Meningitis

Western Diagnosis: A. infl of meninges of brain or spinal cord B. cerebral sx of bacterial invasion - cerebritis C. cerebral sx of viral invasion - encephalitis D. bacteria cause acute meningitis E. virus cause acute aseptic meningitis

=Acute Bacterial Meningitis=

Etiology
1. **Neisseria meningitidis - meningococcus** ---most in 1st yr of life ---epidemics in closed populations 2. **Hemophilus influenza type b** ---decreased incidence due to immunizations ---most in children > 1 month old ---not in adults unless head trauma or immune compromise 3. **Streptococcus pneumoniae - pneumococcus** ---most common in adults ---alcoholics, chronic otitis, sinusitis, mastoiditis, pneumococcal pneumonia, sickle cell disease, asplenism, closed head injury 4. **hematogenous spread or direct communication with exterior**

Signs & Symptoms
1. uri 2. fever, HA, stiff neck, vomiting 3. desperately ill within hours 4. irritability, confusion, drowsiness, stupor, coma 5. seizures, cranial neuropathies 6. infants up to 2 yrs of age - fever, V, irritability, convulsions, highpitched cry, bulging fontanelles a. but sx unpredictable in young children 7. purpural rash with meningeal sns - meningococcemia

Diagnosis
1. accurate dx essential because it can be lethal in hours 2. LP if between 3 mos and 2 yrs of age if unexplained fever and then development of irritability, poor feeding, V, seizures, lethargy 3. + Brudzinski’s and Kernig’s signs

Lab
1. LP 2. CSF - stain, culture

Prognosis
1. early antibiotics - < 10% fatality 2. late dx, neonates, elderly - often fatal

Treatment
1. antibiotics

=Acute Viral Encephalitis and Aseptic Meningitis= A. **encephalitis** 1. acute inflammatory disease of brain due to viral invasion or hypersensitivity to virus or foreign protein B. **aseptic meningitis** 1. febrile meningeal inflammation without bacteria

Etiology
1. primary - viral invasion 2. secondary - immunologic complication of viral infection, in children after viral childhood illness

Signs & Symptoms
1. asx a. fever, malaise without meningeal sns but with abN CSF 2. meningitis a. fever, HA, V, malaise, stiff neck 3. encephalitis a. as in meningitis with the addition of cerebral dysfunction (change in consciousness or personality, seizures, paresis)

Diagnosis
1. must be sure not bacterial 2. CSF examination, culture

Prognosis
1. usually recover completely 2. permanent cerebral sequelae more common in infants

Treatment
1. acyclovir

=Subacute and Chronic Meningitis= A. meningeal infl without antibiotics that last > 2 wks B. if > 1 month, then chronic

Etiology
1. fungi, TB, Lyme disease, AIDS, syphilis, neoplasm 2. cryptococcus is most common fungal offender

Signs & Symptoms
1. as in acute meningitis but evolves slowly over weeks 2. minimal fever 3. progressive course to fatality within a few weeks to months

Diagnosis
1. must R/O structural lesions (tumors, abscess) because of slow development of sx 2. CSF examination

Treatment
1. depends on cause 2. amphotericin B for fungi