Which clinical history findings are characteristic of pneumococcal meningitis?

Updated: Aug 27, 2018
  • Author: Claudia Antonieta Nieves Prado, MD; Chief Editor: John L Brusch, MD, FACP  more...
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Answer

As a cause of meningitis, S pneumoniae usually invades the meninges via the bloodstream. Although there are multiple possible mechanisms by which this pathogen may cross the blood-brain barrier (BBB), it is likely that multiple factors must act in concert to allow for establishment of infection in the CNS. Transcytosis through meningeal vascular endothelial cells, which are key components of the blood brain barrier, is mediated by pneumococcal adherence to platelet-activating factor receptors. Lastly, by directly invading the meninges after basilar skull fracture or other trauma that compromises the dura, S pneumoniae is the most common cause of recurrent bacterial meningitis following such head trauma.

In countries with routine vaccination policies, S pneumoniae infection is the most common cause of sporadic bacterial meningitis in both children and adults.

Most patients with pneumococcal meningitis present with nonspecific signs and symptoms, including fever, irritability, emesis, lethargy, anorexia, and malaise. Neurologic signs and symptoms, including mental status changes, delirium, lethargy, nuchal rigidity with positive Brudzinski and Kernig signs, cranial nerve palsies, and other focal neurological deficits, are usually prominent. A bulging fontanelle and poor feeding may be seen infants. Twenty to 25% of patients of any age with pneumococcal meningitis experience seizures.

Complications of pneumococcal meningitis include hearing loss, seizures, learning disabilities, mental difficulties, and cranial nerve palsies. In a study from Denmark, 240 patients who survived pneumococcal meningitis were examined using audiometry. [48] More than half (54%) had a hearing deficit, with 39% of these not suspected of hearing loss at the time of hospital discharge. Of the 240 study participants, 14% demonstrated profound hearing loss—7% unilateral and 7% bilateral. Significant risk factors for hearing loss included advanced age, the presence of comorbidity, and higher severity of meningitis. Audiometry should be considered in all patients who survive pneumococcal meningitis.

Pneumococcal meningitis carries a greater risk of death and significant neurological sequelae than does meningitis of other bacterial causes (eg, Haemophilus influenzae type B [Hib], Neisseria meningitidis). [30, 31, 47]


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