Meningitis The Basics Steven M Snodgrass M D

Meningitis: The Basics Steven M. Snodgrass M. D.

What is meningitis ? n Inflammation of the meninges/leptomeninges – the pia, arachnoid, and dura mater. n Can have various causes – bacteria, viruses, fungus.

How it happens n NP colonization of susceptible individual and invasion of respiratory tract n Invasion of bloodstream (Bacteremia) n Choroid plexitis n Spread to meninges n Ventriculitis and increased intracranial pressure n Recruitment of inflammatory mediators

How it happens n Damage to blood-brain barrier leads to cerebral edema n Endothelial cell damage, thrombosis n Increase in CSF protein, decrease in glucose from hypoxia, decreased aerobic metabolism n Infarction, Seizures, Abscess formation

Typical presentations n You are seeing a 14 day old infant in the emergency room with a 2 day history of congestion. Parents note infant to be increasingly irritable and lethargic, sleeping through feeds, multiple episodes of vomiting, difficult to console. Fever of 103 rectal. Infant looks pale and feels cool with HR of 225. A spinal tap shows 5000 white blood cells and a gram stain reveals gram negative rods.

Typical presentations n You are seeing a 15 yo high school student in your office with a 24 hour history of lethargy, repeated vomiting, and fever to 102. On exam he is unable to touch his chin to his chest and resists full extension of his knee while lying flat.

Pathogens of Bacterial Meningitis n Neonates (<1 mo) : – Group B streptococcus, E. coli, Listeria n Infants (1 -24 mos): – Haemophilus influenzae type B, Streptococcus pneumoniae, Neisseria meningitidis n Children (>2 yo): – Neisseria (meningococcus), Strep pneumo (pneumococcus), H. flu

Meningococcemia

Gram negative diplococci

Diagnosis n Must maintain a high index of suspicion in many cases n Gold standard is positive culture in CSF, may have CSF positive gram stain n Lumbar puncture and CSF also show pleocytosis, increased protein, and hypoglycorrhea

CSF findings Component Normal Bacterial meningitis Viral meningitis Herpetic Spirochetal encephalitis Glucose mg/d. L 40 -80 <30 >30 40 -110 Protein mg/d. L 20 -50 >100 50 -100 >75 15 -150 WBCs 0 -6 >1000 100 -500 10 -1000 20 -500 Neutrophils 0 >50 % <20 % <50 % <10 % RBCs 0 -2 0 -10 0 -2 100 -500 0 -2

How much does it happen 1 n Pittsburgh similar to US in general – For 5 -17 yo in 2006: – Neisseria 0. 4 -0. 5 cases per 100, 000 with 50% meningitis and 8% mortality – Pneumococcus 3. 3 cases per 100, 000 with 6% meningitis and 2. 5 % mortality – 237 total cases of pneumococcal meningitis – 68 total cases of meningococcal meningitis 1. http: //www. cdc. gov/ncidod/dbmd/abcs/survreports. htm

We’re lucky n 1. 1 cases per 100, 000 in US in 2004 as compared to: n Cases per 100, 000: – Pakistan 4. 4 – Haiti 6. 1 – Iraq 5. 9 – China 7. 7 – India 53. 5

Treatment n Antibiotics – Penicillins, Vancomycin, Cephalosporins n ? Steroids - Dexamethasone n Treat underlying hemodynamic compromise (shock) and other complications n Monitor for and treat sequelae

Complications and Sequelae n n n n Complications: Shock/Sepsis Cerebral edema Subdural empyema Subdural effusion Ventriculitis Abscess Seizures n n n Sequelae: Deafness Developmental delay, cognitive impairments Chronic seizure disorder Hydrocephalus

Vaccines… n Menactra – Protects against four most common serogroups of Neisseria A, C, Y and W-135 – Most cases in infants due to serogroup B – Adolescents and adults aged 11 -55 yo – Give at entry to H. S. , college dorm residents, other at risk groups – Conjugate vaccine as compared to MPSV