CNS I MIM - MENINGITIS! Flashcards
Meningitis Definition
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%
Causes of Bacterial meningitis
S. Pneumo --> 47% N. meningitidis --> 25% GBS --> 12% Listeria --> 8% H. Flu --> 7% (Vaccine)
SYMPTOMS of Meningitis
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
CSF for Bacterial/Viral/Fungal/TB
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
Other causes of meningitis
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
Symptoms for NEONATES
TEMPERATURE INSTABILITY; listless, lethargic, less feeding, failure to thrive, ICP symptoms (bulging fontanelle); seizures
GBS, E COLI, LISTERIA
Symptoms for 4-12 weeks
Same as above, but mainly
S Pneumo, N meningitidis, H Flu
Children 3 mos to 18 years old
Fevers, GI symptoms, headache, nuchal rigidity (more common presentation)
NEISSERIA; S pneumo, H flu if unvaccinated
Adults
Fevers, GI, headache, nuchal rigidity
Mainly S Pneumo!!!!!!
Elderly
Hypothermia, convulsions, altered mental status
S pneumo, N meningitidis, LISTERIA
PNEUMOCOCCUS
Majority of bacterial cases; high mortality!
Encapsulated - higher risk with B cell deficiencies
RHINORRHEA or OTTORHEA + BASILAR SKULL FRACTURE = HIGH RISK
H. FLU
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%
N MENINGIDITIS
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
LISTERIA
Food borne, very common, but only affects IMMUNOCOMPROMISED (very young and very old)
GROUP B STREP
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
TREATING BACTERIAL MENINGITIS
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)
BRAIN ABSCESSES
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
Causes of abscesses
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)
Treating abscesses
CEFTRIAXONE (3rd gen) + METRONIDAZOLE
CEFTAZIDIME (3rd gen) + VANCO (neuro surge)
> 2.5 cm –> SURGERY
Common infections of AIDS patients
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
Meningitis VS. Encephalitis
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
Waiting for labs and presents with meningitis signs?
TREAT EMPIRICALLY WITH CEFTRIAXONE + VANCOMYCIN (covers S. pneumo, H. flu, Neisseria and RESISTANT strep)
Aseptic Meningitis
Any meningitis with LYMPHOCYTE predominance and no apparent cause
Main cause = VIRUSES, but can also be TB, tumors, drugs, etc.
Viral Meningitis
Presents almost identically to bacterial!
Patients may look “less” sick
LYMPHOCYTE PREDOMINANCE, INCREASED CSF PROTEIN, NORMAL GLUCOSE!!!!
Enterovirus
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
Arboviruses
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
Paramyxovirus
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
Causes of Encephalitis – HERPESVIRUS
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
CSF for HSV Encephalitis
Non-specific; ELEVATED RBCs which will be secondary to TEMPORAL LOBE NECROSIS
PCR the CSF for HSV DNA
Treating HSV Encephalitis?
ACYCLOVIR!!!!!! Brings mortality down from 70% to 20%
38% have no sequelae after recovering
WEST NILE VIRUS
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
MOLLARET’S MENINGITIS
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!
