CNS I MIM - MENINGITIS!

Question 1

Meningitis Definition

Answer 1

Inflammation of the meninges

DEFINED by the presence of PLEIOCYTOSIS –> abnormal numbers of WBCs in the CSF

CANNOT MAKE DIAGNOSIS WITHOUT CSF –> LUMBAR PUNCTURE!!!

Adult mortality = 25%

Question 2

Causes of Bacterial meningitis

Answer 2

S. Pneumo --> 47%
N. meningitidis --> 25%
GBS --> 12%
Listeria --> 8%
H. Flu --> 7% (Vaccine)

Question 3

SYMPTOMS of Meningitis

Answer 3

Classic Triad = HEADACHE, FEVER, MENINGISMUS (Nuchal rigidity)

Altered mental status common too – confusion, delirium, lethargy, coma

Increased ICP –> vomiting, seizures, focal deficits (seizures in 30%)

Papilledema –> super rare, so usually indicative of ANOTHER problem

Question 4

CSF for Bacterial/Viral/Fungal/TB

Answer 4

Bacterial: >1000 WBCs, NEUTROPHILS, LOW GLUCOSE, Elevated protein

Viral: High WBCs, but less than 1000; mainly LYMPHOCYTES; NORMAL GLUCOSE; elevated protein

TB/FUNGAL: High WBCs, less than 1000; mainly LMPHOCYTES (like viral);LOW GLUCOSE, High Protein

Should also see elevated opening pressure, elevated LDH, lactate and CRP

Question 5

Other causes of meningitis

Answer 5

VIRAL most common overall (Coxsackie and Echovirus)

Chemical meningitis –> NSAIDs and Bactrim (SMX/TMP)

Metastatic lesions can get to the meninges

Sarcoidosis, Abscesses, Vasculitis of CNS from Lupus

Question 6

Symptoms for NEONATES

Answer 6

TEMPERATURE INSTABILITY; listless, lethargic, less feeding, failure to thrive, ICP symptoms (bulging fontanelle); seizures

GBS, E COLI, LISTERIA

Question 7

Symptoms for 4-12 weeks

Answer 7

Same as above, but mainly

S Pneumo, N meningitidis, H Flu

Question 8

Children 3 mos to 18 years old

Answer 8

Fevers, GI symptoms, headache, nuchal rigidity (more common presentation)

NEISSERIA; S pneumo, H flu if unvaccinated

Question 9

Adults

Answer 9

Fevers, GI, headache, nuchal rigidity

Mainly S Pneumo!!!!!!

Question 10

Elderly

Answer 10

Hypothermia, convulsions, altered mental status

S pneumo, N meningitidis, LISTERIA

Question 11

PNEUMOCOCCUS

Answer 11

Majority of bacterial cases; high mortality!

Encapsulated - higher risk with B cell deficiencies

RHINORRHEA or OTTORHEA + BASILAR SKULL FRACTURE = HIGH RISK

Question 12

H. FLU

Answer 12

Used to be a big deal because of Otitis Media (could spread directly to meninges)

NOW we gots a vaccine for that shit –> 50% to 7%

Question 13

N MENINGIDITIS

Answer 13

MOST COMMON CAUSE OF MENINGITIS IN KIDS AND YOUNG ADULTS (college aged)

Terminal complement deficiencies increase risk; damage to the pharyngeal mucosa by smoking also increases risk

MOST IMPORTANT CLINICAL SIGN IS A RASH ON TOP OF THE CLINICAL TRIAD/REGULAR SYMPTOMS

Pupuric rash in 75% of cases, can develop into meningococcemia where there is multiple organ dissemintation –> DIC, hypotension, ARDS, acute respiratory failure, adrenal insufficiency

Question 14

LISTERIA

Answer 14

Food borne, very common, but only affects IMMUNOCOMPROMISED (very young and very old)

Question 15

GROUP B STREP

Answer 15

Neonates affected as a result of the BIRTHING PROCESS

Can appear within a week of birth as SEPSIS and PNEUMONIA or after a week as MENINGITIS

Prophylactically treat moms with penicillin in 3rd trimester

Question 16

TREATING BACTERIAL MENINGITIS

Answer 16

3rd Gen Cephalos (covers S pneumo, Neisseria, H flu)

+ VANCOMYCIN (resistant pneumo)

+ AMPICILLIN (if risk for Listeria)

Neuro patients with possible HAI –> CEFTAZIDIME + VANCO –> CEFTAZIDIME covers PSEUDOMONAS (common HAI)

Question 17

BRAIN ABSCESSES

Answer 17

Infection of the brain parenchyma, not just the meninges

Space filling lesion that pushes against cortical brain structures –> makes it more likely to cause a focal neurological deficit than meningitis is

Higher risk for PAPILLEDEMA (25%)

Large ring enhancing lesion

Headache, altered mental status, focal deficits, fever, seizures, N/V, papilledema

Question 18

Causes of abscesses

Answer 18

30-50% of time they can arise as a CONTIGUOUS FOCUS OF INFECTION
otitis media, mastoiditis, sinusitis, face/scalp infections, DENTAL INFECTIONS!

