Fundoscopy exam!  If they have papilledema, there is increased intracranial pressure and a lumbar puncture is contraindicated.  This is because removal of CSF from the spinal column coupled with the high intracranial pressure will push the brainstem through the foramen magnum, resulting in herniation.

In papilledema the normally clear, well demarcated border of the optic disc are blurred/fuzzy.

Tube  1: Gram stain and culture and sensitivity

Tube 2: Glucose and Protein

Tube 3: Cell count with differential (PMNs, lymphocytes?)

Tube 4: Latex agglutination for antigens/ PCR

Group B streptococcus: S. agalactiae is the most common cause of meningitis in neonates.

This is followed by E. coli and then L. monocytogenes.

1) Neisseria meningitidis

2) S. pneumoniae

3) H. influenzae (type B)

1) S. pneumoniae

2) N. meningitidis

3) L. monocytogenes (in immunocompromised, pregnant, and elderly patients)

Dexamethasone (glucocorticoid to reduce inflammatory response and lessen ICP)

minimum of 2 IV antibiotics

*because you are giving dexamethasone, an immunosuppressant, you want to make sure the antibiotics you are using are BACTERICIDAL

The bacteria responsible for neonatal meningitis are:

S. agalactiae: gram (+) cocci, catalase (-), NOT inhibited by bacitracin (vs S. pyogenes)

E. coli: gram (-) rod,

L. monocytogenes: gram (+) rod, non spore-forming, catalase (+)

Serotype B is the most common form of N. meningitidis in the US.  This is the serotype that is NOT covered by the vaccines "Menomune" or "Menactra".  These cover only the A,C,Y,W serotypes.

Menomune is a polysaccharide vaccine given to adults/elderly

Menactra is a conjugated vaccine used in children and to revaccinate those that previously had the menomune vaccine.

Rifampin

(or ciprofloxacin)

In utero infection of a fetus by listeria may cause disseminated abscesses or granulomas.

Post-partum listeria infection of a neonate may result in meningitis.

Mycobacterium tuberculosis

You must grow for 3-8 weeks because mycobacteria are very slow growing.

Cryptococcus neoformans is the most common cause of fungal meningitis.

it is acquired from bird droppings and can be diagnosed by india ink staining of the CSF or a latex agglutination test.

This disease really only occurs in the immunocompromised (like most fungal diseases)

Tx = amphotericin B and flucytosine

do NOT give dexamethasone

What viruses commonly cause meningitis?

What viruses commonly cause encephalitis?

Viral Meningitis = Coxsackie A + B, Echovirus, HSV-2, and HIV

Viral Encephalitis = HSV-1, West-Nile, Lacrosse + St. Luis encephalitis viruses.

(E before M as 1 before 2, so HSV-1 causes Encephalitis)

Coxsackievirus and Echovirus

They are both (+)ssRNA, naked

West Nile Virus is a member of flaviviridae.  It is therefore (+)ssRNA, enveloped.

It is transmitted by the mosquito vector and has birds (crows) as the reservoir in the wild.

West Nile Virus infects the anterior horn cells, causing ascending muscle weakness

Other causes of ascending weakness = Guillain Barre and paralytic Rabies.

The California/Lacrosse Encephalitis Virus is a (-)ssRNA virus.  It is transmitted by the mosquito and has the chipmunk and other rodents as its reservoir. 

Elimination of vectors (here: mosquito) is an effective means of preventing disease!

HSV2 is more likely to cause viral meningitis

HSV2 causes neonatal infection, viral meningitis, and genital herpes.

HSV1 is more likely to be responsible for viral encephalitis, which often involves hemorrhagic necrosis of the temporal lobe.

Use imaging studies (CT, MRI) with contrast to diagnose a CNS abscess!

You will likely see a ring-enhancing lesion and a midline shift.

Recall, CT is contraindicated in pregnancy.  MRI is contraindicated in patients with metallic implants.

Rhinocerebral mucormycosis.

This is really only found in immunocompromised patients and is caused by Rhizopus oryzae, a fungus that grows on rotting fruit or bread. 

It is a medical emergency and amphotericin B should be administered alongside surgical debridement of the wounds.

This disease carries a 50% mortality rate despite treatment!

Spinal Epidural Abscess.

This is most often caused by S. aureus, Streptococcus, or Enterobacteriaceae.

MRI imaging is useful in the diagnosis.

Abscess drainage and antibiotics are the treatment, though a laminectomy may be useful in relieving the pressure.

Spread to the abscess location could be via hematogenous route or by direct spread from vertebral osteomyelitis, or finally by direct transfer in procedures like epidural anesthesia.

the JC virus.  PML is a fatal demyelinating disease in which the oligodendrocytes are destroyed.  It is essentially a rapidly progressing MS like disease.

Dx is by finding JC virus DNA in the CSF.

Most people are exposed to this virus, but it only causes a disease state in the immunocompromised.

CJD (creutzfeld-jakob disease).

Do not take corneal transplants from patients with dimentia/ altered mental status.

Measles infection is associated with Subacute Sclerosing Panencephalitis

This is an inflammatory lesion of the brain that results from persistent infection by the measles virus that doesn't fully complete its replicative cycle...

The measles vaccine has more or less eliminated this from the US.

Which is associated with inflammation of the brain producing behavioral, motor, and mental function changes:

Progressive multifocal leukoencephalopathy

Subacute Sclerosing Panencephalitis

SSPE causes inflammation and behavioral changes.  It is associated with a persistent measles infection

PML is caused by the JC virus in immunocompromised people and is not associated with inflammation.

The Sabin vaccine is an oral polio vaccine.  It is an attenuated virus, meaning it is an active virus that has had its virulence removed.

The Salk virus is an injectable polio vaccine.  It is an inactivated (killed) virus.

The Sabin (attenuated) vaccine elicits a better immune response.  However, it is no longer used in the US because there is a (very slight) risk of the virus reverting to its virulent form and causing vaccine associated paralytic polio.

Both vaccines contain the poliovirus serotypes 1, 2, and 3

Poliovirus.

This virus specifically targets anterior horn cells and lower motor neurons. (it is a neurotropic virus)

Polio infection is normally asymptomatic (90%) but when symptomatic can either be a paralytic form or non-paralytic form (spasms and back pain)

Give both the rabies immune globulin (hRIG) and the diploid cell vaccine (hDCV)

as much of the HRIG as possible should be injected at the wound site with the remainder injected into the gluteal region.

This person will either develop Furious Rabies or Paralytic Rabies.  This will eventually progress to coma and death from respiratory failure.

Furious rabies involves hyperactivity, hyperventilation and hypersalivation

Paralytic Rabies involves ascending paralysis (similar to Guillain Barre)