CNS I MIM - MENINGITIS! Flashcards by Connor Benton

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%

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Causes of Bacterial meningitis

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

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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

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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

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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

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Symptoms for NEONATES

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

GBS, E COLI, LISTERIA

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Symptoms for 4-12 weeks

Same as above, but mainly

S Pneumo, N meningitidis, H Flu

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Children 3 mos to 18 years old

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

NEISSERIA; S pneumo, H flu if unvaccinated

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Adults

Fevers, GI, headache, nuchal rigidity

Mainly S Pneumo!!!!!!

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Elderly

Hypothermia, convulsions, altered mental status

S pneumo, N meningitidis, LISTERIA

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PNEUMOCOCCUS

Majority of bacterial cases; high mortality!

Encapsulated - higher risk with B cell deficiencies

RHINORRHEA or OTTORHEA + BASILAR SKULL FRACTURE = HIGH RISK

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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%

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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

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LISTERIA

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

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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

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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!