Acute Pyogenic Meningitis (and general defns) Flashcards Preview

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Define Meningitis and Meningoencephalitis?

Meningitis is the inflammation of the leptomeninges and CSF within the subarachnoid space, Meningoencephalitis is that plus inflammation of the brain parenchyma.


What are the 4 basic kinds of meningitis and what causes them?

1. Chemical Meningitis, which is due to a nonbacterial irritant in the subarachnoid space.
2. Acute Pyogenic meningitis, usually bacterial.
3. Aseptic Meningitis, which is generally acute viral meningitis.
4. Chronic meningitis, which is due to TB, spurochetal or cryptococcal infections.


What are the 2 main causes of acute pyogenic meningitis in neonates (0-6 months)?

E. Coli and group B strep, Listeria. H. Influenza also used to cause this in neonates in developed nations but vaccines have been made to reduce the incidence. However, in 3rd world countries H. influenza may still be an issue with neonatal meningitis.


Which 2 agents causes acute pyogenic meningitis in the elderly?

Strep Pneumo, and Listeria Monocytogens. Other gram neg rods.


What is the main causes of acute pyogenic meningitis in adolescents and young adults?

Neisseria Meningitidis is the main one. S. pneumo can also cause it.


What are the clinical presentations of meningitis?

Signs of infections, on top of neurologic impairment including headache, photophobia, irritability, clouding of consciousness, and neck stiffness.


What would a spinal tap show in an acute pyogenic meningitis patient?

Cloudy or frankly purulent CSF with neutrophils upwards of 90k/mm^3, increased protein concentration, and markedly reduced glucose content. Also increased pressure.


Can CSF fluid from spinal tap be cultured?

Yes, and in fact the cultured pathogen can show up before the neutrophil spike.


What is the "Waterhouse-Friderichsen syndrome"?

Occurs most often with the meningococcal and pneucococcal meningitis, it results from meningitis associated septicemia w/ hemorrhagic infarctions of the adrenal glands and skin petetchiae.


What can be the causative agents of purulent meningitis in the immunocomprimised?

Klebsiella or an anaerobic organism, and this might have an atypical course, uncharacteristic CSF.


What can be seen in the leptomeninges over the surface of the brain in acute purulent meningitis?

An exudate will be evident in that region.


What might follow a pyogenic meningitis event?

It might lead to leptomeningeal fibrosis which can cause hydrocephalus.


What is "Chronic Adhesive Arachoniditis?"

Particularly in pneumococcal meningitis, a lot of the capsular polysaccharides from the organism makes a gelatinous exudate that encourages arachnoid fibrosis, and this arachnoid fibrosis is called chronic adhesive arachnoiditis.


What are the most likely causative agents of meningitis in Children (6 mo - 6 yrs)?

Strep pneumo, Neissera Meningitidis, H. Influenzae type B.


How would you tx bacterial meningitis?

Give Ceftriaxone and Vanco empirically (and add ampicillin if Listeria is suspected).


If the spinal tap reveals increased pressure, decreased glucose, increased lymphocytes and increased proteins, what should we suspect?

Due to increased lymphocytes (and all other findings identical to bacterial meningitis -- except in bacterial we whould have increased PMNs instead), we should suspect TB or fungal meningitis.