • Flex hip, ext knee hamstrings contract • Skin • Purpura • Petechiae/splinter hem, pustular lesionsmicroemboli • Fundi • Neuro Exam

  8. Diagnosis • Parenchymal • CT is the imaging of choice • Brain abscess, encephalitis, toxoplasmosis • Meningeal • Lumbar puncture • Neoplasm, CNS vasculitis, SAH

  9. Diagnosis

  10. Diagnosis • An aseptic profile • Must think about… • Partially treated bacterial infection • Bacterial infections adjacent to the subarachnoid space

  11. Diagnosis • Tests to order on the CSF • Tube #1 cell count with diff • Tube #2 protein,glucose • Tube #4 cell count with diff, gram stain/culture • Tube #3 • Viral cultures • Borrelia (lyme disease) • India ink/cryptococcal antigen (immunocomp) • Acid fast stain/culture for mycobacteria (TB) • Latex agglutination for bacterial Antigens • PCR • Herpes, arbovirus

  12. Lumbar Puncture • Contraindications • Infection in overlying skin • Relative • Coagulopathy • Thrombocytopenia • If delay is anticipated obtain blood cultures and GIVE antibiotics • You have 2 hours after ATB given before sensitivity is effected

  13. Lumbar Puncture • Considerations for not obtaining CT before performing LP • Age <60 • Immunocompetent • No h/o CNS disease • No recent seizure (<1week) • Normal sensorium & cognitition • No papilledema • No focal neuro deficits

  14. Treatment • First priority • Antibiotics • Second priority in some cases • Anti-inflammatories • Third priority • Counter the adverse effects of increased ICP & vasculopathy

  15. Emperic Antibiotics

  16. Emperic Antivirals • Concern of herpes • Acyclovir 10mg/kg IV Q 8 hours

  17. Steroids • Dexamethasone • 10mg IV 15 minutes prior to antibiotics • Shown to decrease M&M in S. pneumoniae but NOT N. meningitidis • N Engl J Med 2002; 347:1549-1556, Nov 14, 2002.

  18. Complications • Seizures • Hyponatremia • SIADH • CVA • Coagulopathies • Cognitive deficits, epilepsy, hydrocephalus, hearing loss affect 25% of survivors

  19. Chemoprophylaxis • Household/school/daycare contacts last 7 days • Direct exposure to secretions • Kissing, sharing utensils/toothbrushes, mouth to mouth, intubation without a mask • First line: rifampin 10mg/kg (max dose 600mg) Q12h x 4 doses • Alternative: ceftriaxone, cipro, sulfisoxazole

  20. Viral Meningitis

  21. Viral Menigitis • 85% secondary to • Echo- • Coxsackie • Entero- • Also consider HSV, and EBV • Neutrophils may predominate in the CSF in the first 24 hours • Consider starting ATB’s until cultures come back (-)

  22. Viral Encephalitis

  23. Viral Encephalitis • Infection of brain parenchyma • Presents of neurological abnormalities distinguish it from meningitis

  24. Epidemiology • Incidence is 1/10 of bacterial meningitis • HSV-1, zoster, EBV,CMV, rabies, arbo • Arbo • LAC (La Crosse)-diagnosed most frequently • SEE(St Louis)-20% mortality in elderly • WEE(Western)- causes seizures in 90% of infected infants, permanent neuro deficits in 50% • EEE(Eastern)- most devastating, mortality 70% • WNV(West Nile)

  25. Pathophysiology • Portals of entry • Arbo-transmitted by mosquitoes, ticks • Rabies-bite by infected animal • Hematogenous dissemination v. travel backwards on axons (HSV,HZV,rabies) • Dysfunction & damage caused by disruption of neural cell function & inflammation

  26. Pathophysiology cont. • Gray matter predominately affected • Cognitive/psychiatric signs, lethargy, seizures • White matter affected in post-infectious encephalomyelitis

  27. Clinical features • New psych symptoms • Cognitive deficit (aphasia, amnesia, confusion) • Seizure • Movement d/o

  28. Diagnosis • MRI-more sensitive than CT • CT • EEG • LP-findings consistent with aseptic meningitis

  29. Differential • Exclude the killers • Bacterial meningitis & SAH • More meningeal symptoms • Lyme, TB, fungal, bacterial, viral, neoplastic • More parenchymal symptoms • Abscess, bacterial endocarditis, post-infectious encephalomyelitis, toxic or metabolic encephalopathy

  30. Treatment • HSV: acyclovir 10mg/kg IV • CMV: ganciclovir • Rabies/EEE/HSVdevastating & usually fatal or residual deficits

  31. Brain Abscess

  32. Brain Abscess • Focal pyogenic infection • Pus-filled cavity ringed by granulation tissue & outer fibrous capsule surrounded by edematous brain tissue

  33. Epidemiology • Paranasal sinus focus • 10-30 y/o • Otic • Bimodal: <20 y/o & >40 y/o

  34. Pathophysiology • Hematogenous spread • 1/3 of cases • Contiguous (middle ear, sinus, teeth) • 1/3 of cases • Otogenic (Bacteroides)temporal lobe/cerebellum • Sinogenic & odontogenic(anaerobic & microaerophilic streptococci)frontal lobe

  35. Clinical Features • Classic triad • HA, fever, focal deficit • <1/3 of cases • Toxic appearance is rare • Seizures, vomiting, confusion, obtundation possible • Frontal lobe-hemiparesis • Temporal lobe- homonymous superior quadrant visual field deficit or aphasia • Cerebellum-limb incoordination or nystagmus

  36. Diagnosis • CT with contrast • LP contraindicated • Biopsy or aspiration for confirmation

  37. Treatment

  38. Questions • 1. CSF analysis returns with the following values: glucose 20 WBC 1200 Protein 300. This profile is consistent with • A. Bacterial meningitis • B. viral meningitis • C. Fungal meningitis • 2. Which of the following is an absolute contraindication to performing an LP • A. Coagulopathy • B. Infection of the overlying skin • C. thrombocytopenia

  39. Questions • 3. T/F Steroids have been shown to decrease morbidity & mortality in meningitis caused by Strep pneumo • 4. T/F Brain abscesses are confirmed by LP. • 5. Which antibiotic regimen should be initiated in an immunocompromised patient suspected of having bacterial meningitis without any allergies • A. Pen G • B. Ceftriaxone & vanco • C. Vanco, gent, & ceftazidime • Answers: 1. A 2. B 3. T 4. F 5. C

More Related