Can arise hematogenously (bacteremia, endocarditis)

Remaining 20% unknown

Bacterial agents usually are POLYMICROBIAL (strep + anaerobe from mouth/URT)

Question 19

Treating abscesses

Answer 19

CEFTRIAXONE (3rd gen) + METRONIDAZOLE

CEFTAZIDIME (3rd gen) + VANCO (neuro surge)

> 2.5 cm –> SURGERY

Question 20

Common infections of AIDS patients

Answer 20

CRYPTOCOCCAL MENINGITIS

CNS TOXOPLASMOSIS –> protozoan, ring enhancing lesions on MRI

NOCARDIA – gram + acid fast rod that originates as a PULMONARY infection in immunocompromised patients; 40% of the time it disseminates to form an abscess in brain –> Treat with TMP/SMX

Question 21

Meningitis VS. Encephalitis

Answer 21

Meningitis has the classic triad; RARELY FOCAL DEFICITS or CONFUSION; If they DO present with confusion/coma –> they will die cause we waited too long

ENCEPHALITIS –> inflammation of the brain parenchyma and presents with EARLY CONFUSION/STUPOR lacking the classic meningitis signs

Question 22

Waiting for labs and presents with meningitis signs?

Answer 22

TREAT EMPIRICALLY WITH CEFTRIAXONE + VANCOMYCIN (covers S. pneumo, H. flu, Neisseria and RESISTANT strep)

Question 23

Aseptic Meningitis

Answer 23

Any meningitis with LYMPHOCYTE predominance and no apparent cause

Main cause = VIRUSES, but can also be TB, tumors, drugs, etc.

Question 24

Viral Meningitis

Answer 24

Presents almost identically to bacterial!

Patients may look “less” sick

LYMPHOCYTE PREDOMINANCE, INCREASED CSF PROTEIN, NORMAL GLUCOSE!!!!

Question 25

Enterovirus

Answer 25

Echovirus, Coxsackie A/B, Polio, Enteroviruses

Fecal oral, summer/fall dominance, young and immunocompromised susceptible

Typically recover WITHOUT sequelae, but agammaglobulinemia can result in CHRONIC ENTEROVIRAL MENINGITIS –> wax and wane for several months or years, usually FATAL; can give IVIG therapy during attacks

Question 26

Arboviruses

Answer 26

Arthropod-transmitted viruses (mosquitoes!)

Most common is ST LOUIS ENCEPHALITIS VIRUS (La Crosse Virus, Jamestown Canyon virus)

Warmer months (mosquitoes)

YOUNGER PATIENTS will present with ASEPTIC MENINGITIS

OLDER PATIENTS will present with ENCEPHALITIS

Question 27

Paramyxovirus

Answer 27

MUMPS!

Most common cause of aseptic meningitis or encephalitis in UNIMMUNIZED populations –> MMR prevents it here in US

Ages 3-9 peak incidence; HEADACHE, VOMITING, FEVER about 5 DAYS AFTER PAROTITIS

Disease lasts 7-10 days, FAVORABLE outcome

Question 28

Causes of Encephalitis – HERPESVIRUS

Answer 28

Most common cause of acute sporadic virlal encephalitis in the US, 95% caused by HSV1

30% as primary infection, 70% as an activated latent HSV1 infection

SUDDEN ONSET, LIFE THREATENING

Affinity for the TEMPORAL LOBE –> bizarre behavior (focal deficit – speech, gustatory, olfactory, hallucinations)

90% with EXTREMELY HIGH FEVER

Very quick progression to altered state of consciousness

Question 29

CSF for HSV Encephalitis

Answer 29

Non-specific; ELEVATED RBCs which will be secondary to TEMPORAL LOBE NECROSIS

PCR the CSF for HSV DNA

Question 30

Treating HSV Encephalitis?

Answer 30

ACYCLOVIR!!!!!! Brings mortality down from 70% to 20%

38% have no sequelae after recovering

Question 31

WEST NILE VIRUS

Answer 31

Usually asymptomatic; 50% have a maculopapular rash

1/150 get meningitis, encephalitis, or BOTH

Advance age is greatest risk factor for WNV meningitis –> significant neurological symptoms, substantial morbidity, 9x likelier to die if > 75

ACUTE FLACCID PARALYSIS (looks like polio!)

Typical CSF findings

IMMUNOASSAY for IgM –> 90% of patients will be IgM+ in 8 days

IgM not made in CSF – so highly indicative of WNV Meningitis

Question 32

MOLLARET’S MENINGITIS

Answer 32

Rare! Also called benign RECURRENT aseptic meningitis

Occurs in OTHERWISE HEALTHY, YOUNG PATIENTS with NO UNDERLYING DISEASE

Recurrent episodes of aseptic meningitis with acute onset of fever, headache and nuchal rigidity

Symptoms resolve in 2-5 days, weeks to months later will experience another episode!

Assume in young healthy patients > 3 episodes!!!!!!

LP –> Mixed PMN and Lymphocyte predominance

Mildly increased protein, large fragile monocytes, glucose normal

HSV2 DNA has been detected –> can give ACYCLOVIR

May look like drug seeking behavior – come to the ER with severe headaches, often, asking for pain meds without an LP –> but LP makes headaches worse with CSF leakage!