CNS Infections J. Ned Pruitt II Associate Professor of Neurology Medical College of Georgia

Case 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 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? More examination or history? Labs? Radiology? Medications?

CNS Infections Meningitis – Bacterial, viral, fungal, chemical, carcinomatous Encephalitis – Bacterial, viral Meningoencephalitis Abscess – Parenchymal, subdural, epidural

CNS 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 Infection Mental Status Cranial nerve and fundiscopic exam Meningeal Signs General exam – rashes, lymphadenpathy Labs – CBCD, BMP, PT/PTT, bHCG, blood cultures, UA C&S Radiology – CT head - uncontrasted if no focal signs, contrast if mass suspected

LP 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

LP Tube #1 – glucose and protein Tube #2 – cell count and differential Tube #3 – gram stain and rountine culture, cyrptococcal antigen, AFB stain and culture Tube #4 – VDRL, or viral studies (PCR)

CSF Characteristics BacterialViralFungalTB Opening Pressure ElevatedSlightly elevated Normal or High Ususally high GlcLowNormalLow ProVery highNormalHigh RbcsFewNone Wbcs (c/mm3) >200<200< DiffPMNsMono

Key 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 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 Meningitis Streptococcus pneumoniae Hemophilus influenzae Listeria moncytogenes Group B streptococcus Niesseria meningitidis

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

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

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

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

Treatment of Bacterial Meningitis PCN G or 3 rd generation cephalosporin and consult ID Steroids – Dexamethasone IV q6 for 4 days

Viral Meningitis Very common Often caused by enteroviruses Treatment is supportive

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 Meningitis Immunocompromised patients – Cryptococcus neoformans – HIV – M. tuberculosis – M. avium Carcinomatous meningitis – Lung, breast

Case 1 Meningitis caused by N. Meningitidis – Treatment with 3 rd generation cephalosporin for 10 days – Dexamethasone – Prophlaxis with Rifampin for contacts