Bacterial meningitis can be a devastating disease if it is not recognized and treated in time. In this video, we'll look at the important symptoms that scream bacterial meningitis, how to initiate treatment, and when to avoid a lumbar puncture at all costs.
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Bacterial meningitis can be a devastating disease, leading to severe neurological deficits and death if not recognized and addressed acutely and aggressively. We will discuss community acquired adult bacterial meningitis in this med mastery lesson. Patients with acute bacterial meningitis will most often present with progressive headaches, fever, and neck stiffness.
Additional common symptoms include nausea and vomiting, photophobia, sleepiness, lethargy, confusion, irritability, delirium, seizures, and or coma. On evaluation, of course, start with your ABCs. Vital signs are critical. Absolutely assess for fever, and for hypotension and for shock. Resuscitate as needed, then run IV fluids at maintenance.
Avoid hypertonic IV fluids as they contribute to brain swelling. Perform your history and physical rapidly time matters. Patient history may not be overly contributory, but you should ask about contact with people with meningitis or pulmonary disease. Also ask about a history of immunocompromised, previous nervous system diseases, surgery or trauma.
Ask about a history of cerebral spinal fluid leak, then assess your level of consciousness, if not following commands perform a coma evaluation. If awake, rapidly evaluate cognition, speech, pupillary function, eye movement, facial sensation, facial symmetry, hearing, for example, just testing finger rubbing, palatal elevation and tongue function.
Assess motor function and tone and major groups. Look for drift on outstretched arms. Assess finger to nose coordination. Note, it's not critical to perform a sensory exam, deep tendon reflexes or gate exam at this juncture. You should however, assess for nuchal rigidity. Also check the skin for non blanching petechial hemorrhages as seen in fulminant meningococcal meningitis. What types of lab tests and imaging should you order?
Well, obtain a fingerstick glucose and order stat complete CBC, blood cultures, metabolic panel erythrocyte sedimentation rate, c reactive protein or CRP, serology, liver function tests, human immunodeficiency virus or HIV testing and coagulation panel. Also order meningococcal and pneumococcal polymerase chain reaction testing or PCR if available at your institution. Then order up vancomycin and a third generation cephalosporin to be prepared and ready as soon as possible.
If suspicion for meningitis is high, also start dexamethasone, 10 milligrams IV every six hours prior to or concomitant with antibiotics. Formal protocols note that if a patient is not immunocompromised, has not suffered from a seizure, has no history of nervous system disease, has no altered consciousness, has no papilledema and fundoscopic exam and no focal deficits, then you can go straight to a lumbar puncture without a CT scan of the brain.
We think this is a stretch, CT scan is obtainable at my institution at least almost instantly, so we go ahead and obtain an emergent noncontrast CT scan of the head for all patients suspected of suffering from bacterial meningitis prior to any lumbar puncture. CT scanning averts the horrific complication of a lumbar puncture inducing brain herniation in a patient with a mass lesion or severely increased intracranial pressure.
If lumbar puncture is being performed without a CT scan, err on the side of a smaller spinal needle and reduce cerebral spinal fluid removal, that is less than six milliliters. As noted earlier, you want to start empiric antibiotics as soon as available after dexamethasone administration. Ideally, the lumbar puncture would be completed before the start of the antibiotics, but don't delay them to do so.
If the CT scan of the head is negative, go ahead and obtain cerebral spinal fluid via lp, approximately 10 to 14 milliliters worth and test it for stat gram stain, chemistries, cell count, culture and sensitivities and keep an additional two tubes for studies consultants may want later. For example, polymerase chain reaction testing, PCR, is used at many centers to determine viral meningitis and or to rapidly screen for various bacterial pathogens.
If possible, obtain an opening pressure via manometry prior to collection of the CSF. If you note deterioration in the patient's neurological status during the lumbar puncture, truncate the procedure and send whatever CSF you've managed to obtain for gram stain and culture. A lumbar puncture should not be performed, and empiric antibiotics should be started if the patient is on anticoagulants, or is coagulopathic, is in septic shock, or has an unstable cardiovascular or respiratory status.
LP would also be contraindicated if there's an infection at the puncture site, or the patient has a large mass lesion in the brain on CT scan. Typical findings discovered via lumbar puncture in a patient with bacterial meningitis include increased opening pressure, that is over 180 millimeters of water, pleocytosis consisting predominantly of polymorphonuclear white cells, or PML's, a glucose of less than 45 milligrams per deciliter and protein greater than 45 milligrams per deciliter.
On the other hand, viral meningitis often shows normal opening pressure, fewer white cells than in bacterial meningitis, and the white cells are predominantly monocytic, normal to minimally lowered glucose and normal to minimally elevated protein. So how do we manage bacterial meningitis? Note empiric antibiotic regimens tend to evolve over time, so consult recent guidelines or your ID team for the latest recommendations.
Currently in 2021, for patients one month of age to 50 years of age use vancomycin and a third generation cephalosporin. Dosing as per your pharmacist recommendations. For patients over 50 years of age, add ampicillin to cover listeria monocytogenes. On the other hand, for babies zero to four weeks, use ampicillin plus cephotaxime, or ampicillin plus an aminoglycoside. For healthcare associated meningitis use vancomycin plus an antipseudomonal beta lactam, such as cefapime, ceftazidime, or meropenem.
Consult your infectious disease team early to help follow the cultures and their sensitivities and to help adjust the antibiotic regimen. Many centers will start an anticonvulsant for significantly compromised patients, and those who have indeed seized. Levetiracetam 500 to 1000 milligrams twice a day is currently commonly used. The anticonvulsant will be continued for the duration of the antibiotic treatment. After initial evaluation and initiation of treatment admit to an intensive care unit until the patient is stable. That is until they are awake and alert and had been extubated, their blood pressure is normalized and there is no evidence of multi system organ failure.