CNS InfectionsCNS Infections

J. Ned Pruitt II

Associate Professor of Neurology

Medical College of Georgia

Case 1Case 1

A 35 yo man is brought to the ER after 5 days of fever and chills. His wife relates that he has been very confused today and she called 911 after a seizure.

PMHx is unremarkable except for a splenectomy at age 14 after a traumatic injury.

Meds – prn tylenol in the last week. NKDA Vaccinations are up to date.

Case 1Case 1

Exam – Ill appearing man. Temp 39 C. Lethargic and can answer simple questions but can give no meaningful history. Neck is stiff to flexion and extension. A fine petechial rash is on his chest and upper arms.

Case 1 – What next?Case 1 – What next?

More examination or history?Labs?Radiology?Medications?

CNS InfectionsCNS Infections

Meningitis– Bacterial, viral, fungal, chemical,

carcinomatousEncephalitis

– Bacterial, viralMeningoencephalitisAbscess

– Parenchymal, subdural, epidural

CNS InfectionsCNS Infections

Signs and symptoms– Fever– Headache– Altered mental status -lethargy to coma– Neck stiffness – meningismus – flex/ext– Increased intracranial pressure – papilledema,

nausea/vomiting, abducens palsies, bulging fontanelle in infants

Exam in suspected CNS Exam in suspected CNS InfectionInfection

Mental StatusCranial nerve and fundiscopic examMeningeal SignsGeneral exam – rashes, lymphadenpathyLabs – CBCD, BMP, PT/PTT, bHCG,

blood cultures, UA C&SRadiology – CT head - uncontrasted if no

focal signs, contrast if mass suspected

LPLP

Increased intracranial pressure is expected – but LP contraindicated if a mass is present or if epidural spinal abscess is suspected

Left lateral decubitus position

L3-L4 interspace or L4-L5 interspace

Think about your studies before the LP

LPLP

Tube #1 – glucose and proteinTube #2 – cell count and differentialTube #3 – gram stain and rountine culture,

cyrptococcal antigen, AFB stain and cultureTube #4 – VDRL, or viral studies (PCR)

CSF CharacteristicsCSF CharacteristicsBacterial Viral Fungal TB

Opening Pressure

Elevated Slightly elevated

Normal or High

Ususally high

Glc Low Normal Low Low

Pro Very high Normal High High

Rbcs Few None None None

Wbcs (c/mm3)

>200 <200 <50 20-30

Diff PMNs Mono Mono Mono

Key CSF FeaturesKey CSF Features

CSF is not liquid gold – get enough to get your answer CSF Glucose is 2/3 of serum glucose

– Important in diabetic patients Traumatic LPs –

– CSF pro increases by 1 for every 1000 rbcs– Tube #1 and Tube#4 for rbcs when SAH is in the

differential not as a routine Very high CSF Protein levels will make CSF yellow Send a full tube of CSF for cytology not just a few cc’s

Case 1Case 1

CT of head negative.LP - OP (opening pressure) 250mm,

glucose 17, protein 92, Rbcs 3, Wbcs 280 with 89% pmns, 11% lymphocytes

Gram stain - + for Gram neg organisms

Bacterial MeningitisBacterial Meningitis

Streptococcus pneumoniaeHemophilus influenzaeListeria moncytogenesGroup B streptococcusNiesseria meningitidis

Bacterial MenigitisBacterial Menigitis

Age less than 3 months-– Group B strep– L. Monocytogenes– E. coli– Strep pneumoniae

Bacterial MeningitisBacterial Meningitis

3 Months to 18 years –– N. meningitidis– S. pneumoniae– H. influenzae

Bacterial MeningitisBacterial Meningitis

Age 18 to 50 years– S. pneumoniae– N. meningitidis– H. influenzae

Bacterial MeningitisBacterial Meningitis

Over age 50 years– S. pnemoniae– L. monocytogenes– Gram (-) bacilli

Treatment of Bacterial Treatment of Bacterial MeningitisMeningitis

PCN G or 3rd generation cephalosporin and consult ID

Steroids – Dexamethasone IV q6 for 4 days

Viral MeningitisViral Meningitis

Very common

Often caused by enteroviruses

Treatment is supportive

Viral Encephalitis Viral Encephalitis

Encephalitis (Meningoencephalitis)– Altered mental status and seizures– Herpes Simplex virus – medial temporal lobe

Acyclovir Management of seizures Very high morbidity and mortality PCR diagnosis of CSF

– West Nile, St Lousi E, EEE, CMV

Chronic MeningitisChronic Meningitis

Immunocompromised patients– Cryptococcus neoformans– HIV– M. tuberculosis– M. avium

Carcinomatous meningitis– Lung, breast

Case 1Case 1

Meningitis caused by N. Meningitidis– Treatment with 3rd generation cephalosporin for

10 days– Dexamethasone– Prophlaxis with Rifampin for contacts