Differences between bacterial & viral meningitis
	Viral	Bacterial
Common microbes	• Enteroviruses (most common) • Arboviruses •Herpes simplex virus type 2	• Adults: Streptococcus pneumoniae & Neisseria meningitidis • Neonates: Group B Streptococcus & gram-negative bacilli.
CSF cell differential	• WBC # <500 • Lymphocytic predominance	·       WBC # often >1000 ·       Neutrophilic predominance
CSF glucose & protein	• Glucose levels are normal or slightly reduced • Protein generally <150 mg/dL	·       Glucose levels <45 mg/dL ·       Protein is often >250 mg/dL
CSF Gram stain & culture	• No organisms identified	·       Often positive for a specific organism

Bacterial Meningitis
S/S	If FND → Abscess
Dx	Answer head CT first when any of the following is present: · Papilledema · SZ · FND · Confusion interfering with the neurological examination When is a bacterial antigen test indicated? When the patient has received antibiotics prior to the LP and the culture may be falsely negative. ·       LP + Cultx ·       if ⤴️ ICP: Initiate Abx → CT –> LP ·       If ⓝ ICP: LP → ABx
Tx	Adults: ·       For regular adults (up to 50): Vanco + ceftriaxone +steroids ·       For elderly: Add ampicillin (go full hard-on baby, fuck all that bacteria the son of bitches who kill people). Peds: ·       < 1 month: cefotaxime + ampicillin ·       1-3 months: cefotaxime + ampicillin + vancomycin ·       > 3 months: ceftriaxone + vancomycin For Nisseria: ·       Respiratory isolation for 24 h ·       Rifampin, ciprofloxacin, or ceftriaxone to the close contacts to decrease nasopharyngeal carriage

Meningitis to Risk Factors
Rocky Mountain Spotted Fever	Fever, Rash that moves from arms to trunk. Tick bites, camping (not necessarily to Rocky Mountains)
Lyme Disease	Travel to Connecticut. Targetoid rash with arthralgias, arrhythmias (tic usually not seen)
Cryptococcal Meningitis	AIDS patient with fever and a headache. >20cmH20 opening pressure Cryptococcal Antigen India Ink
TB	Night Sweats, Weight Loss, Hemoptysis and meningitis.  Homeless, Prison, Endemic Areas (Urban)
Syphilis	primary Chancre, Secondary Erythema Multiforme, Tertiary Any Neuro Sx Get CSF RPR Or CSF Antibodies

Meningiococcal Meningitis
Clx	·       Sx: Headache, nausea/vomiting, severe myalgias ·       Signs: Neck stiffness, AMS, petechial/purpuric rash, meningeal (Kernig & Brudzinski) signs ·       Complications: Multiorgan failure, DIC, adrenal hemorrhage, shock
Tx	·       3rd-gen cephalosporin + vancomycin ·       Glucocorticoids not helpful ·       Chemoprophylaxis (eg, rifampin, ciprofloxacin, ceftriaxone) for all respiratory contacts

C.Neoformans Meningitis
S/S	·       N/V ·       Confusion ·       CN6 Palsy ·       Scattered Skin Papules ·       It blocks arachnoid Villi —+ inc ICP –> (CN6 palsy / enlarged ventricles)
Dx	·       Lumbar puncture
Tx	·       Anti-fungal (may require daily LP)

C.Neoformans Meningitis
S/S	·       N/V ·       Confusion ·       CN6 Palsy ·       Scattered Skin Papules ·       It blocks arachnoid Villi —+ inc ICP –> (CN6 palsy / enlarged ventricles)
Dx	·       Lumbar puncture
Tx	·       Anti-fungal (may require daily LP)

Cryptococcal meningoencephalitis
Clx	• Headache, fever & malaise • Develops over 2 weeks (subacute) • Can be more acute & severe in HIV
Dx	CSF: • High opening pressure • Low glucose, high protein • White blood cells <50/uL with mononuclear predominance • Transparent capsule seen with India ink stain • Cryptococcal antigen positive • Culture on Sabouraud agar
Tx	Initial: Amphotericin B with flucytosine Maintenance: Fluconazole

	Viral (herpes simplex virus) encephalitis
Sx	• Fever • Altered mental status with confusion & agitation • Risk of seizures & coma
Clx	• Hemiparesis, cranial nerve palsies (signs of focal neurologic deficits) • Hyperreflexia
Inv	• Cerebrospinal fluid analysis: ↑ white blood cells (lymphocyte predominant), normal glucose, ↑ protein • Brain magnetic resonance imaging: Temporal lobe abnormalities • Diagnosis: CSF analysis shows presence of viral DNA on PCR
Tx	• Intravenous acyclovir: Start immediately after obtaining CSF fluid

HSV Encephalitis
?	MCC
Sx	Fever + AMS
Dx	CT (⊕ Temporal lobe)
Tx	·       Acyclovir is the best initial therapy for herpes encephalitis. ·       Foscarnet is used for acyclovir-resistant herpes.