CNS INFECTIONS Flashcards

1
Q

types of infections?

A

bacterial
tuberculosis/fungal
viral
rickettsial

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2
Q

what is this?

Becoming less common in the developed world because of
vaccines against common types

In the U.S., main risks are in children, the elderly, and the
immunosuppressed

Clinical presentation is typically acute onset of fever, headache, and meningismus

Diagnosis confirmed by lumbar puncture, usually done after brain imaging

A

Bacterial Meningitis

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3
Q

what is this?

• Organism enters brain via hematogenous spread and
nasopharynx/cribriform plate

• May occasionally appear in epidemics

• Chills, fever, headache, nausea, emesis, stiff neck,
prostration

• Irritability at onset, then confusion, and sometimes coma

Petechial rash on skin
CSF findings
Elevated protein, reduced glucose
Gram-negative diplococci

treated with Ceftriaxone or cefotaxime are appropriate first choices and can be given IM or IV

A

Meningococcal Meningitis (Neisseria meningitidis), Acute Bacterial Meningitis

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4
Q

what is this?

Most cases in childhood (90% of cases prior to age of 5)

In adults it is most common after acute sinusitis, otitis media, skull fracture

Prognosis: fatal in 90% of infants if untreated, spontaneous recovery in adults

CSF and serum isolation of organisms

***Ampicillin, or 3rd-generation cephalosporin

A

Hemophilus Influenzae Meningitis

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5
Q

what is this?

Usually a complication of otitis media, mastoiditis, sinusitis, skull fracture, or upper respiratory infection

Alcoholics, asplenism, and sickle cell disease predispose to this

CSF: Gram-positive diplococci

penicillin, 3rd generation cephalosporin, chloramphenicol for penicillin-allergic

A

Streptococcus pneumoniae

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6
Q

what is this?

Infrequent cause of meningitis

Presentation is similar to other types of meningitis

Complication of cavernous sinus thrombosis, epidural/
subdural abscess, bacterial endocarditis, or penetrating
head trauma

Treatment is with 3rd generation cephalosporin

A

Staphylococcus meningitis

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7
Q

Focal pockets of pus caused by extension and entrapment of
focal infection, usually bacterial

Most often from sinusitis, penetrating trauma, neurosurgery, osteomyelitis of skull

A

abscess and subdural empyema

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8
Q

subacute/chronic meningitis is more common in the?

A

immunocompromised

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9
Q

what are the two types of subacute/chronic meningitis?

A

Pachymeningeal

Leptomeningeal

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10
Q

what is this, Pachymeningeal or
Leptomeningeal?

• Infection (meningitis, mycobacterium, syphilis, Lyme, viral meningitis, cryptococcus or coccidioidal meningitis, amebic
meningitis)

  • Autoimmune conditions (sarcoidosis, RA, Sjogren’s
  • Neoplasm/carcinomatous meningitis
  • Iagrogenic (LP)
  • Spontaneous intracranial hypotension
  • Subarachnoid hemorrhage
A

Pachymeningeal

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11
Q

what is this, Pachymeningeal or Leptomeningeal?

  • Infection
  • If mostly basilar: TB, listeriosis, fungi, amebic
  • Autoimmune (sarcoidosis, Behcet diseast, histiocytosis

• Neoplasm (carcinomatous meningitis or leptomeningeal
glioneuronal tumor)

A

Leptomeningeal

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12
Q

most common fungal meningitis worldwide

Common in areas in which HIV is endemic, Mortality rate 25%

More rapidly progressive in HIV patients, slower in others

Treatment: Induction with amphotericin B + flucytosine for
two weeks, then consolidation with fluconazole for 8 weeks,
then maintenance with low-dose fluconazole for 1 year

A

Cryptococcal meningitis

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13
Q

Prolonged course

Always secondary to TB elsewhere in the body, usually
lungs

Thickened meninges, particularly at the base of the brain

Subacute onset with headache, emesis, fever, irritability, insomnia, anorexia

Prodrome is 2-12 weeks

early stages, signs of mild meningeal infection, Later, papilledema

Diagnosis: CSF
Slightly cloudy (“ground-glass” appearance)
Death in 6-8 weeks
Early is better

A

Tuberculous meningitis

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14
Q

name this viral CNS infection?

Self-limited illness with signs of meningeal irritation

A

Viral (aseptic meningitis)

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15
Q

name this viral CNS infection?

Self-limited illness with signs of brain tissue involvement
such as seizures, confusion, and focal neurologic
abnormalities

A

Viral encephalitis

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16
Q

name this viral CNS infection?

both of above present

A

Meningoencephalitis

17
Q

name this viral CNS infection?

Involves any part of spinal cord with infection of neurons, or demyelination of axons

A

Myelitis

18
Q

diagnosis of viral CNS infection is done how?

A

Virus cultures, PCR (polymerase chain reaction), elevated protein and WBCs, normal glucose

19
Q

Most important cause of fatal encephalitis in the USA

PCR (polymerase chain reaction) verifies diagnosis

  • Acylovir 500 mg 5x/dy for ten days
  • Seizure control with antiepileptic
  • If cerebral edema: consider steroids
A

Herpes Simplex Encephalitis

20
Q

Destruction of anterior horn cells by polio virus, a picornavirus

A

Poliomyelitis

Treatment is supportive

21
Q

this alone, or via opportunistic infections, can cause
neurologic pathology and symptoms

Associated immunosuppression can lead to infection with
viruses (CMV, HSV, VZV, EBV, HBV), parasites (Toxoplasmosis), fungi (Cryptococcus), or rickettsial (syphilis)

A

HIV

22
Q

Treponema pallidum is a corkscrew-shaped bacterium

Primary syphilis with painless chancre

Secondary syphilis appears within a month, usually with a
diffuse maculopapular rash

Diagnosis of neurosyphilis made with lumbar puncture

Definitive diagnosis requires 1) positive serum treponemal
test results, 2) positive CSF VDR or FTA-ABS, and 3) clinical
symptoms

A

Neurosyphilis

23
Q

what is this neurosyphilis classification?

No symptoms, CSF abnormal

A

Asymptomatic

24
Q

what is this neurosyphilis classification?

Signs and symptoms of increased intracranial pressure and focal neurologic signs; if spinal, may have paresthesias, weakness, and atrophy in affected myotomes/dermatomes.
CSF abnormal

A

Meningovascular

25
Q

what is this neurosyphilis classification?

Best example is tabes dorsalis, with paresthesias/ dysesthesias, ataxia, impaired proprioception (due to leptomeningitis); paretic type, with personality changes,
convulsions, and dementia; and optic atrophy with loss of
vision

A

Parenchymatous